Migrate an Apache HBase cluster to a HDInsight 5.1

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This article discusses how to update your Apache HBase cluster on Azure HDInsight to a newer version.

This article applies only if you use the same Azure Storage account for your source and destination clusters. To upgrade with a new or different Storage account for your destination cluster, see Migrate Apache HBase to HDInsight 5.1 with a new Storage account.

The downtime for upgrading may take more than 20 minutes. This downtime caused by the steps to flush all in-memory data, and wait for all procedure to complete and the time to configure and restart the services on the new cluster. Your results vary, depending on the number of nodes, amount of data, and other variables.

Review Apache HBase compatibility

Before upgrading Apache HBase, ensure the HBase versions on the source and destination clusters are compatible. Review the HBase version compatibility matrix and release notes in the HBase Reference Guide to make sure your application is compatible with the new version.

Here's an example compatibility matrix. Y indicates compatibility and N indicates a potential incompatibility:

Compatibility type Major version Minor version Patch
Client-Server wire compatibility N Y Y
Server-Server compatibility N Y Y
File format compatibility N Y Y
Client API compatibility N Y Y
Client binary compatibility N N Y
Server-side limited API compatibility
Stable N Y Y
Evolving N N Y
Unstable N N N
Dependency compatibility N Y Y
Operational compatibility N N Y

For more information about HDInsight versions and compatibility, see Azure HDInsight versions.

Apache HBase cluster migration overview

To upgrade your Apache HBase cluster on Azure HDInsight, complete the following basic steps. For detailed instructions, see the detailed steps and commands, or use the scripts from the section Migrate HBase using scripts for automated migration.

Prepare the source cluster:

  1. Stop data ingestion.
  2. Check cluster health
  3. Stop replication if needed
  4. Flush memstoredata.
  5. Stop HBase.
  6. For clusters with accelerated writes, back up the Write Ahead Log (WAL) directory.

Prepare the destination cluster:

  1. Create the destination cluster.
  2. Stop HBase from Ambari.
  3. Update fs.defaultFS in HDFS service configs to refer to the original source cluster container.
  4. For clusters with accelerated writes, update hbase.rootdir in HBase service configs to refer to the original source cluster container.
  5. Clean Zookeeper data.

Complete the migration:

  1. Clean and migrate the WAL.
  2. Copy apps from the destination cluster's default container to the original source container.
  3. Start all services from the Ambari destination cluster.
  4. Verify HBase.
  5. Delete the source cluster.

Detailed migration steps and commands

Use these detailed steps and commands to migrate your Apache HBase cluster.

Prepare the source cluster

  1. Stop ingestion to the source HBase cluster.

  2. Check Hbase hbck to verify cluster health

    1. Verify HBCK Report page on HBase UI. Healthy cluster doesn't show any inconsistencies Screenshot showing how to verify HBCK report.
    2. If any inconsistencies exist, fix inconsistencies using hbase hbck2

  3. Note down number of regions in online at source cluster, so that the number can be referred at destination cluster after the migration. Screenshot showing total number of regions.

  4. If replication enabled on the cluster, stop and reenable the replication on destination cluster after migration. For more information, see Hbase replication guide

  5. Flush the source HBase cluster you're upgrading.

    HBase writes incoming data to an in-memory store called a memstore. After the memstorereaches a certain size, HBase flushes it to disk for long-term storage in the cluster's storage account. Deleting the source cluster after an upgrade also deletes any data in the memstores. To retain the data, manually flush each table's memstoreto disk before upgrading.

    You can flush the memstoredata by running the flush_all_tables.sh script from the Azure hbase-utils GitHub repository.

    You can also flush memstoredata by running the following HBase shell command from the HDInsight cluster:

    hbase shell
flush "<table-name>"

  6. Wait for 15 mins and verify that all the procedures are completed, and masterProcWal files doesn't have any pending procedures.

    1. Verify the Procedures page to confirm that there are no pending procedures.

      Screenshot showing how to verify master process.

  7. STOP HBase

    1. Sign in to Apache Ambari on the source cluster with https://<OLDCLUSTERNAME>.azurehdinsight.cn

    2. Turn on maintenance mode for HBase.

    3. Stop HBase Masters only first. First stop standby masters, in last stop Active HBase master.

      Screenshot showing how to stop master services.

    4. Stop the HBase service, it stops remaining servers.

    Note

    HBase 2.4.11 doesn't t support some of the old Procedures.

    For more information on connecting to and using Ambari, see Manage HDInsight clusters by using the Ambari Web UI.

    Stopping HBase in the previous steps to avoid creating new master proc WALs.

  8. If your source HBase cluster doesn't have the Accelerated Writes feature, skip this step. For source HBase clusters with Accelerated Writes, back up the WAL directory under HDFS by running the following commands from an SSH session on any of the Zookeeper nodes or worker nodes of the source cluster.

    hdfs dfs -mkdir /hbase-wal-backup
hdfs dfs -cp hdfs://mycluster/hbasewal /hbase-wal-backup

Prepare the destination cluster

  1. In the Azure portal, set up a new destination HDInsight cluster using the same storage account as the source cluster, but with a different container name:

  2. Sign in to Apache Ambari on the new cluster at https://<NEWCLUSTERNAME>.azurehdinsight.cn, and stop the HBase services.

  3. Under Services > HDFS > Configs > Advanced > Advanced core-site, change the fs.defaultFS HDFS setting to point to the original source cluster container name. For example, the setting in the following screenshot should be changed to wasbs://hbase-upgrade-old-2021-03-22.

    Screenshot shows in Ambari, select Services > HDFS > Configs > Advanced > Advanced core-site and change the container name.

  4. If your destination cluster has the Accelerated Writes feature, change the hbase.rootdir path to point to the original source cluster container name. For example, the following path should be changed to hbase-upgrade-old-2021-03-22. If your cluster doesn't have Accelerated Writes, skip this step.

    Screenshot shows in Ambari, change the container name for the HBase rootdir.

  5. Clean the Zookeeper data on the destination cluster by running the following commands in any Zookeeper node or worker node:

    hbase zkcli
rmr /hbase-unsecure
quit

Clean and migrate WAL

Run the following commands, depending on your source HDInsight version and whether the source and destination clusters have Accelerated Writes.

  1. The destination cluster is always HDInsight version 4.0, since HDInsight 3.6 is in Basic support and isn't recommended for new clusters.
  2. The HDFS copy command is hdfs dfs <copy properties starting with -D> -cp <source> <destination> # Serial execution.

Note

  • The <source-container-fullpath> for storage type WASB is wasbs://<source-container-name>@<storageaccountname>.blob.core.chinacloudapi.cn.
  • The <source-container-fullpath> for storage type Azure Data Lake Storage Gen2 is abfs://<source-container-name>@<storageaccountname>.dfs.core.chinacloudapi.cn.

The source cluster is HDInsight 4.0 with Accelerated Writes, and the destination cluster has Accelerated Writes

Clean the WAL FS data for the destination cluster, and copy the WAL directory from the source cluster into the destination cluster's HDFS. Copy the directory by running the following commands in any Zookeeper node or worker node on the destination cluster:

sudo -u hbase hdfs dfs -rm -r hdfs://mycluster/hbasewal
sudo -u hbase hdfs dfs -cp <source-container-fullpath>/hbase-wal-backup/hbasewal hdfs://mycluster/

The source cluster is HDInsight 4.0 without Accelerated Writes, and the destination cluster has Accelerated Writes

Clean the WAL FS data for the destination cluster, and copy the WAL directory from the source cluster into the destination cluster's HDFS. Copy the directory by running the following commands in any Zookeeper node or worker node on the destination cluster:

sudo -u hbase hdfs dfs -rm -r hdfs://mycluster/hbasewal
sudo -u hbase hdfs dfs -cp <source-container-fullpath>/hbase-wals/* hdfs://mycluster/hbasewal

The source cluster is HDInsight 4.0 without Accelerated Writes, and the destination cluster doesn't have Accelerated Writes

Clean the WAL FS data for the destination cluster, and copy the source cluster WAL directory into the destination cluster's HDFS. To copy the directory, run the following commands in any Zookeeper node or worker node on the destination cluster:

sudo -u hbase hdfs dfs -rm -r /hbase-wals/*
sudo -u hbase hdfs dfs -Dfs.azure.page.blob.dir="/hbase-wals" -cp <source-container-fullpath>/hbase-wals /

Complete the migration

  1. Using the sudo -u hdfs user context, copy the folder /hdp/apps/<new-version-name> and its contents from the <destination-container-fullpath> to the /hdp/apps folder under <source-container-fullpath>. You can copy the folder by running the following commands on the destination cluster:

    sudo -u hdfs hdfs dfs -cp /hdp/apps/<hdi-version> <source-container-fullpath>/hdp/apps

    For example:

    sudo -u hdfs hdfs dfs -cp /hdp/apps/4.1.3.6 wasbs://hbase-upgrade-old-2021-03-22@hbaseupgrade.blob.core.chinacloudapi.cn/hdp/apps

  2. On the destination cluster, save your changes, and restart all required services as Ambari indicates.

  3. Point your application to the destination cluster.

    Note

    The static DNS name for your application changes when you upgrade. Rather than hard-coding this DNS name, you can configure a CNAME in your domain name's DNS settings that points to the cluster's name. Another option is to use a configuration file for your application that you can update without redeploying.

  4. Start the ingestion.

  5. Verify HBase consistency and simple Data Definition Language (DDL) and Data Manipulation Language (DML) operations.

  6. If the destination cluster is satisfactory, delete the source cluster.

Migrate HBase using scripts

  1. Note down number of regions in online at source cluster, so that the number can be referred at destination cluster after the migration. Screenshot showing count of number of regions.

  2. Flush the source HBase cluster you're upgrading.

    HBase writes incoming data to an in-memory store called a memstore. After the memstorereaches a certain size, HBase flushes it to disk for long-term storage in the cluster's storage account. Deleting the source cluster after an upgrade also deletes any data in the memstores. To retain the data, manually flush each table's memstoreto disk before upgrading.

    You can flush the memstoredata by running the flush_all_tables.sh script from the Azure hbase-utils GitHub repository.

    You can also flush memstoredata by running the following HBase shell command from the HDInsight cluster:

    hbase shell
flush "<table-name>"

  3. Wait for 15 mins and verify that all the procedures are completed, and masterProcWal files doesn't have any pending procedures.

    1. Verify the Procedures page to confirm that there are no pending procedures.

      Screenshot showing how to verify master process.

  4. Execute the script migrate-to-HDI5.1-hbase-source.sh on the source cluster and migrate-hbase-dest.sh on the destination cluster. Use the following instructions to execute these scripts.

    Note

    These scripts don't copy the HBase old WALs as part of the migration; therefore, the scripts are not to be used on clusters that have either HBase Backup or Replication feature enabled.

  5. On source cluster

    sudo bash migrate-to-HDI5.1-hbase-source.sh

  6. On destination cluster

    sudo bash migrate-hbase-dest.sh  -f <src_default_Fs>

Mandatory argument for the above command:

   -f, --src-fs
   The fs.defaultFS of the source cluster
   For example:
   -f wasb://anynamehbase0316encoder-2021-03-17t01-07-55-935z@anynamehbase0hdistorage.blob.core.chinacloudapi.cn

Troubleshooting

Use case 1:

If Hbase masters and region servers up and regions stuck in transition or only one region, for example, hbase:meta region is assigned. Waiting for other regions to assign

Solution:

  1. ssh into any ZooKeeper node of original cluster and run kinit -k -t /etc/security/keytabs/hbase.service.keytab hbase/<zk FQDN> if this is ESP cluster

  2. Run echo "scan 'hbase:meta'" | hbase shell > meta.out to read the hbase:meta into a file

  3. Run grep "info:sn" meta.out | awk '{print $4}' | sort | uniq to get all RS instance names where the regions were present in old cluster. Output should be like value=<wn FQDN>,16020,........

  4. Create a dummy WAL dir with that wn value

    If the cluster is accelerated write cluster

    hdfs dfs -mkdir hdfs://mycluster/hbasewal/WALs/<wn FQDN>,16020,.........

    If the cluster is nonaccelarated Write cluster

    hdfs dfs -mkdir /hbase-wals/WALs/<wn FQDN>,16020,.........

  5. Restart active Hmaster

Next steps

To learn more about Apache HBase and upgrading HDInsight clusters, see the following articles: