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/*-
* Copyright (C) 2002, 2018, Oracle and/or its affiliates. All rights reserved.
*
* This file was distributed by Oracle as part of a version of Oracle Berkeley
* DB Java Edition made available at:
*
* http://www.oracle.com/technetwork/database/database-technologies/berkeleydb/downloads/index.html
*
* Please see the LICENSE file included in the top-level directory of the
* appropriate version of Oracle Berkeley DB Java Edition for a copy of the
* license and additional information.
*/
package com.sleepycat.je.rep.util;
import static com.sleepycat.je.rep.impl.RepParams.NODE_HOST_PORT;
import java.io.File;
import com.sleepycat.je.Durability;
import com.sleepycat.je.EnvironmentConfig;
import com.sleepycat.je.rep.ReplicatedEnvironment;
import com.sleepycat.je.rep.ReplicationConfig;
import com.sleepycat.je.rep.impl.RepParams;
/**
* A utility to reset the members of a replication group, replacing the group
* with a new group consisting of a single new member as described by the
* arguments supplied to the utility.
*
* This utility is useful when a copy of an existing replicated environment
* needs to be used at a different site, with the same data, but with a
* different initial node that can be used to grow the replication group as
* usual. The utility can also be used to change the group name associated with
* the environment.
*
* The reset environment has a different identity from the environment before
* the reset operation although it contains the same application data. To avoid
* confusion, the reset environment is assigned a new internal unique id. The
* unique id is checked whenever nodes attempt to communicate with each other
* and ensure that all nodes in a group are dealing with the same data.
*
* The reset process is typically accomplished using the steps outlined below.
* It's good practice to back up your environment before running any utilities
* that modify an environment.
*
* - Use {@code DbResetRepGroup} to reset an existing environment.
* {@code DbResetRepGroup} can be used as a command line utility, and must be
* executed locally on the host specified in the -nodeHostPort argument. The
* host must also contain the environment directory.
* Alternatively, {@code DbResetRepGroup} may be used programmatically through
* the provided APIs.
* - Once reset, the environment can be opened with a
* {@code ReplicatedEnvironment}, using the same node configuration as the one
* that was passed in to the utility. No helper host configuration is needed.
* Since the group consists of a single node, it will assume the role of a
* Master, so long as it is created as an electable node.
*
- Additional nodes may now be created and can join the group as newly
* created replicas, as described in {@code ReplicatedEnvironment}. Since these
* new nodes are empty, they should be configured to use the new master as
* their helper node, and will go through the
* replication node lifecycle
* to populate their environment directories. In this case, there will be data
* in the converted master that can only be transferred to the replica through
* a file copy executed with the help of a
* {@link com.sleepycat.je.rep.NetworkRestore}
*
*
* For example:
*
*
* // Run the utility on a copy of an existing replicated environment. Usually
* // this environment will have originated on a different node and its
* // replication group information will contain meta data referring to its
* // previous host. The utility will reset this metadata so that it has a
* // rep group (UniversalRepGroup) with a single node named nodeMars. The node
* // is associated with the machine mars and will communicate on port 5001.
*
* DbResetRepGroup resetUtility =
* new DbResetRepGroup(envDirMars, // env home dir
* "UniversalRepGroup", // group name
* "nodeMars", // node name
* "mars:5001"); // node host,port
* resetUtility.reset();
*
* // Open the reset environment; it will take on the role of master.
* ReplicatedEnvironment nodeMars = new ReplicatedEnvironment(envDirMars, ...);
* ...
* // Bring up additional nodes, which will be initialized from
* // nodeMars. For example, from the machine venus you can now add a new
* // member to the group(UniversalRepGroup) as below.
*
* ReplicationConfig repConfig = null;
* try {
* repConfig = new ReplicationConfig("UniversalRepGroup", // groupName
* "nodeVenus", // nodeName
* "venus:5008"); // nodeHostPort
* repConfig.setHelperHosts("mars:5001");
*
* nodeVenus = new ReplicatedEnvironment(envDirB, repConfig, envConfig);
* } catch (InsufficientLogException insufficientLogEx) {
*
* // log files will be copied from another node in the group
* NetworkRestore restore = new NetworkRestore();
* restore.execute(insufficientLogEx, new NetworkRestoreConfig());
*
* // try opening the node now that the environment files have been
* // restored on this machine.
* nodeVenus = new ReplicatedEnvironment(envDirVenus,
* repConfig,
* envConfig);
* }
* ...
*
*/
public class DbResetRepGroup {
private File envHome;
private String groupName;
private String nodeName;
private String nodeHostPort;
private static final String usageString =
"usage: java -cp je.jar " +
"com.sleepycat.je.rep.util.DbResetRepGroup\n" +
" -h # environment home directory\n" +
" -groupName # replication group name\n" +
" -nodeName # replicated node name\n" +
" -nodeHostPort # host name or IP address\n" +
" and port number to use\n" +
" for this node\n";
/**
* Usage:
*
* java -cp je.jar com.sleepycat.je.rep.util.DbResetRepGroup
* -h <dir> # environment home directory
* -groupName <group name> # replication group name
* -nodeName <node name> # replicated node name
* -nodeHostPort <host name:port number> # host name or IP address
* and port number to use
* for this node
*
*/
public static void main(String[] args) {
DbResetRepGroup converter = new DbResetRepGroup();
converter.parseArgs(args);
converter.reset();
}
private void printUsage(String msg) {
System.err.println(msg);
System.err.println(usageString);
System.exit(-1);
}
private void parseArgs(String[] args) {
int argc = 0;
int nArgs = args.length;
while (argc < nArgs) {
String thisArg = args[argc++].trim();
if (thisArg.equals("-h")) {
if (argc < nArgs) {
envHome = new File(args[argc++]);
} else {
printUsage("-h requires an argument");
}
} else if (thisArg.equals("-groupName")) {
if (argc < nArgs) {
groupName = args[argc++];
} else {
printUsage("-groupName requires an argument");
}
} else if (thisArg.equals("-nodeName")) {
if (argc < nArgs) {
nodeName = args[argc++];
} else {
printUsage("-nodeName requires an argument");
}
} else if (thisArg.equals("-nodeHostPort")) {
if (argc < nArgs) {
nodeHostPort = args[argc++];
try {
NODE_HOST_PORT.validateValue(nodeHostPort);
} catch (IllegalArgumentException e) {
e.printStackTrace();
printUsage("-nodeHostPort is illegal!");
}
} else {
printUsage("-nodeHostPort requires an argument");
}
}
}
if (envHome == null) {
printUsage("-h is a required argument.");
}
if (groupName == null) {
printUsage("-groupName is a required argument.");
}
if (nodeName == null) {
printUsage("-nodeName is a required argument.");
}
if (nodeHostPort == null) {
printUsage("-nodeHostPort is a required argument.");
}
}
private DbResetRepGroup() {
}
/**
* Create a DbResetRepGroup object for this node.
*
* @param envHome The node's replicated environment directory. The
* directory must be accessible on this host.
* @param groupName The name of the new replication group
* @param nodeName The node's name
* @param nodeHostPort The host and port for this node. The utility
* must be executed on this host.
*/
public DbResetRepGroup(File envHome,
String groupName,
String nodeName,
String nodeHostPort) {
this.envHome = envHome;
this.groupName = groupName;
this.nodeName = nodeName;
this.nodeHostPort = nodeHostPort;
}
/**
* Replaces the existing group with the new group having a single new node
* as described by the constructor arguments.
*
* @see DbResetRepGroup
*/
public void reset() {
Durability durability =
new Durability(Durability.SyncPolicy.SYNC,
Durability.SyncPolicy.SYNC,
Durability.ReplicaAckPolicy.NONE);
EnvironmentConfig envConfig = new EnvironmentConfig();
envConfig.setAllowCreate(true);
envConfig.setTransactional(true);
envConfig.setDurability(durability);
ReplicationConfig repConfig =
new ReplicationConfig(groupName, nodeName, nodeHostPort);
repConfig.setHelperHosts(repConfig.getNodeHostPort());
/* Force the re-initialization upon open. */
repConfig.setConfigParam(RepParams.RESET_REP_GROUP.getName(), "true");
/* Open the environment, thus replacing the group. */
ReplicatedEnvironment repEnv =
new ReplicatedEnvironment(envHome, repConfig, envConfig);
repEnv.close();
}
}
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