2. Locate the CLDB Data

About this task

After restoring the ZooKeeper service on the HPE Ezmeral Data Fabric cluster, use the maprcli dump zkinfo command to identify the latest epoch of the CLDB, identify the nodes where replicates of the CLDB are stored, and select one of those nodes to serve the new CLDB node.

Secure cluster must first be converted to non-secure cluster before running the maprcli dump zkinfo command. Perform the following steps as root or use sudo:

NOTE
For non-secure clusters, skip to step 4.

Procedure

  1. On the ZooKeeper nodes, stop Warden and ZooKeeper by running the following commands: 
    service mapr-warden stop
service mapr-zookeeper stop
  2. Convert the secure cluster to non-secure cluster by running the following command on the ZooKeeper nodes:
    NOTE
    The script configure.sh takes comma-separated lists of cluster names and ZooKeeper host names (and optionally ports) or IP addresses.
    /opt/mapr/server/configure.sh -C <host>[:<port>][,<host>:[<port>]...]|<IP>[,<IP>...] -Z <host>[:<port>][,<host>:[<port>]...]|<IP>[,<IP>...] -unsecure -R
  3. Restart ZooKeeper: 
    service mapr-zookeeper restart
  4. Issue the maprcli dump zkinfo command using the -json flag. 
    maprcli dump zkinfo -zkconnect localhost:5181 -json | grep -i "Container ID"
    The output displays the ZooKeeper znodes. For example: 
    maprcli dump zkinfo -zkconnect localhost:5181 -json |grep -i "Container ID" | more 
   "/datacenter/controlnodes/cldb/epoch/1/KvStoreContainerInfo":" Container ID:1   
   VolumeId:1 Master:10.10.104.34:5660-10.10.105.34:5660--9-VALID Servers:
   10.10.104.34:5660-10.10.105.34:5660--9-VALID
   10.10.104.33:5660-10.10.105.33:5660--9-VALID 
   10.10.104.32:5660-10.10.105.32:5660--9-VALID
   Inactive Servers:  Unused Servers:  Latest epoch:9"
    In the above example output, the latest epoch is 9.
  5. In the /datacenter/controlnodes/cldb/epoch/1 directory, locate the CLDB with the latest epoch.
    The Latest Epoch field identifies the current epoch of the CLDB data.
  6. Select a CLDB from among the copies at the latest epoch. For example, 10.10.105.32:5660--9-VALID indicates that the node has a copy at epoch 9 (the latest epoch).

Results

You can now install a new CLDB on the selected node.

What to do next

To convert the non-secure cluster to a secure cluster, run the the following command:
NOTE
The script configure.sh takes comma-separated lists of cluster names and ZooKeeper host names (and optionally ports) or IP addresses.
/opt/mapr/server/configure.sh -C <host>[:<port>][,<host>:[<port>]...]|<IP>[,<IP>...] -Z <host>[:<port>][,<host>:[<port>]...]|<IP>[,<IP>...] -secure -R