org.apache.zookeeper.server.quorum

Class ReadOnlyZooKeeperServer

java.lang.Object

org.apache.zookeeper.server.ZooKeeperServer

org.apache.zookeeper.server.quorum.ReadOnlyZooKeeperServer

All Implemented Interfaces:

ServerStats.Provider, SessionTracker.SessionExpirer

public class ReadOnlyZooKeeperServer
extends ZooKeeperServer

A ZooKeeperServer which comes into play when peer is partitioned from the majority. Handles read-only clients, but drops connections from not-read-only ones.

The very first processor in the chain of request processors is a ReadOnlyRequestProcessor which drops state-changing requests.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.zookeeper.server.ZooKeeperServer

ZooKeeperServer.MissingSessionException, ZooKeeperServer.State

Field Summary

Fields

Modifier and Type	Field and Description
protected QuorumPeer	self

Fields inherited from class org.apache.zookeeper.server.ZooKeeperServer

ALLOW_SASL_FAILED_CLIENTS, CLOSE_SESSION_TXN_ENABLED, DEFAULT_STARTING_BUFFER_SIZE, DEFAULT_THROTTLED_OP_WAIT_TIME, DEFAULT_TICK_TIME, ENABLE_EAGER_ACL_CHECK, ENFORCE_QUOTA, enforceQuota, firstProcessor, GET_CHILDREN_RESPONSE_CACHE_SIZE, GET_DATA_RESPONSE_CACHE_SIZE, GLOBAL_OUTSTANDING_LIMIT, initialConfig, INT_BUFFER_STARTING_SIZE_BYTES, intBufferStartingSizeBytes, jmxDataTreeBean, jmxServerBean, jvmPauseMonitor, listenBacklog, LOG, maxSessionTimeout, minSessionTimeout, ok, reconfigEnabled, SASL_SUPER_USER, secureServerCnxnFactory, serverCnxnFactory, sessionTracker, SKIP_ACL, SNAP_COUNT, state, throttledOpWaitTime, tickTime, ZOOKEEPER_DIGEST_ENABLED

Method Summary

Modifier and Type	Method and Description
void	createSessionTracker()
void	dumpConf(PrintWriter pwriter)
long	getServerId() Returns the id of the associated QuorumPeer, which will do for a unique id of this server.
String	getState()
protected void	registerJMX()
void	registerJMX(ZooKeeperServerBean serverBean, LocalPeerBean localPeerBean)
protected void	setLocalSessionFlag(Request si) If the underlying Zookeeper server support local session, this method will set a isLocalSession to true if a request is associated with a local session.
protected void	setState(ZooKeeperServer.State state) Sets the state of ZooKeeper server.
protected void	setupRequestProcessors()
void	shutdown()
protected void	startSessionTracker()
void	startup()
protected void	unregisterJMX()
protected void	unregisterJMX(ZooKeeperServer zks)
protected void	validateSession(ServerCnxn cnxn, long sessionId) Validate if a particular session can be reestablished.

Methods inherited from class org.apache.zookeeper.server.ZooKeeperServer

authWriteRequest, canShutdown, checkACL, checkPasswd, checkQuota, checkRequestSizeWhenReceivingMessage, closeSession, closeSession, connThrottle, createRequestThrottler, decInProcess, dumpEphemerals, dumpMonitorValues, enqueueRequest, expire, expire, finishSessionInit, getClientPort, getClientPortListenBacklog, getConf, getConnectionDropChance, getDataDirSize, getEphemerals, getGetChildrenResponseCache, getGlobalOutstandingLimit, getInflight, getInitialConfig, getInProcess, getLargeRequestBytes, getLargeRequestMaxBytes, getLargeRequestThreshold, getLastProcessedZxid, getLogDirSize, getMaxClientCnxnsPerHost, getMaxSessionTimeout, getMinSessionTimeout, getNumAliveConnections, getOutstandingHandshakeNum, getOutstandingRequests, getReadResponseCache, getRequestPathMetricsCollector, getSecureClientPort, getSecureServerCnxnFactory, getServerCnxnFactory, getSessionExpiryMap, getSessionTracker, getSnapCount, getSnapSizeInBytes, getThrottledOpWaitTime, getTickTime, getTxnLogElapsedSyncTime, getTxnLogFactory, getZKDatabase, getZkShutdownHandler, getZooKeeperServerListener, getZxid, incInProcess, isCloseSessionTxnEnabled, isDigestEnabled, isEnableEagerACLCheck, isReconfigEnabled, isResponseCachingEnabled, isRunning, killSession, loadData, processConnectRequest, processPacket, processTxn, processTxn, registerMetrics, reopenSession, requestFinished, revalidateSession, serverStats, setClientPortListenBacklog, setCloseSessionTxnEnabled, setCreateSessionTrackerServerId, setDigestEnabled, setEnableEagerACLCheck, setLargeRequestMaxBytes, setLargeRequestThreshold, setMaxSessionTimeout, setMinSessionTimeout, setOwner, setResponseCachingEnabled, setSecureServerCnxnFactory, setServerCnxnFactory, setThrottledOpWaitTime, setTickTime, setTxnLogFactory, setZKDatabase, setZxid, shouldForceWriteInitialSnapshotAfterLeaderElection, shouldThrottle, shutdown, startdata, startJvmPauseMonitor, startRequestThrottler, startServing, startupWithoutServing, submitRequest, submitRequestNow, takeSnapshot, takeSnapshot, truncateLog, unregisterMetrics

Methods inherited from class java.lang.Object

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

Field Detail

self

protected final QuorumPeer self

Method Detail

setupRequestProcessors

protected void setupRequestProcessors()

Overrides:

setupRequestProcessors in class ZooKeeperServer

startup

public void startup()

Overrides:

startup in class ZooKeeperServer

createSessionTracker

public void createSessionTracker()

Overrides:

createSessionTracker in class ZooKeeperServer

startSessionTracker

protected void startSessionTracker()

Overrides:

startSessionTracker in class ZooKeeperServer

setLocalSessionFlag

protected void setLocalSessionFlag(Request si)

Description copied from class: ZooKeeperServer

If the underlying Zookeeper server support local session, this method will set a isLocalSession to true if a request is associated with a local session.

Overrides:

setLocalSessionFlag in class ZooKeeperServer

validateSession

protected void validateSession(ServerCnxn cnxn,
                               long sessionId)
                        throws IOException

Description copied from class: ZooKeeperServer

Validate if a particular session can be reestablished.

Overrides:

validateSession in class ZooKeeperServer

Throws:

IOException

registerJMX

protected void registerJMX()

Overrides:

registerJMX in class ZooKeeperServer

registerJMX

public void registerJMX(ZooKeeperServerBean serverBean,
                        LocalPeerBean localPeerBean)

unregisterJMX

protected void unregisterJMX()

Overrides:

unregisterJMX in class ZooKeeperServer

unregisterJMX

protected void unregisterJMX(ZooKeeperServer zks)

getState

public String getState()

Specified by:

getState in interface ServerStats.Provider

Overrides:

getState in class ZooKeeperServer

getServerId

public long getServerId()

Returns the id of the associated QuorumPeer, which will do for a unique id of this server.

Specified by:

getServerId in interface SessionTracker.SessionExpirer

Overrides:

getServerId in class ZooKeeperServer

shutdown

public void shutdown()

Overrides:

shutdown in class ZooKeeperServer

dumpConf

public void dumpConf(PrintWriter pwriter)

Overrides:

dumpConf in class ZooKeeperServer

setState

protected void setState(ZooKeeperServer.State state)

Description copied from class: ZooKeeperServer

Sets the state of ZooKeeper server. After changing the state, it notifies the server state change to a registered shutdown handler, if any.

The following are the server state transitions:

• During startup the server will be in the INITIAL state.
• After successfully starting, the server sets the state to RUNNING.
• The server transitions to the ERROR state if it hits an internal error. ZooKeeperServerListenerImpl notifies any critical resource error events, e.g., SyncRequestProcessor not being able to write a txn to disk.
• During shutdown the server sets the state to SHUTDOWN, which corresponds to the server not running.

Overrides:

setState in class ZooKeeperServer

Parameters:

state - new server state.