Starting and Stopping an MRS Cluster Component
During MRS cluster O&M, administrators must start or stop cluster components based on service requirements. For example, stopping unused services frees up compute and memory resources. If a service is abnormal, stop and restart it to restore functionality, or restart the service when its configuration updates to apply changes. You can start, stop, and restart components on either the management console or MRS Manager. This section describes how to start and stop MRS cluster components.
Prerequisites
- The IAM users have been synchronized in advance. You can do this by clicking Synchronize next to IAM User Sync on the Dashboard page of the cluster details.
- You have logged in to MRS Manager. For how to log in, see Accessing MRS Manager.
Impact on the System
Some services within the system rely on one another. Therefore, when you start, stop, or restart a service, any services that depend on it will be affected.
- If a service is to be started, the lower-layer services dependent on it must be started first.
- If a service is stopped, the upper-layer services dependent on it are unavailable.
- If a service is restarted, the running upper-layer services dependent on it must be restarted.
Starting and Stopping an MRS Cluster Component
You can start or stop a component on the management console or on FusionInsight Manager as required.
- Log in to the MRS console.
- On the Active Clusters page, select a running target cluster and click its name to go to the cluster details page.
- On the Dashboard page, click Synchronize next to IAM User Sync to synchronize IAM users.
- On the cluster details page, click Components.
- Locate the row that contains the target component and click Stop. Confirm the operation impact and click OK.
After a component is stopped, it cannot provide services for external systems, which may affect the upper-layer services of the cluster. Ensure that the operation does not have any adverse impact before performing this operation.
After the operation is successful, Operating Status of the component changes to Stopped.
- To start a component, click Start in the Operation column of a stopped component and start the component as prompted.
After the operation is successful, Operating Status of the component changes to Started.
Verification:
On the component management page, check the status of the target component. If the status is Stopped after a stop operation or Running after a start operation, the operation was successful.
- Log in to FusionInsight Manager of the MRS cluster.
For details about how to log in to FusionInsight Manager, see Accessing MRS Manager.
- Choose Cluster > Services.
The service list contains all components installed in the cluster. When you select Tile View, the components are displayed as tiles. When you select Table View, the components are displayed in a table.
In this section, the Table View is used by default.
- Locate the target service and click Stop Service in the Operation column.
You can also click the name of the target service. On the displayed service details page, click Stop Service in the upper right corner.
- Enter the password of the current administrator, confirm that the operation does not have any adverse impact, and click OK.
After a component is stopped, it cannot provide services for external systems, which may affect the upper-layer services of the cluster. Ensure that the operation does not have any adverse impact before performing this operation.
After the operation is successful, Running Status of the component changes to Not started.
- To start a component, click Start Service in the Operation column of a stopped component and start the component as prompted.
Verification:
After the operation is successful, Running Status of the component changes to Normal.
FAQs
- Component startup failed
Common causes of startup failures include: the dependent lower-layer service is not started, node resources (memory or disk space) are insufficient, or incorrect component parameter settings prevent service initialization.
Ensure that the dependent lower-layer service is started. Check node resource usage to ensure sufficient memory and disk space. Check whether related alarms appear on the MRS Manager alarm page, and rectify the fault based on the alarm information.
- Upper-layer service exceptions after a component stops
After a service stops, upper-layer services that depend on it may become abnormal or unavailable due to interrupted dependencies.
Before stopping a service, check whether upper-layer services that depend on it can tolerate the impact. If upper-layer services cannot be interrupted, evaluate dependencies before performing the operation. If the service is stopped and an upper-layer service becomes abnormal, restart the service to restore the dependency.
Helpful Links
- For details about how to synchronize MRS cluster configurations, see Synchronizing MRS Component Configuration Parameters.
- For details about how to view MRS cluster component monitoring metrics, see Viewing MRS Cluster Component Monitoring Metrics.
- For details about how to view MRS cluster alarms, see Viewing Alarms of an MRS Cluster.
