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== Join ==

Triggers the specified node to join the ring. This assumes that the node was started with `-Dcassandra.join_ring=false` so that it did not join the ring upon startup.

More and more instrumentation is being added to Cassandra via standard JMX apis.

The nodetool utility (nodeprobe in versions prior to 0.6) provides a simple command line interface to these exposed operations and attributes.

See Operations for a more high-level view of when you would want to use the actions described here.

Note: This utility currently requires the same environment as cassandra itself, namely the same classpath (including log4j.properties), and a valid storage-conf property.

Running bin/nodetool with no arguments produces some usage output.

Starting NodeTool
Missing required option: h
usage: java org.apache.cassandra.tools.NodeCmd --host <arg> <command>

 -h,--host <arg>        node hostname or ip address
 -p,--port <arg>        remote jmx agent port number
 -pw,--password <arg>   remote jmx agent password
 -u,--username <arg>    remote jmx agent username

Available commands:
  ring                   - Print informations on the token ring
  join                   - Join the ring
  info                   - Print node informations (uptime, load, ...)
  cfstats                - Print statistics on column families
  clearsnapshot          - Remove all existing snapshots
  version                - Print cassandra version
  tpstats                - Print usage statistics of thread pools
  drain                  - Drain the node (stop accepting writes and flush all column families)
  decommission           - Decommission the node
  loadbalance            - Loadbalance the node
  compactionstats        - Print statistics on compactions
  disablegossip          - Disable gossip (effectively marking the node dead)
  enablegossip           - Reenable gossip
  disablethrift          - Disable thrift server
  enablethrift           - Reenable thrift server
  snapshot [snapshotname] - Take a snapshot using optional name snapshotname
  netstats [host]        - Print network information on provided host (connecting node by default)
  move <new token>       - Move node on the token ring to a new token
  removetoken status|force|<token> - Show status of current token removal, force completion of pending removal or remove providen token
  flush [keyspace] [cfnames] - Flush one or more column family
  repair [keyspace] [cfnames] - Repair one or more column family
  cleanup [keyspace] [cfnames] - Run cleanup on one or more column family
  compact [keyspace] [cfnames] - Force a (major) compaction on one or more column family
  scrub [keyspace] [cfnames] - Scrub (rebuild sstables for) one or more column family
  invalidatekeycache [keyspace] [cfnames] - Invalidate the key cache of one or more column family
  invalidaterowcache [keyspace] [cfnames] - Invalidate the key cache of one or more column family
  getcompactionthreshold <keyspace> <cfname> - Print min and max compaction thresholds for a given column family
  cfhistograms <keyspace> <cfname> - Print statistic histograms for a given column family
  setcachecapacity <keyspace> <cfname> <keycachecapacity> <rowcachecapacity> - Set the key and row cache capacities of a given column family
  setcompactionthreshold <keyspace> <cfname> <minthreshold> <maxthreshold> - Set the min and max compaction thresholds for a given column family

The -host argument is required, the -port argument is optional and will default to 8080 if not supplied.


The ring command will present node status and an ascii art rendition of the ring, as determined by the node being queried.

bin/nodetool -host ring
Address       Status     Load          Range                                      Ring  Up         459.27 MB     75603446264197340449435394672681112420     |<--|  Up         382.53 MB     137462771597874153173150284137310597304    |   |  Up         511.34 MB     63538518574533451921556363897953848387     |-->|

The format is a little different for later versions - this is from v0.7.6:

Address         Status State   Load            Owns    Token                                       
                                                       113427455640312821154458202477256070484    Up     Normal  459.27 MB       33.33%  0                                      Up     Normal  382.53 MB       33.33%  56713727820156410577229101238628035242    Up     Normal  511.34 MB       33.33%  113427455640312821154458202477256070484 

The Owns column indicates the percentage of the ring (keyspace) handled by that node

The largest token is repeated at the top of the list to indicate that we have a ring. i.e, the first and last printed token are the same, suggesting some kind of continuity


Triggers the specified node to join the ring. This assumes that the node was started with -Dcassandra.join_ring=false so that it did not join the ring upon startup.


Outputs node information including the token, load info (on disk storage), generation number (times started), uptime in seconds, and heap memory usage.

bin/nodetool -host info
Load Info        : 0 bytes.
Generation No    : 1
Uptime (seconds) : 697595
Heap Memory (MB) : 28.18 / 759.81


Triggers the immediate cleanup of keys no longer belonging to this node.

bin/nodetool -host cleanup


Initiates an immediate table compaction.

Note: the compacted tables will not immediately be cleared from the hard disk and will remain on the system until the JVM performs a GC. For more information, read about MemtableSSTables.

bin/nodetool -host compact


Tells the node to move its data elsewhere; opposite of bootstrap. Since 0.5. See https://issues.apache.org/jira/browse/CASSANDRA-435


Flushes memtables on the node and stop accepting writes. Reads will still be processed. Useful for rolling upgrades.


Flushes memtables (in memory) to SSTables (on disk), which also enables CommitLog segments to be deleted.


Removes a dead node from the ring - this command is issued to any other live node (since clearly the dead node cannot respond!).


Cassandra v0.7.1 and v0.7.2 shipped with a bug that caused incorrect row-level bloom filters to be generated when compacting sstables generated with earlier versions. This would manifest in IOExceptions during column name-based queries. v0.7.3 provides "nodetool scrub" to rebuild sstables with correct bloom filters, with no data lost. (If your cluster was never on 0.7.0 or earlier, you don't have to worry about this.) Note that nodetool scrub will snapshot your data files before rebuilding, just in case.

NodeTool (last edited 2014-10-31 23:41:27 by 162)