Package org.apache.hadoop.hbase.zookeeper

Class ClusterStatusTracker

java.lang.Object

org.apache.hadoop.hbase.zookeeper.ZKListener

org.apache.hadoop.hbase.zookeeper.ZKNodeTracker

org.apache.hadoop.hbase.zookeeper.ClusterStatusTracker

@Private
public class ClusterStatusTracker
extends ZKNodeTracker

Tracker on cluster settings up in zookeeper. This is not related to ClusterMetrics. That class is a data structure that holds snapshot of current view on cluster. This class is about tracking cluster attributes up in zookeeper.

Field Summary

Fields

Modifier and Type	Field	Description
private static final org.slf4j.Logger	LOG

Fields inherited from class org.apache.hadoop.hbase.zookeeper.ZKNodeTracker

abortable, node

Fields inherited from class org.apache.hadoop.hbase.zookeeper.ZKListener

watcher

Constructor Summary

Constructors

Constructor	Description
ClusterStatusTracker(ZKWatcher watcher, Abortable abortable)	Creates a cluster status tracker.

Method Summary

Modifier and Type	Method	Description
boolean	isClusterUp()	Checks if cluster is up.
void	setClusterDown()	Sets the cluster as down by deleting the znode.
void	setClusterUp()	Sets the cluster as up.
(package private) static byte[]	toByteArray()	Returns Content of the clusterup znode as a serialized pb with the pb magic as prefix.

Methods inherited from class org.apache.hadoop.hbase.zookeeper.ZKNodeTracker

blockUntilAvailable, blockUntilAvailable, checkIfBaseNodeAvailable, getData, getNode, nodeCreated, nodeDataChanged, nodeDeleted, postStart, start, stop, toString

Methods inherited from class org.apache.hadoop.hbase.zookeeper.ZKListener

getWatcher, nodeChildrenChanged

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Details

LOG

private static final org.slf4j.Logger LOG

Constructor Details

ClusterStatusTracker

public ClusterStatusTracker(ZKWatcher watcher,
 Abortable abortable)

Creates a cluster status tracker.

After construction, use ZKNodeTracker.start() to kick off tracking.

Parameters:

watcher - reference to the ZKWatcher which also contains configuration and constants

abortable - used to abort if a fatal error occurs

Method Details

isClusterUp

public boolean isClusterUp()

Checks if cluster is up.

Returns:

true if the cluster up ('shutdown' is its name up in zk) znode exists with data, false if not

setClusterUp

public void setClusterUp()
                  throws org.apache.zookeeper.KeeperException

Sets the cluster as up.

Throws:

org.apache.zookeeper.KeeperException - unexpected zk exception

setClusterDown

public void setClusterDown()
                    throws org.apache.zookeeper.KeeperException

Sets the cluster as down by deleting the znode.

Throws:

org.apache.zookeeper.KeeperException - unexpected zk exception

toByteArray

static byte[] toByteArray()

Returns Content of the clusterup znode as a serialized pb with the pb magic as prefix.