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TEZ-4479: Eagerly Init/Load FileSystem In Tez Task Containers #274

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TEZ-4479: Eagerly Init/Load FileSystem In Tez Task Containers #274

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8 changes: 8 additions & 0 deletions tez-api/src/main/java/org/apache/tez/dag/api/TezConfiguration.java
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Original file line number Diff line number Diff line change
Expand Up @@ -1131,6 +1131,14 @@ public TezConfiguration(boolean loadDefaults) {

public static final int TASK_HEARTBEAT_TIMEOUT_CHECK_MS_DEFAULT = 30 * 1000;

/**
* String value. Comma seperated list of FileSystem paths which needs to be eagerly initialized.
* For example s3://bucket/,file://,hdfs://localhost:8020/
*/
@ConfigurationScope(Scope.VERTEX)
@ConfigurationProperty
public static final String TEZ_TASK_EAGER_INIT_FS_PATHS = TEZ_TASK_PREFIX + "eager.init.fs.paths";

/**
* Whether to scale down memory requested by each component if the total
* exceeds the available JVM memory
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32 changes: 32 additions & 0 deletions tez-runtime-internals/src/main/java/org/apache/tez/runtime/task/TezChild.java
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Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,7 @@
import java.security.PrivilegedExceptionAction;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
Expand All @@ -40,6 +41,7 @@

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.ipc.RPC;
import org.apache.hadoop.net.NetUtils;
import org.apache.hadoop.security.Credentials;
Expand Down Expand Up @@ -130,6 +132,7 @@ public class TezChild {
private final HadoopShim hadoopShim;
private final TezExecutors sharedExecutor;
private ThreadLocalMap mdcContext;
private static ExecutorService eagerInitFsPool;

public TezChild(Configuration conf, String host, int port, String containerIdentifier,
String tokenIdentifier, int appAttemptNumber, String workingDir, String[] localDirs,
Expand Down Expand Up @@ -503,6 +506,33 @@ public static TezChild newTezChild(Configuration conf, String host, int port, St
hadoopShim);
}

private static void eagerInitFileSystemPaths(Configuration conf) {
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It will be good to measure the time spent on FS init (even for cloudstores) and share the details, before trying out this patch.

Reason: This get inited in TezChild, but for running container, it closes the FileSystem explicitly via "FileSystem.closeAllForUGI(childUGI);". Refer "public ContainerExecutionResult run()" method.

Even if this gets early inited, it will not have major impact in container reuse scenario. It will be good to measure and find out the timing spent in FS init.

Collection<String> eagerInitPaths = conf.getTrimmedStringCollection(
TezConfiguration.TEZ_TASK_EAGER_INIT_FS_PATHS);
if (eagerInitFsPool == null && !eagerInitPaths.isEmpty()) {
eagerInitFsPool = Executors.newCachedThreadPool(new ThreadFactoryBuilder()
.setDaemon(true)
.setNameFormat("Eager-Init-Fs-Thread-%d")
.build());
}
for (String path : eagerInitPaths) {
eagerInitFsPool.execute(new Runnable() {
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before rushing to create lots of fs instances in parallel, look at HADOOP-17313 and why we actually added semaphores to stop apps like tez creating too many at the same time. this code may cause overload problems, or the fs semaphore will hold you back for safety.

best to look at why its taking so long; if s3a bucket existence checks aren't involved, then it'll be whatever auth mechanism is plugged in. same for abfs

@Override
public void run() {
try {
long startTime = System.currentTimeMillis();
FileSystem fs = new Path(path).getFileSystem(conf);
long duration = System.currentTimeMillis() - startTime;
LOG.info("Eagerly initiated FileSystem at path {} in {} ms", path, duration);
} catch (Exception e) {
// swallow the exception since this doesn't block the core functionality
LOG.error("Unable to eager init FileSystem at the path {}", path, e);
}
}
});
}
}

public static void main(String[] args) throws IOException, InterruptedException, TezException {
TezClassLoader.setupTezClassLoader();
final Configuration defaultConf = new Configuration();
Expand Down Expand Up @@ -530,6 +560,8 @@ public static void main(String[] args) throws IOException, InterruptedException,
DAGProtos.ConfigurationProto confProto =
TezUtilsInternal.readUserSpecifiedTezConfiguration(System.getenv(Environment.PWD.name()));
TezUtilsInternal.addUserSpecifiedTezConfiguration(defaultConf, confProto.getConfKeyValuesList());
// eagerly load configured filesystem before it is actually required
eagerInitFileSystemPaths(defaultConf);
UserGroupInformation.setConfiguration(defaultConf);
Credentials credentials = UserGroupInformation.getCurrentUser().getCredentials();

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