Upgrading from DataStax Enterprise 6.0 to 6.7

Instructions for upgrading from DSE 6.0 to 6.7.

dse.yaml

The location of the dse.yaml file depends on the type of installation:

Package installations	/etc/dse/dse.yaml
Tarball installations	`installation_location`/resources/dse/conf/dse.yaml

Upgrade order

Upgrade nodes in this order:

In multiple datacenter clusters, upgrade every node in one datacenter before upgrading another datacenter.
Upgrade the seed nodes within a datacenter first.
Upgrade nodes in this order:
1. DSE Analytics datacenters
2. Transactional/DSE Graph datacenters
3. DSE Search datacenters


OpsCenter version	DSE version
6.7	6.7, 6.0, 5.1
6.5	6.0, 5.1, 5.0 (EOL)
6.1	5.1, 5.0 (EOL), 4.8 (EOSL)
6.0	5.0 (EOL), 4.8 (EOSL), 4.7 (EOSL)

DataStax driver changes

DataStax drivers come in two types:

DataStax drivers for DataStax Enterprise — for use by DSE 4.8 and later
DataStax drivers for Apache Cassandra™ — for use by Apache Cassandra™ and DSE 4.7 and earlier

Note: While the DataStax drivers for Apache Cassandra drivers can connect to DSE 5.0 and later clusters, DataStax strongly recommends upgrading to the DSE drivers. The DSE drivers provide functionality for all DataStax Enterprise features.

DataStax Enterprise and Apache Cassandra™ configuration files


Configuration file	Installer-Services and package installations	Installer-No Services and tarball installations
DataStax Enterprise configuration files
byoh-env.sh	/etc/dse/byoh-env.sh	`install_location`/bin/byoh-env.sh
dse.yaml	/etc/dse/dse.yaml	`install_location`/resources/dse/conf/dse.yaml
logback.xml	/etc/dse/cassandra/logback.xml	`install_location`/resources/logback.xml
spark-env.sh	/etc/dse/spark/spark-env.sh	`install_location`/resources/spark/conf/spark-env.sh
spark-defaults.conf	/etc/dse/spark/spark-defaults.conf	`install_location`/resources/spark/conf/spark-defaults.conf
Cassandra configuration files
cassandra.yaml	/etc/cassandra/cassandra.yaml	`install_location`/conf/cassandra.yaml
cassandra.in.sh	/usr/share/cassandra/cassandra.in.sh	`install_location`/bin/cassandra.in.sh
cassandra-env.sh	/etc/cassandra/cassandra-env.sh	`install_location`/conf/cassandra-env.sh
cassandra-rackdc.properties	/etc/cassandra/cassandra-rackdc.properties	`install_location`/conf/cassandra-rackdc.properties
cassandra-topology.properties	/etc/cassandra/cassandra-topology.properties	`install_location`/conf/cassandra-topology.properties
jmxremote.password	/etc/cassandra/jmxremote.password	`install_location`/conf/jmxremote.password
Tomcat server configuration file
server.xml	/etc/dse/resources/tomcat/conf/server.xml	`install_location`/resources/tomcat/conf/server.xml

cassandra.yaml

The location of the cassandra.yaml file depends on the type of installation:

Package installations	/etc/dse/cassandra/cassandra.yaml
Tarball installations	`installation_location`/resources/cassandra/conf/cassandra.yaml

Upgrading major Cassandra version

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

DataStax Enterprise 6.7 is compatible with Cassandra 3.11.
DataStax Enterprise 6.0 is compatible with Cassandra 3.11.
DataStax Enterprise 5.1 uses Cassandra 3.11.
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.

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 instructions to upgrade from DataStax Enterprise (DSE) 6.0 to DSE 6.7.

Always upgrade to latest patch release on your current version before you upgrade to a higher version. Fixes included in the latest patch release might help or smooth the upgrade process.

The latest 6.0.x version of DSE is 6.0.10.

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

Apache Cassandra™ version change

SSTables must be upgraded for DataStax Enterprise upgrades between versions that include changes.

DataStax Enterprise 6.7 is compatible with Cassandra 3.11.
DataStax Enterprise 6.0 is compatible with Cassandra 3.11.
DataStax Enterprise 5.1 uses Cassandra 3.11.
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.

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.

Tip: 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 restrictions and limitations during the upgrade process

Do not enable new features.
Do not run nodetool repair. If you have the OpsCenter Repair Service configured, turn off the Repair Service.
Ensure OpsCenter compatibility. OpsCenter 6.7 is required for managing DSE 6.7 clusters. See the compatibility table.
During the upgrade, do not bootstrap or decommission nodes.
Do not issue these types of CQL queries during a rolling restart: DDL and TRUNCATE.
Failure to upgrade SSTables results in a significant performance impact and increased disk usage. Upgrading is not complete until the SSTables are upgraded.
NodeSync waits to start until all nodes are upgraded.

Note: Nodes on different versions might show a schema disagreement during an upgrade.

Restrictions for DSE Analytic (Spark) nodes

Do not run analytics jobs until all nodes are upgraded.
All nodes in the cluster must be upgraded to the new version before Spark Worker and Spark Master will start.

DSE Graph nodes restrictions

Graph nodes have the same restrictions as the workload they run on. Do not alter graph schema during upgrades. Workload-specific restrictions apply for analytics and search nodes, such as no OLAP queries during upgrades.

DSE Search upgrade restrictions and limitations

Do not update schemas.
Do not reindex DSE Search nodes during upgrade.

Restrictions for nodes using any kind of security

Do not change security credentials or permissions until the upgrade is complete on all nodes.
If you are not already using Kerberos, do not set up Kerberos authentication before upgrading. First upgrade the cluster, and then set up Kerberos.

Upgrading drivers and possible impact when driver versions are incompatible

Be sure to check driver compatibility. Depending on the driver version, you might need to recompile your client application code. See .

During upgrades, you might experience driver-specific impact when clusters have mixed versions of drivers. If your cluster has mixed versions, the protocol version is negotiated with the first host that the driver connects to. To avoid driver version incompatibility during upgrades, use one of these workarounds:

Protocol version: Because some drivers can use different protocol versions, force the protocol version at start up. For example, keep the Java driver at its current protocol version while the driver upgrade is happening. Switch to the Java driver to the new protocol version only after the upgrade is complete on all nodes in the cluster.
Initial contact points: Ensure that the list of initial contact points contains only hosts with the oldest driver version. For example, the initial contact points contain only Java driver v2.

For details on protocol version negotiation, see protocol versions with mixed clusters in the Java driver version you're using, for example, Java driver.

Preparing to upgrade

Follow these steps to prepare each node for upgrading from DSE 6.0 to DSE 6.7.

Note: These steps are performed in your current version and use DSE 6.0 documentation.

Carefully review Planning your DataStax Enterprise upgrade.
Before upgrading, be sure that each node has ample free disk space.
The required space depends on the compaction strategy. See Disk space.
Familiarize yourself with the changes and features in this release:
- DataStax Enterprise 6.7 release notes.
- General upgrading advice for any version. Be sure to read NEWS.txt all the way back to your current version.
- DataStax Enterprise changes in CHANGES.txt.
- DataStax driver changes.
Verify that your current product version is DSE 6.0.0 or later.
```
dse -v
```
These instructions are valid only for upgrades from DSE 6.0 to DSE 6.7.
Upgrade to the latest patch release on your current version. The latest 6.0.x version of DSE is 6.0.10.
Always upgrade to latest patch release on your current version before you upgrade to a higher version. Fixes included in the latest patch release might help or smooth the upgrade process.
To prevent potential problems, upgrade the SSTables on each node to ensure that all SSTables are on the current version.
```
nodetool upgradesstables
```
If the SSTables are already on the current version, the command returns immediately and no action is taken.
Verify the Java runtime version and upgrade to the recommended version.
```
java -version
```
- Recommended. OpenJDK 8 (1.8.0_151 minimum)
  Note: Recommendation changed due to the end of public updates for Oracle JRE/JDK 8. See Oracle Java SE Support Roadmap.
- Supported. Oracle Java SE 8 (JRE or JDK) (1.8.0_151 minimum)
Important: Although Oracle JRE/JDK 8 is supported, DataStax does more extensive testing on OpenJDK 8.
Run nodetool repair to ensure that data on each replica is consistent with data on other nodes.
Install the libaio package for optimal performance.
RHEL platforms:
```
sudo yum install libaio
```
Debian:
```
sudo apt-get install libaio1
```
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.

Upgrade steps

To upgrade from DSE 6.0 to DSE 6.7, follow these steps on each node in the recommended . The upgrade process requires upgrading and restarting one node at a time.

Note: These steps are performed in your upgraded version and use DSE 6.7 documentation.

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.
Important: 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.
Stop the node. See Stopping a DataStax Enterprise node.
- To stop DataStax Enterprise running as a service:
```
sudo service dse stop
```
- To stop DataStax Enterprise running as a stand-alone process:
```
bin/dse cassandra-stop
```
Use the appropriate method to install the new product version on a supported platform:
Note: Install the new product version using the same installation type that is on the system, otherwise problems might result.

To configure the new version:

Compare your backup files to the new configuration files. Look for any deprecated, removed, or changed settings.

Review changes in and .

After the upgrade and before restarting with 6.7.0, remove deprecated settings and use new settings.

cassandra.yaml changes


Memtable settings
Deprecated cassandra.yaml settings
`memtable_heap_space_in_mb memtable_offheap_space_in_mb`
Replace with this setting
`memtable_space_in_mb` Governs heap and offheap space allocation to set a threshold for automatic memtable flush. The calculated default is 1/4 of the heap size.
Changed setting
`memtable_allocation_type: offheap_objects` The default method the database uses to allocate and manage memtable memory is offheap_objects.


User-defined functions (UDF) settings
Deprecated cassandra.yaml settings
`user_defined_function_warn_timeout user_defined_function_fail_timeout`
Replace with these settings
`user_defined_function_warn_micros: 500 user_defined_function_fail_micros: 10000 user_defined_function_warn_heap_mb: 200 user_defined_function_fail_heap_mb: 500 user_function_timeout_policy: die` Settings are in microseconds since Java UDFs run faster. The new timeouts are not equivalent to the deprecated settings.


Internode encryption settings
Deprecated cassandra.yaml setting
`server_encryption_options: store_type: JKS`
Replace with these settings
`server_encryption_options: keystore_type: JKS truststore_type: JKS` Valid type options are JKS, JCEKS, PKCS12, or PKCS11.


Internode encryption settings
Deprecated cassandra.yaml setting
`server_encryption_options: store_type: JKS`
Replace with these settings
`server_encryption_options: keystore_type: JKS truststore_type: JKS` Valid type options are JKS, JCEKS, PKCS12, or PKCS11.


Client-to-node encryption settings
Deprecated cassandra.yaml setting
`client_encryption_options: store_type: JKS`
Replace with these settings
`client_encryption_options: keystore_type: JKS truststore_type: JKS` Valid type options are JKS, JCEKS, PKCS12, or PKCS11.

dse.yaml changes


Spark resource and encryption options
Deprecated dse.yaml setting
`spark_ui_options: server_encryption_options: store_type: JKS`
Replace with these settings
`spark_ui_options: server_encryption_options: keystore_type: JKS truststore_type: JKS` Valid options are JKS, JCEKS, PKCS12, or PKCS11.

Merge the applicable configuration file modifications into the new version.

Ensure that keyspace replication factors are correct for your environment:
- Check the keyspace replication factor for analytics keyspaces.
- Check the keyspace replication factor for system_auth and dse_security keyspaces.
When upgrading DSE to versions earlier than 5.1.16, 6.0.8, or 6.7.4 inclusive, if any tables are using DSE Tiered Storage, remove all txn_compaction log files from second-level tiers and lower. For example, given the following dse.yaml configuration, remove txn_compaction log files from /mnt2 and /mnt3 directories:
```
tiered_storage_options:
    strategy1:
        tiers:
            - paths:
                - /mnt1
            - paths:
                - /mnt2
            - paths:
                - /mnt3
```
The following example removes the files using the find command:
```
find /mnt2 -name "*_txn_compaction_*.log" -type f -delete &&
find /mnt3 -name "*_txn_compaction_*.log" -type f -delete
```
Warning: Failure to complete this step may result in data loss.
Start the node.
- Package installations
- Tarball installations
Verify that the upgraded datacenter names match the datacenter names in the keyspace schema definition:
```
nodetool status
```
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.
Repeat the upgrade on each node in the cluster following the recommended upgrade order.

After the upgrade

After all nodes are upgraded and running on DSE 6.7:

If you use the OpsCenter Repair Service, turn on the Repair Service.
Remove any previously installed JTS JAR files from the classpaths in your DSE installation. JTS (Java Topology Suite) is distributed with DSE 6.7.
Spark Jobserver uses DSE custom version 8.0.4.45. Ensure that applications use the compatible Spark Jobserver API from the DataStax repository.
DSE 6.7 introduces, and enables by default, the DSE Metrics Collector, a diagnostics information aggregator used to help facilitate DSE problem resolution. For more information on the DSE Metrics Collector, see DataStax Enterprise Metrics Collector.