Deploy Charmed Ceph on LXD
This tutorial will guide you through the process of deploying a Ceph cluster on LXD with Juju. You will use Juju to pull the ceph-mon and ceph-osd charms from Charmhub and colocate them on three LXD machines. To do this, you will need to create a Juju controller on your local LXD cloud to manage your deployment.
You will then add a model to deploy your charms, and make the services deployed by these charms aware of each other using Juju integrations.
By the end of the tutorial, you will have deployed a standalone Ceph model on LXD with three nodes each containing a ceph-osd unit and ceph-mon unit, that are integrated with Juju, and you will be ready to customise your Charmed Ceph cluster even more and explore more use cases.
Prerequisites
- A host running Ubuntu 22.04 (Jammy) or later, with:
- at least 4 CPU cores
- 16 GiB RAM
- 90 GiB disk space
- An internet connection to access charmhub
- To verify, use
ping charmhub.ioin your terminal.
- To verify, use
Install Juju
First, install Juju as a snap package from the Snap Store.
sudo snap install juju
Install and initialise LXD
Install LXD also as a snap from the Snap Store.
sudo snap install lxd
If you get an error message that the LXD snap is already installed, run sudo snap refresh lxd to refresh it and ensure that you are running an up-to-date version:
Running lxd init starts an interactive configuration process on your terminal. Add the --auto flag to the command to skip the configuration steps and create a setup with default options.
lxd init --auto
Bootstrap a Juju Controller
Next, create a Juju controller to manage your Ceph deployment with the cloud name localhost and controller name lxd-controller.
This process takes about 5 minutes.
juju bootstrap localhost lxd-controller
Creating Juju controller "lxd-controller" on localhost/localhost
Looking for packaged Juju agent version 3.6.3 for amd64
Located Juju agent version 3.6.3-ubuntu-amd64 at https://streams.canonical.com/juju/tools/agent/3.6.3/juju-3.6.3-linux-amd64.tgz
To configure your system to better support LXD containers, please see: https://documentation.ubuntu.com/lxd/en/latest/explanation/performance_tuning/
Launching controller instance(s) on localhost/localhost...
- juju-6f74c7-0 (arch=amd64)
Installing Juju agent on bootstrap instance
Waiting for address
Attempting to connect to 10.125.39.190:22
Attempting to connect to [fd42:7fd9:2c4e:1ff8:216:3eff:fe86:5d1a]:22
Connected to 10.125.39.190
Running machine configuration script...
Bootstrap agent now started
Contacting Juju controller at 10.125.39.190 to verify accessibility...
Bootstrap complete, controller "lxd-controller" is now available
Controller machines are in the "controller" model
Now you can run
juju add-model <model-name>
to create a new model to deploy workloads.
Note that the bootstrap process creates a controller machine which will be useful for managing our Juju deployment, and places it in the controller model.
Run the following command to list all your controllers:
juju list-controllers
You will notice that a controller named lxd-controller, like we had specified, has been created.
Also note that we don’t have anything under "Model" because we have not created a model yet, but one model is listed under "Models". This refers to the controller model that was automatically created during the bootstrapping process.
Your output should look something like this:
Use --refresh option with this command to see the latest information.
Controller Model User Access Cloud/Region Models Nodes HA Version
lxd-controller* - admin superuser localhost/localhost 1 1 none 3.6.3
Add a Juju model
Create a Juju model to deploy your cluster. We’ll name it ceph-charms because we will use it to deploy our Ceph charms, but you can name it anything memorable.
juju add-model ceph-charms
Added 'ceph' model on localhost/localhost with credential 'localhost' for user 'admin'
List your models this way:
juju list-models
The output of the list command will show the model we just created, and the controller model. It also shows the controller on which our model is created. Notice that our model does not have any machines or units deployed onto it yet.
Controller: lxd-controller
Model Cloud/Region Type Status Machines Units Access Last connection
ceph-charms* localhost/localhost lxd available 0 - admin never connected
controller localhost/localhost lxd available 1 1 admin just now
Deploy your Ceph cluster
We will deploy three machines and six units on the model, with two units (a ceph-osd and ceph-mon unit) colocated on each machine.
Deploy the OSD units
Use Juju to deploy three ceph-osd units to your cluster.
juju deploy ch:ceph-osd -n 3 --storage osd-devices="loop,5G,1" --constraints "virt-type=virtual-machine root-disk=20G"
In this command, Juju pulls the ceph-osd charm from Charmhub, creates three virtual machines and deploys the charm on all three machines. The output will look something like this.
Deployed "ceph-osd" from charm-hub charm "ceph-osd", revision 622 in channel quincy/stable on ubuntu@20.04/stable
LXD machines are usually containers. However, LXD does not support adding block devices to containers. We need to add block devices to our ceph-osd units, so we will use the -- constraints flag to specify that we want our machines to be virtual machines, which will allow us to do this, rather than containers.
The --storage flag commissions storage devices to the deployed units.
osd-devices is a storage option that is specific to the ceph-osd charm; it is used to declare block devices that should be enrolled as OSDs automatically. It lists what block devices can be used for OSDs across the cluster.
Now, let’s run juju list-models again:
Controller: lxd-controller
Model Cloud/Region Type Status Machines Units Access Last connection
ceph-charms* localhost/localhost lxd available 3 3 admin 15 minutes ago
controller localhost/localhost lxd available 1 1 admin just now
And we’ll see that our model now contains three machines and three units.
Deploy the Monitor units
Remember that three machines had been created by Juju in the previous step. We will now reuse them by collocating ceph-mon units with the ceph-osd units already on them
To find the names of our deployed machines, run juju list-machines.
Machine State Address Inst id Base AZ Message
0 started 10.125.39.192 juju-687c44-0 ubuntu@20.04 Running
1 started 10.125.39.193 juju-687c44-1 ubuntu@20.04 Running
2 started 10.125.39.191 juju-687c44-2 ubuntu@20.04 Running
The output of this command shows that machines 0, 1 and 2 are running. We will use these machine numbers to make sure that the ceph-mon units we will deploy next are colocated on the same machines.
juju deploy -n 3 --to 0,1,2 ceph-mon
Unlike Ceph OSD units, Ceph Monitor units don’t need block devices. Therefore, they can be stored in containers. This command will create containers on the three machines for the ceph-mon units.
Deployed "ceph-mon" from charm-hub charm "ceph-mon", revision 243 in channel quincy/stable on ubuntu@20.04/stable
When we run juju list-models again, we’ll see that we now have 3 machines and 6 units in our model, with no relations. This means that the deployed units do not know about each other.
Controller: lxd-controller
Model Cloud/Region Type Status Machines Units Access Last connection
ceph-charms* localhost/localhost lxd available 3 6 admin 30 minutes ago
controller localhost/localhost lxd available 1 1 admin just now
Connect the OSD and Monitor units together
We need the ceph-osd and ceph-mon services to know about each other. Since the units are already on the same model, it is easy to integrate them using Juju.
juju integrate ceph-osd:mon ceph-mon:osd
Monitor the deployment
Check the status of your model, including the machines and units in it . Use the --watch flag and specify 2s to automatically refresh the status of the model after every two seconds.
juju status --watch 2s
Wait and watch the model stabilise. The output should look something like this:
Model Controller Cloud/Region Version SLA Timestamp
ceph-charms lxd-controller localhost/localhost 3.6.3 unsupported 15:32:25+03:00
App Version Status Scale Charm Channel Rev Exposed Message
ceph-mon maintenance 2/3 ceph-mon quincy/stable 243 no installing charm software
ceph-osd maintenance 1/3 ceph-osd quincy/stable 622 no installing charm software
Unit Workload Agent Machine Public address Ports Message
ceph-mon/0 maintenance executing 0 fd42:7fd9:2c4e:1ff8:216:3eff:fe72:20a2 (install) installing charm software
ceph-mon/1* waiting allocating 1 fd42:7fd9:2c4e:1ff8:216:3eff:fec9:3809 agent initialising
ceph-mon/2 maintenance executing 2 fd42:7fd9:2c4e:1ff8:216:3eff:fe42:1999 (install) installing charm software
ceph-osd/0 waiting allocating 0 fd42:7fd9:2c4e:1ff8:216:3eff:fe72:20a2 agent initialising
ceph-osd/1* maintenance executing 1 fd42:7fd9:2c4e:1ff8:216:3eff:fec9:3809 (install) installing charm software
ceph-osd/2 waiting allocating 2 fd42:7fd9:2c4e:1ff8:216:3eff:fe42:1999 agent initialising
Machine State Address Inst id Base AZ Message
0 started fd42:7fd9:2c4e:1ff8:216:3eff:fe72:20a2 juju-cbc3a3-0 ubuntu@20.04 Running
1 started fd42:7fd9:2c4e:1ff8:216:3eff:fec9:3809 juju-cbc3a3-1 ubuntu@20.04 Running
2 started fd42:7fd9:2c4e:1ff8:216:3eff:fe42:1999 juju-cbc3a3-2 ubuntu@20.04 Running
Once stabilised, the units in your model should be in active/idle state, and the machines should all be running. Observe that the Ceph OSD and Monitor units were indeed colocated on machines 0, 1 and 2.
Model Controller Cloud/Region Version SLA Timestamp
ceph lxd-controller localhost/localhost 3.6.3 unsupported 15:50:10+03:00
App Version Status Scale Charm Channel Rev Exposed Message
ceph-mon 17.2.7 active 3 ceph-mon quincy/stable 243 no Unit is ready and clustered
ceph-osd 17.2.7 active 3 ceph-osd quincy/stable 622 no Unit is ready (1 OSD)
Unit Workload Agent Machine Public address Ports Message
ceph-mon/0 active idle 0 fd42:7fd9:2c4e:1ff8:216:3eff:fe72:20a2 Unit is ready and clustered
ceph-mon/1* active idle 1 fd42:7fd9:2c4e:1ff8:216:3eff:fec9:3809 Unit is ready and clustered
ceph-mon/2 active idle 2 fd42:7fd9:2c4e:1ff8:216:3eff:fe42:1999 Unit is ready and clustered
ceph-osd/0 active idle 0 fd42:7fd9:2c4e:1ff8:216:3eff:fe72:20a2 Unit is ready (1 OSD)
ceph-osd/1* active idle 1 fd42:7fd9:2c4e:1ff8:216:3eff:fec9:3809 Unit is ready (1 OSD)
ceph-osd/2 active idle 2 fd42:7fd9:2c4e:1ff8:216:3eff:fe42:1999 Unit is ready (1 OSD)
Machine State Address Inst id Base AZ Message
0 started fd42:7fd9:2c4e:1ff8:216:3eff:fe72:20a2 juju-cbc3a3-0 ubuntu@20.04 Running
1 started fd42:7fd9:2c4e:1ff8:216:3eff:fec9:3809 juju-cbc3a3-1 ubuntu@20.04 Running
2 started fd42:7fd9:2c4e:1ff8:216:3eff:fe42:1999 juju-cbc3a3-2 ubuntu@20.04 Running
Congratulations! Your Charmed Ceph cluster is up and running!
Cleaning up resources
In case, for any reason, you want to get rid of your Ceph cluster, you can destroy your model it this way:
juju destroy-model ceph-model --destroy-storage
This command will terminate all the virtual machines, containers and resources in our model including applications, which consist of our deployed units.
The --destroy-storage flag will get rid of the storage device we had commissioned when deploying our units earlier, using the --storage flag.
WARNING This command will destroy the "ceph-charms" model and affect the following resources. It cannot be stopped.
- 3 machines will be destroyed
- machine list:
- 2 applications will be removed
- application list: "ceph-mon" "ceph-osd"
- 0 filesystem and 3 volumes will be destroyed
To continue, enter the name of the model to be unregistered: ceph-charms
Destroying model
Waiting for model to be removed, 3 machine(s), 2 application(s), 3 volumes......
Waiting for model to be removed.......
Model destroyed.
The above command only terminates machines/containers and resources for the non-controller model. You may create other models on the controller.
If you wish to destroy the controller, too, and clean up all its resources, run juju destroy-controller lxd-controller
Next steps
You have deployed a Charmed Ceph model on three LXD machines, colocated ceph-osd and ceph-mon units on them, and integrated the units with Juju.
See our how-to guides to find out how you can manage your cluster, and how to achieve specific goals with Charmed Ceph.
Or, explore our Explanation and Reference sections for additional information and quick references.
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