saveconfig.json(5)saveconfig.json(5)NAMEsaveconfig.json - Saved configuration file for rtslib-fb and LIO kernel
target
DESCRIPTION
/etc/target/saveconfig.json is the default location for storing the
configuration of the Linux kernel target, also known as LIO. Since the
target is in the kernel, tools like targetctl or targetcli must be used
to save and restore the configuration across reboots.
Generating or modifying this file by hand, or with other tools, is also
supported. This fills a gap for users whose needs are not met by the
targetcli configuration shell, who cannot use the rtslib Python
library, and yet also wish to avoid directly manipulating LIO's con‐
figfs interface.
OVERVIEW
The configuration file is in the "json" text format, which is both
human- and machine-readable. Its format is very closely modeled on the
layout and terminology that LIO uses. Attributes may be string, bool‐
ean, or numeric values. All sizes are expressed in bytes.
LAYOUT
TOP LEVEL SUMMARY
storage_objects describes mappings of resources on the local machine
that can be used to emulate block devices.
fabric_modules describes settings for LIO fabrics -- the hardware or
software protocols that transport SCSI commands -- such as iSCSI or
Fibre Channel over Ethernet (FCoE).
targets describes the SCSI target endpoints that export storage objects
over a fabric.
storage_objects
All storage objects must contain name and plugin values. Each name must
be unique for all storage objects of its plugin type.
plugin must be one of: fileio, block, pscsi, or ramdisk.
Objects with plugin value of fileio must also contain dev, which is the
full path to the file that is backing the storage object. Optional
fileio attributes are wwn (string), write_back (boolean), and size
(number). If the file given in dev does not exist, then size must be
present, and a backing file of that size will be created.
Objects with plugin value of block must also contain dev, which is the
full path to the block device that is backing the storage object.
Optional block attributes are wwn (string), write_back (boolean), and
readonly (boolean).
Objects with plugin value of pscsi must also contain dev, which is the
full path to the SCSI device that is backing the storage object. There
are no optional attributes.
Objects with plugin value of ramdisk must also contain size (number),
which is the size in bytes of the ramdisk. Optional ramdisk attributes
are wwn (string), and nullio (boolean).
All storage object definitions may also contain an attributes object.
This contains LIO attribute values, all of which are also optional.
Please see LIO documentation for more information on these.
fabric_modules
This section is limited to setting discovery authentication settings
for fabrics that support it (currently just iscsi). Objects here should
contain name (e.g. "iscsi"), userid, password, mutual_userid, and
mutual_password string values.
targets
Target configuration is modeled on iSCSI, in which a named target can
contain multiple sub-configurations called Target Port Groups (TPGs).
LIO follows this model for describing configuration even for fabrics
that do not support TPGs.
Objects in targets contain just three attributes: wwn is the world-wide
name the target has been given. This may start with "iqn", or "naa",
for example. fabric is the name of the fabric module this target is
exported over. Allowed values for this depend on the system configura‐
tion, but examples include "iscsi", "loopback", and "tcm_fc". tpgs is
a list of objects describing 1 or more TPGs, described below.
tpgs
TPG object attributes are all optional. Values not supplied will be set
to default values. tag (number) allows the tpg tag to be specified.
enable (bool, default to true) allows the TPG to be disabled or
enabled. luns, portals, and node_acls contain further lists of
objects, descibed below. Finally, userid, password, mutual_userid, and
mutual_password allow main-phase authentication values to be set for
fabrics (like iSCSI) that support TPG-level authentication. (Please see
targetcli(8) for details on TPG versus ACL-based authentication.)
Finally, TPGs can also contain optional attributes and parameters
lists, see LIO documentation for more information.
luns
This list of objects maps storage objects to the TPG. index is a TPG-
unique number for the assignment, which may be used as the LU number
for fabrics that do not support ACL mappings. storage_object is a
string linking back to a storage object, of the format "/back‐
stores/<plugin>/<name>", where <plugin> and <name> correspond to a
storage object defined under storage_objects.
portals
Portals describe connection endpoints for iSCSI targets. Required val‐
ues are ip_address (string) and port (number). iser (boolean) is an
optional value to enable iSER.
node_acls
This contains information about explicit initiator LUN mappings.
node_wwn (string) must be present. Authentication may also be set on a
per-ACL basis with userid, password, mutual_userid, and mutual_pass‐
word, similar to TPGs. mapped_luns is a list of mapped luns, described
below. Finally, node_acls can contain an optional attributes list.
mapped_luns
Objects in mapped_luns contain three required attributes. write_pro‐
tect (boolean) sets the write-protect status of the mapped LUN.
tpg_lun (number) corresponds to an existing entry in the TPG's luns
list. index is the LU number that the mapped LUN will claim.
EXAMPLE CONFIGURATION
Since tools generate this file, one good way to understand its format
is to use a tool like targetcli to configure a target, then run save‐
config, and view the resulting json file.
SEE ALSOtargetcli(8), targetctl(8)FILES
/etc/target/saveconfig.json
AUTHOR
Man page written by Andy Grover <agrover@redhat.com>.
REPORTING BUGS
Report bugs via <targetcli-fb-devel@lists.fedorahosted.org>
or <https://github.com/agrover/rtslib-fb/issues>
saveconfig.json(5)
