37.5. Managing Nodes #
Before performing instructions from this section, create a cluster.
37.5.1. Viewing Nodes #
In the navigation panel, go to Infrastructure → Clusters.
Click the name of the 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:
Primary/Leader.
Standby/Follower.
Cascade.
Referee.
Parent node: The primary/leader node of the cluster.
Status / Current operation: 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.
Error: 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 standby/follower node to the primary/leader node.
Application: The application used for connecting the standby/follower node to the primary/leader node.
Connection: The date and time when the standby/follower node connected to the primary/leader node.
Horizon visibility: The transaction visibility horizon of the node.
Lag: The data lag between the primary/leader and the standby/follower node, in bytes.
This column includes additional information:
Send: The amount of WAL generated by the primary/leader node, but not yet sent to the standby/follower node.
Write: The amount of WAL sent to the standby/follower node, but not yet written to the memory.
Flush: The amount of WAL written to the memory of the standby/follower node, but not yet saved to the disk.
Replay: The amount of WAL saved to the disk of the standby/follower node, but not yet applied to the database.
Lag time: The time lag between the primary/leader and the standby/follower node, in seconds.
This column includes additional information:
Write: The time passed between the primary/leader node sending WAL to the standby/follower node and the standby/follower node writing it to the memory.
Flush: The time passed between the standby/follower node writing WAL to the memory and saving it to the disk.
Replay: The time passed between the standby/follower node saving WAL to the disk and applying it to the database.
Reply time: The date and time when the primary/leader node last received information from the standby/follower node.
Actions.
For more information about available actions, refer to the corresponding instructions.
37.5.2. Selecting a New Primary/Leader Node #
In the navigation panel, go to Infrastructure → Clusters.
Click the name of the cluster.
Click
next to the standby/follower node. Confirm the operation and click Delete.
37.5.3. Adding a Standby/Follower Node #
In the navigation panel, go to Infrastructure → Clusters.
Click the name of the 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 that the instance uses to accept client connections.
Click Save.
37.5.4. 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 that the instance uses to accept client connections.
From Referee operating mode, select one of the following values:
referee
referee_with_wal
For more information, refer to the official Postgres Pro documentation on the referee node in the BiHA cluster.
Click Save.
37.5.5. Replacing a Referee Node #
You can replace the server to host the referee node in your BiHA cluster. The new referee is installed on the new server, while the current referee instance is removed from the cluster, and you can decide how to handle the removed instance.
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 the new 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 that the instance uses to accept client connections.
From Referee operating mode, select one of the following values:
referee
referee_with_wal
For more information, refer to the official Postgres Pro documentation on the referee node in the BiHA cluster.
From Current referee, select the actions you want to perform with the current referee instance:
Restart as standalone instance
Stop, keeping data catalog
Delete with all data
Click Save.
37.5.6. Deleting a Node #
Important
You can only delete standby/follower or referee nodes.
To delete the primary/leader node, select a new primary/leader node first.
Deleted nodes cannot be restored.
In the navigation panel, go to Infrastructure → Clusters.
Click the name of the cluster.
Click
next to the node. Select one of the following values:
Restart as standalone instance: Delete the node, but keep the instance in the
Startedstate.Stop, keeping data catalog: Delete the node, but keep the instance in the
Stoppedstate.Delete with all data: Delete the node and instance.
Confirm the operation and click Delete.
You can also delete standby/follower nodes when editing the topology of the cluster. To do this, in the top-right corner of the page, click Edit topology.