Upgrades for DataStax Enterprise 5.0.x patch releases

Upgrade restrictions and limitations

Advanced preparation for upgrading DSE Search nodes

• Tune the schema before you upgrade. For DSE 5.0.10 and later, all field definitions in the schema are validated and must be DSE Search compatible, even if the fields are not indexed, have docValues applied, or used for copy-field source.
• The default behavior of automatic resource generation includes all columns. To improve performance, take action to prevent the fields from being loaded from the database to the indexing path. In the schema, remove or comment out unused fields.
• 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 you changed the schema, do a full reindex:

  dsetool reload_core keyspace_name.table_name schema=filepath solrconfig=filepath reindex=true deleteAll=true distributed=false

Preparing to upgrade

Follow these steps to prepare each node for the upgrade:

1. Familiarize yourself with the changes and features in the new release:
   • DataStax Enterprise 5.0 release notes.
   • General upgrading advice for any version. Be sure to read NEWS.txt all the way back to your current version.
   • Apache Cassandra™ changes in CHANGES.txt.
   • DataStax driver changes.
2. Stop the OpsCenter Repair Service if enabled:
   • 6.7
   • 6.5
   • 6.1
3. Before upgrading, be sure that each node has adequate free disk space.
   Determine current DSE data disk space usage:

   sudo du -sh /var/lib/cassandra/data/
   3.9G	/var/lib/cassandra/data/

   Determine available disk space:

   sudo df -hT /
   Filesystem     Type  Size  Used Avail Use% Mounted on
   /dev/sda1      ext4   59G   16G   41G  28% /

   Important: The required space depends on the compaction strategy. See Disk space
4. Run nodetool repair to ensure that data on each replica is consistent with data on other nodes:

   nodetool repair -pr

5. Back up any customized configuration files since they may be overwritten with default values during installation of the new version.
   Tip: If you backed up your installation using instructions in Backing up and restoring DSE, your original configuration files are included in the archive.
6. Upgrade the SSTables on each node to ensure that all SSTables are on the current version:

   nodetool upgradesstables

   Warning: Failure to upgrade SSTables when required results in a significant performance impact and increased disk usage.

   Tip: 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. DataStax recommends running the upgradesstables command on one node at a time or when using racks, one rack at a time.

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

7. Upgrades from 5.0.0 to 5.0.8 and from DSE 5.1.0 and 5.1.1 to DSE 5.1.2 and later DSE 5.1.x releases
   Restart the node with this start-up parameter:

   -Dcassandra.force_3_0_protocol_version=true

   For example:

   installation_location/bin/dse cassandra -Dcassandra.force_3_0_protocol_version=true

   Note: While mixed versions exist during the upgrade, do not add or remove columns from existing tables.

   After the restart is complete, remove the flag.

Upgrade steps

1. DSE Analytics nodes only: Kill all Spark worker processes:

   for pid in $(jps | grep Worker | awk '{print $1}'); do kill -9 $pid; done

2. Flush the commit log of the current installation:

   nodetool drain

3. Stop the node:
   • Package installations:

     sudo service dse stop

   • Tarball installations:

     installation_dir/bin/dse cassandra-stop

4. Use the appropriate method to install the new product version.
   Warning: Install the new product version using the same installation type that is on the system, otherwise problems might result.
   Warning: TTL expiration timestamps are susceptible to the year 2038 problem. If the TTL value is long and an expiration date that is greater than the maximum threshold of 2038-01-19T03:14:06+00:00, the data is immediately expired and purged on the next compaction. DataStax strongly recommends upgrading to DSE 5.0.15 or later and taking required action to protect against silent data loss.
5. Compare changes in the new configuration files with the backup configuration files after the upgrade but before restarting, remove deprecated settings, and update any new settings if required.
   Tip: Use the DSE yaml_diff tool to compare backup YAML files with the upgraded YAML files:

   cd /usr/share/dse/tools/yamls

   ./yaml_diff path/to/yaml-file-old path/to/yaml-file-new
   ...
    CHANGES 
   =========
   authenticator:
   - AllowAllAuthenticator
   + com.datastax.bdp.cassandra.auth.DseAuthenticator
   
   authorizer:
   - AllowAllAuthorizer
   + com.datastax.bdp.cassandra.auth.DseAuthorizer
   
   roles_validity_in_ms:
   - 2000
   + 120000
   ...

6. Start the node.
   • Installer-Services and Package and installations:

     sudo service dse start

   • Installer-No Services and Tarball installations:

     installation_dir/bin/dse cassandra

7. Verify that the upgraded datacenter names match the datacenter names in the keyspace schema definition:
   • Get the node's datacenter name:

     nodetool status | grep "Datacenter"
     Datacenter: datacenter-name

   • Verify that the node's datacenter name matches the datacenter name for a keyspace:

     cqlsh --execute "DESCRIBE KEYSPACE keyspace-name;" | grep "replication"
     CREATE KEYSPACE keyspace-name WITH replication = {'class': 'NetworkTopologyStrategy, 'datacenter-name': '3'};

8. Review the logs for warnings, errors, and exceptions:

   grep -w 'WARNING\|ERROR\|exception' /var/log/cassandra/*.log

   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.

   Tip: Non standard log locations are configured in dse-env.sh.
9. Repeat the upgrade process on each node in the cluster following the recommended order.
10. If you use the OpsCenter Repair Service restart it:
    • 6.8
    • 6.7
    • 6.5
    • 6.1
11. After the entire cluster upgrade is complete: upgrade the SSTables on one node at a time or, when using racks, one rack at a time.
    Warning: Failure to upgrade SSTables when required results in a significant performance impact and increased disk usage and possible data loss. Upgrading is not complete until the SSTables are upgraded.

    nodetool upgradesstables

    Tip: 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. DataStax recommends running the upgradesstables command on one node at a time or when using racks, one rack at a time.
    Important: You can run the upgradesstables command before all the nodes are upgraded as long as you run the command on only one node at a time or when using racks, one rack at a time. Running upgradesstables on too many nodes at once will degrade performance.