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https://issues.apache.org/jira/browse/TWILL-61?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16399161#comment-16399161
]
ASF GitHub Bot commented on TWILL-61:
-------------------------------------
Github user anew commented on a diff in the pull request:
https://github.com/apache/twill/pull/67#discussion_r174571807
--- Diff:
twill-core/src/main/java/org/apache/twill/internal/AbstractTwillService.java ---
@@ -216,11 +217,52 @@ protected final void shutDown() throws Exception {
return zkClient.setData(liveNodePath, serializeLiveNode());
}
+ /**
+ * Creates the live node for the service. If the node already exists, it
will be deleted before creation.
+ *
+ * @return A {@link OperationFuture} that will be completed when the
creation is done.
+ */
private OperationFuture<String> createLiveNode() {
- String liveNodePath = getLiveNodePath();
+ final String liveNodePath = getLiveNodePath();
LOG.info("Create live node {}{}", zkClient.getConnectString(),
liveNodePath);
- return ZKOperations.ignoreError(zkClient.create(liveNodePath,
serializeLiveNode(), CreateMode.EPHEMERAL),
-
KeeperException.NodeExistsException.class, liveNodePath);
+ final SettableOperationFuture<String> resultFuture =
SettableOperationFuture.create(liveNodePath,
+
Threads.SAME_THREAD_EXECUTOR);
+ OperationFuture<String> createFuture = zkClient.create(liveNodePath,
serializeLiveNode(), CreateMode.EPHEMERAL);
+ Futures.addCallback(createFuture, new FutureCallback<String>() {
+ final FutureCallback<String> thisCallback = this;
+
+ @Override
+ public void onSuccess(String result) {
+ LOG.info("Live node created {}{}", zkClient.getConnectString(),
liveNodePath);
+ resultFuture.set(result);
+ }
+
+ @Override
+ public void onFailure(final Throwable createFailure) {
+ if (!(createFailure instanceof
KeeperException.NodeExistsException)) {
+ resultFuture.setException(createFailure);
+ }
+
+ // If the node already exists, it is due to previous run attempt
that left an ephemeral node.
--- End diff --
how can it leave an ephemeral node? Doesn't that mean there must be a
zombie process holding on to that node?
> Second launch attempt of AM always failed
> -----------------------------------------
>
> Key: TWILL-61
> URL: https://issues.apache.org/jira/browse/TWILL-61
> Project: Apache Twill
> Issue Type: Bug
> Components: yarn
> Reporter: Terence Yim
> Assignee: Terence Yim
> Priority: Major
> Fix For: 0.5.0-incubating
>
>
> YARN would make multiple attempts to launch an application. Currently second
> or above attempts would always fail due to creation of /runId/state node in
> ZK fail (node exists) because runId is generated on client side and doesn't
> change between attempts.
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