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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespa.zookeeper;
import com.yahoo.cloud.config.ZookeeperServerConfig;
import com.yahoo.net.HostName;
import org.junit.After;
import org.junit.Before;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.TemporaryFolder;
import java.io.File;
import java.io.IOException;
import java.nio.file.Path;
import java.time.Duration;
import java.util.Arrays;
import java.util.concurrent.Phaser;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertSame;
/**
* Tests dynamic reconfiguration of zookeeper cluster.
*
* @author hmusum
*/
public class ReconfigurerTest {
private File cfgFile;
private File idFile;
private TestableReconfigurer reconfigurer;
@Rule
public TemporaryFolder folder = new TemporaryFolder();
@Before
public void setup() throws IOException {
cfgFile = folder.newFile();
idFile = folder.newFile("myid");
reconfigurer = new TestableReconfigurer(new TestableVespaZooKeeperAdmin());
}
@Test
public void testReconfigure() {
ZookeeperServerConfig initialConfig = createConfig(3, true);
reconfigurer.startOrReconfigure(initialConfig);
assertSame(initialConfig, reconfigurer.activeConfig());
// Cluster grows
ZookeeperServerConfig nextConfig = createConfig(5, true);
reconfigurer.startOrReconfigure(nextConfig);
assertEquals("node1:2181", reconfigurer.connectionSpec());
assertEquals("server.0=node0:2182:2183;2181,server.1=node1:2182:2183;2181,server.2=node2:2182:2183;2181,server.3=node3:2182:2183;2181,server.4=node4:2182:2183;2181",
reconfigurer.servers());
assertEquals(2, reconfigurer.reconfigurations());
assertSame(nextConfig, reconfigurer.activeConfig());
// Cluster shrinks
nextConfig = createConfig(3, true);
reconfigurer.startOrReconfigure(nextConfig);
assertEquals(3, reconfigurer.reconfigurations());
assertEquals("node1:2181", reconfigurer.connectionSpec());
assertEquals("server.0=node0:2182:2183;2181,server.1=node1:2182:2183;2181,server.2=node2:2182:2183;2181",
reconfigurer.servers());
assertSame(nextConfig, reconfigurer.activeConfig());
// Cluster loses node1, but node3 joins. Indices are shuffled.
nextConfig = createConfig(3, true, 1);
reconfigurer.startOrReconfigure(nextConfig);
assertEquals(4, reconfigurer.reconfigurations());
assertEquals("server.0=node0:2182:2183;2181,server.1=node2:2182:2183;2181,server.2=node3:2182:2183;2181",
reconfigurer.servers());
assertSame(nextConfig, reconfigurer.activeConfig());
}
@Test
public void testReconfigureFailsWithReconfigInProgressThenSucceeds() {
reconfigurer = new TestableReconfigurer(new TestableVespaZooKeeperAdmin().failures(3));
ZookeeperServerConfig initialConfig = createConfig(3, true);
reconfigurer.startOrReconfigure(initialConfig);
assertSame(initialConfig, reconfigurer.activeConfig());
ZookeeperServerConfig nextConfig = createConfig(5, true);
reconfigurer.startOrReconfigure(nextConfig);
assertEquals("node1:2181", reconfigurer.connectionSpec());
assertEquals("server.0=node0:2182:2183;2181,server.1=node1:2182:2183;2181,server.2=node2:2182:2183;2181,server.3=node3:2182:2183;2181,server.4=node4:2182:2183;2181",
reconfigurer.servers());
assertEquals(2, reconfigurer.reconfigurations());
assertSame(nextConfig, reconfigurer.activeConfig());
}
@Test
public void testDynamicReconfigurationDisabled() {
ZookeeperServerConfig initialConfig = createConfig(3, false);
reconfigurer.startOrReconfigure(initialConfig);
assertSame(initialConfig, reconfigurer.activeConfig());
ZookeeperServerConfig nextConfig = createConfig(5, false);
reconfigurer.startOrReconfigure(nextConfig);
assertSame(initialConfig, reconfigurer.activeConfig());
assertEquals(0, reconfigurer.reconfigurations());
}
@After
public void stopReconfigurer() {
reconfigurer.deconstruct();
}
private ZookeeperServerConfig createConfig(int numberOfServers, boolean dynamicReconfiguration, int... retiredIndices) {
Arrays.sort(retiredIndices);
ZookeeperServerConfig.Builder builder = new ZookeeperServerConfig.Builder();
builder.zooKeeperConfigFile(cfgFile.getAbsolutePath());
builder.myidFile(idFile.getAbsolutePath());
for (int i = 0, index = 0; i < numberOfServers; i++, index++) {
boolean retired = Arrays.binarySearch(retiredIndices, index) >= 0;
if (retired) i--;
builder.server(newServer(i, "node" + index, retired));
}
builder.myid(0);
builder.dynamicReconfiguration(dynamicReconfiguration);
return builder.build();
}
private ZookeeperServerConfig.Server.Builder newServer(int id, String hostName, boolean retired) {
ZookeeperServerConfig.Server.Builder builder = new ZookeeperServerConfig.Server.Builder();
builder.id(id);
builder.hostname(hostName);
builder.retired(retired);
return builder;
}
private static class MockQuorumPeer implements QuorumPeer {
final Phaser phaser = new Phaser(2); // Runner and test thread.
@Override public void start(Path path) { assertEquals(1, phaser.arriveAndAwaitAdvance()); }
@Override public void shutdown(Duration timeout) { assertEquals(1, phaser.arriveAndAwaitAdvance()); }
}
private static class TestableReconfigurer extends Reconfigurer implements VespaZooKeeperServer {
private final TestableVespaZooKeeperAdmin zooKeeperAdmin;
private final Phaser phaser = new Phaser(2);
private QuorumPeer serverPeer;
TestableReconfigurer(TestableVespaZooKeeperAdmin zooKeeperAdmin) {
super(zooKeeperAdmin, new Sleeper() {
@Override
public void sleep(Duration duration) {
// Do nothing
}
},
false,
Reconfigurer.TIMEOUT);
this.zooKeeperAdmin = zooKeeperAdmin;
HostName.setHostNameForTestingOnly("node1");
}
void startOrReconfigure(ZookeeperServerConfig newConfig) {
serverPeer = startOrReconfigure(newConfig, this, MockQuorumPeer::new);
phaser.arriveAndAwaitAdvance(); // Let runner thread see us setting the peer—used below in start(Path)—the first time.
}
String connectionSpec() {
return zooKeeperAdmin.connectionSpec;
}
String servers() {
return zooKeeperAdmin.servers;
}
int reconfigurations() {
return zooKeeperAdmin.reconfigurations;
}
@Override
public void shutdown() {
serverPeer.shutdown(Duration.ofSeconds(1));
}
@Override
public void start(Path configFilePath) {
phaser.awaitAdvance(phaser.arriveAndDeregister());
serverPeer.start(configFilePath);
}
@Override
public boolean reconfigurable() {
return true;
}
}
private static class TestableVespaZooKeeperAdmin implements VespaZooKeeperAdmin {
String connectionSpec;
String servers;
int reconfigurations = 0;
private int failures = 0;
private int attempts = 0;
public TestableVespaZooKeeperAdmin failures(int failures) {
this.failures = failures;
return this;
}
@Override
public void reconfigure(String connectionSpec, String servers) throws ReconfigException {
if (++attempts < failures)
throw new ReconfigException("Reconfig failed");
this.connectionSpec = connectionSpec;
this.servers = servers;
this.reconfigurations++;
}
}
}
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