org.rhq.cassandra

Class ClusterInitService

java.lang.Object

org.rhq.cassandra.ClusterInitService

public final class ClusterInitService
extends Object

This class provides operations to ensure a cluster is initialized and in a consistent state. It does not offer functionality for initializing a cluster but rather to make sure that nodes have started up and are accepting client connections for example.

Author:

John Sanda, Jirka Kremser

Constructor Summary

Constructors

Constructor and Description
ClusterInitService()

Method Summary

Methods

Modifier and Type	Method and Description
boolean	isNativeTransportRunning(String storageNode, int jmxPort)
boolean	ping(String[] storageNodes, int[] jmxPorts, int numHosts) Pings the storage nodes to verify if they are available and native transport is running.
void	waitForClusterToStart(String[] storageNodes, int[] jmxPorts) This method attempts to establish a Thrift RPC connection to each host.
void	waitForClusterToStart(String[] storageNodes, int[] jmxPorts, int numHosts, int retries) This method attempts to establish a Thrift RPC connection to each host for the number specified.
void	waitForClusterToStart(String[] storageNodes, int[] jmxPorts, int numHosts, long delay, int retries, int initialWait) This method attempts to establish a Thrift RPC connection to each host for the number specified.
void	waitForSchemaAgreement(String[] storageNodes, int[] jmxPorts) Waits for the cluster to reach schema agreement.

Methods inherited from class java.lang.Object

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

Constructor Detail

ClusterInitService

public ClusterInitService()

Method Detail

ping

public boolean ping(String[] storageNodes,
           int[] jmxPorts,
           int numHosts)

Pings the storage nodes to verify if they are available and native transport is running.

Parameters:

storageNodes - storage node addresses

jmxPorts - JMX ports

numHosts - minimum number of active hosts

Returns:

[true] cluster available with at least minimum number of hosts available, [false] otherwise

waitForClusterToStart

public void waitForClusterToStart(String[] storageNodes,
                         int[] jmxPorts)

This method attempts to establish a Thrift RPC connection to each host. If the connection fails, the host is retried after going through the other, remaining hosts. A runtime exception will be thrown after 10 failed retries.

After connecting to all nodes, this method will then sleep for a fixed delay. See #waitForClusterToStart(int, java.util.List, int) for details.

Parameters:

storageNodes - The cluster nodes to which a connection should be made

jmxPorts - JMX port for each cluster node address

waitForClusterToStart

public void waitForClusterToStart(String[] storageNodes,
                         int[] jmxPorts,
                         int numHosts,
                         int retries)

This method attempts to establish a Thrift RPC connection to each host for the number specified. In other words, if there are four hosts and numHosts is 2, this method will block only until it can connect to two of the hosts. If the connection fails, the host is retried after going through the other, remaining hosts.

After connecting to all cluster nodes, this method will sleep for 10 seconds before returning. This is to give the cluster a chance to create the system auth schema and to create the cassandra super user. Cassandra has a hard-coded delay of 10 sceonds before it creates the super user, which means the rhq schema cannot be created before that.

Parameters:

numHosts - The number of hosts to which a successful connection has to be made before returning.

retries - The number of times to retry connecting. A runtime exception will be thrown when the number of failed connections exceeds this value.

waitForClusterToStart

public void waitForClusterToStart(String[] storageNodes,
                         int[] jmxPorts,
                         int numHosts,
                         long delay,
                         int retries,
                         int initialWait)

This method attempts to establish a Thrift RPC connection to each host for the number specified. In other words, if there are four hosts and numHosts is 2, this method will block only until it can connect to two of the hosts. If the connection fails, the host is retried after going through the other, remaining hosts.

After connecting to all cluster nodes, this method will sleep for 10 seconds before returning. This is to give the cluster a chance to create the system auth schema and to create the cassandra super user. Cassandra has a hard-coded delay of 10 sceonds before it creates the super user, which means the rhq schema cannot be created before that.

Parameters:

numHosts - The number of hosts to which a successful connection has to be made before returning.

delay - The amount of time wait between attempts to make a connection

retries - The number of times to retry connecting. A runtime exception will be thrown when the number of failed connections exceeds this value.

initialWait - The amount of seconds before first try.

waitForSchemaAgreement

public void waitForSchemaAgreement(String[] storageNodes,
                          int[] jmxPorts)
                            throws Exception

Waits for the cluster to reach schema agreement. During cluster initialization before and while schema changes propagate throughout the cluster, there could be multiple schema versions found among nodes. Schema agreement is reached when there is a single schema version and all nodes are on that version.

Parameters:

hosts - The cluster nodes

Throws:

Exception

isNativeTransportRunning

public boolean isNativeTransportRunning(String storageNode,
                               int jmxPort)
                                 throws Exception

Throws:

Exception