Monitoring cluster and application service status can help identify and resolve problems in the cluster environment. The following tools assist in displaying cluster status information:
The Cluster Status Tool
The clustat utility
Members that are not running the cluster software cannot determine or report the status of other members of the cluster.
Cluster and service status includes the following information:
Cluster member system status
Service status and which cluster system is running the service or owns the service
The following tables describe how to analyze the status information shown by the Cluster Status Tool and the clustat utility.
|Dead||The member system is unable to participate as a cluster member. The most basic cluster software is not running on the node.|
Table 4-1. Member Status for the Cluster Status Tool
|Online||The node is communicating with other nodes in the cluster.|
Table 4-2. Member Status for clustat
|Started||The service resources are configured and available on the cluster system that owns the service.|
|Pending||The service has failed on a member and is pending start on another member.|
|Disabled||The service has been disabled, and does not have an assigned owner. A disabled service is never restarted automatically by the cluster.|
|Stopped||The service is not running; it is waiting for a member capable of starting the service. A service remains in the stopped state if autostart is disabled.|
|Failed||The service has failed to start on the cluster and cannot successfully stop the service. A failed service is never restarted automatically by the cluster.|
Table 4-3. Service Status
The Cluster Status Tool displays the current cluster status in the Services area and automatically updates the status every 10 seconds. Additionally, you can display a snapshot of the current cluster status from a shell prompt by invoking the clustat utility. Example 4-1 shows the output of the clustat utility.
# clustat Member Status: Quorate, Group Member Member Name State ID ------ ---- ----- -- tng3-2 Online 0x0000000000000002 tng3-1 Online 0x0000000000000001 Service Name Owner (Last) State -------- ----- ----- ------ ----- webserver (tng3-1 ) failed email tng3-2 started
Example 4-1. Output of clustat
To monitor the cluster and display status at specific time intervals from a shell prompt, invoke clustat with the -i time option, where time specifies the number of seconds between status snapshots. The following example causes the clustat utility to display cluster status every 10 seconds:
#clustat -i 10