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https://issues.apache.org/jira/browse/FLINK-8707?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16370223#comment-16370223
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Alexander Gardner commented on FLINK-8707:
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Attaching the lsof output, removing any refs to real boxes or locations.
> Excessive amount of files opened by flink task manager
> ------------------------------------------------------
>
> Key: FLINK-8707
> URL: https://issues.apache.org/jira/browse/FLINK-8707
> Project: Flink
> Issue Type: Bug
> Components: JobManager
> Affects Versions: 1.3.2
> Environment: NAME="Red Hat Enterprise Linux Server"
> VERSION="7.3 (Maipo)"
> Two boxes, each with a Job Manager & Task Manager, using Zookeeper for HA.
> flink.yaml below with some settings (removed exact box names) etc:
> env.log.dir: ...some dir...residing on the same box
> env.pid.dir: some dir...residing on the same box
> metrics.reporter.jmx.class: org.apache.flink.metrics.jmx.JMXReporter
> metrics.reporters: jmx
> state.backend: filesystem
> state.backend.fs.checkpointdir: file:///some_nfs_mount
> state.checkpoints.dir: file:///some_nfs_mount
> state.checkpoints.num-retained: 3
> high-availability.cluster-id: /tst
> high-availability.storageDir: file:///some_nfs_mount/ha
> high-availability: zookeeper
> high-availability.zookeeper.path.root: /flink
> high-availability.zookeeper.quorum: ...list of zookeeper boxes
> env.java.opts.jobmanager: ...some extra jar args
> jobmanager.archive.fs.dir: some dir...residing on the same box
> jobmanager.web.submit.enable: true
> jobmanager.web.tmpdir: some dir...residing on the same box
> env.java.opts.taskmanager: some extra jar args
> taskmanager.tmp.dirs: some dir...residing on the same box/var/tmp
> taskmanager.network.memory.min: 1024MB
> taskmanager.network.memory.max: 2048MB
> blob.storage.directory: some dir...residing on the same box
> Reporter: Alexander Gardner
> Priority: Blocker
> Fix For: 1.5.0
>
> Attachments: box1-jobmgr-lsof, box1-taskmgr-lsof, box2-jobmgr-lsof,
> box2-taskmgr-lsof
>
>
> ** NOTE ** - THE COMPONENT IS TASK MANAGER NOT JOB MANAGER
> The job manager has less FDs than the task manager.
>
> Hi
> A support alert indicated that there were a lot of open files for the boxes
> running Flink.
> There were 4 flink jobs that were dormant but had consumed a number of msgs
> from Kafka using the FlinkKafkaConsumer010.
> A simple general lsof:
> $ lsof | wc -l -> returned 153114 open file descriptors.
> Focusing on the TaskManager process (process ID = 12154):
> $ lsof | grep 12154 | wc -l- > returned 129322 open FDs
> $ lsof -p 12154 | wc -l -> returned 531 FDs
> There were 228 threads running for the task manager.
>
> Drilling down a bit further, looking at a_inode and FIFO entries:
> $ lsof -p 12154 | grep a_inode | wc -l = 100 FDs
> $ lsof -p 12154 | grep FIFO | wc -l = 200 FDs
> $ /proc/12154/maps = 920 entries.
> Apart from lsof identifying lots of JARs and SOs being referenced there were
> also 244 child processes for the task manager process.
> Noticed that in each environment, a creep of file descriptors...are the above
> figures deemed excessive for the no of FDs in use? I know Flink uses Netty -
> is it using a separate Selector for reads & writes?
> Additionally Flink uses memory mapped files? or direct bytebuffers are these
> skewing the numbers of FDs shown?
> Example of one child process ID 6633:
> java 12154 6633 dfdev 387u a_inode 0,9 0 5869 [eventpoll]
> java 12154 6633 dfdev 388r FIFO 0,8 0t0 459758080 pipe
> java 12154 6633 dfdev 389w FIFO 0,8 0t0 459758080 pipe
> Lasty, cannot identify yet the reason for the creep in FDs even if Flink is
> pretty dormant or has dormant jobs. Production nodes are not experiencing
> excessive amounts of throughput yet either.
>
>
>
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