Ubuntu Manpage: targetcli - administration shell for storage targets

NAME

       targetcli - administration shell for storage targets

DESCRIPTION

       targetcli  is  a  shell for viewing, editing, and saving the configuration of the kernel's
       target subsystem, also known as LIO. It enables the administrator to assign local  storage
       resources backed by either files, volumes, local SCSI devices, or ramdisk, and export them
       to remote systems via network fabrics, such as iSCSI or FCoE.

       The configuration layout is tree-based, similar to a filesystem, and  is  navigated  in  a
       similar manner.

USAGE

       targetcli

       targetcli [cmd]

       Invoke  targetcli  as  root  to enter the configuration shell, or follow with a command to
       execute but do not enter the shell.  Use ls to list nodes below the current path.   Moving
       around  the  tree  is  accomplished  by  the  cd  command, or by entering the new location
       directly. Objects are created using create, removed using  delete.   Use  help  <cmd>  for
       additional  usage  information.  Tab-completion  is  available  for  commands  and command
       arguments.

       Configuration changes in targetcli are made immediately to the  underlying  kernel  target
       configuration.  Settings  will  not  be retained across reboot unless saveconfig is either
       explicitly called,  or  implicitly  by  exiting  the  shell  with  the  global  preference
       auto_save_on_exit set to true, the default.

QUICKSTART

       To create an iSCSI target and share a file-backed LUN without any auth checks:

       $ sudo targetcli
       /> backstores/fileio create test /tmp/test.img 100m
       /> iscsi/ create iqn.2006-04.com.example:test-target
       /> cd iscsi/iqn.2006-04.com.example:test-target/tpg1/
       tpg1/> luns/ create /backstores/fileio/test
       tpg1/> set attribute generate_node_acls=1
       tpg1/> exit

       Although  by  default targetcli saves the running configuration upon exit, a distribution-
       specific service must be enabled  to  restore  the  saved  configuration  on  reboot.  See
       distribution documentation for specifics, but for example:

       $ sudo systemctl enable target.service

       See EXAMPLES below for more detailed information on commands and using the shell.

BACKSTORES

Backstores are different kinds of local storage resources that the kernel target uses to
"back" the SCSI devices it exports. The mappings to local storage resources that each
backstore creates are called storage objects.

FILEIO
Allows files to be treated as disk images. When storage objects of this type are created,
they can support either write-back or write-thru operation. Using write-back enables the
local filesystem cache, which will improve performance but increase the risk of data loss.
It is also possible to use fileio with local block device files, if buffered operation is
needed.

Fileio also supports using an existing file, or creating a new file. New files are
sparsely allocated by default.

BLOCK
Allows a local disk block device to be shared.

PSCSI
Allows a local SCSI device of any type to be shared. It is generally advised to prefer the
block backstore if sharing a block SCSI device is desired.

RAMDISK
Allows kernel memory to be shared as a block SCSI device. Since memory is volatile, the
contents of the ramdisk will be lost if the system restarts, and this backstore is best
used for testing only.

It also supports "nullio" mode, which is not backed by any storage. It discards all
writes, and returns all-zeroes for reads.

USERSPACE-BACKED
Backstores starting with "user:" are not supported in the kernel, but rely on a userspace
process to handle requests. See tcmu-runner(8) for more information on creating backstores
of this type.

TARGETS

       Targets are instances of a fabric, which adapts the kernel target to a specific  transport
       protocol  such  as  iSCSI, Fibre Channel, or SBP-2. Creating a target in targetcli enables
       that target to be configured. The name of the target, its WWN (world wide name), may  link
       the  configuration  to  a specific hardware endpoint, like SRP for example, or it may not,
       like iSCSI.

       Aside from "backstores", all other top-level configuration nodes in targetcli are  fabrics
       that  may  have targets created for them. Fabrics that require hardware are only listed if
       the hardware is present and configured properly.

   CREATING A TARGET
       Use the create command within a fabric's node to create a target. If the fabric's  targets
       are  tied  to  hardware  then targetcli will constrain the WWN to available hardware WWNs.
       These can be shown via tab-completion. If the fabric is not  tied  to  hardware,  such  as
       iSCSI,  then targetcli will either auto-generate a WWN if none is given, or check that the
       given WWN has the correct format. All WWNs are prefaced by  their  type,  such  as  "iqn",
       "naa", or "ib", and may be given with or without colons.

       iSCSI  supports  multiple  WWN  formats:  iqn,  naa, and eui. Other fabrics support single
       formats only.

CONFIGURING A TARGET

       Not all fabrics have the  same  capabilities.  Targets  on  different  fabrics  will  have
       different  configuration  node  layouts.  iSCSI  has  the most to configure; other fabrics
       present subsets of iSCSI's feature set.

CONFIGURING ISCSI

iSCSI has the most options for configuration.

TPGS
TPGs (Target Portal Groups) allow the iSCSI to support multiple complete configurations
within one target. This is useful for complex quality-of-service configurations. targetcli
will automatically create one TPG when the target is created, and almost all setups only
need one.

PORTALS
An iSCSI target may be reached via multiple IP addresses and ports. These addr:port pairs
are called portals. Both IPv4 and IPv6 addresses are supported.

When a target is created, targetcli automatically creates a default portal listening on
all IPv4 addresses (shown as 0.0.0.0) on port 3260. If a different configuration is
needed, the default portal can be removed and portals configured as desired.

If the hardware supports it, iSER (iSCSI Extensions for RDMA) may be enabled via the
enable_iser command within each portal's node.

LUNS
The kernel target exports SCSI Logical Units, also called LUNs. This section links the
previously-defined storage objects with the target, and defines which number (the Logical
Unit Number) the device will use. Note that if ACLs are being used, a lun mapping must be
created under the ACL that refers back to the TPG LUN.

ACLS
ACLs (Access Control Lists) allow different configuration, depending on the initiator that
is connecting to the target. This includes both per-initiator authentication settings as
well as per-initiator LUN mappings.

create <wwn> in the acls node creates an ACL for an initiator, and create within the ACL
creates a LUN mapping. (This can either refer to the TPG LUN, or to the storage object, in
which case the TPG LUN will be configured as well.) Global setting auto_add_mapped_luns
affects this, see below.

AUTHENTICATION
iSCSI supports authentication via the CHAP protocol, which uses a username and password.
The initiator may be required to supply valid credentials to the target, and the target
may also be required to supply credentials back to the initiator. The latter is referred
to as mutual authentication.

Furthermore, authentication credentials may be different for each session phase (Discovery
or Normal), and authentication in a Normal session may be set at the TPG level, or per-
ACL.

Discovery Authentication
iSCSI Discovery sessions allow the initiator to connect to a portal and discover targets
with the SendTargets command, but not access them. The four parameters userid, password,
mutual_userid, and mutual_password are configured via set discovery_auth command within
the top-level iscsi configuration node. 1-way authentication is enabled if userid and
password are both set, and mutual authentication is enabled if all four are set.
Authentication is disabled by unsetting the parameters.

Normal Authentication
Similarly, the four parameters userid, password, mutual_userid, and mutual_password are
configured via set auth command within the TPG node and ACL nodes. However, LIO only uses
one or the other, depending on the TPG's generate_node_acls attribute setting. If
generate_node_acls is 1, the TPG-wide settings will be used. If generate_node_acls is 0,
then the user-created ACLs' settings will be used.

Enable generate_node_acls with set attribute generate_node_acls=1 within the TPG node.
This can be thought of as "ignore ACLs mode" -- both authentication and LUN mapping will
then use the TPG settings.

No Authentication
Authentication is disabled by clearing the TPG "authentication" attribute: set attribute
authentication=0. Although initiator names are trivially forgeable, generate_node_acls
still works here to either ignore user-defined ACLs and allow all, or check that an ACL
exists for the connecting initiator.

CONFIGURING FIBRE CHANNEL (QLA2XXX)

       Operation as  a  target  requires  that  /sys/module/qla2xxx/parameters/qlini_mode  report
       "disabled".  This  may  require  passing  the qlini_mode=disabled parameter to the qla2xxx
       module when it loads.

CONFIGURING FIBRE CHANNEL OVER ETHERNET (TCM_FC)

       Ensure fcoeadm -i shows a working endpoint.

CONFIGURING SRP

       SRP (SCSI RDMA Protocol) requires that RDMA-capable hardware  is  present.  It  uses  "ib"
       WWNs.

CONFIGURING LOOPBACK

       Storage objects may be re-exported as local SCSI devices with this fabric.

CONFIGURING OTHER FABRICS

       Other fabrics may be present. They are for specialized uses. Use at your own risk.

EXAMPLES

DEFINING A STORAGE OBJECT WITHIN A BACKSTORE
backstores/fileio create disk1 /disks/disk1.img 140M
Creates a storage object named disk1 with the given path and size. targetcli supports
common size abbreviations like 'M', 'G', and 'T'.

EXPORTING A STORAGE OBJECT VIA ISCSI
iscsi/ create
Creates an iSCSI target with a default WWN. It will also create an initial target portal
group called tpg1.

iqn.2003-01.org.linux-iscsi.test2.x8664:sn123456789012/tpg1/
An example of changing to the configuration node for the given target's first target
portal group (TPG). This is equivalent to giving the command prefixed by "cd". (Although
more can be useful for certain setups, most configurations have a single TPG per target.
In this case, configuring the TPG is equivalent to configuring the overall target.)

portals/ create
Add a portal, i.e. an IP address and TCP port via which the target can be contacted by
initiators. Only required if the default 0.0.0.0:3260 portal is not present.

luns/ create /backstores/fileio/disk1
Create a new LUN in the TPG, attached to the storage object that has previously been
defined. The storage object now shows up under the /backstores configuration node as
activated.

acls/ create iqn.1994-05.com.redhat:4321576890
Creates an ACL (access control list) entry for the given iSCSI initiator.

acls/iqn.1994-05.com.redhat:4321576890 create 2 0
Gives the initiator access to the first exported LUN (lun0), which the initiator will see
as lun2. The default is to give the initiator read/write access; if read-only access was
desired, an additional "1" argument would be added to enable write-protect. (Note: if
global setting auto_add_mapped_luns is true, this step is not necessary.)

EXPORTING A STORAGE OBJECT VIA FCOE
tcm_fc/ create 20:00:00:19:99:a8:34:bc
Create an FCoE target with the given WWN. targetcli can tab-complete the WWN based on
registered FCoE interfaces. If none are found, verify that they are properly configured
and are shown in the output of fcoeadm -i.

tcm_fc/20:00:00:19:99:a8:34:bc/
If auto_cd_after_create is set to false, change to the configuration node for the given
target, equivalent to giving the command prefixed by cd.

luns/ create /backstores/fileio/disk1
Create a new LUN for the interface, attached to a previously defined storage object. The
storage object now shows up under the /backstores configuration node as activated.

acls/ create 00:99:88:77:66:55:44:33
Create an ACL (access control list), for defining the resources each initiator may access.
The default behavior is to auto-map existing LUNs to the ACL; see help for more
information.

The LUN should now be accessible via FCoE.

OTHER COMMANDS

       saveconfig
       Save the current configuration settings to a file, from which settings will be restored if
       the  system  is  rebooted. By default, this will save the configuration to /etc/rtslib-fb-
       target/saveconfig.json.

       This command is executed from the configuration root node.

       restoreconfig
       Restore target configuration from a file, the default is the file listed under saveconfig.
       This will fail if there is already an established config, unless the clear_existing option
       is set to true.

       This command is executed from the configuration root node.

       clearconfig
       Clears the entire current local configuration. The parameter  confirm=true  must  also  be
       given, as a precaution.

       This command is executed from the configuration root node.

       sessions [ list | detail ] [sid]
       Lists the current open sessions or a specific session, with or without details.

       This command is executed from the configuration root node.

       exit
       Leave the configuration shell.

SETTINGS GROUPS

Settings are broken into groups. Individual settings are accessed by get <group> <setting>
and set <group> <setting>=<value>, and the settings of an entire group may be displayed by
get <group>. All except for global are associated with a particular configuration node.

GLOBAL
Shell-related user-specific settings are in global, and are visible from all configuration
nodes. They are mostly shell display options, but some starting with auto_ affect shell
behavior and may merit customization. These include auto_save_on_exit, which controls if
exiting targetcli saves the configuration; auto_add_mapped_luns, to automatically add
existing LUNs to new ACLs, and new LUNS to existing ACLs; and auto_cd_after_create, to
change working path to newly-created nodes. Global settings are user-specific and are
saved to ~/.targetcli/ upon exit, unlike other groups, which are system-wide and kept in
/etc/rtslib-fb-target/saveconfig.json.

BACKSTORE-SPECIFIC
attribute
/backstore/<type>/<name> configuration node. Contains values relating to the backstore and
storage object.

ISCSI-SPECIFIC
discovery_auth
/iscsi configuration node. Set the normal and mutual authentication userid and password
for discovery sessions, as well as enabling or disabling it. By default it is disabled --
no authentication is required for discovery.

parameter
/iscsi/<target_iqn>/tpgX configuration node. ISCSI-specific parameters such as AuthMethod,
MaxBurstLength, IFMarker, DataDigest, and similar.

attribute
/iscsi/<target_iqn>/tpgX configuration node. Contains implementation-specific settings for
the TPG, such as authentication, to enforce or disable authentication for the full-feature
phase (i.e. non-discovery).

auth
/iscsi/<target_iqn>/tpgX/acls/<initiator_iqn> configuration node. Set the userid and
password for full-feature phase for this ACL.

FILES

       /etc/rtslib-fb-target/saveconfig.json
       /etc/rtslib-fb-target/backup/*

AUTHOR

       Written by Jerome Martin <jxm@risingtidesystems.com>.
       Man page written by Andy Grover <agrover@redhat.com>.

REPORTING BUGS

       Report bugs via <targetcli-fb-devel@lists.fedorahosted.org>
       or <https://github.com/open-iscsi/targetcli-fb/issues>

                                                                                     targetcli(8)