Promoting a node to master

If a master node fails, we might want to promote a different node to master while you resolve the failure.

When we are promoting a node to master, ensure that you adhere to the cluster architecture rules. For example, specify the supplementary masters in order. We cannot specify tertiary and quaternary masters if there is no secondary master. For a complete list of the cluster configuration rules, see Cluster configuration rules. Promoting a node to a master falls into two main categories:

• Promoting a node to a supplementary master - secondary master, tertiary master, or quaternary master.
• Promoting a node to primary master.

Parent topic: Cluster support

Promoting a node to a supplementary master

We can use the local management interface of the primary master to update the cluster configuration and select the supplementary masters. To promote a node to secondary, tertiary, or quaternary master, complete these steps:

Steps

1. Open the Cluster Configuration page from the primary master local management interface.
2. Go to the General tab.
3. Change the values in the master fields. That is, Secondary master, Tertiary master, Quaternary master.

4. Save and deploy the updates.

Promoting a node to primary master when the original primary master is unavailable

• Nodes are automatically updated with information for the new primary master. If a node is not reachable by the primary master at the time of promotion, there is a delay of up to 15 minutes from the time that connectivity is restored before the node is notified of the new primary master.

• If the original primary master is reconnected to the primary master, it is automatically demoted to the role of a normal node.
• If the network is segregated and two different nodes are promoted to primary master in the different networks, automatic recovery is not possible when the network connectivity is re-established. In this situation, a manual merge of the segregated cluster is required. This step is achieved by removing all nodes from one of the clusters and joining these nodes back into the other cluster. This situation occurs only when both of the following conditions are met:
  • Connectivity in the cluster is lost.
  • The administrator promotes two different nodes to the primary master role while network connectivity is lost.

Use the local management interface of the appliance that we are promoting to primary master to update the configuration. You can promote a non-master node or one of the supplementary masters if available. To promote the selected node to primary master, complete these steps:

Steps

1. Access the local management interface of the node to promote to primary master.

2. Select System > Network Settings > Cluster Configuration.

3. Select the General tab.

4. Select Set this appliance as a Primary Master.
5. Use the available menu to set the Primary master IP address. Select the first management interface of the appliance.

6. Save and deploy the changes.

Promoting a node to primary master when the original primary master is available

• Nodes are automatically updated with information for the new primary master. If a node is not reachable by the primary master at the time of promotion, there is a delay of up to 15 minutes from the time that connectivity is restored before the node is notified of the new primary master.

• We can promote another node to primary master only if it is currently contactable by the current primary master.

Use the local management interface of the current primary master to update the configuration.

Steps

1. Access the local management interface of the current primary master.

2. Select System > Network Settings > Cluster Configuration.

3. Select the General tab.

4. Select a new primary master from the list of nodes in the drop-down list.

5. If applicable, update the rest of the configuration to ensure that we do not break any of the clustering rules.

6. Save and deploy the changes.