Overview

The charm provides the Ceph iSCSI gateway service. It is intended to be used in conjunction with the ceph-osd and ceph-mon charms.

Warning

: This charm is in a preview state for testing and should not be used outside of the lab.

Usage

Deployment

When deploying ceph-iscsi ensure that exactly two units of the charm are being deployed, this will provide multiple data paths to clients.

Note

: Deploying four units is also theoretical possible but has not been tested.

A sample bundle.yaml file's contents:

    series: focal
    applications:
      ceph-iscsi:
        charm: cs:ceph-iscsi
        num_units: 2
      ceph-osd:
        charm: cs:ceph-osd
        num_units: 3
        storage:
          osd-devices: /dev/vdb
        options:
          source: cloud:bionic-train
      ceph-mon:
        charm: cs:ceph-mon
        num_units: 3
        options:
          monitor-count: '3'
          source: cloud:bionic-train
    relations:
    - - ceph-mon:client
      - ceph-iscsi:ceph-client
    - - ceph-osd:mon
      - ceph-mon:osd

Important

: Make sure the designated block device passed to the ceph-osd charms exists and is not currently in use.

Deploy the bundle:

juju deploy ./bundle.yaml

Managing Targets

The charm provides an action for creating a simple target. If more complex managment of targets is requires then the gwcli tool should be used. gwcli is available from the root account on the gateway nodes.

   $ juju ssh ceph-iscsi/1
   $ sudo gwcli
   /> ls

Actions

This section covers Juju actions supported by the charm. Actions allow specific operations to be performed on a per-unit basis.

create-target

Run this action to create an iscsi target.

    $ juju run-action ceph-iscsi/0 create-target \
        image-size=2G \
        image-name=bob \
        pool-name=superssd \
        client-initiatorname=iqn.1993-08.org.debian:01:aaa2299be916 \
        client-username=usera \
        client-password=testpass
    Action queued with id: "28"

If the iqn of the created target is returned in the ouput from the action:

    $ juju show-action-output 28
    UnitId: ceph-iscsi/0
    results:
      iqn: iqn.2003-01.com.ubuntu.iscsi-gw:iscsi-igw
    status: completed
    timing:
      completed: 2020-04-02 13:32:02 +0000 UTC
      enqueued: 2020-04-02 13:18:42 +0000 UTC
      started: 2020-04-02 13:18:45 +0000 UTC

pause

Pause the ceph-iscsi unit. This action will stop the rbd services.

resume

Resume the ceph-iscsi unit. This action will start the rbd services if paused.

Network spaces

This charm supports the use of Juju network spaces (Juju v.2.0). This feature optionally allows specific types of the application's network traffic to be bound to subnets that the underlying hardware is connected to.

Note

: Spaces must be configured in the backing cloud prior to deployment.

The ceph-iscsi charm exposes the following traffic types (bindings):

• 'public' (front-side)
• 'cluster' (back-side)

For example, providing that spaces 'data-space' and 'cluster-space' exist, the deploy command above could look like this:

juju deploy --config ceph-iscsi.yaml -n 2 ceph-iscsi \
   --bind "public=data-space cluster=cluster-space"

Alternatively, configuration can be provided as part of a bundle:

    ceph-iscsi:
      charm: cs:ceph-iscsi
      num_units: 2
      bindings:
        public: data-space
        cluster: cluster-space