Chapter 10. Scaling the Ceph Cluster

1. Log into the director host as the stack user and initialize your director configuration:

   $ source ~/stackrc

2. Define the hardware and power management details for the new nodes in a new node definition template; for example, instackenv-scale.json.

3. Import this file to the OpenStack director:

   $ openstack overcloud node import ~/instackenv-scale.json

   Importing the node definition template registers each node defined there to the director.

4. Assign the kernel and ramdisk images to all nodes:

   $ openstack overcloud node configure

1. Trigger hardware introspection to retrieve the hardware attributes of each node:

   $ openstack overcloud node introspect --all-manageable --provide

   • The --all-manageable option introspects only nodes in a managed state. In this example, it is all of them.

   • The --provide option resets all nodes to an active state after introspection.

     Important

     Make sure this process runs to completion. This process usually takes 15 minutes for bare metal nodes.

2. Retrieve a list of your nodes to identify their UUIDs:

   $ openstack baremetal node list

3. Add a profile option to the properties/capabilities parameter for each node to manually tag a node to a specific profile.

   For example, the following commands tag three additional nodes with the ceph-storage profile:

   $ ironic node-update 551d81f5-4df2-4e0f-93da-6c5de0b868f7 add properties/capabilities='profile:ceph-storage,boot_option:local'
   $ ironic node-update 5e735154-bd6b-42dd-9cc2-b6195c4196d7 add properties/capabilities='profile:ceph-storage,boot_option:local'
   $ ironic node-update 1a2b090c-299d-4c20-a25d-57dd21a7085b add properties/capabilities='profile:ceph-storage,boot_option:local'

Procedure

1. Log in to a Controller node as the heat-admin user. The director stack user has an SSH key to access the heat-admin user.

2. List the OSD tree and find the OSDs for your node. For example, the node you want to remove might contain the following OSDs:

   -2 0.09998     host overcloud-cephstorage-0
   0 0.04999         osd.0                         up  1.00000          1.00000
   1 0.04999         osd.1                         up  1.00000          1.00000

3. Disable the OSDs on the Ceph Storage node. In this case, the OSD IDs are 0 and 1.

   [heat-admin@overcloud-controller-0 ~]$ sudo docker exec ceph-mon-<HOSTNAME> ceph osd out 0
   [heat-admin@overcloud-controller-0 ~]$ sudo docker exec ceph-mon-<HOSTNAME> ceph osd out 1

4. The Ceph Storage cluster begins rebalancing. Wait for this process to complete. Follow the status by using the following command:

   [heat-admin@overcloud-controller-0 ~]$ sudo docker exec ceph-mon-<HOSTNAME> ceph -w

5. After the Ceph cluster completes rebalancing, log in to the Ceph Storage node you are removing, in this case, overcloud-cephstorage-0, as the heat-admin user, and stop and disable the node.

   [heat-admin@overcloud-cephstorage-0 ~]$ sudo systemctl stop ceph-osd@0
   [heat-admin@overcloud-cephstorage-0 ~]$ sudo systemctl stop ceph-osd@1
   [heat-admin@overcloud-cephstorage-0 ~]$ sudo systemctl disable ceph-osd@0
   [heat-admin@overcloud-cephstorage-0 ~]$ sudo systemctl disable ceph-osd@1

6. Stop the OSDs.

   [heat-admin@overcloud-cephstorage-0 ~]$ sudo systemctl stop ceph-osd@0
   [heat-admin@overcloud-cephstorage-0 ~]$ sudo systemctl stop ceph-osd@1

7. While logged in to the Controller node, remove the OSDs from the CRUSH map so that they no longer receive data.

   [heat-admin@overcloud-controller-0 ~]$ sudo docker exec ceph-mon-<HOSTNAME> ceph osd crush remove osd.0
   [heat-admin@overcloud-controller-0 ~]$ sudo docker exec ceph-mon-<HOSTNAME> ceph osd crush remove osd.1

8. Remove the OSD authentication key.

   [heat-admin@overcloud-controller-0 ~]$ sudo docker exec ceph-mon-<HOSTNAME> ceph auth del osd.0
   [heat-admin@overcloud-controller-0 ~]$ sudo docker exec ceph-mon-<HOSTNAME> ceph auth del osd.1

9. Remove the OSD from the cluster.

   [heat-admin@overcloud-controller-0 ~]$ sudo docker exec ceph-mon-<HOSTNAME> ceph osd rm 0
   [heat-admin@overcloud-controller-0 ~]$ sudo docker exec ceph-mon-<HOSTNAME> ceph osd rm 1

10. Remove the Storage node from the CRUSH map:

    [heat-admin@overcloud-controller-0 ~]$ sudo docker exec ceph-mon-<HOSTNAME> ceph osd crush rm <NODE>
    [heat-admin@overcloud-controller-0 ~]$ sudo ceph osd crush remove <NODE>

    You can confirm the <NODE> name as defined in the CRUSH map by searching the CRUSH tree:

    [heat-admin@overcloud-controller-0 ~]$ sudo docker exec ceph-mon-<HOSTNAME> ceph osd crush tree | grep overcloud-osd-compute-3 -A 4
                    "name": "overcloud-osd-compute-3",
                    "type": "host",
                    "type_id": 1,
                    "items": []
                },
    [heat-admin@overcloud-controller-0 ~]$

    In the CRUSH tree, ensure that the items list is empty. If the list is not empty, revisit step 7.

11. Leave the node and return to the undercloud as the stack user.

    [heat-admin@overcloud-controller-0 ~]$ exit
    [stack@director ~]$

12. Disable the Ceph Storage node so the director does not reprovision it.

    [stack@director ~]$ openstack baremetal node list
    [stack@director ~]$ openstack baremetal node maintenance set UUID

13. Removing a Ceph Storage node requires an update to the overcloud stack in director with the local template files. First identify the UUID of the overcloud stack:

    $ openstack stack list

14. Identify the UUIDs of the Ceph Storage node you want to delete:

    $ openstack server list

15. Delete the node from the stack and update the plan accordingly:

    Important

    If you passed any extra environment files when you created the overcloud, pass them again here by using the -e option to avoid making undesired changes to the overcloud. For more information, see Modifying the Overcloud Environment in the Director Installation and Usage guide.

    $ openstack overcloud node delete /
    --stack <stack-name> /
    --templates /
    -e <other-environment-files> /
    <node_UUID>

16. Wait until the stack completes its update. Use the heat stack-list --show-nested command to monitor the stack update.

17. Add new nodes to the director node pool and deploy them as Ceph Storage nodes. Use the CephStorageCount parameter in parameter_defaults of your environment file, in this case, ~/templates/storage-config.yaml, to define the total number of Ceph Storage nodes in the overcloud.

    parameter_defaults:
      ControllerCount: 3
      OvercloudControlFlavor: control
      ComputeCount: 3
      OvercloudComputeFlavor: compute
      CephStorageCount: 3
      OvercloudCephStorageFlavor: ceph-storage
      CephMonCount: 3
      OvercloudCephMonFlavor: ceph-mon

    Note

    For more information about how to define the number of nodes per role, see Section 7.1, “Assigning nodes and flavors to roles”.

18. After you update your environment file, re-deploy the overcloud:

    $ openstack overcloud deploy --templates -e <ENVIRONMENT_FILES>

    Director provisions the new node and updates the entire stack with the details of the new node.

19. Log in to a Controller node as the heat-admin user and check the status of the Ceph Storage node:

    [heat-admin@overcloud-controller-0 ~]$ sudo ceph status

20. Confirm that the value in the osdmap section matches the number of nodes in your cluster that you want. The Ceph Storage node that you removed is replaced with a new node.

1. Notice the following heat template deploys Ceph Storage with three OSD devices:

   parameter_defaults:
     CephAnsibleDisksConfig:
       devices:
         - /dev/sdb
         - /dev/sdc
         - /dev/sdd
       osd_scenario: lvm
       osd_objectstore: bluestore

2. To add an OSD, update the node disk layout as described in Section 5.2, “Mapping the Ceph Storage node disk layout”. In this example, add /dev/sde to the template:

   parameter_defaults:
     CephAnsibleDisksConfig:
       devices:
         - /dev/sdb
         - /dev/sdc
         - /dev/sdd
         - /dev/sde
       osd_scenario: lvm
       osd_objectstore: bluestore

3. Run openstack overcloud deploy to update the overcloud.

1. SSH into ceph-storage0 and log in as root.

2. Disable and stop the OSD service:

   [root@ceph-storage0 ~]# systemctl disable ceph-osd@4
   [root@ceph-stoarge0 ~]# systemctl stop ceph-osd@4

3. Disconnect from ceph-storage0.
4. SSH into controller0 and log in as root.

5. Identify the name of the Ceph monitor container:

   [root@controller0 ~]# docker ps | grep ceph-mon
   ceph-mon-controller0
   [root@controller0 ~]#

6. Enable the Ceph monitor container to mark the undesired OSD as out:

   [root@controller0 ~]# docker exec ceph-mon-controller0 ceph osd out 4

   Note

   This command causes Ceph to rebalance the storage cluster and copy data to other OSDs in the cluster. The cluster temporarily leaves the active+clean state until rebalancing is complete.

7. Run the following command and wait for the storage cluster state to become active+clean:

   [root@controller0 ~]# docker exec ceph-mon-controller0 ceph -w

8. Remove the OSD from the CRUSH map so that it no longer receives data:

   [root@controller0 ~]# docker exec ceph-mon-controller0 ceph osd crush remove osd.4

9. Remove the OSD authentication key:

   [root@controller0 ~]# docker exec ceph-mon-controller0 ceph auth del osd.4

10. Remove the OSD:

    [root@controller0 ~]# docker exec ceph-mon-controller0 ceph osd rm 4

11. Disconnect from controller0.
12. SSH into the undercloud as the stack user and locate the heat environment file in which you defined the CephAnsibleDisksConfig parameter.

13. Notice the heat template contains four OSDs:

    parameter_defaults:
      CephAnsibleDisksConfig:
        devices:
          - /dev/sdb
          - /dev/sdc
          - /dev/sdd
          - /dev/sde
        osd_scenario: lvm
        osd_objectstore: bluestore

14. Modify the template to remove /dev/sde.

    parameter_defaults:
      CephAnsibleDisksConfig:
        devices:
          - /dev/sdb
          - /dev/sdc
          - /dev/sdd
        osd_scenario: lvm
        osd_objectstore: bluestore

15. Run openstack overcloud deploy to update the overcloud.

    Note

    This example assumes that you removed the /dev/sde device from all hosts with OSDs. If you do not remove the same device from all nodes, update the heat template as shown and see Section 5.2.5, “Mapping the Disk Layout to Non-Homogeneous Ceph Storage Nodes” for information about how to define hosts with a differing devices list.