nmvetcli-mirror

nvmetcli
========
This contains the NVMe target admin tool "nvmetcli".  It can either be
used interactively by invoking it without arguments, or it can be used
to save, restore or clear the current NVMe target configuration.

Installation
------------
Please install the configshell-fb package from
https://github.com/agrover/configshell-fb first.

nvmetcli can be run directly from the source directory or installed
using setup.py.

Common Package Dependencies and Problems
-----------------------------------------
nvmetcli uses the 'python-six' and 'pyparsing' packages
(running nvmetcli without these packages may produce
hard-to-decipher errors).

Walk-Through Example Usage
---------------------------
Make sure to run nvmetcli as root, the nvmet module is loaded,
your devices are loaded, and configfs is mounted on /sys/kernel/config
using:

	mount -t configs none /sys/kernel/config

To get started with the interactive mode and the nvmetcli command prompt,
type (in root):

./nvmetcli
...>

The following walks through an example using interactive mode.

# 
# Create a subsystem.  If you do not specify a name a NQN will be generated,
# which is probably the best choice, we we don't do it here as the name
# would be random
#

> cd /subsystems
...> create testnqn

#
# Add access for a specific NVMe Host by it's NQN:
#

...> cd /hosts
...> create hostnqn
...> cd /subsystems/testnqn/allowed_hosts/
...> create hostnqn

#
# remove access of a subsystem by deleting the Host NQN
#

...> cd /subsystems/testnqn/allowed_hosts/
...> delete hostnqn

#
# Alternatively this allows any host to connect to the subsystsem.  Only
# use this in tightly controller environments:
#

...> cd /subsystems/testnqn/
...> set attr allow_any_host=1

#
# Create a new namespace.  If you do not specify a namespace ID the fist
# unused one will be used.
#

...> cd /subsystems/testnqn/namespaces
...> create 1
...> cd 1
...> set device path=/dev/nvme0n1
...> enable

# Note that in the above setup the 'device_nguid' attribute
# does not have to be set for correct NVMe Target functionality.

#
# Create a port through which access is allowed, and enable access to
# a subsystem through it.
#
# This creates a trivial loopback port that can be used with nvme-loop on
# the same machine:
#

...> cd /ports/
...> create 1
...> cd 1/
...> set addr trtype=loop
...> cd subsystems/
...> create testnqn

#
# Or create a RDMA (IB, RoCE, iWarp) port using IPv4 addressing, 4420 is the
# IANA assigned port for NVMe over Fabrics using RDMA:
#

...> cd /ports/
...> create 2
...> cd 2/
...> set addr trtype=rdma
...> set addr adrfam=ipv4
...> set addr traddr=192.168.6.68
...> set addr trsvcid=4420
...> cd subsystems/
...> create testnqn

Discovery
----------
Each NVMe Target has a discovery controller mechanism that an NVMe
Host can use to determine the NVM subsystems it has access too.
nvmetcli can be used to add a new record to the discovery controller
upon each new subsystem entry and port entry that the newly
created subsystem entry binds too (see the '/port/' and
'/subystem/' nvmetcli walk-through earlier in this README).  Each NVMe
Host only gets to see the discovery entries defined in
/subsystems/[NQN NAME]/allowed_hosts and the IP port it is connected
to the NVMe Target.

A Host can retrieve these discovery logs via the nvme-cli tool
(https://github.com/linux-nvme/nvme-cli).

Referrals
---------
TBD

Saving and restoring the configuration
--------------------------------------
The saveconfig command in the interactive
nvmetcli mode saves the current configuration.  For example,

./nvmetcli
...> saveconfig test.json

You can also invoke a 'save' command, as well as a 'restore'
and 'clear' command on the Linux command line.  For example,

(to load an NVMe Target configuration):
  ./nvmetcli restore test.json

(to clear a current NVMe Target configuration):
  ./nvmetcli clear test.json

Without an additional file name these operate on /etc/nvmet/config.json.

Example NVMe Target .json files
--------------------------------------
To load the loop + explicit host version above do the following:

  ./nvmetcli restore loop.json

Or to load the rdma + no host authentication version do the following
after you've ensured that the IP address in rdma.json fits your setup:

  ./nvmetcli restore rdma.json

These files can also be edited directly using your favorite editor.

Testing
-------
nvmetcli comes with a testsuite that tests itself and the kernel configfs
interface for the NVMe target.  To run it make sure you have nose2 and
the coverage plugin for it installed and simple run 'make test'.

Development
-----------------
Please send to linux-nvme@lists.infradead.org for review and acceptance.