Restart and Failover
If a PowerCenter Integration Service process becomes unavailable, the Service Manager tries to restart it or fails it over to another node based on the shutdown mode, the service configuration, and the operating mode for the service. Restart and failover behavior is different for services that run on a single node, primary and backup nodes, or on a grid.
When the PowerCenter Integration Service fails over, the behavior of completed tasks depends on the following situations:
- •If a completed task reported a completed status to the PowerCenter Integration Service process prior to the PowerCenter Integration Service failure, the task will not restart.
- •If a completed task did not report a completed status to the PowerCenter Integration Service process prior to the PowerCenter Integration Service failure, the task will restart.
Running on a Single Node
When a single process is running, the failover behavior depends on the following sources of failure:
- Service Process
If the service process shuts down unexpectedly, the Service Manager tries to restart the service process. If the Service Manager cannot restart the process, the process stops or fails.
When you restart the process, the PowerCenter Integration Service restores the state of operation for the service and restores workflow schedules, service requests, and workflows.
The failover and recovery behavior of the PowerCenter Integration Service after a service process fails depends on the operating mode:
- - Normal. When you restart the process, the workflow fails over on the same node. The PowerCenter Integration Service can recover the workflow based on the workflow state and recovery strategy. If the workflow is enabled for high availability recovery, the PowerCenter Integration Service restores the state of operation for the workflow and recovers the workflow from the point of interruption. The PowerCenter Integration Service performs failover and recovers the schedules, requests, and workflows. If a scheduled workflow is not enabled for high availability recovery, the PowerCenter Integration Service removes the workflow from the schedule.
- - Safe. When you restart the process, the workflow does not fail over and the PowerCenter Integration Service does not recover the workflow. It performs failover and recovers the schedules, requests, and workflows when you enable the service in normal mode.
- Service
When the PowerCenter Integration Service becomes unavailable, you must enable the service and start the service processes. You can manually recover workflows and sessions based on the state and the configured recovery strategy.
The workflows that run after you start the service processes depend on the operating mode:
- - Normal. Workflows start if they are configured to run continuously or on initialization. You must reschedule all other workflows.
- - Safe. Scheduled workflows do not start. You must enable the service in normal mode for the scheduled workflows to run.
- Node
- When the node becomes unavailable, the restart and failover behavior is the same as restart and failover for the service process, based on the operating mode.
Running on a Primary Node
When both primary and backup services are running, the failover behavior depends on the following sources of failure:
- Service Process
When you disable the service process on a primary node, the service process fails over to a backup node. When the service process on a primary node shuts down unexpectedly, the Service Manager tries to restart the service process before failing it over to a backup node.
After the service process fails over to a backup node, the PowerCenter Integration Service restores the state of operation for the service and restores workflow schedules, service requests, and workflows.
The failover and recovery behavior of the PowerCenter Integration Service after a service process fails depends on the operating mode:
- - Normal. The PowerCenter Integration Service can recover the workflow based on the workflow state and recovery strategy. If the workflow was enabled for high availability recovery, the PowerCenter Integration Service restores the state of operation for the workflow and recovers the workflow from the point of interruption. The PowerCenter Integration Service performs failover and recovers the schedules, requests, and workflows. If a scheduled workflow is not enabled for high availability recovery, the PowerCenter Integration Service removes the workflow from the schedule.
- - Safe. The PowerCenter Integration Service does not run scheduled workflows and it disables schedule failover, automatic workflow recovery, workflow failover, and client request recovery. It performs failover and recovers the schedules, requests, and workflows when you enable the service in normal mode.
- Service
When the PowerCenter Integration Service becomes unavailable, you must enable the service and start the service processes. You can manually recover workflows and sessions based on the state and the configured recovery strategy. Workflows start if they are configured to run continuously or on initialization. You must reschedule all other workflows.
The workflows that run after you start the service processes depend on the operating mode:
- - Normal. Workflows start if they are configured to run continuously or on initialization. You must reschedule all other workflows.
- - Safe. Scheduled workflows do not start. You must enable the service in normal mode to run the scheduled workflows.
- Node
- When the node becomes unavailable, the failover behavior is the same as the failover for the service process, based on the operating mode.
Running on a Grid
When a service is running on a grid, the failover behavior depends on the following sources of failure:
- Master Service Process
If you disable the master service process, the Service Manager elects another node to run the master service process. If the master service process shuts down unexpectedly, the Service Manager tries to restart the process before electing another node to run the master service process.
The master service process then reconfigures the grid to run on one less node. The PowerCenter Integration Service restores the state of operation, and the workflow fails over to the newly elected master service process.
The PowerCenter Integration Service can recover the workflow based on the workflow state and recovery strategy. If the workflow was enabled for high availability recovery, the PowerCenter Integration Service restores the state of operation for the workflow and recovers the workflow from the point of interruption. When the PowerCenter Integration Service restores the state of operation for the service, it restores workflow schedules, service requests, and workflows. The PowerCenter Integration Service performs failover and recovers the schedules, requests, and workflows.
If a scheduled workflow is not enabled for high availability recovery, the PowerCenter Integration Service removes the workflow from the schedule.
- Worker Service Process
If you disable a worker service process, the master service process reconfigures the grid to run on one less node. If the worker service process shuts down unexpectedly, the Service Manager tries to restart the process before the master service process reconfigures the grid.
After the master service process reconfigures the grid, it can recover tasks based on task state and recovery strategy.
Because workflows do not run on the worker service process, workflow failover is not applicable.
- Service
- When the PowerCenter Integration Service becomes unavailable, you must enable the service and start the service processes. You can manually recover workflows and sessions based on the state and the configured recovery strategy. Workflows start if they are configured to run continuously or on initialization. You must reschedule all other workflows.
- Node
- When the node running the master service process becomes unavailable, the failover behavior is the same as the failover for the master service process. When the node running the worker service process becomes unavailable, the failover behavior is the same as the failover for the worker service process.
Note: You cannot configure a PowerCenter Integration Service to fail over in safe mode when it runs on a grid.