Introduction

• Consider the wording: a Controller can be operated as a Standalone Controller instance or as a Controller Cluster. The term Controller instance refers to the standalone instance or to a Controller Cluster member instance.
• The outage of a Controller instance will not stop the execution of workflows with Agents.
• However, if a workflow includes jobs that are executed with different Agents then the workflow will not be completed and will be put on hold as switching of Agents during workflow execution is performed by the Controller.
• Testing by SOS includes performing tests for the scenario when a Controller is not available for 24 hours and the Agent executes any scheduled orders. Once the Controller instance is started again then job execution results are updated to the JOC Cockpit History and become visible with the GUI.
• For information about the behavior in case of outages see JS7 - FAQ - What happens to workflows in case of outage of a Controller?

Controller Cluster

If you operate a Controller Cluster then an automated fail-over takes place should the active Controller instance fail. A fail-over typically occurs within 3-5s. Should the standby Controller instance fail then this does not affect the active Controller instance. Running a JS7 high availability cluster gives you the relaxed option not to have to take immediate action if one instance fails. However, should you intend to immediately make available the failed Controller Cluster member instance then the steps explained below similarly apply to the failed instance.

The below troubleshooting hints are intended for users operating a Standalone Controller, the steps explained are not required for users operating a Controller Cluster.

Troubleshooting

The Controller is the component in JS7 that holds job-related configurations and that orchestrates Agents. The outage of a Controller instance does not prevent the execution of workflows with jobs running on a single Agent. However, it affects the execution of workflows that include jobs running on a number of Agents as switching of Agents during workflow execution is performed by the Controller. 

A Controller instance outage can be handled either by resolving the issue with the current Controller instance, e.g. by restarting or by relocating the ./state directory to a new Controller instance. This directory holds the Controller instance's journal. To relocate a Controller instance copy the journal files to the new Controller instance. Refer to the JS7 - Moving Components - Relocating a Controller article for the steps to apply.