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https://issues.apache.org/jira/browse/YARN-799?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13682739#comment-13682739
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Chris Riccomini commented on YARN-799:
--------------------------------------
Good deal. I'll send in a patch in 5m.
> CgroupsLCEResourcesHandler tries to write to cgroup.procs
> ---------------------------------------------------------
>
> Key: YARN-799
> URL: https://issues.apache.org/jira/browse/YARN-799
> Project: Hadoop YARN
> Issue Type: Bug
> Components: nodemanager
> Affects Versions: 2.0.4-alpha, 2.0.5-alpha
> Reporter: Chris Riccomini
>
> The implementation of
> bq.
> ./hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/util/CgroupsLCEResourcesHandler.java
> Tells the container-executor to write PIDs to cgroup.procs:
> {code}
> public String getResourcesOption(ContainerId containerId) {
> String containerName = containerId.toString();
> StringBuilder sb = new StringBuilder("cgroups=");
> if (isCpuWeightEnabled()) {
> sb.append(pathForCgroup(CONTROLLER_CPU, containerName) +
> "/cgroup.procs");
> sb.append(",");
> }
> if (sb.charAt(sb.length() - 1) == ',') {
> sb.deleteCharAt(sb.length() - 1);
> }
> return sb.toString();
> }
> {code}
> Apparently, this file has not always been writeable:
> https://patchwork.kernel.org/patch/116146/
> http://lkml.indiana.edu/hypermail/linux/kernel/1004.1/00536.html
> https://lists.linux-foundation.org/pipermail/containers/2009-July/019679.html
> The RHEL version of the Linux kernel that I'm using has a CGroup module that
> has a non-writeable cgroup.procs file.
> {quote}
> $ uname -a
> Linux criccomi-ld 2.6.32-131.4.1.el6.x86_64 #1 SMP Fri Jun 10 10:54:26 EDT
> 2011 x86_64 x86_64 x86_64 GNU/Linux
> {quote}
> As a result, when the container-executor tries to run, it fails with this
> error message:
> bq. fprintf(LOGFILE, "Failed to write pid %s (%d) to file %s - %s\n",
> This is because the executor is given a resource by the
> CgroupsLCEResourcesHandler that includes cgroup.procs, which is non-writeable:
> {quote}
> $ pwd
> /cgroup/cpu/hadoop-yarn/container_1370986842149_0001_01_000001
> $ ls -l
> total 0
> -r--r--r-- 1 criccomi eng 0 Jun 11 14:43 cgroup.procs
> -rw-r--r-- 1 criccomi eng 0 Jun 11 14:43 cpu.rt_period_us
> -rw-r--r-- 1 criccomi eng 0 Jun 11 14:43 cpu.rt_runtime_us
> -rw-r--r-- 1 criccomi eng 0 Jun 11 14:43 cpu.shares
> -rw-r--r-- 1 criccomi eng 0 Jun 11 14:43 notify_on_release
> -rw-r--r-- 1 criccomi eng 0 Jun 11 14:43 tasks
> {quote}
> I patched CgroupsLCEResourcesHandler to use /tasks instead of /cgroup.procs,
> and this appears to have fixed the problem.
> I can think of several potential resolutions to this ticket:
> 1. Ignore the problem, and make people patch YARN when they hit this issue.
> 2. Write to /tasks instead of /cgroup.procs for everyone
> 3. Check permissioning on /cgroup.procs prior to writing to it, and fall back
> to /tasks.
> 4. Add a config to yarn-site that lets admins specify which file to write to.
> Thoughts?
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