Chapter 3. Cluster Expansion

To expand an existing Gluster cluster already imported and managed by the Web Administration environment, perform the following sequence of actions:

Create New Nodes

Before initiating cluster expansion in the Web Administration interface, create new Gluster storage nodes to be imported in Web Administration. For detailed instructions, see the Expanding Volumes section in the Red Hat Gluster Storage Administration Guide.

New Alert

After successfully expanding the cluster with new nodes, an alert is generated in the Notifications panel of the Web Administration interface as displayed in the following screen:

expansion alert

In this screen, new peers represents new storage nodes that were created in the previous cluster expansion process.

New Event

Additionally, a new Event is also generated about the availability of new storage nodes for expansion as displayed in the following screen:

expansion event

Running Tendrl-ansible installation for new nodes

After the storage nodes are identified by Web Administration, run tendrl-ansible installation by adding the new hosts in the inventory file. For detailed installation instructions, see the Installing Web Administration chapter in the Red Hat Gluster Storage Web Administration Quick Start Guide.

Cluster Expansion in Web Administration

After tendrl-ansible is executed, the expand cluster option becomes available in the Web Administration interface. Follow these instructions to expand the cluster:

Procedure. Expanding Cluster

  1. Log in to the Web Administration interface and click All Clusters interface from the interface selector drop-down.

  2. In the Clusters view, locate the cluster to be expanded. It will be labelled as Expansion required.

    expansion1

  3. At the far right of the cluster row, click the vertical ellipsis and then click Expand.

    expansion2

  4. The available hosts to be added are listed. Click Expand.

    expand hypothethica

  5. The cluster expansion task is submitted.

    expansion4
  6. The cluster is successfully expanded and ready for use.
expansion5

3.1. Unmanaging Cluster

The following are the reasons to unmanage a cluster:

  1. Import cluster fails
  2. Removal of a cluster that is no longer under management and used for monitoring
  3. A way to remove orphaned cluster entries

Unmanage a cluster from Web Administration

To unmanage a cluster:

  1. Log in to the Web Administration interface and select the All Clusters view from drop-down.

  2. Locate the cluster from the list of imported clusters. At the far right of the cluster row, click the vertical ellipsis and then click Unmanage.

    unmanage cluster2

  3. A confirmation box appears. Click Unmanage to proceed.

    unmanage cluster3

  4. The unmanage cluster task is submitted. To view the task progress, click View Task Progress.

    unmanage cluster final
  5. The status shows Completed after the unmanage task is successfully completed.
unmanage cluster 5
Note

After a cluster is unmanaged, it will not reappear immediately for reimport in the Web Administration environment. When the cluster is unmanaged, the tendrl-node-agent service undergoes synchronization with the nodes in the cluster. Based on the number of nodes in the cluster, expect a delay ranging from 60 seconds to a few minutes for the unmanaged cluster to reappear in the Web Administration environment.

3.2. Troubleshooting Cluster Expansion

Scenario: Cluster Expansion task failed

In this scenario, the cluster explansion task fails.

Resolution

If cluster expansion fails, check if tendrl-ansible was executed successfully and ensure the node agents are correctly configured. If cluster expansion failed due to errors, resolve the errors on affected nodes and re-initiate the Expand Cluster action.

To verify tendrl-ansible execution steps, see the Web Administration Installation section of the Red Hat Gluster Storage Web Administration Quick Start Guide.

For detailed instructions on expanding cluster, navigate to the Cluster Expansion section of this Guide.