Step 1: Verify Cluster Readiness for a Patch

Before you apply a patch, check that the cluster is ready for a patch to be applied. In addition to the prerequisites, consider verifying that the cluster utilizes best practices which will facilitate a more optimal patch installation.

Patch Install Prerequisites

Before you apply a patch on the cluster, verify that all CLDB nodes are running and that container 1 is fully replicated on each CLDB node.

Run maprcli dump containerinfo -ids 1 -json. In the output, all CLDBs should be listed under ActiveServers and each node should report a VALID state.

For example:

...
      "data":[ 
             { 
                "ContainerId":1, 
                "Epoch":3, 
                "Master":"<masterCLDB_IP>:5660--3-VALID", 
                "ActiveServers":{  
                  "IP:Port":[ 
                      "<masterCLDB_IP>:5660--3-VALID", 
                      "<slaveCLDB_IP>:5660--3-VALID", 
                      "<slaveCLDB_IP>:5660--3-VALID"
                   ] 
              }, 
                  "InactiveServers":{    
                   }, 
                  "UnusedServers":{ 
              },
...

Note: RESYNC state will display when container 1 is not fully replicated on that node. You must wait until each CLDB node has a VALID state for container 1 before proceeding with the patch installation.

For more information, see dump containerinfo

Best Practices for Patch Installation

Failure to follow the best practices may, in some cases, impact the speed in which the patch installation completes. Check to see if your cluster abides by the following best practices:

The volume min replication setting should be greater than or equal to 2 for CLDB volume.

This ensures that container 1 always has at least two valid copies. Run the following command to list the current replication setting:

maprcli dump volumeinfo -volumename mapr.cldb.internal -json

In the output, the "VolumeMinReplication” parameter lists the current replication setting for the named volume. For more information, see maprcli dump volumeinfo.

No under replicated volumes should exist on the cluster.

Run the following command to check for under-replicated volumes:

maprcli alarm list

For more information, see maprcli alarm list.

Each CLDB node should be configured to have a minimum of 3 disks in its storage pool.

Run the following command on each CLDB node to get a list of the disks configured for each storage pool:

mrconfig sp list [-v]

In this example output, there are three disks associated with SP1:

ListSPs resp: status 0:2 No. of SPs (2), totalsize 4562260 MB, totalfree 4537550 MB 
SP 0: name SP1, Online, size 2736933 MB, free 2724749 MB, path /dev/sdb, log 200 MB, port 5660, 
guid a3055a6db41f285b005883bbd701c1e5, clusterUuid -5009075714600063565-100367519220387605, disks /dev/sdb /dev/sdd /dev/sde

For more information, see mrconfig sp list.