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https://issues.apache.org/jira/browse/YARN-1677?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Ding Yuan updated YARN-1677:
----------------------------
Attachment: yarn-1677.patch
> Potential bugs in exception handlers
> ------------------------------------
>
> Key: YARN-1677
> URL: https://issues.apache.org/jira/browse/YARN-1677
> Project: Hadoop YARN
> Issue Type: Bug
> Components: nodemanager
> Affects Versions: 2.2.0
> Reporter: Ding Yuan
> Attachments: yarn-1677.patch
>
>
> Hi Yarn developers,
> We are a group of researchers on software reliability, and recently we did a
> study and found that majority of the most severe failures in hadoop are
> caused by bugs in exception handling logic. Therefore we built a simple
> checking tool that automatically detects some bug patterns that have caused
> some very severe failures. I am reporting some of the results for Yarn here.
> Any feedback is much appreciated!
> ==========================
> Case 1:
> Line: 551, File:
> "org/apache/hadoop/yarn/server/nodemanager/containermanager/monitor/ContainersMonitorImpl.java"
> {noformat}
> switch (monitoringEvent.getType()) {
> case START_MONITORING_CONTAINER:
> .. ..
> default:
> // TODO: Wrong event.
> }
> {noformat}
> The switch fall-through (handling any potential unexpected event) is empty.
> Should we at least print an error message here?
> ==========================
> ==========================
> Case 2:
> Line: 491, File:
> "org/apache/hadoop/yarn/server/nodemanager/NodeStatusUpdaterImpl.java"
> {noformat}
> } catch (Throwable e) {
> // TODO Better error handling. Thread can die with the rest of the
> // NM still running.
> LOG.error("Caught exception in status-updater", e);
> }
> {noformat}
> The handler of this very general exception only logs the error. The TODO
> seems to indicate it is not sufficient.
> ==========================
> ==========================
> Case 3:
> Line: 861, File:
> "org/apache/hadoop/yarn/server/nodemanager/containermanager/localizer/ResourceLocalizationService.java"
> for (LocalResourceStatus stat : remoteResourceStatuses) {
> LocalResource rsrc = stat.getResource();
> LocalResourceRequest req = null;
> try {
> req = new LocalResourceRequest(rsrc);
> } catch (URISyntaxException e) {
> // TODO fail? Already translated several times...
> }
> The handler for URISyntaxException is empty, and the TODO seems to indicate
> it is not sufficient.
> The same code pattern can also be found at:
> Line: 901, File:
> "org/apache/hadoop/yarn/server/nodemanager/containermanager/localizer/ResourceLocalizationService.java"
> Line: 838, File:
> "org/apache/hadoop/yarn/server/nodemanager/containermanager/localizer/ResourceLocalizationService.java"
> Line: 878, File:
> "org/apache/hadoop/yarn/server/nodemanager/containermanager/localizer/ResourceLocalizationService.java"
> At line: 803, File:
> org/apache/hadoop/yarn/applications/distributedshell/ApplicationMaster.java,
> the handler of URISyntaxException also seems not sufficient:
> {noformat}
> try {
> shellRsrc.setResource(ConverterUtils.getYarnUrlFromURI(new URI(
> shellScriptPath)));
> } catch (URISyntaxException e) {
> LOG.error("Error when trying to use shell script path specified"
> + " in env, path=" + shellScriptPath);
> e.printStackTrace();
> // A failure scenario on bad input such as invalid shell script path
> // We know we cannot continue launching the container
> // so we should release it.
> // TODO
> numCompletedContainers.incrementAndGet();
> numFailedContainers.incrementAndGet();
> return;
> }
> {noformat}
> ==========================
> ==========================
> Case 4:
> Line: 627, File:
> "org/apache/hadoop/yarn/server/resourcemanager/rmapp/attempt/RMAppAttemptImpl.java"
> {noformat}
> try {
> /* keep the master in sync with the state machine */
> this.stateMachine.doTransition(event.getType(), event);
> } catch (InvalidStateTransitonException e) {
> LOG.error("Can't handle this event at current state", e);
> /* TODO fail the application on the failed transition */
> }
> {noformat}
> The handler of this exception only logs the error. The TODO seems to indicate
> it is not sufficient.
> This exact same code pattern can also be found at:
> Line: 573, File:
> "org/apache/hadoop/yarn/server/resourcemanager/rmapp/RMAppImpl.java"
> ==========================
> ==========================
> Case 5: empty handler for exception: java.lang.InterruptedException
> Line: 123, File: "org/apache/hadoop/yarn/server/webproxy/WebAppProxy.java"
> {noformat}
> public void join() {
> if(proxyServer != null) {
> try {
> proxyServer.join();
> } catch (InterruptedException e) {
> }
> }
> }
> {noformat}
> The InterruptedException is completely ignored. As a result, any events
> causing this interrupt will be lost.
> More info on why InterruptedException shouldn't be ignored:
> http://stackoverflow.com/questions/1087475/when-does-javas-thread-sleep-throw-interruptedexception
> This pattern of handling InterruptedException can be found in a few other
> places:
> Line: 434, File:
> org/apache/hadoop/yarn/server/resourcemanager/ResourceManager.java
> {noformat}
> try {
> event = eventQueue.take();
> } catch (InterruptedException e) {
> LOG.error("Returning, interrupted : " + e);
> return; // TODO: Kill RM.
> }
> {noformat}
> Line: 722, File:
> "org/apache/hadoop/yarn/server/nodemanager/containermanager/localizer/ResourceLocalizationService.java"
> Line: 191, File:
> "org/apache/hadoop/yarn/server/nodemanager/containermanager/monitor/ContainersMonitorImpl.java"
> Line: 393, File:
> "org/apache/hadoop/yarn/util/LinuxResourceCalculatorPlugin.java"
> Line: 258, File:
> "org/apache/hadoop/yarn/server/nodemanager/containermanager/localizer/LocalizedResource.java"
> ==========================
> ==========================
> Case 6: potential divide by zero
> line: 581, File:
> org/apache/hadoop/yarn/server/resourcemanager/scheduler/fifo/FifoScheduler.java
> {noformat}
> int availableContainers =
> node.getAvailableResource().getMemory() / capability.getMemory();
> // TODO: A buggy
> // application
> // with this
> // zero would
> // crash the
> // scheduler.
> {noformat}
> Should this potential divide by zero be handled?
> ==========================
> ==========================
> Case 7:
> Line: 260, File:
> "org/apache/hadoop/yarn/server/nodemanager/containermanager/localizer/LocalizedResource.java"
> {noformat}
> } catch (YarnException e) {
> // TODO cleanup
> return;
> }
> {noformat}
> The error handler simply returns without proper clean up.
> ==========================
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