Add or replace nodes

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After you install, configure PowerVC operations manager (OpsMgr) and successfully install PowerVC on single node, you can choose to move to multinode. You can also choose to replace one of the nodes in the cluster with another node.

This topic explains the procedure for adding or replacing a node.

Notes:

Legacy install of PowerVC is not supported for add node, replace node, resync node, and compute plane node registration.
If LDAP is already configured before adding or replacing nodes, you must reconfigure LDAP after performing the add or replace node operation.
When adding or replacing a node, make sure that the NTP is active and the time is in sync on all nodes before you perform operations such as install, add node, or replace node and prevent any issues related to host or VM deployment.
Make sure that you disable IPv6 before you proceed with the installation procedure. For details, see Disable IPv6 topic.
Restore operation is supported only on a single or a three node cluster. After upgrading to PowerVC 2.2.1, you can add two more nodes to convert a cluster into three node cluster. Later, you can add two more nodes to convert a three node cluster to a five node cluster. You can take a backup of five node cluster and restore the same on a three node cluster.
Registration or deregistration of a host, storage, or a fabric is supported even when a node goes down. After the node is up, you can run powervc-opsmgr resync_node -s <source_host> -d <dest_host> to sync the conf files on the source host and destination host.
After the new nodes are added, services that are on the current node do not move to the new nodes automatically. You must move the services to the new nodes manually. However, the services automatically move to the new nodes when the current node goes down or is unavailable. Also, if a new service is added, the new service goes to the node with minimum load.
You can optionally run the powervc-health-check addnode command before performing an add or replace operation. For more information about the health check commands, see the powervc-health-check command in the CLI commands page.

Add nodes

Prerequisite

Configure the Yum repository for PowerVC install through RHN and make sure these repositories are enabled.

High Availability (HA repo is not available with standard RHEL subscription. For subscription details, see Red Hat^® Enterprise Linux^® High Availability Add-On ).
Codeready Builder (CRB) (for RHEL 9.x only) with these RPMs, libknet1 and mysql-libs.

You must provide two more nodes that are identical to the existing node that is, the nodes must have same distro or version. PowerVC supports five-node control plane cluster.

Run powervc-opsmgr addnodes -c <cluster name> -s to add nodes. This converts single node setup to multinode. The command captures IP addresses of new nodes and updates inventory for the cluster. PowerVC can be installed on new nodes.

After installing OpsMgr and creating a cluster, you can install PowerVC on single node and later add multiple nodes (up to three nodes). For more details about subcommands, run powervc-opsmgr addnodes -h.

Note:

In this command powervc-opsmgr addnodes -c <cluster name> -s, -s option is needed if systems are registered with RHN repo. Before you add nodes, if the initial system is registered with RHN, make sure that the other systems are also registered with RHN.
Run powervc-opsmgr addnodes -c <cluster name> -s -f in case of add nodes failure.

Example

[onecloud-user@Hostname ~]$ sudo powervc-opsmgr addnodes -c <cluster_name> -s
+--------------------------------------------------------------------------------+
|                                PowerVC Addnodes                                |
+--------------------------------------------------------------------------------+
   INFO:
     Nodes
        * Adding Nodes to PowerVC.
        * Add nodes takes input exactly for 2 nodes.
     Sudo User
        * Sudo user with same username and password across all nodes is required.
+--------------------------------------------------------------------------------+
   PowerVC AddNode Information
     Node 1
        Enter IP/Hostname for Node 1        : <IP or Hostname>
        Enter Password for Node 1 [onecloud-user]:
     Node 2
        Enter IP/Hostname for Node 2        : <IP or Hostname>
        Enter Password for Node 2 [onecloud-user]:
+--------------------------------------------------------------------------------+
|                   PowerVC Addnodes - Passwordless connection                   |
+--------------------------------------------------------------------------------+
Establishing passwordless connection

Upon addition of nodes, you can access nodes via virtual IP.

Replace a node

Prerequisite

You must provide details of the node that must be removed and the node to be added. The new node must have same distro or version.

Configure the Yum repository for PowerVC install through RHN and make sure these repos are enabled.

High Availability (HA repo is not available with standard RHEL subscription. For subscription details, see Red Hat^® Enterprise Linux^® High Availability Add-On ).
Codeready Builder (CRB) (for RHEL 9.x only) with these RPMs, libknet1 and mysql-libs.

Run powervc-opsmgr replacenode -c <cluster name> -s to replace a node. The command captures IP addresses of the node to be removed and the new node to be added. Later, the node is removed from the cluster and the new node is added to the cluster. Upon addition of the new node, the command uninstalls the removed node for future use if it is accessible. For more details about subcommands, run powervc-opsmgr replacenodes -h.

Notes:

In this command powervc-opsmgr replacenode -c <cluster name> -s, -s option is needed if systems are registered with RHN repo. Before you replace a node, if the systems are registered with RHN, make sure that the new system is also registered with RHN.
If you are running replace node from a non primary / bootstrap node then perform these steps.
1. Edit powervc/group_vars/all/mode.yml to set powervc_operation_mode.
2. Run powervc-opsmgr replacenode command.

Example

[onecloud-user@Hostname ~]$ sudo powervc-opsmgr replacenode -c <cluster_name> -s
+--------------------------------------------------------------------------------+
|                              PowerVC Replacenode                               |
+--------------------------------------------------------------------------------+
   INFO:
     Replacenode
        * Replace faulty node in the cluster.
        * Replacenode operation can't be initiated from the same node getting replaced.
+--------------------------------------------------------------------------------+
     PowerVC ReplaceNode to replace
        Enter IP/Hostname of node to be replaced: <IP or Hostname>
+--------------------------------------------------------------------------------+
   INFO:
     Primary/Bootstrap node as Replacenode
        * Provided Node '<IP or Hostname>' is the current Primary/Bootstrap node.
        * Next node in the cluster 'sam' will become Primary/Bootstrap node.
        * '<IP or Hostname>' is updated as Primary/Bootstrap node.
+--------------------------------------------------------------------------------+
+--------------------------------------------------------------------------------+
   INFO:
     Nodes
        * Adding Nodes to PowerVC.
        * Add Node operation here takes exactly one node.
     Sudo User
        * Sudo user with same username and password across all nodes is required.
+--------------------------------------------------------------------------------+
   PowerVC AddNode Information
     Node 1
        Enter IP/Hostname for Node 1        : <IP or Hostname>
        Enter Password for Node 1 [onecloud-user]:
+--------------------------------------------------------------------------------+
+--------------------------------------------------------------------------------+

You can access nodes via virtual IP.