34.5. Managing Nodes of BiHA Clusters #
Before performing instructions from this section, create a BiHA cluster.
34.5.1. Viewing Nodes #
In the navigation panel, go to Infrastructure → Clusters.
Click the name of the BiHA cluster.
The table of nodes with the following columns will be displayed:
Instance: The unique name of the instance.
This column includes additional information:
Type: The type of the node.
Possible values:
Leader
Follower
Referee
Parent node: The leader of the BiHA cluster.
Node status: The status of the instance.
Possible values:
Unknown: The status of the instance is unknown.
Initialization scheduled: The instance initialization was scheduled.
Initializing: The instance is being initialized.
Initialized: The instance is initialized.
Restoring: The instance is being created from a backup.
Restored: The instance is created from a backup.
Restore canceled: The creation of an instance from a backup was canceled.
Starting: The instance is being started.
Started: The instance is started.
Stopping: The instance is being stopped.
Stopped: The instance is stopped.
Restarting: The instance is being restarted.
Reloading: The cluster is being reloaded.
Failed: There is an error with the instance.
Scheduled for removal: The instance is being deleted.
Base backup: A backup is being created for the instance.
Agent not responding: The agent installed on the instance server is not responding.
Replication mode.
Possible values:
Synchronous
Asynchronous
This column includes additional information:
Status: The status of replication.
Possible values:
Active
Inactive
Network Address: The network address of the node.
This column includes additional information:
Server: The server where the instance is installed.
User: The role used for connecting the follower node to the leader role. Usually, this is the
biha_replication_userrole.Application: The application used for connecting the follower node to the leader node.
Connection: The date and time when the follower node connected to the leader node.
Horizon Visibility: The transaction visibility horizon of the node.
Lag: The data lag between the leader and the follower node, in bytes.
This column includes additional information:
Send: The amount of WAL generated by the leader node, but not yet sent to the follower node.
Write: The amount of WAL sent to the follower node, but not yet written to the memory.
Flush: The amount of WAL written to the memory of the follower node, but not yet saved to the disk.
Replay: The amount of WAL saved to the disk of the follower node, but not yet applied to the database.
Lag time: The time lag between the leader and the follower node, in seconds.
This column includes additional information:
Write: The time passed between the leader node sending WAL to the follower node and the follower node writing it to the memory.
Flush: The time passed between the follower node writing WAL to the memory and saving it to the disk.
Replay: The time passed between the follower node saving WAL to the disk and applying it to the database.
Reply time: The date and time when the leader node last received information from the follower node.
Actions.
For more information about available actions, refer to other instructions in this section.
34.5.2. Selecting a New Leader Node #
In the navigation panel, go to Infrastructure → Clusters.
Click the name of the BiHA cluster.
Click
next to the follower node. Confirm the operation and click Delete.
34.5.3. Adding a Follower Node #
In the navigation panel, go to Infrastructure → Clusters.
Click the name of the BiHA cluster.
In the top-right corner of the page, click Edit topology.
Click Add server.
From Server, select a server to install the instance.
When the server is selected, the following instance information is displayed:
Data directory: The path to the server directory where the main instance directories and files are located.
Network address and Port: The network address and port number that the instance uses to accept client connections.
Click Save.
34.5.4. Adding a Referee Node #
In the navigation panel, go to Infrastructure → Clusters.
Click the name of the BiHA cluster.
In the top-right corner of the page, click Edit topology.
From Referee, select a server to install the instance.
When the server is selected, the following instance information is displayed:
Data directory: The path to the server directory where the main instance directories and files are located.
Network address and Port: The network address and port number that the instance uses to accept client connections.
Select Referee operating mode. There are referee and referee_with_wal operating modes available.
For more information, refer to the official Postgres Pro documentation on the referee node in the BiHA cluster.
Click Save.
34.5.5. Deleting a Node #
Important
You can only delete follower or referee nodes. To delete the leader node, select a new leader node first.
Deleted nodes cannot be restored.
In the navigation panel, go to Infrastructure → Clusters.
Click the name of the BiHA cluster.
Click
next to the node. Select one of the following values:
Update configuration and remove node from the cluster: Delete the node, but keep the instance in the
Startedstate.Stop and remove from the cluster: Delete the node, but keep the instance in the
Stoppedstate.Remove with all data: Delete the node and instance.
Confirm the operation and click Delete.
You can also delete follower nodes when editing the topology of the BiHA cluster. To do this, in the top-right corner of the page, click Edit topology.