CP Subsystem

You can use the CP Subsystem menu item to manage and monitor the CP subsystem in a cluster.

Status

Data and Metrics

The CP subsystem dashboard displays the following tables:

Table 1. CP subsystem
Field Description

CP Members

The number of accessible CP members and the CP member count that’s configured on the cluster.

Promote Member to CP

This button is available only to admin users.

Remove CP Member

This button is available only to admin users.

Restart CP Subsystem

This button is available only to admin users.

Table 2. CP subsystem stats
Field Description

Member

Address of the CP member.

Nodes

Number of Raft nodes that the member is running.

Destroyed Groups

Total number of Raft groups that have been destroyed.

Active Members

Total number of active CP members.

Missing Members

Total number of missing CP members.

Table 3. CP group metrics
Field Description

Group Name

Name of the Raft group.

Group Id

Group identifier.

Member Count

Total number of members in the group.

To see more details about a particular group, click on the down arrow next to the group name.

Table 4. CP session metrics
Field Description

Member

Address of the CP member

Id

Session ID.

Version

The number of session heartbeats that the member has received.

Creation Time

Time at which the session was created.

Expiration Time

Time at which the session will expire.

Status Banner

A banner is always displayed at the top of the page with a message about the current CP subsystem status.

This banner may display one of the following messages:

  • CP Subsystem is not enabled: The cluster is not configured with a CP member count of at least 3.

  • All CP members are accessible: Number of accessible CP members is at least the same as the configured CP member count.

  • One CP member is not accessible: One CP member is missing and the minority count in the CP subsystem is greater than 1. For example, this value is shown when 6 accessible CP members are available and the configured count is 7. In this example, the minority count is 3 members and the majority count is 4 members.

  • Multiple CP members are not accessible: Multiple CP members are missing, but their count is less than the minority.

  • Minority of the CP members are not accessible: The minority of CP members are missing.

  • Majority of the CP members are not accessible: The majority of CP members are missing.

Promoting Members to CP Members

You can promote any existing member that is not part of the CP subsystem to a CP member.

This action is available only to admin users.

  1. Go to CP Subsystem > Dashboard, and click Promote.

  2. Select an AP member (one of the members that do not participate in the CP subsystem) from the dropdown.

    Lite members are not displayed in the dropdown list because they do not store data and cannot be promoted to CP members.

If everything goes well, a success message is displayed.

Promote Member to CP Confirmation

If an exception occurs, an error notification is displayed.

Removing CP Members

You can manually remove a disconnected CP member from the CP subsystem, using Management Center.

If a CP member loses connection with the rest of the cluster, the CP subsystem will wait for 4 hours by default before connecting to a new CP member. You can configure this time in the missing-cp-member-auto-removal-seconds option. See Configuring CP Subsystem in the Platform documentation.

This action is available only to admin users.

  1. Go to CP Subsystem > Dashboard, and click Remove.

  2. Select a CP member from the dropdown.

    Although this member is not connected to the Management Center, it is known by the cluster’s CP subsystem.

If everything goes well, a success message is displayed.

Remove CP Member Confirmation

If an exception occurs, an error notification is displayed.

Restarting CP Subsystem

If the majority of CP members crash, you can restart the CP subsystem to delete all CP data and trigger a new round of the discovery process.

This action is available only to admin users.

Go to CP Subsystem > Dashboard, and click Restart.

If everything goes well, a success message is displayed.

If an exception occurs, an error notification is displayed.