Provided by: containers-storage_1.43.0+ds1-8ubuntu0.1_amd64 bug

NAME

       storage.conf - Syntax of Container Storage configuration file

DESCRIPTION

       The  STORAGE  configuration  file specifies all of the available container storage options
       for tools using shared container storage, but in a TOML format that  can  be  more  easily
       modified and versioned.

FORMAT

       The  [TOML  format][toml] is used as the encoding of the configuration file.  Every option
       and subtable listed here is nested under a global "storage" table.  No  bare  options  are
       used. The format of TOML can be simplified to:

              [table]
              option = value

              [table.subtable1]
              option = value

              [table.subtable2]
              option = value

STORAGE TABLE

       The storage table supports the following options:

       driver=""
         Copy  On  Write  (COW)  container  storage  driver.  Valid drivers are "overlay", "vfs",
       "devmapper", "aufs", "btrfs", and "zfs". Some drivers (for example,  "zfs",  "btrfs",  and
       "aufs")  may  not  work  if  your  kernel lacks support for the filesystem.  This field is
       required to guarantee proper operation.  Valid rootless drivers  are  "btrfs",  "overlay",
       and  "vfs".  Rootless users default to the driver defined in the system configuration when
       possible.  When the system configuration uses an  unsupported  rootless  driver,  rootless
       users default to "overlay" if available, otherwise "vfs".

       graphroot=""
         container  storage  graph dir (default: "/var/lib/containers/storage") Default directory
       to store all writable  content  created  by  container  storage  programs.   The  rootless
       graphroot path supports environment variable substitutions (ie. $HOME/containers/storage).
       When changing the graphroot location on an SELINUX system, ensure the labeling matches the
       default locations labels with the following commands:

              # semanage fcontext -a -e /var/lib/containers/storage /NEWSTORAGEPATH
              # restorecon -R -v /NEWSTORAGEPATH

       In rootless mode you would set

              # semanage fcontext -a -e $HOME/.local/share/containers NEWSTORAGEPATH
              $ restorecon -R -v /NEWSTORAGEPATH

       rootless_storage_path="$HOME/.local/share/containers/storage"
         Storage  path  for rootless users. By default the graphroot for rootless users is set to
       $XDG_DATA_HOME/containers/storage,     if     XDG_DATA_HOME     is     set.      Otherwise
       $HOME/.local/share/containers/storage  is  used.  This field can be used if administrators
       need to change the storage location for all users.  The  rootless  storage  path  supports
       environment variable substitutions (ie. $HOME/containers/storage)

       A  common  use  case for this field is to provide a local storage directory when user home
       directories are NFS-mounted (podman does not support container storage over NFS).

       runroot=""
         container storage run dir  (default:  "/run/containers/storage")  Default  directory  to
       store  all  temporary writable content created by container storage programs. The rootless
       runroot path supports environment variable substitutions (ie. $HOME/containers/storage)

   STORAGE OPTIONS TABLE
       The storage.options table supports the following options:

       additionalimagestores=[]
         Paths to additional container image stores. Usually these are read/only  and  stored  on
       remote network shares.

       pull_options    =    {enable_partial_images   =   "false",   use_hard_links   =   "false",
       ostree_repos=""}

       Allows specification of how storage is populated when  pulling  images.  This  option  can
       speed   the   pulling   process   of   images   compressed   with   format   zstd:chunked.
       Containers/storage looks for files within images that are being pulled  from  a  container
       registry  that  were  previously pulled to the host.  It can copy or create a hard link to
       the existing file when it finds them, eliminating the need to pull them from the container
       registry.  These  options  can deduplicate pulling of content, disk storage of content and
       can allow the kernel to use less memory when running containers.

       containers/storage supports four keys
         * enable_partial_images="true" | "false"
           Tells containers/storage to look for files previously pulled in storage
           rather then always pulling them from the container registry.
         * use_hard_links = "false" | "true"
           Tells containers/storage to use hard links rather then create new files in
           the image, if an identical file already existed in storage.
         * ostree_repos = ""
           Tells containers/storage where an ostree repository exists that might have
           previously pulled content which can be used when attempting to avoid
           pulling content from the container registry

       remap-uids="" remap-gids=""
         Remap-UIDs/GIDs is the mapping  from  UIDs/GIDs  as  they  should  appear  inside  of  a
       container,  to  the  UIDs/GIDs  outside  of  the container, and the length of the range of
       UIDs/GIDs.  Additional mapped sets can be listed and will  be  heeded  by  libraries,  but
       there  are  limits  to  the  number of mappings which the kernel will allow when you later
       attempt to run a container.

       Example
            remap-uids = 0:1668442479:65536
            remap-gids = 0:1668442479:65536

       These mappings tell the container engines to map UID 0 inside  of  the  container  to  UID
       1668442479  outside.   UID  1  will  be  mapped  to  1668442480.  UID  2 will be mapped to
       1668442481, etc, for the next 65533 UIDs in succession.

       remap-user="" remap-group=""
         Remap-User/Group is a user name which can be used to look up one or more UID/GID  ranges
       in the /etc/subuid or /etc/subgid file.  Mappings are set up starting with an in-container
       ID of 0 and then a host-level ID taken from the lowest range that  matches  the  specified
       name,  and  using the length of that range. Additional ranges are then assigned, using the
       ranges which specify the lowest host-level IDs first, to  the  lowest  not-yet-mapped  in-
       container ID, until all of the entries have been used for maps.

       Example
            remap-user = "containers"
            remap-group = "containers"

       root-auto-userns-user=""
         Root-auto-userns-user  is  a  user name which can be used to look up one or more UID/GID
       ranges in the /etc/subuid and /etc/subgid file.   These  ranges  will  be  partitioned  to
       containers  configured to create automatically a user namespace.  Containers configured to
       automatically create a user namespace can still overlap with containers having an explicit
       mapping set.  This setting is ignored when running as rootless.

       auto-userns-min-size=1024
         Auto-userns-min-size is the minimum size for a user namespace created automatically.

       auto-userns-max-size=65536
         Auto-userns-max-size is the maximum size for a user namespace created automatically.

       disable-volatile=true
         If  disable-volatile  is set, then the "volatile" mount optimization is disabled for all
       the containers.

   STORAGE OPTIONS FOR AUFS TABLE
       The storage.options.aufs table supports the following options:

       mountopt=""
         Comma separated list of default options to be used to mount container images.  Suggested
       value "nodev". Mount options are documented in the mount(8) man page.

   STORAGE OPTIONS FOR BTRFS TABLE
       The storage.options.btrfs table supports the following options:

       min_space=""
         Specifies the min space in a btrfs volume.

       size=""
         Maximum  size  of a container image.   This flag can be used to set quota on the size of
       container images. (format: [], where unit = b (bytes), k (kilobytes), m (megabytes), or  g
       (gigabytes))

   STORAGE OPTIONS FOR THINPOOL (devicemapper) TABLE
       The  storage.options.thinpool  table  supports  the following options for the devicemapper
       driver:

       autoextend_percent=""
         Tells the thinpool driver the amount by which the thinpool needs to be  grown.  This  is
       specified  in  terms of % of pool size. So a value of 20 means that when threshold is hit,
       pool will be grown by 20% of existing pool size. (default: 20%)

       autoextend_threshold=""
         Tells the driver the thinpool extension threshold in terms of percentage of  pool  size.
       For example, if threshold is 60, that means when pool is 60% full, threshold has been hit.
       (default: 80%)

       basesize=""
         Specifies the size to use when creating the base device, which limits the size of images
       and containers. (default: 10g)

       blocksize=""
         Specifies a custom blocksize to use for the thin pool. (default: 64k)

       directlvm_device=""
         Specifies  a  custom  block  storage device to use for the thin pool. Required for using
       graphdriver devicemapper.

       directlvm_device_force=""
         Tells driver to wipe device (directlvm_device) even if device already has a  filesystem.
       (default: false)

       fs="xfs"
         Specifies the filesystem type to use for the base device. (default: xfs)

       log_level=""
         Sets the log level of devicemapper.

              0: LogLevelSuppress 0 (default)
              2: LogLevelFatal
              3: LogLevelErr
              4: LogLevelWarn
              5: LogLevelNotice
              6: LogLevelInfo
              7: LogLevelDebug

       metadata_size=""
         metadata_size  is  used  to  set  the pvcreate --metadatasize options when creating thin
       devices. (Default 128k)

       min_free_space=""
         Specifies the min free space percent in a thin pool required for new device creation  to
       succeed. Valid values are from 0% - 99%. Value 0% disables. (default: 10%)

       mkfsarg=""
         Specifies extra mkfs arguments to be used when creating the base device.

       mountopt=""
         Comma separated list of default options to be used to mount container images.  Suggested
       value "nodev". Mount options are documented in the mount(8) man page.

       size=""
         Maximum size of a container image.  This flag can be used to set quota on  the  size  of
       container  images. (format: [], where unit = b (bytes), k (kilobytes), m (megabytes), or g
       (gigabytes))

       use_deferred_deletion=""
         Marks thinpool device for deferred deletion. If the thinpool is in use when  the  driver
       attempts  to  delete  it,  the driver will attempt to delete device every 30 seconds until
       successful, or when it restarts.  Deferred deletion permanently deletes the device and all
       data stored in the device will be lost. (default: true).

       use_deferred_removal=""
         Marks  devicemapper block device for deferred removal.  If the device is in use when its
       driver attempts to remove it, the driver tells the kernel to remove the device as soon  as
       possible.   Note  this  does  not  free  up the disk space, use deferred deletion to fully
       remove the thinpool.  (default: true).

       xfs_nospace_max_retries=""
         Specifies the maximum number of retries XFS should attempt to complete  IO  when  ENOSPC
       (no space) error is returned by underlying storage device. (default: 0, which means to try
       continuously.)

   STORAGE OPTIONS FOR OVERLAY TABLE
       The storage.options.overlay table supports the following options:

       ignore_chown_errors = "false"
         ignore_chown_errors can be set to allow a non privileged user running with a  single UID
       within  a user namespace to run containers. The user can pull and use any image even those
       with multiple uids.  Note multiple UIDs will be squashed down to the default  uid  in  the
       container.   These  images  will  have  no  separation between the users in the container.
       (default: false)

       inodes=""
         Maximum inodes in a read/write layer.   This flag can be used to  set  a  quota  on  the
       inodes allocated for a read/write layer of a container.

       force_mask = "0000|shared|private"
         ForceMask specifies the permissions mask that is used for new files and directories. The
       values "shared" and "private" are accepted.  (default: "").  Octal  permission  masks  are
       also accepted.

              • ``: Not set All files/directories, get set with the permissions identified within
                the image.

              • private: it is equivalent to 0700.   All  files/directories  get  set  with  0700
                permissions.  The owner has rwx access to the files. No other users on the system
                can access the files.  This setting could  be  used  with  networked  based  home
                directories.

              • shared:  it  is  equivalent  to  0755.  The owner has rwx access to the files and
                everyone else can read, access and execute  them.  This  setting  is  useful  for
                sharing  containers  storage  with other users.  For instance, a storage owned by
                root could be shared to rootless users as an additional store.  NOTE:  All  files
                within the image are made readable and executable by any user on the system. Even
                /etc/shadow within your image is now readable by any user.

       OCTAL: Users can experiment with other OCTAL Permissions.

       Note: The force_mask Flag is an experimental feature, it could change in the future.  When
       "force_mask"    is    set    the    original    permission   mask   is   stored   in   the
       "user.containers.override_stat" xattr and the "mount_program" option  must  be  specified.
       Mount  programs  like "/usr/bin/fuse-overlayfs" present the extended attribute permissions
       to processes within containers rather than the "force_mask"  permissions.

       mount_program=""
         Specifies the path to a custom program to use  instead  of  using  kernel  defaults  for
       mounting  the  file  system.  In rootless mode, without the CAP_SYS_ADMIN capability, many
       kernels  prevent  mounting  of  overlay  file  systems,  requiring  you   to   specify   a
       mount_program.  The  mount_program option is also required on systems where the underlying
       storage is btrfs, aufs, zfs, overlay, or ecryptfs based file systems.
         mount_program = "/usr/bin/fuse-overlayfs"

       mountopt=""
         Comma separated list of default options to be used to mount container images.  Suggested
       value "nodev". Mount options are documented in the mount(8) man page.

       skip_mount_home=""
         Tell storage drivers to not create a PRIVATE bind mount on their home directory.

       size=""
         Maximum  size of a read/write layer.   This flag can be used to set quota on the size of
       a read/write layer of a container. (format: [], where unit = b (bytes), k  (kilobytes),  m
       (megabytes), or g (gigabytes))

   STORAGE OPTIONS FOR VFS TABLE
       The storage.options.vfs table supports the following options:

       ignore_chown_errors = "false"
         ignore_chown_errors can be set to allow a non privileged user running with a  single UID
       within a user namespace to run containers. The user can pull and use any image even  those
       with  multiple  uids.   Note multiple UIDs will be squashed down to the default uid in the
       container.  These images will have no separation  between  the  users  in  the  container.
       (default: false)

   STORAGE OPTIONS FOR ZFS TABLE
       The storage.options.zfs table supports the following options:

       fsname=""
         File System name for the zfs driver

       mountopt=""
         Comma separated list of default options to be used to mount container images.  Suggested
       value "nodev". Mount options are documented in the mount(8) man page.

       size=""
         Maximum size of a container image.   This flag can be used to set quota on the  size  of
       container  images. (format: [], where unit = b (bytes), k (kilobytes), m (megabytes), or g
       (gigabytes))

SELINUX LABELING

       When running on an SELinux system, if you move the containers storage graphroot directory,
       you must make sure the labeling is correct.

       Tell  SELinux  about  the new containers storage by setting up an equivalence record. This
       tells  SELinux  to  label  content  under  the  new  path,  as  if  it  was  stored  under
       /var/lib/containers/storage.

              semanage fcontext -a -e /var/lib/containers NEWSTORAGEPATH
              restorecon -R -v NEWSTORAGEPATH

       In rootless mode, you would set

              semanage fcontext -a -e $HOME/.local/share/containers NEWSTORAGEPATH
              restorecon -R -v NEWSTORAGEPATH

       The  semanage  command above tells SELinux to setup the default labeling of NEWSTORAGEPATH
       to match /var/lib/containers.  The restorecon command tells SELinux to apply the labels to
       the actual content.

       Now  all  new  content created in these directories will automatically be created with the
       correct label.

QUOTAS

       Container storage implements XFS project quota controls for overlay storage containers and
       volumes.  The  directory  used  to  store the containers must be an XFS file system and be
       mounted with the pquota option.

       Example /etc/fstab entry:

              /dev/podman/podman-var /var xfs defaults,x-systemd.device-timeout=0,pquota 1 2

       Container storage generates project ids for each container and builtin volume,  but  these
       project ids need to be unique for the XFS file system.

       The  xfs_quota  tool  can  be used to assign a project id to the storage driver directory,
       e.g.:

              echo 100000:/var/lib/containers/storage/overlay >> /etc/projects
              echo 200000:/var/lib/containers/storage/volumes >> /etc/projects
              echo storage:100000 >> /etc/projid
              echo volumes:200000 >> /etc/projid
              xfs_quota -x -c 'project -s storage volumes' /<xfs mount point>

       In the example above, the storage directory project id will be used as  a  "start  offset"
       and all containers will be assigned larger project ids (e.g. >= 100000).  Then the volumes
       directory project id will be used as a "start offset" and all  volumes  will  be  assigned
       larger  project  ids (e.g. >= 200000).  This is a way to prevent xfs_quota management from
       conflicting with containers/storage.

FILES

       Distributions often provide a /usr/share/containers/storage.conf file  to  define  default
       storage    configuration.    Administrators   can   override   this   file   by   creating
       /etc/containers/storage.conf to specify their own configuration. Likewise  rootless  users
       can  create a storage.conf file to override the system storage.conf files. Files should be
       stored in the $XDG_CONFIG_HOME/containers/storage.conf file.  If $XDG_CONFIG_HOME  is  not
       set then the file $HOME/.config/containers/storage.conf is used.

       Note: The storage.conf file overrides all other strorage.conf files. Container engines run
       by users with a storage.conf file in their home directory do not use options in the system
       storage.conf files.

       /etc/projects  -  XFS  persistent  project root definition /etc/projid -  XFS project name
       mapping file

SEE ALSO

       semanage(8),  restorecon(8),  mount(8),  fuse-overlayfs(1),   xfs_quota(8),   projects(5),
       projid(5)

HISTORY

       May  2017,  Originally  compiled by Dan Walsh dwalsh@redhat.commailto:dwalsh@redhat.com⟩
       Format  copied  from  crio.conf  man  page  created   by   Aleksa   Sarai   asarai@suse.demailto:asarai@suse.de