Cassandra Management and Maintenance - Real-time Analytics with Storm and Cassandra - page 171

The nodetool commands
The nodetool command in Cassandra is the most handy tool in the hands of a Cassandra
administrator. It has all the tools and commands that are required for all types of situational
handling of various nodes. Let's look at a few widely used ones closely:
• Ring : This command depicts the state of nodes (normal, down, leaving, joining,
and so on). The ownership of the token range and percentage ownership of the
keys along with the data centre and rack details is as follows:
bin/nodetool -host 192.168.1.54 ring
The output will be something like this:
192.168.1.54 datacenter1rack1 Up Normal 755.25 MB
50.00% 0
192.168.1.51 datacenter1rack1 Up Normal 400.62 MB
0.00% 42535295865117307932921825928971026431
192.168.1.55 datacenter1rack1 Down Normal 793.06 MB
25.00% 42535295865117307932921825928971026432
192.168.1.56 datacenter1rack1 Up Normal 793.06 MB
25.00% 85070591730234615865843651857942052864
• Join : This is the option you can use with nodetool , which needs to be ex-
ecuted to add the new node to the cluster. When a new node joins the cluster, it
starts streaming the data from other nodes until it receives all the keys as per its
designated ownership based on the token in the ring. The status for this can be
checked using the netsat commands:
mydomain@my-cass3:/home/ubuntu$ /usr/local/cassandra/
apache- cassandra-1.1.6/bin/nodetool -h 10.3.12.29
netstats | grep - v 0%
Mode: JOINING
Not sending any streams.
Streaming from: /10.3.12.179
my_keyspace: /var/lib/cassandra/data/my_keyspace/mycf/
my_keyspace-mycf- hf-46129-Data.db sections=1
progress=238226599194/307961954748 - 77%
Pool Name Active Pending