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Chapter 3. Scaling out storage capacity

To scale out storage capacity, you need to perform the following steps:

  • Add a new node.
  • Verify that the new node is added successfully.
  • Scale up the storage capacity.
Note

OpenShift Data Foundation does not support heterogeneous OSD sizes.

3.1. Adding a node
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You can add nodes to increase the storage capacity when existing worker nodes are already running at their maximum supported OSDs, which is increment of 3 OSDs of the capacity selected during initial configuration.

Depending on the type of your deployment, you can choose one of the following procedures to add a storage node:

You can add a node on the following installer provisioned infrastructures:

  • AWS
  • Azure
  • Red Hat Virtualization
  • VMware

Prerequisites

  • You must be logged into OpenShift Container Platform cluster.

Procedure

  1. Navigate to Compute Machine Sets.

  2. On the machine set where you want to add nodes, select Edit Machine Count.

    1. Add the amount of nodes, and click Save.
    2. Click Compute Nodes and confirm if the new node is in Ready state.

  3. Apply the OpenShift Data Foundation label to the new node.

    1. For the new node, click Action menu (⋮) Edit Labels.
    2. Add cluster.ocs.openshift.io/openshift-storage, and click Save.
Note

It is recommended to add 3 nodes, one each in different zones. You must add 3 nodes and perform this procedure for all of them.

Verification steps

You can add a node on an AWS or VMware user-provisioned infrastructure.

Prerequisites

  • You must be logged into OpenShift Container Platform cluster.

Procedure

  1. Depending on whether you are adding a node on an AWS or a VMware user-provisioned infrastructure, perform the following steps:

    • For AWS:

      1. Create a new AWS machine instance with the required infrastructure. See Platform requirements.
      2. Create a new OpenShift Container Platform node using the new AWS machine instance.

    • For VMware:

      1. Create a new virtual machine (VM) on vSphere with the required infrastructure. See Platform requirements.
      2. Create a new OpenShift Container Platform worker node using the new VM.

  2. Check for certificate signing requests (CSRs) related to OpenShift Data Foundation that are in Pending state. 

    $ oc get csr

  3. Approve all the required OpenShift Data Foundation CSRs for the new node. 

    $ oc adm certificate approve <Certificate_Name>
    <Certificate_Name>
    Is the name of the CSR.
  4. Click Compute Nodes, confirm if the new node is in Ready state.

  5. Apply the OpenShift Data Foundation label to the new node using any one of the following:

    From User interface
    1. For the new node, click Action Menu (⋮) Edit Labels.
    2. Add cluster.ocs.openshift.io/openshift-storage, and click Save.
    From Command line interface

    • Apply the OpenShift Data Foundation label to the new node. 

      $ oc label node <new_node_name> cluster.ocs.openshift.io/openshift-storage=""
      <new_node_name>
      Is the name of the new node.
Note

It is recommended to add 3 nodes, one each in different zones. You must add 3 nodes and perform this procedure for all of them.

Verification steps

3.1.3. Adding a node using a local storage device
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You can add a node on the following:

  • Bare metal
  • IBM Z or LinuxONE
  • VMware
  • Red Hat Virtualization

Prerequisites

  • You must be logged into the OpenShift Container Platform cluster.
  • You must have three OpenShift Container Platform worker nodes with the same storage type and size attached to each node (for example, 2TB SSD or 2TB NVMe drive) as the original OpenShift Data Foundation StorageCluster was created with.
  • If you upgraded to OpenShift Data Foundation version 4.9 from a previous version, and have not already created the LocalVolumeDiscovery and LocalVolumeSet objects, follow the procedure described in Post-update configuration changes for clusters backed by local storage.

Procedure

  1. Depending on the type of infrastructure, perform the following steps:

    • For VMware:

      1. Create a new virtual machine (VM) on vSphere with the required infrastructure. See Platform requirements.
      2. Create a new OpenShift Container Platform worker node using the new VM.

    • For Red Hat Virtualization:

      1. Create a new VM on Red Hat Virtualization with the required infrastructure. See Platform requirements.
      2. Create a new OpenShift Container Platform worker node using the new VM.

    • For bare metal:

      1. Get a new bare metal machine with the required infrastructure. See Platform requirements.
      2. Create a new OpenShift Container Platform node using the new bare metal machine.

    • For IBM Z or LinuxONE:

      1. Get a new IBM Z or LinuxONE machine with the required infrastructure. See Platform requirements.
      2. Create a new OpenShift Container Platform node using the new IBM Z or LinuxONE machine.

  2. Check for certificate signing requests (CSRs) related to OpenShift Data Foundation that are in Pending state. 

    $ oc get csr

  3. Approve all the required OpenShift Data Foundation CSRs for the new node. 

    $ oc adm certificate approve <Certificate_Name>
    <Certificate_Name>
    Is the name of the CSR.
  4. Click Compute Nodes, confirm if the new node is in Ready state.

  5. Apply the OpenShift Data Foundation label to the new node using any one of the following:

    From User interface
    1. For the new node, click Action Menu (⋮) Edit Labels.
    2. Add cluster.ocs.openshift.io/openshift-storage, and click Save.
    From Command line interface

    • Apply the OpenShift Data Foundation label to the new node. 

      $ oc label node <new_node_name> cluster.ocs.openshift.io/openshift-storage=""
      <new_node_name>
      Is the name of the new node.

  6. Click Operators Installed Operators from the OpenShift Web Console.

    From the Project drop-down list, make sure to select the project where the Local Storage Operator is installed.

  7. Click Local Storage.

  8. Click the Local Volume Discovery tab.

    1. Beside the LocalVolumeDiscovery, click Action menu (⋮) Edit Local Volume Discovery.
    2. In the YAML, add the hostname of the new node in the values field under the node selector.
    3. Click Save.

  9. Click the Local Volume Sets tab.

    1. Beside the LocalVolumeSet, click Action menu (⋮) Edit Local Volume Set.

    2. In the YAML, add the hostname of the new node in the values field under the node selector.

      Figure 3.1. YAML showing the addition of new hostnames

      Screenshot of YAML showing the addition of new hostnames.
    3. Click Save.
Note

It is recommended to add 3 nodes, one each in different zones. You must add 3 nodes and perform this procedure for all of them.

Verification steps

Prerequisites

  • You must be logged into the OpenShift Container Platform cluster.
  • You must have three OpenShift Container Platform worker nodes with the same storage type and size attached to each node (for example, 2TB SSD drive) as the original OpenShift Data Foundation StorageCluster was created with.
  • If you have upgraded from a previous version of OpenShift Data Foundation and have not already created a LocalVolumeDiscovery object, follow the procedure described in Post-update configuration changes for clusters backed by local storage.

Procedure

  1. Get a new IBM Power machine with the required infrastructure. See Platform requirements.

  2. Create a new OpenShift Container Platform node using the new IBM Power machine.

    1. Check for certificate signing requests (CSRs) related to OpenShift Data Foundation that are in Pending state. 

      $ oc get csr

    2. Approve all the required OpenShift Data Foundation CSRs for the new node. 

      $ oc adm certificate approve <Certificate_Name>
      <Certificate_Name>
      Is the name of the CSR.
    3. Click Compute Nodes, confirm if the new node is in Ready state.

    4. Apply the OpenShift Data Foundation label to the new node using any one of the following:

      From User interface
      1. For the new node, click Action Menu (⋮) Edit Labels.
      2. Add cluster.ocs.openshift.io/openshift-storage and click Save.
      From Command line interface

      • Apply the OpenShift Data Foundation label to the new node. 

        $ oc label node <new_node_name> cluster.ocs.openshift.io/openshift-storage=""
      <new_node_name>
      Is the name of the new node.

    5. Click Operators Installed Operators from the OpenShift Web Console.

      From the Project drop-down list, make sure to select the project where the Local Storage Operator is installed.

    6. Click Local Storage.

    7. Click the Local Volume Discovery tab.

      1. Click the Action menu (⋮) next to LocalVolumeDiscovery Edit Local Volume Discovery.
      2. In the YAML, add the hostname of the new node in the values field under the node selector.
      3. Click Save.

    8. Click the Local Volume tab.

      1. Beside the LocalVolume, click Action menu (⋮) Edit Local Volume.

      2. In the YAML, add the hostname of the new node in the values field under the node selector.

        Figure 3.2. YAML showing the addition of new hostnames

        Screenshot of YAML showing the addition of new hostnames.
      3. Click Save.
Note

It is recommended to add 3 nodes, one each in different zones. You must add 3 nodes and perform this procedure for all of them.

Verification steps

3.1.5. Verifying the addition of a new node
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  1. Execute the following command and verify that the new node is present in the output: 

    $ oc get nodes --show-labels | grep cluster.ocs.openshift.io/openshift-storage= |cut -d' ' -f1

  2. Click Workloads Pods, confirm that at least the following pods on the new node are in Running state:

    • csi-cephfsplugin-*
    • csi-rbdplugin-*

3.2. Adding capacity to a newly added node
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To add capacity to a newly added node, either use the Add Capacity option to expand the storage cluster with 3 OSDs or use the new flexible scaling feature that allows you to expand the storage cluster by any number of OSDs if it is enabled.

To add capacity by 3 OSDs for dynamic and local storage using the Add Capacity option in the user interface, see Scaling up storage by adding capacity. The Add Capacity option is available for storage clusters with or without the flexible scaling feature enabled.

3.2.2. Add capacity using YAML
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With flexible scaling enabled, you can add capacity by 1 or more OSDs at a time using the YAML instead of the default set of 3 OSDs. However, you need to make sure that you add disks in a way that the cluster remains balanced.

Flexible scaling is supported only for the internal-attached mode of storage cluster creation.

To enable flexible scaling, create a cluster with 3 nodes, and fewer than 3 availability zones. The OpenShift Web Console detects the 3 nodes spread across fewer than 3 availability zones and enables flexible scaling.

Important

You can not enable or disable the flexible scaling feature after creating the storage cluster.

3.2.2.1. Verifying if flexible scaling is enabled
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Procedure

  • In the Web Console, click Home Search.

    1. Enter StorageCluster in the search field.
    2. Click ocs-storagecluster.

    3. In the YAML tab, search for the keys flexibleScaling in spec section and failureDomain in status section.

      If flexible scaling is true and failureDomain is set to host, flexible scaling feature is enabled. 

      spec:
flexibleScaling: true
[…]
status:
failureDomain: host

To add OSDs to your storage cluster flexibly through the YAML, perform the following steps:

Prerequisites

  • Administrator access to the OpenShift Container Platform web console.
  • A storage cluster with flexible scaling enabled.
  • Additional disks available for adding capacity.

Procedure

  1. In the OpenShift Web Console, click Home Search.

    1. Search for ocs-storagecluster in the search field and click on ocs-storagecluster from the search result.
    2. Click the Action menu (⋮) next to the storage cluster you want to scale up.
    3. Click Edit Storage Cluster. You are redirected to the YAML.
  2. In the YAML, search for the key count. This count parameter scales up the capacity.

  3. Increase the count by the number of OSDs you want to add to your cluster.

    Important

    Ensure the count parameter in the YAML is incremented depending on the number of available disks and also make sure that you add disks in a way that the cluster remains balanced.

  4. Click Save.
Note

You might need to wait a couple of minutes for the storage cluster to reach the Ready state.

Verification steps

  • Verify the Raw Capacity card.

    1. In the OpenShift Web Console, click Storage OpenShift Data Foundation.
    2. In the Status card of the Overview tab, click Storage System and then click the storage system link from the pop up that appears.

    3. In the Block and File tab, check the Raw Capacity card.

      Note that the capacity increases based on your selections.

      Note

      The raw capacity does not take replication into account and shows the full capacity.

  • Verify that the new OSDs and their corresponding new Persistent Volume Claims (PVCs) are created.

    • To view the state of the newly created OSDs:

      1. Click Workloads Pods from the OpenShift Web Console.

      2. Select openshift-storage from the Project drop-down list.

        Note

        If the Show default projects option is disabled, use the toggle button to list all the default projects.

    • To view the state of the PVCs:

      1. Click Storage Persistent Volume Claims from the OpenShift Web Console.

      2. Select openshift-storage from the Project drop-down list.

        Note

        If the Show default projects option is disabled, use the toggle button to list all the default projects.

  • Optional: If cluster-wide encryption is enabled on the cluster, verify that the new OSD devices are encrypted.

    1. Identify the node(s) where the new OSD pod(s) are running. 

      $ oc get -o=custom-columns=NODE:.spec.nodeName pod/<OSD-pod-name>
      <OSD-pod-name>

      Is the name of th OSD pod.

      For example: 

      oc get -o=custom-columns=NODE:.spec.nodeName pod/rook-ceph-osd-0-544db49d7f-qrgqm

    2. For each of the nodes identified in the previous step, do the following:

      1. Create a debug pod and open a chroot environment for the selected host(s). 

        $ oc debug node/<node name>
        <node name>

        Is the name of the node. 

        $ chroot /host

      2. Check for the crypt keyword beside the ocs-deviceset name(s). 

        $ lsblk
Important

Cluster reduction is supported only with the Red Hat Support Team’s assistance.

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