Provided by: libguestfs-tools_1.40.2-1ubuntu1_amd64 bug

NAME

       virt-builder - Build virtual machine images quickly

SYNOPSIS

        virt-builder os-version
           [-o|--output DISKIMAGE] [--size SIZE] [--format raw|qcow2]
           [--arch ARCHITECTURE] [--attach ISOFILE]
           [--append-line FILE:LINE] [--chmod PERMISSIONS:FILE]
           [--commands-from-file FILENAME] [--copy SOURCE:DEST]
           [--copy-in LOCALPATH:REMOTEDIR] [--delete PATH] [--edit FILE:EXPR]
           [--firstboot SCRIPT] [--firstboot-command 'CMD+ARGS']
           [--firstboot-install PKG,PKG..] [--hostname HOSTNAME]
           [--install PKG,PKG..] [--link TARGET:LINK[:LINK..]] [--mkdir DIR]
           [--move SOURCE:DEST] [--password USER:SELECTOR]
           [--root-password SELECTOR] [--run SCRIPT]
           [--run-command 'CMD+ARGS'] [--scrub FILE] [--sm-attach SELECTOR]
           [--sm-register] [--sm-remove] [--sm-unregister]
           [--ssh-inject USER[:SELECTOR]] [--truncate FILE]
           [--truncate-recursive PATH] [--timezone TIMEZONE] [--touch FILE]
           [--uninstall PKG,PKG..] [--update] [--upload FILE:DEST]
           [--write FILE:CONTENT] [--no-logfile]
           [--password-crypto md5|sha256|sha512] [--selinux-relabel]
           [--sm-credentials SELECTOR]

        virt-builder -l|--list [--long] [--list-format short|long|json] [os-version]

        virt-builder --notes os-version

        virt-builder --print-cache

        virt-builder --cache-all-templates

        virt-builder --delete-cache

        virt-builder --get-kernel DISKIMAGE
           [--format raw|qcow2] [--output OUTPUTDIR]

DESCRIPTION

       Virt-builder is a tool for quickly building new virtual machines.  You can build a variety
       of VMs for local or cloud use, usually within a few minutes or less.  Virt-builder also
       has many ways to customize these VMs.  Everything is run from the command line and nothing
       requires root privileges, so automation and scripting is simple.

       Note that virt-builder does not install guests from scratch.  It takes cleanly prepared,
       digitally signed OS templates and customizes them.  This approach is used because it is
       much faster, but if you need to do fresh installs you may want to look at virt-install(1)
       and oz-install(1).

       The easiest way to get started is by looking at the examples in the next section.

EXAMPLES

   List the virtual machines available
        virt-builder --list

       will list out the operating systems available to install.  A selection of freely
       redistributable OSes is available as standard.  You can add your own too (see below).

       After choosing a guest from the list, you may want to see if there are any installation
       notes:

        virt-builder --notes fedora-27

   Build a virtual machine
        virt-builder fedora-27

       will build a Fedora 25 image for the same architecture as virt-builder (so running it from
       an i686 installation will try to build an i686 image, if available).  This will have all
       default configuration (minimal size, no user accounts, random root password, only the bare
       minimum installed software, etc.).

       You do not need to run this command as root.

       The first time this runs it has to download the template over the network, but this gets
       cached (see "CACHING").

       The name of the output file is derived from the template name, so above it will be
       fedora-27.img.  You can change the output filename using the -o option:

        virt-builder fedora-27 -o mydisk.img

       You can also use the -o option to write to existing devices or logical volumes.

        virt-builder fedora-27 --format qcow2

       As above, but write the output in qcow2 format to fedora-27.qcow2.

        virt-builder fedora-27 --size 20G

       As above, but the output size will be 20 GB.  The guest OS is resized as it is copied to
       the output (automatically, using virt-resize(1)).

        virt-builder fedora-27 --arch i686

       As above, but using an i686 template, if available.

   Setting the root password
        virt-builder fedora-27 --root-password file:/tmp/rootpw

       Create a Fedora 25 image.  The root password is taken from the file /tmp/rootpw.

       Note if you don’t set --root-password then the guest is given a random root password which
       is printed on stdout.

       You can also create user accounts.  See "USERS AND PASSWORDS" below.

   Set the hostname
        virt-builder fedora-27 --hostname virt.example.com

       Set the hostname to "virt.example.com".

   Installing software
       To install packages from the ordinary (guest) software repository (eg. dnf or apt):

        virt-builder fedora-27 --install "inkscape,@Xfce Desktop"

       (In Fedora, "@" is used to install groups of packages.  On Debian you would install a
       meta-package instead.)

       To update the installed packages to the latest version:

        virt-builder debian-7 --update

       For guests which use SELinux, like Fedora and Red Hat Enterprise Linux, you may need to do
       SELinux relabelling after installing or updating packages (see "SELINUX" below):

        virt-builder fedora-27 --update --selinux-relabel

   Customizing the installation
       There are many options that let you customize the installation.  These include:
       --run/--run-command, which run a shell script or command while the disk image is being
       generated and lets you add or edit files that go into the disk image.
       --firstboot/--firstboot-command, which let you add scripts/commands that are run the first
       time the guest boots.  --edit to edit files.  --upload to upload files.

       For example:

        cat <<'EOF' > /tmp/dnf-update.sh
        dnf -y --best update
        EOF

        virt-builder fedora-27 --firstboot /tmp/dnf-update.sh

       or simply:

        virt-builder fedora-27 --firstboot-command 'dnf -y --best update'

       which makes the dnf(8) "update" command run once the first time the guest boots.

       Or:

        virt-builder fedora-27 \
          --edit '/etc/dnf/dnf.conf:
                    s/gpgcheck=1/gpgcheck=0/'

       which edits /etc/dnf/dnf.conf inside the disk image (during disk image creation, long
       before boot).

       You can combine these options, and have multiple options of all types.

OPTIONS

       --help
           Display help.

       --arch ARCHITECTURE
           Use the specified architecture for the output image.  This means there must be sources
           providing the requested template for the requested architecture.

           See also "ARCHITECTURE".

       --attach ISOFILE
           During the customization phase, the given disk is attached to the libguestfs
           appliance.  This is used to provide extra software repositories or other data for
           customization.

           You probably want to ensure the volume(s) or filesystems in the attached disks are
           labelled (or use an ISO volume name) so that you can mount them by label in your run-
           scripts:

            mkdir /tmp/mount
            mount LABEL=EXTRA /tmp/mount

           You can have multiple --attach options, and the format can be any disk format (not
           just an ISO).

           See also: --run, "Installing packages at build time from a side repository",
           genisoimage(1), virt-make-fs(1).

       --attach-format FORMAT
           Specify the disk format for the next --attach option.  The "FORMAT" is usually "raw"
           or "qcow2".  Use "raw" for ISOs.

       --cache DIR
       --no-cache
           --cache DIR sets the directory to use/check for cached template files.  If not set,
           defaults to either $XDG_CACHE_HOME/virt-builder/ or $HOME/.cache/virt-builder/.

           --no-cache disables template caching.

       --cache-all-templates
           Download all templates to the cache and then exit.  See "CACHING".

           Note this doesn't cache everything.  More templates might be uploaded.  Also this
           doesn't cache packages (the --install, --update options).

       --check-signature
       --no-check-signature
           Check/don’t check the digital signature of the OS template.  The default is to check
           the signature and exit if it is not correct.  Using --no-check-signature bypasses this
           check.

           See also --fingerprint.

       --colors
       --colours
           Use ANSI colour sequences to colourize messages.  This is the default when the output
           is a tty.  If the output of the program is redirected to a file, ANSI colour sequences
           are disabled unless you use this option.

       --curl CURL
           Specify an alternate curl(1) binary.  You can also use this to add curl parameters,
           for example to disable https certificate checks:

            virt-builder --curl "curl --insecure" [...]

       --delete-cache
           Delete the template cache.  See "CACHING".

       --no-delete-on-failure
           Don’t delete the output file on failure to build.  You can use this to debug failures
           to run scripts.  See "DEBUGGING BUILDS" for ways to debug images.

           The default is to delete the output file if virt-builder fails (or, for example, some
           script that it runs fails).

       --fingerprint 'AAAA BBBB ...'
           Check that the index and templates are signed by the key with the given fingerprint.
           (The fingerprint is a long string, usually written as 10 groups of 4 hexadecimal
           digits).

           You can give this option multiple times.  If you have multiple source URLs, then you
           can have either no fingerprint, one fingerprint or multiple fingerprints.  If you have
           multiple, then each must correspond 1-1 with a source URL.

       --format qcow2
       --format raw
           For ordinary builds, this selects the output format.  The default is raw.

           With --get-kernel this specifies the input format.

           To create an old-style qcow2 file (for compatibility with RHEL 6 or very old qemu <
           1.1), after running virt-builder, use this command:

            qemu-img amend -f qcow2 -o compat=0.10 output.qcow2

       --get-kernel IMAGE
           This option extracts the kernel and initramfs from a previously built disk image
           called "IMAGE" (in fact it works for any VM disk image, not just ones built using
           virt-builder).

           Note this method is deprecated: there is a separate tool for this, virt-get-kernel(1),
           which has more options for the file extraction.

           The kernel and initramfs are written to the current directory, unless you also specify
           the --output "outputdir" directory name.

           The format of the disk image is automatically detected unless you specify it by using
           the --format option.

           In the case where the guest contains multiple kernels, the one with the highest
           version number is chosen.  To extract arbitrary kernels from the disk image, see
           guestfish(1).  To extract the entire /boot directory of a guest, see virt-copy-out(1).

       --gpg GPG
           Specify an alternate gpg(1) (GNU Privacy Guard) binary.  By default virt-builder looks
           for either "gpg2" or "gpg" in the $PATH.

           You can also use this to add gpg parameters, for example to specify an alternate home
           directory:

            virt-builder --gpg "gpg --homedir /tmp" [...]

       -l [os-version]
       --list [os-version]
       --list --list-format format [os-version]
       --list --long [os-version]
           List all the available templates if no guest is specified, or only for the specified
           one.

           It is possible to choose with --list-format the output format for the list templates:

           short
               The default format, prints only the template identifier and, next to it, its short
               description.

           long
               Prints a textual list with the details of the available sources, followed by the
               details of the available templates.

           json
               Prints a JSON object with the details of the available sources and the details of
               the available templates.

               The "version" key in the main object represents the "compatibility version", and
               it is bumped every time the resulting JSON output is incompatible with the
               previous versions (for example the structure has changed, or non-optional keys are
               no more present).

           --long is a shorthand for the "long" format.

           See also: --source, --notes, "SOURCES OF TEMPLATES".

       --machine-readable
       --machine-readable=format
           This option is used to make the output more machine friendly when being parsed by
           other programs.  See "MACHINE READABLE OUTPUT" below.

       -m MB
       --memsize MB
           Change the amount of memory allocated to --run scripts.  Increase this if you find
           that --run scripts or the --install option are running out of memory.

           The default can be found with this command:

            guestfish get-memsize

       --network
       --no-network
           Enable or disable network access from the guest during the installation.

           Enabled is the default.  Use --no-network to disable access.

           The network only allows outgoing connections and has other minor limitations.  See
           "NETWORK" in virt-rescue(1).

           If you use --no-network then certain other options such as --install will not work.

           This does not affect whether the guest can access the network once it has been booted,
           because that is controlled by your hypervisor or cloud environment and has nothing to
           do with virt-builder.

           Generally speaking you should not use --no-network.  But here are some reasons why you
           might want to:

           1.  Because the libguestfs backend that you are using doesn't support the network.
               (See: "BACKEND" in guestfs(3)).

           2.  Any software you need to install comes from an attached ISO, so you don't need the
               network.

           3.  You don’t want untrusted guest code trying to access your host network when
               running virt-builder.  This is particularly an issue when you don't trust the
               source of the operating system templates.  (See "SECURITY" below).

           4.  You don’t have a host network (eg. in secure/restricted environments).

       --no-sync
           Do not sync the output file on exit.

           Virt-builder "fsync"s the output file or disk image when it exits.

           The reason is that qemu/KVM’s default caching mode is "none" or "directsync", both of
           which bypass the host page cache.  Therefore these would not work correctly if you
           immediately started the guest after running virt-builder - they would not see the
           complete output file.  (Note that you should not use these caching modes - they are
           fundamentally broken for this and other reasons.)

           If you are not using these broken caching modes, you can use --no-sync to avoid this
           unnecessary sync and gain considerable extra performance.

       --notes os-version
           List any notes associated with this guest, then exit (this does not do the install).

       -o filename
       --output filename
           Write the output to filename.  If you don’t specify this option, then the output
           filename is generated by taking the "os-version" string and adding ".img" (for raw
           format) or ".qcow2" (for qcow2 format).

           Note that the output filename could be a device, partition or logical volume.

           When used with --get-kernel, this option specifies the output directory.

       --print-cache
           Print information about the template cache.  See "CACHING".

       -q
       --quiet
           Don’t print ordinary progress messages.

       --size SIZE
           Select the size of the output disk, where the size can be specified using common names
           such as "32G" (32 gigabytes) etc.

           Virt-builder will resize filesystems inside the disk image automatically.

           If the size is not specified, then one of two things happens.  If the output is a
           file, then the size is the same as the template.  If the output is a device,
           partition, etc then the size of that device is used.

           To specify size in bytes, the number must be followed by the lowercase letter b, eg:
           "--size 10737418240b".

       --smp N
           Enable N ≥ 2 virtual CPUs for --run scripts to use.

       --source URL
           Set the source URL to look for indexes.

           You can give this option multiple times to specify multiple sources.

           See also "SOURCES OF TEMPLATES" below.

           Note that you should not point --source to sources that you don’t trust (unless the
           source is signed by someone you do trust).  See also the --no-network option.

       --no-warn-if-partition
           Do not emit a warning if the output device is a partition.  This warning avoids a
           common user error when writing to a USB key or external drive, when you should
           normally write to the whole device (--output /dev/sdX), not to a partition on the
           device (--output /dev/sdX1).  Use this option to suppress this warning.

       -v
       --verbose
           Enable debug messages and/or produce verbose output.

           When reporting bugs, use this option and attach the complete output to your bug
           report.

       -V
       --version
           Display version number and exit.

       -x  Enable tracing of libguestfs API calls.

   Customization options
       --append-line FILE:LINE
           Append a single line of text to the "FILE".  If the file does not already end with a
           newline, then one is added before the appended line.  Also a newline is added to the
           end of the "LINE" string automatically.

           For example (assuming ordinary shell quoting) this command:

            --append-line '/etc/hosts:10.0.0.1 foo'

           will add either "10.0.0.1 foo⏎" or "⏎10.0.0.1 foo⏎" to the file, the latter only if
           the existing file does not already end with a newline.

           "⏎" represents a newline character, which is guessed by looking at the existing
           content of the file, so this command does the right thing for files using Unix or
           Windows line endings.  It also works for empty or non-existent files.

           To insert several lines, use the same option several times:

            --append-line '/etc/hosts:10.0.0.1 foo'
            --append-line '/etc/hosts:10.0.0.2 bar'

           To insert a blank line before the appended line, do:

            --append-line '/etc/hosts:'
            --append-line '/etc/hosts:10.0.0.1 foo'

       --chmod PERMISSIONS:FILE
           Change the permissions of "FILE" to "PERMISSIONS".

           Note: "PERMISSIONS" by default would be decimal, unless you prefix it with 0 to get
           octal, ie. use 0700 not 700.

       --commands-from-file FILENAME
           Read the customize commands from a file, one (and its arguments) each line.

           Each line contains a single customization command and its arguments, for example:

            delete /some/file
            install some-package
            password some-user:password:its-new-password

           Empty lines are ignored, and lines starting with "#" are comments and are ignored as
           well.  Furthermore, arguments can be spread across multiple lines, by adding a "\"
           (continuation character) at the of a line, for example

            edit /some/file:\
              s/^OPT=.*/OPT=ok/

           The commands are handled in the same order as they are in the file, as if they were
           specified as --delete /some/file on the command line.

       --copy SOURCE:DEST
           Copy files or directories recursively inside the guest.

           Wildcards cannot be used.

       --copy-in LOCALPATH:REMOTEDIR
           Copy local files or directories recursively into the disk image, placing them in the
           directory "REMOTEDIR" (which must exist).

           Wildcards cannot be used.

       --delete PATH
           Delete a file from the guest.  Or delete a directory (and all its contents,
           recursively).

           You can use shell glob characters in the specified path.  Be careful to escape glob
           characters from the host shell, if that is required.  For example:

            virt-customize --delete '/var/log/*.log'.

           See also: --upload, --scrub.

       --edit FILE:EXPR
           Edit "FILE" using the Perl expression "EXPR".

           Be careful to properly quote the expression to prevent it from being altered by the
           shell.

           Note that this option is only available when Perl 5 is installed.

           See "NON-INTERACTIVE EDITING" in virt-edit(1).

       --firstboot SCRIPT
           Install "SCRIPT" inside the guest, so that when the guest first boots up, the script
           runs (as root, late in the boot process).

           The script is automatically chmod +x after installation in the guest.

           The alternative version --firstboot-command is the same, but it conveniently wraps the
           command up in a single line script for you.

           You can have multiple --firstboot options.  They run in the same order that they
           appear on the command line.

           Please take a look at "FIRST BOOT SCRIPTS" for more information and caveats about the
           first boot scripts.

           See also --run.

       --firstboot-command 'CMD+ARGS'
           Run command (and arguments) inside the guest when the guest first boots up (as root,
           late in the boot process).

           You can have multiple --firstboot options.  They run in the same order that they
           appear on the command line.

           Please take a look at "FIRST BOOT SCRIPTS" for more information and caveats about the
           first boot scripts.

           See also --run.

       --firstboot-install PKG,PKG..
           Install the named packages (a comma-separated list).  These are installed when the
           guest first boots using the guest’s package manager (eg. apt, yum, etc.) and the
           guest’s network connection.

           For an overview on the different ways to install packages, see "INSTALLING PACKAGES".

       --hostname HOSTNAME
           Set the hostname of the guest to "HOSTNAME".  You can use a dotted hostname.domainname
           (FQDN) if you want.

       --install PKG,PKG..
           Install the named packages (a comma-separated list).  These are installed during the
           image build using the guest’s package manager (eg. apt, yum, etc.) and the host’s
           network connection.

           For an overview on the different ways to install packages, see "INSTALLING PACKAGES".

           See also --update, --uninstall.

       --link TARGET:LINK[:LINK..]
           Create symbolic link(s) in the guest, starting at "LINK" and pointing at "TARGET".

       --mkdir DIR
           Create a directory in the guest.

           This uses "mkdir -p" so any intermediate directories are created, and it also works if
           the directory already exists.

       --move SOURCE:DEST
           Move files or directories inside the guest.

           Wildcards cannot be used.

       --no-logfile
           Scrub "builder.log" (log file from build commands) from the image after building is
           complete.  If you don't want to reveal precisely how the image was built, use this
           option.

           See also: "LOG FILE".

       --password USER:SELECTOR
           Set the password for "USER".  (Note this option does not create the user account).

           See "USERS AND PASSWORDS" for the format of the "SELECTOR" field, and also how to set
           up user accounts.

       --password-crypto md5|sha256|sha512
           When the virt tools change or set a password in the guest, this option sets the
           password encryption of that password to "md5", "sha256" or "sha512".

           "sha256" and "sha512" require glibc ≥ 2.7 (check crypt(3) inside the guest).

           "md5" will work with relatively old Linux guests (eg. RHEL 3), but is not secure
           against modern attacks.

           The default is "sha512" unless libguestfs detects an old guest that didn't have
           support for SHA-512, in which case it will use "md5".  You can override libguestfs by
           specifying this option.

           Note this does not change the default password encryption used by the guest when you
           create new user accounts inside the guest.  If you want to do that, then you should
           use the --edit option to modify "/etc/sysconfig/authconfig" (Fedora, RHEL) or
           "/etc/pam.d/common-password" (Debian, Ubuntu).

       --root-password SELECTOR
           Set the root password.

           See "USERS AND PASSWORDS" for the format of the "SELECTOR" field, and also how to set
           up user accounts.

           Note: In virt-builder, if you don't set --root-password then the guest is given a
           random root password.

       --run SCRIPT
           Run the shell script (or any program) called "SCRIPT" on the disk image.  The script
           runs virtualized inside a small appliance, chrooted into the guest filesystem.

           The script is automatically chmod +x.

           If libguestfs supports it then a limited network connection is available but it only
           allows outgoing network connections.  You can also attach data disks (eg. ISO files)
           as another way to provide data (eg. software packages) to the script without needing a
           network connection (--attach).  You can also upload data files (--upload).

           You can have multiple --run options.  They run in the same order that they appear on
           the command line.

           See also: --firstboot, --attach, --upload.

       --run-command 'CMD+ARGS'
           Run the command and arguments on the disk image.  The command runs virtualized inside
           a small appliance, chrooted into the guest filesystem.

           If libguestfs supports it then a limited network connection is available but it only
           allows outgoing network connections.  You can also attach data disks (eg. ISO files)
           as another way to provide data (eg. software packages) to the script without needing a
           network connection (--attach).  You can also upload data files (--upload).

           You can have multiple --run-command options.  They run in the same order that they
           appear on the command line.

           See also: --firstboot, --attach, --upload.

       --scrub FILE
           Scrub a file from the guest.  This is like --delete except that:

           ·   It scrubs the data so a guest could not recover it.

           ·   It cannot delete directories, only regular files.

       --selinux-relabel
           Relabel files in the guest so that they have the correct SELinux label.

           This will attempt to relabel files immediately, but if the operation fails this will
           instead touch /.autorelabel on the image to schedule a relabel operation for the next
           time the image boots.

           You should only use this option for guests which support SELinux.

       --sm-attach SELECTOR
           Attach to a pool using "subscription-manager".

           See "SUBSCRIPTION-MANAGER" for the format of the "SELECTOR" field.

       --sm-credentials SELECTOR
           Set the credentials for "subscription-manager".

           See "SUBSCRIPTION-MANAGER" for the format of the "SELECTOR" field.

       --sm-register
           Register the guest using "subscription-manager".

           This requires credentials being set using --sm-credentials.

       --sm-remove
           Remove all the subscriptions from the guest using "subscription-manager".

       --sm-unregister
           Unregister the guest using "subscription-manager".

       --ssh-inject USER[:SELECTOR]
           Inject an ssh key so the given "USER" will be able to log in over ssh without
           supplying a password.  The "USER" must exist already in the guest.

           See "SSH KEYS" for the format of the "SELECTOR" field.

           You can have multiple --ssh-inject options, for different users and also for more keys
           for each user.

       --timezone TIMEZONE
           Set the default timezone of the guest to "TIMEZONE".  Use a location string like
           "Europe/London"

       --touch FILE
           This command performs a touch(1)-like operation on "FILE".

       --truncate FILE
           This command truncates "FILE" to a zero-length file. The file must exist already.

       --truncate-recursive PATH
           This command recursively truncates all files under "PATH" to zero-length.

       --uninstall PKG,PKG..
           Uninstall the named packages (a comma-separated list).  These are removed during the
           image build using the guest’s package manager (eg. apt, yum, etc.).  Dependent
           packages may also need to be uninstalled to satisfy the request.

           See also --install, --update.

       --update
           Do the equivalent of "yum update", "apt-get upgrade", or whatever command is required
           to update the packages already installed in the template to their latest versions.

           See also --install, --uninstall.

       --upload FILE:DEST
           Upload local file "FILE" to destination "DEST" in the disk image.  File owner and
           permissions from the original are preserved, so you should set them to what you want
           them to be in the disk image.

           "DEST" could be the final filename.  This can be used to rename the file on upload.

           If "DEST" is a directory name (which must already exist in the guest) then the file is
           uploaded into that directory, and it keeps the same name as on the local filesystem.

           See also: --mkdir, --delete, --scrub.

       --write FILE:CONTENT
           Write "CONTENT" to "FILE".

REFERENCE

   INSTALLING PACKAGES
       There are several approaches to installing packages or applications in the guest which
       have different trade-offs.

       Installing packages at build time

       If the guest OS you are installing is similar to the host OS (eg.  both are Linux), and if
       libguestfs supports network connections, then you can use --install to install packages
       like this:

        virt-builder fedora-27 --install inkscape

       This uses the guest’s package manager and the host’s network connection.

       Updating packages at build time

       To update the installed packages in the template at build time:

        virt-builder fedora-27 --update

       Most of the templates that ship with virt-builder come with a very minimal selection of
       packages (known as a "JEOS" or "Just Enough Operating System"), which are up to date at
       the time the template is created, but could be out of date by the time you come to install
       an OS from the template.  This option updates those template packages.

       Installing packages at first boot

       Another option is to install the packages when the guest first boots:

        virt-builder fedora-27 --firstboot-install inkscape

       This uses the guest’s package manager and the guest’s network connection.

       The downsides are that it will take the guest a lot longer to boot first time, and there’s
       nothing much you can do if package installation fails (eg. if a network problem means the
       guest can't reach the package repositories).

       Installing packages at build time from a side repository

       If the software you want to install is not available in the main package repository of the
       guest, then you can add a side repository.  Usually this is presented as an ISO (CD disk
       image) file containing extra packages.

       You can create the disk image using either genisoimage(1) or virt-make-fs(1).  For
       genisoimage, use a command like this:

        genisoimage -o extra-packages.iso -R -J -V EXTRA cdcontents/

       Create a script that mounts the ISO and sets up the repository.  For dnf, create
       /tmp/install.sh containing:

        mkdir /tmp/mount
        mount LABEL=EXTRA /tmp/mount

        cat <<'EOF' > /etc/yum.repos.d/extra.repo
        [extra]
        name=extra
        baseurl=file:///tmp/mount
        enabled=1
        EOF

        dnf -y install famousdatabase

       For apt, create /tmp/install.sh containing:

        mkdir /tmp/mount
        mount LABEL=EXTRA /tmp/mount

        apt-cdrom -d=/tmp/mount add
        apt-get -y install famousdatabase

       Use the --attach option to attach the CD / disk image and the --run option to run the
       script:

        virt-builder fedora-27 \
          --attach extra-packages.iso \
          --run /tmp/install.sh

   USERS AND PASSWORDS
       The --root-password option is used to change the root password (otherwise a random
       password is used).  This option takes a password "SELECTOR" in one of the following
       formats:

       --root-password file:FILENAME
           Read the root password from "FILENAME".  The whole first line of this file is the
           replacement password.  Any other lines are ignored.  You should create the file with
           mode 0600 to ensure no one else can read it.

       --root-password password:PASSWORD
           Set the root password to the literal string "PASSWORD".

           Note: this is not secure since any user on the same machine can see the cleartext
           password using ps(1).

       --root-password random
           Choose a random password, which is printed on stdout.  The password has approximately
           120 bits of randomness.

           This is the default.

       --root-password disabled
           The root account password is disabled.  This is like putting "*" in the password
           field.

       --root-password locked:file:FILENAME
       --root-password locked:password:PASSWORD
       --root-password locked:random
           The root account is locked, but a password is placed on the account.  If first
           unlocked (using "passwd -u") then logins will use the given password.

       --root-password locked
       --root-password locked:disabled
           The root account is locked and password is disabled.

       Creating user accounts

       To create user accounts, use the useradd(8) command with --firstboot-command like this:

        virt-builder --firstboot-command \
           'useradd -m -p "" rjones ; chage -d 0 rjones'

       The above command will create an "rjones" account with no password, and force the user to
       set a password when they first log in.  There are other ways to manage passwords, see
       useradd(8) for details.

   KEYBOARD LAYOUT
       Because there are so many different ways to set the keyboard layout in Linux
       distributions, virt-builder does not yet attempt to have a simple command line option.
       This section describes how to set the keyboard for some common Linux distributions.

       Keyboard layout with systemd

       For distros that use systemd "localectl", use a command like this:

        virt-builder fedora-27 \
          --firstboot-command 'localectl set-keymap uk'

       See localectl(1) and
       https://www.happyassassin.net/2013/11/23/keyboard-layouts-in-fedora-20-and-previously/ for
       more details.

       Keyboard layout using /etc/sysconfig/keyboard

       For RHEL ≤ 6, Fedora ≤ 18 and similar, upload or modify the keyboard configuration file
       using the --upload, --write or --edit options.  For example:

        virt-builder centos-6 \
          --edit '/etc/sysconfig/keyboard: s/^KEYTABLE=.*/KEYTABLE="uk"/'

       The format of this file can be found documented in many places online.

       Keyboard layout with Debian-derived distros

       For Debian-derived distros using /etc/default/keyboard, upload or modify the keyboard file
       using the --upload, --write or --edit options.  For example:

        virt-builder debian-8 \
          --edit '/etc/default/keyboard: s/^XKBLAYOUT=.*/XKBLAYOUT="gb"/'

       See https://wiki.debian.org/Keyboard.

   LANGUAGE
       Most Linux distributions support multiple locale settings so that you can have guest
       messages printed in another language such as Russian.

       However there is no single setting which controls this, since extra packages may need to
       be installed to support console and X fonts, and keyboard input methods.  The packages
       required, and their configuration is highly distro-specific, and it is outside the scope
       of virt-builder to do this.

       This section contains examples for some common Linux distributions.

       Setting Japanese in Fedora 25

        virt-builder fedora-27 \
          --size 20G \
          --update \
          --install @japanese-support \
          --install @xfce \
          --install xorg-x11-server-Xorg,xorg-x11-drivers,rsyslog \
          --link /usr/lib/systemd/system/graphical.target:/etc/systemd/system/default.target \
          --firstboot-command 'localectl set-locale LANG=ja_JP.utf8' \
          --firstboot-command 'localectl set-keymap jp' \
          --firstboot-command 'systemctl isolate graphical.target'

       Setting Japanese in Debian 8 (Jessie)

       Note that although this enables Japanese in the text console too, it is unlikely that you
       will see properly rendered Japanese there.  However Japanese is properly rendered in X
       applications and terminals.

        pkgs=locales,xfce4,\
        ibus,ibus-anthy,\
        fonts-ipafont-gothic,fonts-ipafont-mincho,\
        fonts-takao-mincho,\
        xfonts-intl-japanese,xfonts-intl-japanese-big,\
        iceweasel-l10n-ja,manpages-ja

        virt-builder debian-8 \
          --size 20G \
          --install $pkgs \
          --edit '/etc/locale.gen: s,^#\s*ja,ja,' \
          --write '/etc/default/locale:LANG="ja_JP.UTF-8"' \
          --run-command "locale-gen"

   LOG FILE
       Scripts and package installation that runs at build time (--run, --run-command, --install,
       --update, but not firstboot) is logged in one of the following locations:

       /tmp/builder.log
           On Linux, BSD, and other non-Windows guests.

       C:\Temp\builder.log
           On Windows, DOS guests.

       /builder.log
           If /tmp or C:\Temp is missing.

       If you don’t want the log file to appear in the final image, then use the --no-logfile
       command line option.

   SSH KEYS
       The --ssh-inject option is used to inject ssh keys for users in the guest, so they can
       login without supplying a password.

       The "SELECTOR" part of the option value is optional; in this case, --ssh-inject "USER"
       means that we look in the current user’s ~/.ssh directory to find the default public ID
       file.  That key is uploaded.  "default public ID" is the default_ID_file file described in
       ssh-copy-id(1).

       If specified, the "SELECTOR" can be in one of the following formats:

       --ssh-inject USER:file:FILENAME
           Read the ssh key from FILENAME.  FILENAME is usually a .pub file.

       --ssh-inject USER:string:KEY_STRING
           Use the specified "KEY_STRING".  "KEY_STRING" is usually a public string like ssh-rsa
           AAAA.... user@localhost.

       In any case, the ~USER/.ssh directory and the ~USER/.ssh/authorized_keys file will be
       created if not existing already.

   FIRST BOOT SCRIPTS
       The --firstboot and --firstboot-command options allow you to execute commands at the first
       boot of the guest.  To do so, an init script for the guest init system is installed, which
       takes care of running all the added scripts and commands.

       Supported operating systems are:

       Linux
           Init systems supported are: systemd, System-V init (known also as sysvinit), and
           Upstart (using the System-V scripts).

           Note that usually init scripts run as root, but with a more limited environment than
           what could be available from a normal shell: for example, $HOME may be unset or empty.

           The output of the first boot scripts is available in the guest as
           ~root/virt-sysprep-firstboot.log.

       Windows
           rhsrvany.exe, available from sources at https://github.com/rwmjones/rhsrvany, or
           pvvxsvc.exe, available with SUSE VMDP is installed to run the first boot scripts.  It
           is required, and the setup of first boot scripts will fail if it is not present.

           rhsrvany.exe or pvvxsvc.exe is copied from the location pointed to by the
           "VIRT_TOOLS_DATA_DIR" environment variable; if not set, a compiled-in default will be
           used (something like /usr/share/virt-tools).

           The output of the first boot scripts is available in the guest as C:\Program
           Files\Guestfs\Firstboot\log.txt.

   SUBSCRIPTION-MANAGER
       It is possible to automate the registration and attaching of the system using
       "subscription-manager".  This is typical on Red Hat Enterprise Linux guests.  There are
       few options which ease this process, avoid executing commands manually and exposing
       passwords on command line.

       --sm-register starts the registration process, and requires --sm-credentials to be
       specified; the format of the "SELECTOR" of --sm-credentials is one of the following
       formats:

       --sm-credentials USER:file:FILENAME
           Read the password for the specified "USER" from FILENAME.

       --sm-credentials USER:password:PASSWORD
           Use the literal string "PASSWORD" for the specified "USER".

       --sm-attach attaches the system to subscriptions; the format of its "SELECTOR" is one of
       the following:

       --sm-attach auto
           "subscription-manager" attaches to the best-fitting subscriptions for the system.

       --sm-attach file:FILENAME
           Read the pool ID from FILENAME.

       --sm-attach pool:POOL
           Use the literal string "POOL" as pool ID.

       --sm-remove removes all the subscriptions from the guest, while --sm-unregister completely
       unregister the system.

   INSTALLATION PROCESS
       When you invoke virt-builder, installation proceeds as follows:

       ·   The template image is downloaded.

           If the template image is present in the cache, the cached version is used instead.
           (See "CACHING").

       ·   The template signature is checked.

       ·   The template is uncompressed to a tmp file.

       ·   The template image is resized into the destination, using virt-resize(1).

       ·   Extra disks are attached (--attach).

       ·   A new random seed is generated for the guest.

       ·   Guest customization is performed, in the order specified on the command line.

       ·   SELinux relabelling is done (--selinux-relabel).

   IMPORTING THE DISK IMAGE
       Importing into libvirt

       Import the disk image into libvirt using virt-install(1) --import option.

        virt-install --import \
          --name guest --ram 2048 \
          --disk path=disk.img,format=raw --os-variant fedora27

       Notes:

       1.  You must specify the correct format.  The format is "raw" unless you used
           virt-builder’s --format option.

       2.  --os-variant is highly recommended, because it will present optimum devices to enable
           the guest to run most efficiently.  To get a list of all variants, do:

            osinfo-query os

           The above tool is provided by libosinfo package.

       3.  You can run virt-install as root or non-root.  Each works slightly differently because
           libvirt manages a different set of virtual machines for each user.  In particular
           virt-manager normally shows the root-owned VMs, whereas Boxes shows the user-owned
           VMs, and other tools probably work differently as well.

       Importing into OpenStack

       Import the image into Glance (the OpenStack image store) by doing:

        glance image-create --name fedora-27-image --file fedora-27.img \
          --disk-format raw --container-format bare \
          --is-public True

       The --file parameter is the virt-builder-generated disk image.  It should match
       virt-builder’s --output option.  The --disk-format parameter should match virt-builder’s
       --format option (or "raw" if you didn't use that option).  The --container-format should
       always be "bare" since virt-builder doesn't put images into containers.

       You can use the "glance image-show fedora-27-image" command to display the properties of
       the image.

       To boot up an instance of your image on a Nova compute node, do:

        nova boot fedora-27-server --image fedora-27-image \
          --flavor m1.medium

       Use "nova flavor-list" to list possible machine flavors.  Use "nova list" to list running
       instances.

       Booting directly using qemu or KVM

       The qemu command line is not very stable or easy to use, hence libvirt should be used if
       possible.  However a command line similar to the following could be used to boot the
       virtual machine:

        qemu-system-x86_64 \
          -machine accel=kvm:tcg \
          -cpu host \
          -m 2048 \
          -drive file=disk.img,format=raw,if=virtio

       As with libvirt, it is very important that the correct format is chosen.  It will be "raw"
       unless the --format option was used.

   CONFIGURATION MANAGEMENT
       Puppet

       To enable the Puppet agent in a guest, install the package, point the configuration at
       your Puppetmaster, and ensure the agent runs at boot.

       A typical virt-builder command would be:

        virt-builder fedora-27 \
          --hostname client.example.com \
          --update \
          --install puppet \
          --append-line '/etc/puppet/puppet.conf:[agent]' \
          --append-line '/etc/puppet/puppet.conf:server = puppetmaster.example.com/' \
          --run-command 'systemctl enable puppet' \
          --selinux-relabel

       The precise instructions vary according to the Linux distro.  For further information see:
       https://docs.puppet.com/puppet/latest/install_pre.html

   DEBUGGING BUILDS
       If virt-builder itself fails, then enable debugging (-v) and report a bug (see "BUGS"
       below).

       If virt-builder fails because some script or package it is installing fails, try using
       --no-delete-on-failure to preserve the output file, and continue reading this section.

       If virt-builder is successful but the image doesn't work, here are some things to try:

       Use virt-rescue
           Run virt-rescue(1) on the disk image:

            virt-rescue -a disk.img

           This gives you a rescue shell.  You can mount the filesystems from the disk image on
           /sysroot and examine them using ordinary Linux commands.  You can also chroot into the
           guest to reinstall the bootloader.  The virt-rescue man page has a lot more
           information and examples.

       Use guestfish
           Run guestfish(1) on the disk image:

            guestfish -a disk.img -i

           Use guestfish commands like "ll /directory" and "cat /file" to examine directories and
           files.

       Use guestmount
           Mount the disk image safely on the host using FUSE and guestmount(1):

            mkdir /tmp/mp
            guestmount -a disk.img -i /tmp/mp
            cd /tmp/mp

           To unmount the disk image do:

            fusermount -u /tmp/mp

       Add a serial console
           If the guest hangs during boot, it can be helpful to add a serial console to the
           guest, and direct kernel messages to the serial console.  Adding the serial console
           will involve looking at the documentation for your hypervisor.  To direct kernel
           messages to the serial console, add the following on the kernel command line:

            console=tty0 console=ttyS0,115200

   SOURCES OF TEMPLATES
       virt-builder reads the available sources from configuration files, with the .conf
       extension and located in the following paths:

       ·   $XDG_CONFIG_HOME/virt-builder/repos.d/ ($XDG_CONFIG_HOME is $HOME/.config if not set).

       ·   $XDG_CONFIG_DIRS/virt-builder/repos.d/ (where $XDG_CONFIG_DIRS means any of the
           directories in that environment variable, or just /etc/xdg if not set)

       Each .conf file in those paths has a simple text format like the following:

        [libguestfs.org]
        uri=http://libguestfs.org/download/builder/index.asc
        gpgkey=file:///etc/xdg/virt-builder/repos.d/libguestfs.gpg

       The part in square brackets is the repository identifier, which is used as unique
       identifier.

       The following fields can appear:

       "uri=URI"
           The URI of the index file which this repository refers to.

           This field is required.

       "gpgkey=URI"
           This optional field represents the URI (although only file:// URIs are accepted) of
           the key used to sign the index file.  If not present, the index file referred by
           uri=.. is not signed.

       "proxy=MODE"
           This optional field specifies the proxy mode, to be used when downloading the index
           file of this repository.  The possible values are:

           no, off
               No proxy is being used at all, even overriding the system configuration.

           system
               The proxy used is the system one.

           anything else
               Specifies the actual proxy configuration to be used, overriding the system
               configuration.

           If not present, the assumed value is to respect the proxy settings of the system (i.e.
           as if system would be specified).

       "format=FORMAT"
           This optional field specifies the format of the repository.  The possible values are:

           native
               The native format of the "virt-builder" repository.  See also "Creating and
               signing the index file" below.

           simplestreams
               The URI represents the root of a Simple Streams v1.0 tree of metadata.

               For more information about Simple Streams, see also
               https://launchpad.net/simplestreams.

           If not present, the assumed value is "native".

       For serious virt-builder use, you may want to create your own repository of templates.

       Libguestfs.org repository

       Out of the box, virt-builder downloads the file
       http://libguestfs.org/download/builder/index.asc which is an index of available templates
       plus some information about each one, wrapped up in a digital signature.  The command
       "virt-builder --list" lists out the information in this index file.

       The templates hosted on libguestfs.org were created using shell scripts, kickstart files
       and preseed files which can be found in the libguestfs source tree, in
       "builder/templates".

       Setting up the repository

       You can set up your own site containing an index file and some templates, and then point
       virt-builder at the site by creating a .conf file pointing to it.

       Note that if your index is signed, you will need to properly fill gpgkey=.. in your .conf
       file, making sure to deploy also the GPG key file.

        virt-builder --source https://example.com/builder/index.asc \
           --fingerprint 'AAAA BBBB ...' \
           --list

       You can host this on any web or FTP server, or a local or network filesystem.

       Setting up a GPG key

       If you don’t have a GnuPG key, you will need to set one up.  (Strictly speaking this is
       optional, but if your index and template files are not signed then virt-builder users will
       have to use the --no-check-signature flag every time they use virt-builder.)

       To create a key, see the GPG manual http://www.gnupg.org/gph/en/manual.html.

       Export your GPG public key:

        gpg --export -a "you@example.com" > pubkey

       Create the templates

       There are many ways to create the templates.  For example you could clone existing guests
       (see virt-sysprep(1)), or you could install a guest by hand (virt-install(1)).  To see how
       the templates were created for virt-builder, look at the scripts in "builder/templates"

       Virt-builder supports any image format (e.g. raw, qcow2, etc) as template, both as-is, and
       compressed as XZ.  This way, existing images (e.g. cleaned using virt-sysprep(1)) can be
       used as templates.

       For best results when compressing the templates, use the following xz options (see
       nbdkit-xz-plugin(1) for further explanation):

        xz --best --block-size=16777216 disk

       Creating and signing the index file

       The index file has a simple text format (shown here without the digital signature):

        [fedora-18]
        name=Fedora® 18
        osinfo=fedora18
        arch=x86_64
        file=fedora-18.xz
        checksum[sha512]=...
        format=raw
        size=6442450944
        compressed_size=148947524
        expand=/dev/sda3

        [fedora-19]
        name=Fedora® 19
        osinfo=fedora19
        arch=x86_64
        file=fedora-19.xz
        checksum[sha512]=...
        revision=3
        format=raw
        size=4294967296
        compressed_size=172190964
        expand=/dev/sda3

       The part in square brackets is the "os-version", which is the same string that is used on
       the virt-builder command line to build that OS.

       The index file creation and signature can be eased with the virt-builder-repository(1)
       tool.

       After preparing the "index" file in the correct format, clearsign it using the following
       command:

        gpg --clearsign --armor index

       This will create the final file called index.asc which can be uploaded to the server (and
       is the uri=.. URL).  As noted above, signing the index file is optional, but recommended.

       The following fields can appear:

       "name=NAME"
           The user-friendly name of this template.  This is displayed in the --list output but
           is otherwise not significant.

       "osinfo=ID"
           This optional field maps the operating system to the associated libosinfo ID.  Virt-
           builder does not use it (yet).

       "arch=ARCH"
           The architecture of the operating system installed within the template. This field is
           required.

       "file=PATH"
           The path (relative to the index) of the xz-compressed template.

           Note that absolute paths or URIs are not permitted here.  This is because virt-builder
           has a "same origin" policy for templates so they cannot come from other servers.

       "sig=PATH"
           This option is deprecated.  Use the checksum field instead.

           The path (relative to the index) of the GPG detached signature of the xz file.

           Note that absolute paths or URIs are not permitted here.  This is because virt-builder
           has a "same origin" policy for templates so they cannot come from other servers.

           The file can be created as follows:

            gpg --detach-sign --armor -o disk.xz.sig disk.xz

       "checksum[sha512]=7b882fe9b82eb0fef..."
           The SHA-512 checksum of the file specified in file=.. is checked after it is
           downloaded.  To work out the signature, do:

            sha512sum disk.xz

           Note if you use this, you don’t need to sign the file, ie. don’t use "sig".  This
           option overrides "sig".

       "checksum=7b882fe9b82eb0fef..."
           "checksum" is an alias for "checksum[sha512]".

           If you need to interoperate with virt-builder = 1.24.0 then you have to use "checksum"
           because that version would give a parse error with square brackets and numbers in the
           key of a field.  This is fixed in virt-builder ≥ 1.24.1.

       "revision=N"
           The revision is an integer which is used to control the template cache.  Increasing
           the revision number causes clients to download the template again even if they have a
           copy in the cache.

           The revision number is optional.  If omitted it defaults to 1.

       "format=raw"
       "format=qcow2"
           Specify the format of the disk image; in case it is compressed, that is the format
           before the compression.  If not given, the format is autodetected, but generally it is
           better to be explicit about the intended format.

           Note this is the source format, which is different from the --format option (requested
           output format).  Virt-builder does on-the-fly conversion from the source format to the
           requested output format.

       "size=NNN"
           The virtual size of the image in bytes.  This is the size of the image when
           uncompressed.  If using a non-raw format such as qcow2 then it means the virtual disk
           size, not the size of the qcow2 file.

           This field is required.

           Virt-builder also uses this as the minimum size that users can request via the --size
           option, or as the default size if there is no --size option.

       "compressed_size=NNN"
           The actual size of the disk image in bytes, i.e. what was specified in file=...  This
           is just used for information (when using "long", and "json" formats of --list).

       "expand=/dev/sdaX"
           When expanding the image to its final size, instruct virt-resize(1) to expand the
           named partition in the guest image to fill up all available space.  This works like
           the virt-resize --expand option.

           You should usually put the device name of the guest’s root filesystem here.

           It’s a good idea to use this, but not required.  If the field is omitted then virt-
           resize will create an extra partition at the end of the disk to cover the free space,
           which is much less user-friendly.

       "lvexpand=/dev/VolGroup/LogVol"
           When expanding the image to its final size, instruct virt-resize(1) to expand the
           named logical volume in the guest image to fill up all available space.  This works
           like the virt-resize --lv-expand option.

           If the guest uses LVM2 you should usually put the LV of the guest’s root filesystem
           here.  If the guest does not use LVM2 or its root filesystem is not on an LV, don't
           use this option.

       "notes=NOTES"
           Any notes that go with this image, especially notes describing what packages are in
           the image, how the image was prepared, and licensing information.

           This information is shown in the --notes and --list --long modes.

           You can use multi-line notes here by indenting each new line with at least one
           character of whitespace (even on blank lines):

            notes=This image was prepared using
             the following kickstart script:
                                           <-- one space at beginning of line
             part /boot --fstype ext3
             ...

       "hidden=true"
           Using the hidden flag prevents the template from being listed by the --list option
           (but it is still installable).  This is used for test images.

       "aliases=ALIAS1 ALIAS2 ..."
           This optional field specifies a list of aliases, separated by spaces, for the image.
           For example, an alias could be used to always point to the latest version of a certain
           image, leaving the old versions available in the index instead of updating the same
           image (see the "revision" field).

       Running virt-builder against multiple sources

       It is possible to use multiple sources with virt-builder.  The recommended way is to
       deploy .conf files pointing to the index files. Another way is to specify the sources
       using multiple --source and/or --fingerprint options:

        virt-builder \
          --source http://example.com/s1/index.asc \
          --source http://example.com/s2/index.asc

       You can provide N or 1 fingerprints.  In the case where you provide N fingerprints, N =
       number of sources and there is a 1-1 correspondence between each source and each
       fingerprint:

        virt-builder \
          --source http://example.com/s1/index.asc --fingerprint '0123 ...' \
          --source http://example.com/s2/index.asc --fingerprint '9876 ...'

       In the case where you provide 1 fingerprint, the same fingerprint is used for all sources.

       You "must" provide at least 1 fingerprint.

       Licensing of templates

       You should be aware of the licensing of images that you distribute.  For open source
       guests, provide a link to the source code in the "notes" field and comply with other
       requirements (eg. around trademarks).

       Formal specification of the index file

       The index file format has a formal specification defined by the flex scanner and bison
       parser used to parse the file.  This can be found in the following files in the libguestfs
       source tree:

        builder/index-scan.l
        builder/index-parse.y

       A tool called virt-index-validate(1) is available to validate the index file to ensure it
       is correct.

       Note that the parser and tool can work on either the signed or unsigned index file (ie.
       index or index.asc).

       The index is always encoded in UTF-8.

   CACHING
       Caching templates

       Since the templates are usually very large, downloaded templates are cached in the user’s
       home directory.

       The location of the cache is $XDG_CACHE_HOME/virt-builder/ or $HOME/.cache/virt-builder.

       You can print out information about the cache directory, including which guests are
       currently cached, by doing:

        virt-builder --print-cache

       The cache can be deleted if you want to save space by doing:

        virt-builder --delete-cache

       You can download all (current) templates to the local cache by doing:

        virt-builder --cache-all-templates

       To disable the template cache, use --no-cache.

       Only templates are cached.  The index and detached digital signatures are not cached.

       Caching packages

       Virt-builder uses curl(1) to download files and it also uses the current "http_proxy"
       (etc) settings when installing packages (--install, --update).

       You may therefore want to set those environment variables in order to maximize the amount
       of local caching that happens.  See "ENVIRONMENT VARIABLES" and curl(1).

       Local mirrors

       To increase both speed and reliability of installing packages, you can set up a local
       mirror of the target distribution, and point the guest package manager at that.

       Using a local mirror with Fedora

       To install a Fedora guest using a local mirror:

        virt-builder fedora-27 \
          --edit '/etc/yum.repos.d/fedora.repo:
              s{.*baseurl=.*}{baseurl=http://example.com/mirror/};
              s{.*metalink=.*}{};
          ' \
          --edit '/etc/yum.repos.d/fedora-updates.repo:
              s{.*baseurl=.*}{baseurl=http://example.com/mirror-updates/};
              s{.*metalink=.*}{};
          ' \
          --run-command 'dnf -y update' \
          --install 'pkg1,pkg2,...'

       Using a local mirror with Debian

       Assuming that you are using "apt-proxy" to mirror the repository, you should create a new
       sources.list file to point to your proxy (see https://help.ubuntu.com/community/AptProxy)
       and then do:

        virt-builder debian-8 \
          --upload sources.list:/etc/apt/sources.list \
          --run-command 'apt-get -y update' \
          --install 'pkg1,pkg2,...'

   DIGITAL SIGNATURES
       Virt-builder uses GNU Privacy Guard (GnuPG or gpg) to verify that the index and templates
       have not been tampered with.

       The source points to an index file, which is optionally signed.

       Virt-builder downloads the index and checks that the signature is valid and the signer’s
       fingerprint matches the specified fingerprint (ie. the one specified in gpgkey=.. in the
       .conf, or with --fingerprint, in that order).

       For checking against the built-in public key/fingerprint, this requires importing the
       public key into the user’s local gpg keyring (that’s just the way that gpg works).

       When a template is downloaded, its signature is checked in the same way.

       Although the signatures are optional, if you don’t have them then virt-builder users will
       have to use --no-check-signature on the command line.  This prevents an attacker from
       replacing the signed index file with an unsigned index file and having virt-builder
       silently work without checking the signature.  In any case it is highly recommended that
       you always create signed index and templates.

   ARCHITECTURE
       Virt-builder can build a guest for any architecture no matter what the host architecture
       is.  For example an x86-64 guest on an ARM host.

       However certain options may not work, specifically options that require running commands
       in the guest during the build process: --install, --update, --run, --run-command.  You may
       need to replace these with their firstboot-equivalents.

       An x86-64 host building 32 bit i686 guests should work without any special steps.

   SECURITY
       Virt-builder does not need to run as root (in fact, should not be run as root), and
       doesn't use setuid, "sudo" or any similar mechanism.

       --install, --update, --run and --run-command are implemented using an appliance (a small
       virtual machine) so these commands do not run on the host.  If you are using the
       libguestfs libvirt backend and have SELinux enabled then the virtual machine is
       additionally encapsulated in an SELinux container (sVirt).

       However these options will have access to the host’s network and since the template may
       contain untrusted code, the code might try to access host network resources which it
       should not.  You can use --no-network to prevent this.

       Firstboot commands run in the context of the guest when it is booted, and so the security
       of your hypervisor / cloud should be considered.

       Virt-builder injects a random seed into every guest which it builds.  This helps to ensure
       that TCP sequence numbers, UUIDs, ssh host keys etc are truly random when the guest boots.

       You should check digital signatures and not ignore any signing errors.

   CLONES
       If you wish to create many new guests of the same type, it is tempting to run virt-builder
       once and then copy the output file.  You should not do this.  You should run virt-builder
       once for each new guest you need.

       The reason is that each clone needs to have (at least) a separate random seed, and
       possibly other unique features (such as filesystem UUIDs) in future versions of virt-
       builder.

       Another thing you should not do is to boot the guest, then clone the booted disk image.
       The reason is that some guests create unique machine IDs, SSH host keys and so on at first
       boot, and you would not want clones to have duplicate identities.

       See also: virt-sysprep(1).

   PERFORMANCE
       The most important aspect of getting good performance is caching.  Templates gets
       downloaded into the cache the first time they are used, or if you use the
       --cache-all-templates option.  See "CACHING" above for further information.

       Packages required for the --install and --update options are downloaded using the host
       network connection.  Setting the "http_proxy", "https_proxy" and "ftp_proxy" environment
       variables to point to a local web cache may ensure they only need to be downloaded once.
       You can also try using a local package repository, although this can be complex to set up
       and varies according to which Linux distro you are trying to install.

       Using --no-sync

       Use --no-sync.  However read the caveats in the "OPTIONS" section above, since this can
       cause disk corruption if not used correctly.

       Skipping virt-resize

       Virt-builder can skip the virt-resize step under certain conditions.  This makes virt-
       builder much faster.  The conditions are:

       ·   the output must be a regular file (not a block device), and

       ·   the user did not use the --size option, and

       ·   the output format is the same as the template format (usually raw).

       pxzcat

       Virt-builder uses an internal implementation of pxzcat (parallel xzcat) if liblzma was
       found at build time.  If liblzma was not found at build time, regular "xzcat" is used
       which is single-threaded.

       User-Mode Linux

       You can use virt-builder with the User-Mode Linux (UML) backend.  This may be faster when
       running virt-builder inside a virtual machine (eg. in the cloud).

       To enable the UML backend, read the instructions in "USER-MODE LINUX BACKEND" in
       guestfs(3).

       Currently you have to use the --no-network option.  This should be fixed in a future
       version.

       The qcow2 output format is not supported by UML.  You can only create raw-format guests.

   SELINUX
       Guests which use SELinux (such as Fedora and Red Hat Enterprise Linux) require that each
       file has a correct SELinux label.

       Virt-builder does not know how to give new files a label, so there are two possible
       strategies it can use to ensure correct labelling:

       Using --selinux-relabel
           This runs setfiles(8) just before finalizing the guest, which sets SELinux labels
           correctly in the disk image.

           This is the recommended method.

       --touch /.autorelabel
           Guest templates may already contain a file called /.autorelabel or you may touch it.

           For guests that use SELinux, this causes restorecon(8) to run at first boot.  Guests
           will reboot themselves once the first time you use them, which is normal and harmless.

       Please note that if your guest uses SELinux, and you are doing operations on it which
       might create new files or change existing ones, you are recommended to use
       --selinux-relabel.  This will help in making sure that files have the right SELinux
       labels.

MACHINE READABLE OUTPUT

       The --machine-readable option can be used to make the output more machine friendly, which
       is useful when calling virt-builder from other programs, GUIs etc.

       Use the option on its own to query the capabilities of the virt-builder binary.  Typical
       output looks like this:

        $ virt-builder --machine-readable
        virt-builder
        arch
        config-file
        customize
        json-list
        pxzcat

       A list of features is printed, one per line, and the program exits with status 0.

       It is possible to specify a format string for controlling the output; see "ADVANCED
       MACHINE READABLE OUTPUT" in guestfs(3).

ENVIRONMENT VARIABLES

       For other environment variables which affect all libguestfs programs, see "ENVIRONMENT
       VARIABLES" in guestfs(3).

       "http_proxy"
       "https_proxy"
       "no_proxy"
           Set the proxy for downloads.  These environment variables (and more) are actually
           interpreted by curl(1), not virt-builder.

       "HOME"
           Used to determine the location of the template cache, and the location of the user'
           sources.  See "CACHING" and "SOURCES OF TEMPLATES".

       "VIRT_TOOLS_DATA_DIR"
           This can point to the directory containing data files used for Windows firstboot
           installation.

           Normally you do not need to set this.  If not set, a compiled-in default will be used
           (something like /usr/share/virt-tools).

           This directory may contain the following files:

           rhsrvany.exe
               This is the RHSrvAny Windows binary, used to install a "firstboot" script in
               Windows guests.  It is required if you intend to use the --firstboot or
               --firstboot-command options with Windows guests.

               See also: "https://github.com/rwmjones/rhsrvany"

           pvvxsvc.exe
               This is a Windows binary shipped with SUSE VMDP, used to install a "firstboot"
               script in Windows guests.  It is required if you intend to use the --firstboot or
               --firstboot-command options with Windows guests.

       "XDG_CACHE_HOME"
           Used to determine the location of the template cache.  See "CACHING".

       "XDG_CONFIG_HOME"
           Used to determine the location of the user' sources.  See "SOURCES OF TEMPLATES".

       "XDG_CONFIG_DIRS"
           Used to determine the location of the system sources.  See "SOURCES OF TEMPLATES".

EXIT STATUS

       This program returns 0 if successful, or non-zero if there was an error.

SEE ALSO

       guestfs(3), guestfish(1), guestmount(1), virt-builder-repository(1), virt-copy-out(1),
       virt-customize(1), virt-get-kernel(1), virt-install(1), virt-rescue(1), virt-resize(1),
       virt-sysprep(1), oz-install(1), gpg(1), gpg2(1), curl(1), virt-make-fs(1), genisoimage(1),
       http://libguestfs.org/.

AUTHOR

       Richard W.M. Jones http://people.redhat.com/~rjones/

COPYRIGHT

       Copyright (C) 2013 Red Hat Inc.

LICENSE

       This program is free software; you can redistribute it and/or modify it under the terms of
       the GNU General Public License as published by the Free Software Foundation; either
       version 2 of the License, or (at your option) any later version.

       This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
       without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
       See the GNU General Public License for more details.

       You should have received a copy of the GNU General Public License along with this program;
       if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
       Boston, MA 02110-1301 USA.

BUGS

       To get a list of bugs against libguestfs, use this link:
       https://bugzilla.redhat.com/buglist.cgi?component=libguestfs&product=Virtualization+Tools

       To report a new bug against libguestfs, use this link:
       https://bugzilla.redhat.com/enter_bug.cgi?component=libguestfs&product=Virtualization+Tools

       When reporting a bug, please supply:

       ·   The version of libguestfs.

       ·   Where you got libguestfs (eg. which Linux distro, compiled from source, etc)

       ·   Describe the bug accurately and give a way to reproduce it.

       ·   Run libguestfs-test-tool(1) and paste the complete, unedited output into the bug
           report.