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Chapter 2. Deploy OpenShift Container Storage using local storage devices

Deploying OpenShift Container Storage on OpenShift Container Platform using local storage devices provides you with the option to create internal cluster resources. Follow this deployment method to use local storage to back persistent volumes for your OpenShift Container Platform applications.

Use this section to deploy OpenShift Container Storage on IBM Z infrastructure where OpenShift Container Platform is already installed.

2.1. Installing Red Hat OpenShift Container Storage Operator

You can install Red Hat OpenShift Container Storage Operator using the Red Hat OpenShift Container Platform Operator Hub.

Prerequisites

  • Access to an OpenShift Container Platform cluster using an account with cluster-admin and operator installation permissions.
  • You have at least three worker nodes in the Red Hat OpenShift Container Platform cluster.
  • You have satisfied any additional requirements required. For more information, see Planning your deployment.
Note
  • When you need to override the cluster-wide default node selector for OpenShift Container Storage, you can use the following command to specify a blank node selector for the openshift-storage namespace (create openshift-storage namespace in this case):

    $ oc annotate namespace openshift-storage openshift.io/node-selector=
  • Taint a node as infra to ensure only Red Hat OpenShift Container Storage resources are scheduled on that node. This helps you save on subscription costs. For more information, see How to use dedicated worker nodes for Red Hat OpenShift Container Storage chapter in Managing and Allocating Storage Resources guide.

Procedure

  1. Log in to OpenShift Web Console.
  2. Click OperatorsOperatorHub.
  3. Search for OpenShift Container Storage from the list of operators and click on it.
  4. Click Install.
  5. Set the following options on the Install Operator page:

    1. Channel as stable-4.8.
    2. Installation Mode as A specific namespace on the cluster.
    3. Installed Namespace as Operator recommended namespace openshift-storage. If Namespace openshift-storage does not exist, it will be created during the operator installation.
    4. Approval Strategy as Automatic or Manual.
    5. Click Install.

      If you select Automatic updates, the Operator Lifecycle Manager (OLM) automatically upgrades the running instance of your operator without any intervention.

      If you select Manual updates, the OLM creates an update request. As a cluster administrator, you must then manually approve that update request to have the operator updated to the new version.

Verification step

  • Verify that the OpenShift Container Storage Operator shows a green tick indicating successful installation.

2.2. Installing Local Storage Operator

You can install the Local Storage Operator using the Red Hat OpenShift Container Platform Operator Hub.

Prerequisite

  • Access to an OpenShift Container Platform cluster using an account with cluster-admin and Operator installation permissions.

Procedure

  1. Log in to the OpenShift Web Console.
  2. Click Operators → OperatorHub.
  3. Type local storage in the Filter by keyword…​ box to search for Local Storage operator from the list of operators and click on it.
  4. Click Install.
  5. Set the following options on the Install Operator page:

    1. Channel as stable-4.8.
    2. Installation Mode as A specific namespace on the cluster.
    3. Installed Namespace as Operator recommended namespace openshift-local-storage.
    4. Approval Strategy as Automatic.
  6. Click Install.

Verification step

  • Verify that the Local Storage Operator shows the Status as Succeeded.

2.3. Finding available storage devices (optional)

This step is additional information and can be skipped as the disks are automatically discovered during storage cluster creation. Use this procedure to identify the device names for each of the three or more worker nodes that you have labeled with the OpenShift Container Storage label cluster.ocs.openshift.io/openshift-storage='' before creating Persistent Volumes (PV) for IBM Z.

Procedure

  1. List and verify the name of the worker nodes with the OpenShift Container Storage label.

    $ oc get nodes -l=cluster.ocs.openshift.io/openshift-storage=

    Example output:

    NAME          STATUS   ROLES    AGE     VERSION
    bmworker01    Ready    worker   6h45m   v1.16.2
    bmworker02    Ready    worker   6h45m   v1.16.2
    bmworker03    Ready    worker   6h45m   v1.16.2
  2. Log in to each worker node that is used for OpenShift Container Storage resources and find the unique by-id device name for each available raw block device.

    $ oc debug node/<node name>

    Example output:

    $ oc debug node/bmworker01
    Starting pod/bmworker01-debug ...
    To use host binaries, run `chroot /host`
    Pod IP: 10.0.135.71
    If you don't see a command prompt, try pressing enter.
    sh-4.2# chroot /host
    sh-4.4# lsblk
    NAME                         MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
    loop0                          7:0    0   500G  0 loop
    sda                            8:0    0   120G  0 disk
    |-sda1                         8:1    0   384M  0 part /boot
    `-sda4                         8:4    0 119.6G  0 part
    `-coreos-luks-root-nocrypt   253:0    0 119.6G  0 dm   /sysroot
    sdb                            8:16   0   500G  0 disk

    In this example, for bmworker01, the available local device is sdb.

  3. Identify the unique ID for each of the devices selected in Step 2.

    sh-4.4#ls -l /dev/disk/by-id/  | grep sdb
    lrwxrwxrwx. 1 root root  9 Feb  3 16:49 scsi-360050763808104bc2800000000000259 -> ../../sdb
    lrwxrwxrwx. 1 root root  9 Feb  3 16:49 scsi-SIBM_2145_00e020412f0aXX00 -> ../../sdb
    lrwxrwxrwx. 1 root root  9 Feb  3 16:49 scsi-0x60050763808104bc2800000000000259 -> ../../sdb

    In the above example, the ID for the local device sdb

    scsi-0x60050763808104bc2800000000000259
  4. Repeat the above step to identify the device ID for all the other nodes that have the storage devices to be used by OpenShift Container Storage. See this Knowledge Base article for more details.

2.4. Creating OpenShift Container Storage cluster on IBM Z

Use this procedure to create storage cluster on IBM Z.

Prerequisites

Procedure

  1. Log into the OpenShift Web Console.
  2. Click Operators → Installed Operators to view all the installed operators.

    Ensure that the Project selected is openshift-storage.

  3. Click OpenShift Container Storage.
  4. Click Create Instance link of Storage Cluster.
  5. Select Internal-Attached devices for the Select Mode. By default, Internal is selected.
  6. Create a storage cluster using the wizard that includes disk discovery, storage class creation, and storage cluster creation.

    You are prompted to install the Local Storage Operator if it is not already installed. Click Install and install the operator as described in Installing Local Storage Operator.

    Discover disks

    You can discover a list of potentially usable disks on the selected nodes. Block disks and partitions that are not in use and available for provisioning persistent volumes (PVs) are discovered.

    1. Choose one of the following:

      • All nodes to discover disks in all the nodes.
      • Select nodes to discover disks from a subset of the listed nodes.

        To find specific worker nodes in the cluster, you can filter nodes on the basis of Name or Label. Name allows you to search by name of the node and Label allows you to search by selecting the predefined label.

        If the nodes selected do not match the OpenShift Container Storage cluster requirement of an aggregated 30 CPUs and 72 GiB of RAM, a minimal cluster will be deployed. For minimum starting node requirements, see Resource requirements section in Planning guide.

        Note

        If the nodes to be selected are tainted and not discovered in the wizard, follow the steps provided in the Red Hat Knowledgebase Solution as a workaround to add tolerations for Local Storage Operator resources.

    2. Click Next.
    Create Storage Class

    You can create a dedicated storage class to consume storage by filtering a set of storage volumes.

    1. Enter the Volume Set Name.
    2. Enter the Storage Class Name. By default, the volume set name appears for the storage class name.
    3. The nodes selected for disk discovery in the earlier step are displayed in the Filter Disks section. Choose one of the following:

      • All nodes to select all the nodes for which you discovered the devices.
      • Select nodes to select a subset of the nodes for which you discovered the devices.

        To find specific worker nodes in the cluster, you can filter nodes on the basis of Name or Label. Name allows you to search by name of the node and Label allows you to search by selecting the predefined label.

        It is recommended that the worker nodes are spread across three different physical nodes, racks or failure domains for high availability.

        Note

        Ensure OpenShift Container Storage rack labels are aligned with physical racks in the datacenter to prevent a double node failure at the failure domain level.

    4. Select the required Disk Type. The following options are available:

      All

      Selects all types of disks present on the nodes. By default, this option is selected.

      SSD/NVME

      Selects only SSD NVME type of disks.

      HDD

      Selects only HDD type of disks.

    5. In the Advanced section, you can set the following:

      Volume Mode

      Block is selected by default.

      Disk Size

      Minimum and maximum available size of the device that needs to be included.

      Note

      You must set a minimum size of 100GB for the device.

      Max Disk Limit

      This indicates the maximum number of PVs that can be created on a node. If this field is left empty, then PVs are created for all the available disks on the matching nodes.

    6. (Optional) You can view the selected capacity of the disks on the selected nodes using the Select Capacity chart.

      This chart might take a few minutes to reflect the disks that are discovered in the previous step.

      You can click on the Nodes and Disks links on the chart to bring up the list of nodes and disks to view more details.

    7. Click Next.
    8. Click Yes in the message alert to confirm the creation of the storage class.

      After the local volume set and storage class are created, it is not possible to go back to the step.

    Create Storage Cluster
    1. Select the required storage class.

      You might need to wait a couple of minutes for the storage nodes corresponding to the selected storage class to get populated. The nodes corresponding to the storage class are displayed based on the storage class that you selected from the drop down list.

    2. Click Next.
    3. (Optional) In the Encryption section, set the toggle to Enabled to enable data encryption on the cluster. Security configuration:
    4. Click Save.
    5. Click Next to review your storage cluster.
    6. Click Create.

      The Create button is enabled only when a minimum of three nodes are selected. A new storage cluster with the number of volumes equal to the total number of devices attached to each node is created. The default configuration uses a replication factor of 1.

      To expand the capacity of the initial cluster, see Scaling Storage guide.