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)