Adding and Deleting an MRS Cluster Component
When creating an MRS cluster, you can select service components to be included in the cluster. After the cluster is created, administrators can manually add or delete components for MRS on the console.
Notes and Constraints
- Normal clusters: Only custom clusters of MRS 3.1.2 or later allow you to add or delete a component.
- LTS clusters: Only custom clusters of MRS 3.1.2-LTS.3 or a later LTS version allow you to add or delete a component.
Prerequisites
- You have configured permissions for the user group to which the IAM users belong.
Adding or deleting a service in a cluster is a high-risk operation. Bind the MRS FullAccess, MRS Administrator, Server Administrator, Tenant Guest, MRS Administrator, or Tenant Administrator policy to the user group before you perform this operation.
For details about the permissions, see Synchronizing IAM Users to MRS.
- You have synchronized IAM users. (On the Dashboard tab page, click Synchronize next to IAM User Sync to synchronize IAM users.)
- You can add services only on nodes or node groups that are in normal state.
- If the service to be deleted has upper-layer dependencies, the service cannot be deleted. Only one service can be deleted at a time.
Adding an MRS Cluster Component
- Log in to the MRS console.
- On the Active Clusters page, select a running cluster and click its name to switch to the cluster details page.
- On the cluster details page, choose Components and click Add Service.
- In the service list, select the services to be added and click Next.
- For details about the components supported by each MRS version, see List of MRS Component Versions.
- When you add a service, the underlying services that it depends on are automatically selected. You can add multiple services at the same time.
- Components (MapReduce, YARN, and HDFS) in the Hadoop service cannot be added separately.
- If Hadoop is not installed in a cluster, after Hadoop is added, you need to refresh the console and synchronize IAM users again to submit jobs on the job management page.
- After the Spark2x/Spark component is added, if you need to perform operations on Spark SQL through the Hue Web UI, restart the Hue service first.
- On the Topology Adjustment page, select the nodes where the service is to be deployed. For details about the deployment scheme, see Table 2.
- Confirm the operation impact and click OK. After the service is added, you can view the added service on the Components page. Table 1 describes the component status.
Table 1 Component status description Status Type
Status
Description
Operating Status
Started
The service is started.
Stopped
The service is stopped.
Failed to start
Failed to start the role instance.
Failed to stop
Failed to stop the role instance.
Unknown
Initial service status after the background system restarts.
Health Status
Good
Indicates that all role instances in the service are running properly.
Faulty
The running status of at least one role instance is Faulty or the status of the service on which the current service depends is abnormal.
If the running status of a service is Faulty, an alarm is generated. Rectify the fault based on the alarm information.
Unknown
All role instances in the service are in the Unknown state.
Restoring
The background system is restarting the service.
Partially Healthy
When a dependent service fails, external systems cannot access its related APIs. This affects upper-layer businesses that rely on the service.
HBase, Hive, Spark, and Loader may be in the Partially Healthy state.- If YARN is installed but is abnormal, HBase is in the Partially Healthy state.
- If HBase is installed but is abnormal, Hive, Spark, and Loader are in the Partially Healthy state.
Configuration Status
Synchronized
Indicates that the latest configuration takes effect.
Configuration expired
The latest configuration does not take effect after the parameter modification. You need to restart related services.
Configuration failed
If a communication or read/write exception occurs during parameter configuration, you can use the synchronization configuration function to rectify the fault.
Configuring
Parameters are being configured.
Unknown
Current configuration status cannot be obtained.
Deleting an MRS Cluster Component
- Log in to the MRS console.
- On the Active Clusters page, select a running cluster and click its name to switch to the cluster details page.
- Click Components, locate the row that contains the target component, and click Delete.
Enter DELETE in the displayed Delete Service dialog box and click OK to confirm the deletion.
- If the service to be deleted has upper-layer dependencies, the service cannot be deleted. Only one service can be deleted at a time.
- All installed services except Hadoop (HDFS, YARN, MapReduce), Ranger, DBService, KrbServer, LdapServer, and meta services can be deleted.
- Before deleting a service, back up the service data to prevent data loss.
Helpful Links
If the current cluster does not allow you to add or delete components, create an MRS cluster and select components that meet the requirements. For details, see Buying MRS Clusters.
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