Setting Maintenance Mode
Set Maintenance Mode to supppress alerts when performing hardware or software maintenance, changing configuration settings, troubleshooting, decommissioning, or removing cluster nodes.
Setting Maintenance Mode enables you to suppress alerts and omit bulk operations for specific services, components, and hosts in an Ambari-managed cluster. Explicitly setting Maintenance Mode for a service implicitly sets Maintenance Mode for components and hosts that run the service. While Maintenance Mode prevents bulk operations being performed on the service, component, or host, you may explicitly start and stop a service, component, or host while in Maintenance Mode.
Four common instances in which you might want to set Maintenance Mode are; to perform maintenance, to test a configuration change, to delete a service completely, and to address alerts. Specific use-case examples:
- You want to perform hardware, firmware, or OS maintenance on a host.
- While performing maintenance, you want to be able to do the
following:
- Prevent alerts generated by all components on this host.
- Be able to stop, start, and restart each component on the host.
- Prevent host-level or service-level bulk operations from starting, stopping, or restarting components on this host.
To achieve these goals, explicitly set Maintenance Mode for the host. Putting a host in Maintenance Mode implicitly puts all components on that host in Maintenance Mode.
- You want to test a service configuration change.
- To text configuration changes,you want to ensure the
following conditions:
- No alerts are generated by any components in this service.
- No host-level or service-level bulk operations start, stop, or restart components in this service.
To achieve these goals, explicitly set Maintenance Mode for the service. Putting a service in Maintenance Mode implicitly turns on Maintenance Mode for all components in the service.
You will stop, start, and restart the service using a rolling restart to test whether restarting activates the change.
- You want to stop a service.
- To stop a service completely, you want to ensure the
following conditions:
- No warnings are generated by the service.
- No components start, stop, or restart due to host-level actions or bulk operations.
To achieve these goals, explicitly set Maintenance Mode for the service. Putting a service in Maintenance Mode implicitly turns on Maintenance Mode for all components in the service.
- You want to stop a host component from generating alerts.
- To stop a host component from generating alerts, you must be
able to do the following:
- Check the component.
- Assess warnings and alerts generated for the component.
- Prevent alerts generated by the component while you check its condition.