Help Center > > User Guide> Managing Active Clusters> Patch Operation Guide> Rolling Patches

Rolling Patches

Updated at: Apr 28, 2020 GMT+08:00

The rolling patch function indicates that patches are installed or uninstalled for one or more services in a cluster by performing a rolling service restart (restarting services or instances in batches), without interrupting the services or within a minimized service interruption interval. Services in a cluster are divided into the following three types based on whether they support rolling patch:

  • Services supporting rolling patch installation or uninstallation: All businesses or part of them (varying depending on different services) of the services are not interrupted during patch installation or uninstallation.
  • Services not supporting rolling patch installation or uninstallation: Businesses of the services are interrupted during patch installation or uninstallation.
  • Services with some roles supporting rolling patch installation or uninstallation: Some businesses of the services are not interrupted during patch installation or uninstallation.
Table 1 provides services and instances that support or do not support rolling restart in the MRS cluster.
Table 1 Services and instances that support or do not support rolling restart

Service

Instance

Whether to Support Rolling Restart

HDFS

NameNode

Yes

Zkfc

JournalNode

HttpFS

DataNode

Yarn

ResourceManager

Yes

NodeManager

Hive

MetaStore

Yes

WebHCat

HiveServer

MapReduce

JobHistoryServer

Yes

HBase

HMaster

Yes

RegionServer

ThriftServer

RESTServer

Spark

JobHistory

Yes

JDBCServer

SparkResource

No

Hue

Hue

No

Tez

TezUI

No

Loader

Sqoop

No

Zookeeper

Quorumpeer

Yes

Kafka

Broker

Yes

MirrorMaker

No

Flume

Flume

Yes

MonitorServer

Storm

Nimbus

Yes

UI

Supervisor

Logviewer

Installing a Patch

  1. Log in to the MRS management console.
  2. Choose Clusters > Active Clusters and click the name of the cluster to be queried to enter the page displaying the cluster's basic information.
  3. On the Patches page, click Install in the Operation column.
  4. On the Warning page, enable or disable Rolling Patch.

    Figure 1 Rolling patch installation
    • Enabling the rolling patch installation function: Services are not stopped before patch installation, and rolling service restart is performed after the patch installation. This minimizes the impact on cluster services but takes more time than common patch installation.
    • Disabling the rolling patch uninstallation function: All services are stopped before patch uninstallation, and all services are restarted after the patch uninstallation. This temporarily interrupts the cluster and the services but takes less time than rolling patch uninstallation.
    • The rolling patch installation function is not available in clusters with less than two Master nodes and three Core nodes.

  5. Click OK to install the target patch.
  6. View the patch installation progress.

    1. Access MRS Manager. For details, see Accessing MRS Manager or Accessing MRS Manager Supporting Kerberos Authentication.
    2. Choose System > Manage Patch. On the Manage Patch page, you can view the patch installation progress.

    For the isolated host nodes in the cluster, follow instructions in Restoring Patches for the Isolated Hosts to restore the patch.

Uninstalling a Patch

  1. Log in to the MRS management console.
  2. Choose Clusters > Active Clusters and click the name of the cluster to be queried to enter the page displaying the cluster's basic information.
  3. On the Patches page, click Uninstall in the Operation column.
  4. On the Warning page, enable or disable Rolling Patch.

    Figure 2 Rolling patch uninstallation
    • Enabling the rolling patch uninstallation function: Services are not stopped before patch uninstallation, and rolling service restart is performed after the patch uninstallation. This minimizes the impact on cluster services but takes more time than common patch uninstallation.
    • Disabling the rolling patch uninstallation function: All services are stopped before patch uninstallation, and all services are restarted after the patch uninstallation. This temporarily interrupts the cluster and the services but takes less time than rolling patch uninstallation.
    • The rolling patch uninstallation function is not available in clusters with less than two Master nodes and three Core nodes.

  5. Click OK to uninstall the target patch.
  6. View the patch uninstallation progress.

    1. Access MRS Manager. For details, see Accessing MRS Manager or Accessing MRS Manager Supporting Kerberos Authentication.
    2. Choose System > Manage Patch. On the Manage Patch page, you can view the patch uninstallation progress.

    For the isolated host nodes in the cluster, follow instructions in Restoring Patches for the Isolated Hosts to restore the patch.

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