Upgrade to DataStax Enterprise 4.7 or 4.8

Follow these instructions to upgrade from DataStax Enterprise 4.0, 4.5, and 4.6 to DataStax Enterprise 4.7 or 4.8.

Read and understand these instructions before upgrading. Carefully reviewing the planning and upgrade instructions can prevent errors and data loss.

Apache Cassandra® version change

Upgrading 4.0, 4.5, and 4.6 to DataStax Enterprise 4.7 or 4.8 includes a major Cassandra version change.

Be sure to follow the recommendations for upgrading the SSTables.

Upgrading SSTables is required for upgrades that contain major Apache Cassandra releases:

  • DataStax Enterprise 5.0 uses Cassandra 3.0.

  • DataStax Enterprise 4.7 to 4.8 use Cassandra 2.1.

  • DataStax Enterprise 4.0 to 4.6 use Cassandra 2.0.

Upgrading to DataStax Enterprise 4.7 includes these changes:

  • A Cassandra version change from 2.0 to 2.1, and changes the default value of the commitlog_total_space_in_mb value in cassandra.yaml from 1024 MB to 8192 MB. Adjust the commitlog_total_space_in_mb setting for your environment to ensure that you do not run out of disk space after upgrade.

  • Logging is changed from log4j to logback, with changes to logging retention policies. Configure the logger by setting options in logback.xml.

General recommendations

DataStax recommends backing up your data prior to any version upgrade, including logs and custom configurations. A backup provides the ability to revert and restore all the data used in the previous version if necessary.

OpsCenter provides a Backup Service that manages enterprise-wide backup and restore operations for DataStax Enterprise clusters. OpsCenter 6.5 and later is recommended.

Upgrade restrictions and limitations

Restrictions and limitations apply while a cluster is in a partially upgraded state.

With these exceptions, the cluster continues to work as though it were on the earlier version of DataStax Enterprise until all of the nodes in the cluster are upgraded.

  • General upgrade restrictions

    • Do not enable new features.

    • Do not run nodetool repair.

    • During the upgrade, do not bootstrap or decommission nodes.

    • Do not issue these types of CQL queries during a rolling restart: DDL and TRUNCATE.

    • During the upgrade, the nodes on different versions might show a schema disagreement.

    • Failure to upgrade SSTables when required results in a significant performance impact and increased disk usage. Upgrading is not complete until the SSTables are upgraded.

  • Restrictions for DSE Analytic (Spark) nodes

    • Do not run analytics jobs until all nodes are upgraded.

    • When upgrading to a major version of DSE, all nodes in a DSE datacenter that run Spark must be on the same version of Spark and the Spark jobs must be compiled for that version. Each datacenter acting as a Spark cluster must be on the same upgraded DSE version before reinitiating Spark jobs.

      In the case where Spark jobs run against Graph keyspaces, you must update all of the nodes in the cluster first to avoid Spark jobs failing.

  • Restrictions for DSE Search (Solr) nodes

    • Do not update schemas.

    • Do not reindex DSE Search nodes during upgrade.

    • Do not issue these types of queries during a rolling restart: BATCH or TRUNCATE.

    • During the upgrade process on a cluster with mixed versions where DataStax Enterprise 4.7 or 4.8 supports pagination and earlier versions do not, issuing queries from the upgraded nodes returns only FetchSize results. (4.7 or 4.8)

  • Restrictions for nodes using any kind of security

    • Do not change security credentials or permissions until after the upgrade is complete.

Preparing to upgrade from 4.0, 4.5, or 4.6 to 4.7 or 4.8

Follow these steps to prepare to upgrade from DataStax Enterprise 4.0, 4.5, and 4.6 to DataStax Enterprise 4.7 or 4.8.

  1. Before upgrading, be sure that each node has adequate free disk space.

    The required space depends on the compaction strategy. See Disk space.

  2. Familiarize yourself with the changes and features in this release:

    • DataStax Enterprise release notes for 4.7 and 4.8.

    • General upgrading advice for any version and New features for Apache Cassandra 2.1 in NEWS.txt. Be sure to read the NEWS.txt all the way back to your current version.

    • Apache Cassandra changes in CHANGES.txt.

  3. Verify your current product version. If necessary, upgrade to one these required interim versions before upgrading to 4.7 or 4.8:

    • DataStax Enterprise 4.0 and later

    • DataStax Community or open source Apache Cassandra 2.0.x

  4. Upgrade the SSTables on each node to ensure that all SSTables are on the current version.

    This is required for DataStax Enterprise upgrades that include a major Cassandra version changes.

    nodetool upgradesstables

    If the SSTables are already on the current version, the command returns immediately and no action is taken. See SSTable compatibility and upgrade version.

    Use the --jobs option to set the number of SSTables that upgrade simultaneously. The default setting is 2, which minimizes impact on the cluster. Set to 0 to use all available compaction threads. For information about nodetool upgradesstables, including how to speed it up, see the DataStax Support KB article Nodetool upgradesstables FAQ.

    Failure to upgrade SSTables results in a significant performance impact and increased disk usage.

  5. Verify the Java runtime version and upgrade to the recommended version.

    java -version

    The latest version of Oracle Java SE Runtime Environment 7 or 8 or OpenJDK 7 is recommended. The JDK is recommended for development and production systems. The JDK provides useful troubleshooting tools that are not in the JRE, such as jstack, jmap, jps, and jstat.

    If using Oracle Java 7, you must use at least 1.7.0_25. If using Oracle Java 8, you must use at least 1.8.0_40.

  6. Run nodetool repair to ensure that data on each replica is consistent with data on other nodes.

  7. DSE Search nodes:

    All unique key elements must be indexed in the Solr schema. To verify unique key elements, review schema.xml to ensure that all unique key fields must have indexed=true. If required, make changes to schema.xml and reload the Solr core.

  8. Back up the configuration files you use to a folder that is not in the directory where you normally run commands. The configuration files are overwritten with default values during installation of the new version.

Steps for upgrading from 4.0, 4.5, or 4.6 to 4.7 or 4.8

The DataStax installer upgrades DataStax Enterprise and automatically performs many upgrade tasks.

The upgrade process for DataStax Enterprise provides minimal downtime (ideally zero). During this process, upgrade and restart one node at a time while other nodes continue to operate online. With a few exceptions, the cluster continues to work as though it were on the earlier version of DataStax Enterprise until all of the nodes in the cluster are upgraded.

Follow these steps on each node to upgrade from DataStax Enterprise 4.0, 4.5, and 4.6 to DataStax Enterprise 4.7 or 4.8.

  1. Upgrade order matters. Upgrade nodes in this order:

    1. In multiple datacenter clusters, upgrade every node in one datacenter before upgrading another datacenter.

    2. Upgrade the seed nodes within a datacenter first.

    3. DSE Analytics datacenters

      1. For DSE Analytics nodes using DSE Hadoop, upgrade the Job Tracker node first. Then upgrade Hadoop nodes, followed by Spark nodes.

    4. Transactional/DSE Graph datacenters

    5. DSE Search datacenters: With a few exceptions, the cluster continues to work as though it were on the earlier version of DataStax Enterprise until all of the nodes in the cluster are upgraded. Upgrade and restart the nodes one at a time. Other nodes in the cluster continue to operate at the earlier version until all nodes are upgraded.

  2. DSE Analytics nodes: Kill all Spark worker processes.

  3. DSE Search nodes: Review these considerations and take appropriate actions:

    • If your schema.xml contains fieldTypes using docValuesFormat="Disk", you must modify the file to remove the docValuesFormat attribute, reload, and optimize your index to rewrite to the default codec. This a requirement for Solr 4.10 and above.

    • To maintain 4.6 query behavior:

      • Disable driver pagination by editing the dse.yaml file and setting cql_solr_query_paging: off. DataStax Enterprise 4.7 or 4.8 integrates native driver paging with Solr cursor-based paging.

    • You can turn on paging after you verify the upgrade.

  1. To flush the commit log of the old installation:

    nodetool -h hostname drain

    This step saves time when nodes start up after the upgrade, and prevents DSE Search nodes from having to reindex data.

    This step is mandatory when upgrading between major Cassandra versions that change SSTable formats, rendering commit logs from the previous version incompatible with the new version.

  2. Stop the node: (4.7, 4.8).

  3. Install the new product version on a supported platform using the same installation type tha you used previously (such as a package or tarball). The upgrade proceeds with installation regardless of the installation type. If you use a different installation type, the upgrade might result in issues.

  4. To configure the new product version:

    1. Compare your backup configuration files to the new configuration files. Look for any deprecated, removed, or changed settings. Be sure you are familiar with the Apache Cassandra and DataStax Enterprise changes and features in the new release.

    2. Merge the applicable modifications into the new version.

  5. Start the node:

    • Installer-Services and Package installations: See Starting DataStax Enterprise as a service (4.7, 4.8).

    • Installer-No Services and Tarball installations: See Starting DataStax Enterprise as a stand-alone process 4.7, 4.8).

  6. Verify that the upgraded datacenter names match the datacenter names in the keyspace schema definition:

    nodetool status

  7. Review the logs for warnings, errors, and exceptions.

    Warnings, errors, and exceptions are frequently found in the logs when starting an upgraded node. Some of these log entries are informational to help you execute specific upgrade-related steps. If you find unexpected warnings, errors, or exceptions, contact DataStax Support.

    During upgrade of DSE Analytics nodes, exceptions about the Task Tracker are logged in the nodes that are not yet upgraded to 4.7 or 4.8. The jobs succeed after the entire cluster is upgraded.

    Because DataStax Enterprise 4.7 and 4.8 use Cassandra 2.1, the output.log includes the following warnings:

    • Deprecated cassandra.yaml options are removed:

      • multithreaded_compaction

      • memtable_flush_queue_size

      • compaction_preheat_key_cache

      • in_memory_compaction_limit_in_mb

      • preheat_kernel_page_cache

    • cassandra-env.sh change from JVM_OPTS="$JVM_OPTS -javaagent:$CASSANDRA_HOME/lib/jamm-0.2.5.jar" to JVM_OPTS="$JVM_OPTS -javaagent:$CASSANDRA_HOME/lib/jamm-0.3.0.jar"

  8. In DataStax Enterprise 4.8, audit log tables use DateTieredCompactionStrategy (DTCS). See audit log tables.

    DataStax recommends changing tables that were created in earlier releases to use DTCS:

    ALTER TABLE dse_audit.audit_log WITH COMPACTION={'class':'DateTieredCompactionStrategy'};

  9. Repeat the upgrade on each node in the cluster following the recommended order.

  10. If existing tables use the DSE In-Memory option:

    1. Turn off SSTable compression:

      ALTER TABLE <tablename> WITH compression = {'sstable_compression' : ''} ;

    2. Rewrite existing SSTables without compression:

      nodetool upgradesstables -a <keyspacename> <tablename>

      Use the --jobs option to set the number of SSTables that upgrade simultaneously. The default setting is 2, which minimizes impact on the cluster. Set to 0 to use all available compaction threads.

  11. Upgrade the SSTables on the remaining nodes:

    nodetool upgradesstables

    Failure to upgrade SSTables when required results in a significant performance impact and increased disk usage. Upgrading is not complete until the SSTables are upgraded.

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