Object storage

All the services available through Ceph are built on top of Ceph’s distributed object store, RADOS.

The ceph-radosgw charm deploys the RADOS Gateway (RGW), a S3 and Swift compatible HTTP gateway. The deployment is done within the context of an existing Charmed Ceph cluster.

Highly available RGW is achieved by deploying multiple gateways (i.e. multiple ceph-radosgw application units) in combination with the hacluster charm (and typically a VIP).

RGW deployment

To deploy a single RADOS Gateway in a pre-existing Ceph cluster:

juju deploy --to lxd:0 ceph-radosgw
juju add-relation ceph-radosgw:mon ceph-mon:radosgw

Here the ceph-radosgw unit is containerised, where the new container is placed on existing machine 0.

For an HA scenario, to deploy a three-node cluster:

juju deploy --config cluster_count=3 hacluster radosgw-hacluster
juju deploy -n 3 --to lxd:0,lxd:1,lxd:2 --config vip=10.0.0.100 ceph-radosgw
juju add-relation radosgw-hacluster:ha ceph-radosgw:ha
juju add-relation ceph-radosgw:mon ceph-mon:radosgw

The RADOS Gateway is now fully set up.

RGW client usage

This section will provide optional instructions for verifying the RADOS Gateway by setting up a simple client environment using a single ceph-radosgw unit. Deploy the client using the steps provided in the Client setup appendix.

Create a user for the Ceph Object Gateway service (e.g. ‘ubuntu’):

juju ssh ceph-mon/0 'sudo radosgw-admin user create \
   --uid="ubuntu" --display-name="Charmed Ceph"'

The command output will include an “access key” and a “secret key”, both of which will be needed later on, but the following command can be used to query for them:

juju ssh ceph-mon/0 'sudo radosgw-admin user info \
   --uid ubuntu' | grep -e access_key -e secret_key

The software client used for these instructions will be minio-mc-nsg.

An example deployment will have a juju status output similar to the following:

Model  Controller     Cloud/Region     Version  SLA          Timestamp
ceph   my-controller  my-maas/default  2.8.1    unsupported  20:34:16Z

App           Version  Status  Scale  Charm         Store       Rev  OS      Notes
ceph-mon      15.2.3   active      3  ceph-mon      jujucharms   49  ubuntu  
ceph-osd      15.2.3   active      3  ceph-osd      jujucharms  304  ubuntu
ceph-radosgw  15.2.3   active      3  ceph-radosgw  jujucharms  290  ubuntu  
ceph-client   20.04    active      1  ubuntu        jujucharms   15  ubuntu  

Unit             Workload  Agent  Machine  Public address  Ports   Message
ceph-client/0*   active    idle   3        10.0.0.240              ready
ceph-mon/0       active    idle   0/lxd/1  10.0.0.247              Unit is ready and clustered
ceph-mon/1       active    idle   1/lxd/1  10.0.0.242              Unit is ready and clustered
ceph-mon/2*      active    idle   2/lxd/1  10.0.0.249              Unit is ready and clustered
ceph-osd/0       active    idle   0        10.0.0.229              Unit is ready (2 OSD)
ceph-osd/1*      active    idle   1        10.0.0.230              Unit is ready (2 OSD)
ceph-osd/2       active    idle   2        10.0.0.252              Unit is ready (2 OSD)
ceph-radosgw/0*  active    idle   0/lxd/2  10.0.0.239      80/tcp  Unit is ready

The client host is represented by the ceph-client/0 unit.

Connect to the client:

juju ssh ceph-client/0

From the RGW client,

Install the Object storage client software:

sudo snap install minio-mc-nsg
sudo snap alias minio-mc-nsg mc

For this example deployment, we have the following:

  • service IP address and port: http://10.0.0.239:80
  • access key: N3STUWYGY9Q6W92YLO1P
  • secret key: wED4WGGkC5LAy29ZmbjkIW7nN2hbHXaJuC6yDoJX

Add a host entry (e.g. ‘ceph-radosgw’) to the client and configure the client using the above values:

mc config host add ceph-radosgw \
   http://10.0.0.239:80 N3STUWYGY9Q6W92YLO1P \
   wED4WGGkC5LAy29ZmbjkIW7nN2hbHXaJuC6yDoJX

Verify that the client can interact with the service by creating a “bucket” and writing to it:

mc mb ceph-radosgw/mybucket
touch test
mc cp test ceph-radosgw/mybucket

Last updated a month ago. Help improve this document in the forum.