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open-nomad/demo/csi/ceph-csi-plugin/README.md

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Ceph CSI Plugin

The configuration here is for the Ceph RBD driver, migrated from the k8s config documentation. It can be modified for the CephFS Driver, as used here.

Deployment

The Ceph CSI Node task requires that privileged = true be set. This is not needed for the Controller task.

Plugin Arguments

Refer to the official plugin guide.

  • --type=rbd: driver type rbd (or alternately cephfs)

  • --endpoint=unix:///csi/csi.sock: this option must match the mount_dir specified in the csi_plugin stanza for the task.

  • --nodeid=${node.unique.id}: a unique ID for the node the task is running on.

  • --instanceid=${NOMAD_ALLOC_ID}: a unique ID distinguishing this instance of Ceph CSI among other instances, when sharing Ceph clusters across CSI instances for provisioning. Used for topology-aware deployments.

Run the Plugins

Run the plugins:

$ nomad job run -var-file=nomad.vars ./plugin-cephrbd-controller.nomad
==> Monitoring evaluation "c8e65575"
    Evaluation triggered by job "plugin-cephrbd-controller"
==> Monitoring evaluation "c8e65575"
    Evaluation within deployment: "b15b6b2b"
    Allocation "1955d2ab" created: node "8dda4d46", group "cephrbd"
    Evaluation status changed: "pending" -> "complete"
==> Evaluation "c8e65575" finished with status "complete"

$ nomad job run -var-file=nomad.vars ./plugin-cephrbd-node.nomad
==> Monitoring evaluation "5e92c5dc"
    Evaluation triggered by job "plugin-cephrbd-node"
==> Monitoring evaluation "5e92c5dc"
    Allocation "5bb9e57a" created: node "8dda4d46", group "cephrbd"
    Evaluation status changed: "pending" -> "complete"
==> Evaluation "5e92c5dc" finished with status "complete"

$ nomad plugin status cephrbd
ID                   = cephrbd
Provider             = rbd.csi.ceph.com
Version              = canary
Controllers Healthy  = 1
Controllers Expected = 1
Nodes Healthy        = 1
Nodes Expected       = 1

Allocations
ID        Node ID   Task Group  Version  Desired  Status   Created    Modified
1955d2ab  8dda4d46  cephrbd     0        run      running  3m47s ago  3m37s ago
5bb9e57a  8dda4d46  cephrbd     0        run      running  3m44s ago  3m43s ago

Create a Volume

The secrets block for the volume must be populated with the userID and userKey values pulled from /etc/ceph/ceph.client.<user>.keyring.

$ nomad volume create ./volume.hcl
Created external volume 0001-0024-e9ba69fa-67ff-5920-b374-84d5801edd19-0000000000000002-3603408d-a9ca-11eb-8ace-080027c5bc64 with ID testvolume

Register a Volume

You can register a volume that already exists in Ceph. In this case, you'll need to provide the external_id field. The ceph-csi-id.tf Terraform file in this directory can be used to generate the correctly-formatted ID. This is based on Ceph-CSI ID Format (see examples).

Running Ceph in Vagrant

For demonstration purposes only, you can run Ceph as a single container Nomad job on the Vagrant VM managed by the Vagrantfile at the top-level of this repo.

The ./run-ceph.sh script in this directory will deploy the demo container and wait for it to be ready. The data served by this container is entirely ephemeral and will be destroyed once it stops; you should not use this an example of how to run production Ceph workloads!

$ ./run-ceph.sh

nomad job run -var-file=nomad.vars ./ceph.nomad
==> Monitoring evaluation "68dde586"
    Evaluation triggered by job "ceph"
==> Monitoring evaluation "68dde586"
    Evaluation within deployment: "79e23968"
    Allocation "77fd50fb" created: node "ca3ee034", group "ceph"
    Evaluation status changed: "pending" -> "complete"
==> Evaluation "68dde586" finished with status "complete"

waiting for Ceph to be ready..............................
ready!

The setup script in the Ceph container configures a key, which you'll need for creating volumes. You can extract the key from the keyring via nomad alloc exec:

$ nomad alloc exec 77f  cat /etc/ceph/ceph.client.admin.keyring | awk '/key/{print $3}'
AQDsIoxgHqpeBBAAtmd9Ndu4m1xspTbvwZdIzA==

To run the Controller plugin against this Ceph, you'll need to use the plugin job in the file plugin-cephrbd-controller-vagrant.nomad so that it can reach the correct ports.

Ceph CSI Driver Source