How to Check for and Handle Empty/Orphan Cgroups
(Doc ID 2717308.1)
Last updated on OCTOBER 19, 2020
Applies to:Big Data Appliance Integrated Software - Version 4.5.0 and later
After the steps in, Impala and Yarn Jobs Have Degraded Performance Over Time On Systems with Heavy Linux Control Group Usage (Doc ID 2411555.1) are followed, cgroups created before following the note remain. No cgroups created after following the note linger. The NodeManager logs do not contain any occurrences of "Unable to delete cgroup".
If the cgroup structures which remain on the system were created before following the MOS note (2411555.1) and subsequent NodeManager restart and are empty (meaning that kernel has removed all files) or they are "orphaned" structures, they can be removed manually. In these cases the NodeManager restart does not clear up the empty or "orphaned" cgroup structures. Note: Rather than manually removing the files, a node reboot would also clear them up.
Otherwise they can not be removed manually.
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