Upgrade a cluster's operating system

Upgrade a Redis Enterprise Software cluster's operating system to a later major version.

To upgrade the operating system (OS) on a Redis Enterprise Software cluster to a later major version, perform a rolling upgrade. Because you upgrade one node at a time, you can upgrade your cluster's OS without downtime.

Prerequisites

Before you upgrade a cluster's operating system:

1. Upgrade all nodes in the cluster to a Redis Enterprise Software version that supports the OS's current version and upgrade version.

   To learn which versions of Redis Enterprise Software support specific OS versions, see Supported platforms.

2. If the cluster contains databases that use modules:

   1. Update all nodes in the cluster to Redis Enterprise Software version 7.2.4-52 or later before you upgrade the OS.

   2. Check the status of modules using rladmin:

      rladmin status modules
      

      The output lists the module versions installed on the cluster and the module versions used by existing databases:

      CLUSTER MODULES:
      MODULE                                                                      VERSION                            
      RedisBloom                                                                  2.6.3                              
      RediSearch 2                                                                2.8.4                              
      RedisGears                                                                  2.0.12                             
      RedisGraph                                                                  2.10.12                            
      RedisJSON                                                                   2.6.6                              
      RedisTimeSeries                                                             1.10.6                             
      
      DATABASE MODULES:
      DB:ID    NAME       MODULE              VERSION     ARGS                     STATUS                            
      db:1     db1        RediSearch 2        2.6.9       PARTITIONS AUTO          OK, OLD MODULE VERSION            
      db:1     db1        RedisJSON           2.4.7                                OK, OLD MODULE VERSION  
      

   3. If any databases use custom modules, manually uploaded modules, or modules marked with OLD MODULE VERSION, upload module packages for the OS upgrade version to a cluster node. See Install a module on a cluster for instructions.

      Note:

      The uploaded module packages have the following requirements:

      • The module is compiled for the OS upgrade version.

      • The module version matches the version currently used by databases.

3. If the cluster uses custom directories, make sure the OS upgrade version also supports custom directories, and specify the same custom directories during installation for all nodes. See Customize installation directories for details.

Perform OS rolling upgrade

To upgrade the cluster's operating system, use one of the following rolling upgrade methods:

• Extra node method - recommended if you have additional resources available

• Replace node method - recommended if you cannot temporarily allocate additional resources

Extra node upgrade method

1. Create a node with the OS upgrade version.

2. Install the cluster's current Redis Enterprise Software version on the new node using the installation package for the OS upgrade version.

3. Add the new node to the cluster.

4. Remove one node running the earlier OS version from the cluster.

5. Repeat the previous steps until all nodes with the earlier OS version are removed. If the final node to remove from the cluster is the primary node, demote it to a secondary node before you remove it.

Replace node upgrade method

1. Remove a node with the earlier OS version from the cluster.

2. Uninstall Redis Enterprise Software from the removed node:

   sudo ./rl_uninstall.sh
   

3. Either upgrade the existing node to the OS upgrade version, or create a new node with the OS upgrade version.

4. Install the cluster's current Redis Enterprise Software version on the upgraded node using the installation package for the OS upgrade version.

5. Add the new node to the cluster.

   If you want to reuse the removed node's ID when you add the node to the cluster, run rladmin cluster join with the replace_node flag:

   rladmin cluster join nodes <cluster_member_ip_address> username <username> password <password> replace_node <node_id>
   

6. Verify node health:

   1. Run rlcheck on all nodes:

      rlcheck
      

      The output lists the result of each verification test:

      ##### Welcome to Redis Enterprise Cluster settings verification utility ####
      Running test: verify_bootstrap_status
                      PASS
      ...
      Running test: verify_encrypted_gossip
                      PASS
      Summary:
      -------
      ALL TESTS PASSED.
      

      For healthy nodes, the expected output is ALL TESTS PASSED.

   2. Run rladmin status on the new node:

      rladmin status extra all
      

      The expected output is the OK status for the cluster, nodes, endpoints, and shards:

      CLUSTER:
      OK. Cluster master: 2 (<IP.address>)
      Cluster health: OK, [0, 0.0, 0.0]
      failures/minute - avg1 0.00, avg15 0.00, avg60 0.00.
      ...
      

7. Repeat the previous steps until all nodes with the earlier OS version are replaced. If the final node to remove from the cluster is the primary node, demote it to a secondary node before you remove it.