In this recipe, we will look at how to troubleshoot communication issues between nodes and how we can quickly find common errors.
To step through the recipe, the user must have completed the Setting up multi-node HBase cluster recipe in Chapter 9, HBase Administration and have gone through the previous recipes in this chapter. It is good to have a basic knowledge of the DNS and TCP communication.
Connect to the
master1.cyrus.commaster node in the cluster and switch to userhadoop.The first thing is to check which connections are already established to the nodes. This can be seen with the following command, as shown here:
Check the reachability of nodes in the cluster using the following commands and also ensure reverse lookup for each host in the cluster:
$ ping master1.cyrus.com $ ping dn1.cyrus.com $ nslookup "IP of Namenode, RM and Datanodes"
If there is a reachability issue, check for firewall rules on any intermediate network devices...