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][juju-docs-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 \
        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-docs-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