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* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.solr.cloud;
import java.lang.invoke.MethodHandles;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.TimeUnit;
import org.apache.lucene.util.LuceneTestCase.Slow;
import org.apache.lucene.util.TestUtil;
import org.apache.solr.cloud.SolrCloudTestCase;
import org.apache.solr.client.solrj.impl.CloudSolrClient;
import org.apache.solr.common.cloud.SolrZkClient;
import org.apache.solr.common.cloud.ZkStateReader;
import org.apache.solr.common.util.ExecutorUtil;
import org.apache.solr.util.DefaultSolrThreadFactory;
import org.apache.zookeeper.CreateMode;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Stress test LiveNodes watching.
*
* Does bursts of adds to live_nodes using parallel threads to and verifies that after each
* burst a ZkStateReader detects the correct set.
*/
@Slow
public class TestStressLiveNodes extends SolrCloudTestCase {
private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
/** A basic cloud client, we'll be testing the behavior of it's ZkStateReader */
private static CloudSolrClient CLOUD_CLIENT;
/** The addr of the zk server used in this test */
private static String ZK_SERVER_ADDR;
/* how many seconds we're willing to wait for our executor tasks to finish before failing the test */
private final static int WAIT_TIME = TEST_NIGHTLY ? 60 : 30;
@BeforeClass
private static void createMiniSolrCloudCluster() throws Exception {
// we only need 1 node, and we don't care about any configs or collections
// we're going to fake all the live_nodes changes we want to fake.
configureCluster(1).configure();
// give all nodes a chance to come alive
TestTolerantUpdateProcessorCloud.assertSpinLoopAllJettyAreRunning(cluster);
CLOUD_CLIENT = cluster.getSolrClient();
CLOUD_CLIENT.connect(); // force connection even though we aren't sending any requests
ZK_SERVER_ADDR = cluster.getZkServer().getZkAddress();
}
@AfterClass
private static void afterClass() throws Exception {
CLOUD_CLIENT.close();
CLOUD_CLIENT = null;
}
private static SolrZkClient newSolrZkClient() {
assertNotNull(ZK_SERVER_ADDR);
// WTF is CloudConfigBuilder.DEFAULT_ZK_CLIENT_TIMEOUT private?
return new SolrZkClient(ZK_SERVER_ADDR, 15000);
}
/** returns the true set of live nodes (currently in zk) as a sorted list */
private static List<String> getTrueLiveNodesFromZk() throws Exception {
SolrZkClient client = newSolrZkClient();
try {
ArrayList<String> result = new ArrayList<>(client.getChildren(ZkStateReader.LIVE_NODES_ZKNODE, null, true));
Collections.sort(result);
return result;
} finally {
client.close();
}
}
/**
* returns the cached set of live nodes (according to the ZkStateReader in our CloudSolrClient)
* as a sorted list.
* This is done in a sleep+retry loop until the result matches the expectedCount, or a few iters have passed
* (this way we aren't testing how fast the watchers complete, just that they got the correct result)
*/
private static List<String> getCachedLiveNodesFromLocalState(final int expectedCount) throws Exception {
ArrayList<String> result = null;
for (int i = 0; i < 10; i++) {
result = new ArrayList<>(CLOUD_CLIENT.getZkStateReader().getClusterState().getLiveNodes());
if (expectedCount != result.size()) {
log.info("sleeping #{} to give watchers a chance to finish: {} != {}",
i, expectedCount, result.size());
Thread.sleep(200);
} else {
break;
}
}
if (expectedCount != result.size()) {
log.error("gave up waiting for live nodes to match expected size: {} != {}",
expectedCount, result.size());
}
Collections.sort(result);
return result;
}
public void testStress() throws Exception {
// do many iters, so we have "bursts" of adding nodes that we then check
final int numIters = atLeast(TEST_NIGHTLY ? 1000 : 100);
for (int iter = 0; iter < numIters; iter++) {
// sanity check that ZK says there is in fact 1 live node
List<String> actualLiveNodes = getTrueLiveNodesFromZk();
assertEquals("iter"+iter+": " + actualLiveNodes.toString(),
1, actualLiveNodes.size());
// only here do we forcibly update the cached live nodes so we don't have to wait for it to catch up
// with all the ephemeral nodes that vanished after the last iteration
CLOUD_CLIENT.getZkStateReader().updateLiveNodes();
// sanity check that our Cloud Client's local state knows about the 1 (real) live node in our cluster
List<String> cachedLiveNodes = getCachedLiveNodesFromLocalState(actualLiveNodes.size());
assertEquals("iter"+iter+" " + actualLiveNodes.size() + " != " + cachedLiveNodes.size(),
actualLiveNodes, cachedLiveNodes);
// start spinning up some threads to add some live_node children in parallel
// we don't need a lot of threads or nodes (we don't want to swamp the CPUs
// just bursts of concurrent adds) but we do want to randomize it a bit so we increase the
// odds of concurrent watchers firing regardless of the num CPUs or load on the machine running
// the test (but we deliberately don't look at availableProcessors() since we want randomization
// consistency across all machines for a given seed)
final int numThreads = TestUtil.nextInt(random(), 2, 5);
// use same num for all thrashers, to increase likely hood of them all competing
// (diff random number would mean heavy concurrency only for ~ the first N=lowest num requests)
//
// this does not need to be a large number -- in fact, the higher it is, the more
// likely we are to see a mistake in early watcher triggers get "corrected" by a later one
// and overlook a possible bug
final int numNodesPerThrasher = TestUtil.nextInt(random(), 1, 5);
log.info("preparing parallel adds to live nodes: iter={}, numThreads={} numNodesPerThread={}",
iter, numThreads, numNodesPerThrasher);
// NOTE: using ephemeral nodes
// so we can't close any of these thrashers until we are done with our assertions
final List<LiveNodeTrasher> thrashers = new ArrayList<>(numThreads);
for (int i = 0; i < numThreads; i++) {
thrashers.add(new LiveNodeTrasher("T"+iter+"_"+i, numNodesPerThrasher));
}
try {
final ExecutorService executorService = ExecutorUtil.newMDCAwareFixedThreadPool
(thrashers.size()+1, new DefaultSolrThreadFactory("test_live_nodes_thrasher_iter"+iter));
executorService.invokeAll(thrashers);
executorService.shutdown();
if (! executorService.awaitTermination(WAIT_TIME, TimeUnit.SECONDS)) {
for (LiveNodeTrasher thrasher : thrashers) {
thrasher.stop();
}
}
assertTrue("iter"+iter+": thrashers didn't finish even after explicitly stopping",
executorService.awaitTermination(WAIT_TIME, TimeUnit.SECONDS));
// sanity check the *real* live_nodes entries from ZK match what the thrashers added
int totalAdded = 1; // 1 real live node when we started
for (LiveNodeTrasher thrasher : thrashers) {
totalAdded += thrasher.getNumAdded();
}
actualLiveNodes = getTrueLiveNodesFromZk();
assertEquals("iter"+iter, totalAdded, actualLiveNodes.size());
// verify our local client knows the correct set of live nodes
cachedLiveNodes = getCachedLiveNodesFromLocalState(actualLiveNodes.size());
assertEquals("iter"+iter+" " + actualLiveNodes.size() + " != " + cachedLiveNodes.size(),
actualLiveNodes, cachedLiveNodes);
} finally {
for (LiveNodeTrasher thrasher : thrashers) {
// shutdown our zk connection, freeing our ephemeral nodes
thrasher.close();
}
}
}
}
/** NOTE: has internal counter which is not thread safe, only call() in one thread at a time */
public static final class LiveNodeTrasher implements Callable<Integer> {
private final String id;
private final int numNodesToAdd;
private final SolrZkClient client;
private boolean running = false;;
private int numAdded = 0;
/** ID should ideally be unique amongst any other instances */
public LiveNodeTrasher(String id, int numNodesToAdd) {
this.id = id;
this.numNodesToAdd = numNodesToAdd;
this.client = newSolrZkClient();
}
/** returns the number of nodes actually added w/o error */
public Integer call() {
running = true;
// NOTE: test includes 'running'
for (int i = 0; running && i < numNodesToAdd; i++) {
final String nodePath = ZkStateReader.LIVE_NODES_ZKNODE + "/thrasher-" + id + "-" + i;
try {
client.makePath(nodePath, CreateMode.EPHEMERAL, true);
numAdded++;
} catch (Exception e) {
log.error("failed to create: " + nodePath, e);
}
}
return numAdded;
}
public int getNumAdded() {
return numAdded;
}
public void close() {
client.close();
}
public void stop() {
running = false;
}
}
}