Github user vanzin commented on a diff in the pull request:
https://github.com/apache/spark/pull/8007#discussion_r38494894
--- Diff:
core/src/main/scala/org/apache/spark/scheduler/cluster/YarnSchedulerBackend.scala
---
@@ -91,6 +96,43 @@ private[spark] abstract class YarnSchedulerBackend(
}
/**
+ * Override the DriverEndpoint to add extra logic for the case when an
executor is disconnected.
+ * We should check the cluster manager and find if the loss of the
executor was caused by YARN
+ * force killing it due to preemption.
+ */
+ private class YarnDriverEndpoint(rpcEnv: RpcEnv, sparkProperties:
ArrayBuffer[(String, String)])
+ extends DriverEndpoint(rpcEnv, sparkProperties) {
+
+ /**
+ * When onDisconnected is received at the driver endpoint, the
superclass DriverEndpoint
+ * handles it by assuming the Executor was lost for a bad reason and
removes the executor
+ * immediately.
+ *
+ * In YARN's case however it is crucial to talk to the application
master and ask why the
+ * executor had exited. In particular, the executor may have exited
due to the executor
+ * having been preempted. If the executor "exited normally" according
to the application
+ * master then we pass that information down to the TaskSetManager to
inform the
+ * TaskSetManager that tasks on that lost executor should not count
towards a job failure.
+ */
+ override def onDisconnected(rpcAddress: RpcAddress): Unit = {
+ addressToExecutorId.get(rpcAddress).foreach { executorId =>
--- End diff --
Man this is pretty hard to read. I wonder if something like this would
compile:
addressToExecutorId.get(rpcAddress).foreach { executorId =>
yarnSchedulerEndpoint.askForExecutorLossReason(executorId,
reason =>
driverEndpoint.askWithRetry[Boolean](RemoveExecutor(executorId, reason),
e => {
logWarning(s"Attempted to get executor loss reason" +
s" for $rpcAddress but got no response. Marking as slave
lost.", e)
driverEndpoint.askWithRetry[Boolean](RemoveExecutor(executorId,
SlaveLost()))
})
}
Since this is the only call site for `askForExecutorLossReason` that I can
see, it might be better to just inline the code. Should make it more readable.
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