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  1. Fred Flint
  2. Sunday, March 04, 2018
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Applied kernelcare to two OpenVZ nodes yesterday.

042stab127.2

One of them seems ok but the other one had problems overnight. Really high swap and load even though there was still plenty of unused memory. Individual containers had all their vswap used. Not all containers are using vswap. I rebooted the containers that have vswap and that seemed to correct the swap/load. It's too much of a coincidence that this happened the evening I updated the kernel. Nothing else was done and this server has been running continuously for months

The other node is still ok. Hopefully restarting the containers corrected it and I won't have to roll back the kernel.

Both nodes are Supermicro with Intel(R) Xeon(R) CPU E3-1230 v3 @ 3.30GHz and 16GB RAM

Both running kcare 042stab127.2

Base kernel is different though

The one still working is 2.6.32-042stab113.21
The one that had a problem is 2.6.32-042stab108.8
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  1. 04.03.2018 15:03:15
  2. # 1
Fred Flint Accepted Answer
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BTW, they were both running the same kcare kernel before the update. The last one released before this meltdown/Spectre one.
  1. 05.03.2018 17:03:40
  2. # 2
Fred Flint Accepted Answer
So am I the only one having this problem? It is definitely something related to Kernelcare. It happen right after I had a heavy process run that clears out all the cache and causes high load for a few minutes. Right after that, instead of the load subsiding, it skyrocketed. Load average was 200 when it is normally below 4. CPU wait state was hopping around between 50% and 95% which means it's waiting for I/O.

I disabled the heavy cron job for now but I suspect the problem is still there and could be triggered again when the heavy cron job runs.
  1. 05.03.2018 18:03:36
  2. # 3
Fred Flint Accepted Answer
I should point out that I have updated other servers with the native 042stab127.2 kernel, not kernelcare, and haven't seen this problem.
  1. 05.03.2018 18:03:55
  2. # 4
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Fred, please create a ticket at https://cloudlinux.zendesk.com (KernelCare department) so our support team can help you with the issue.
  1. 09.03.2018 23:03:12
  2. # 5
Peter Laws Accepted Answer
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Was there any outcome to this? Was it KC? I've been scared to yum update kernelcare for a while now...
  1. 10.03.2018 13:03:25
  2. # 6
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A ticket #26416 has been created to investigate the issue.
BTW, yum update kernelcare shouldn't bring in any problems with binary patches that KC applies.
  1. 10.03.2018 19:03:54
  2. # 7
Peter Laws Accepted Answer
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I'm stupid, I thought you needed the latest KC to upgrade to stab127.2...... Seems I've had this kernel version for ages.... :o

as (_8(|) says..... d'oh
  1. 14.03.2018 15:03:11
  2. # 8
Fred Flint Accepted Answer
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So far, the high load problem has not re-occurred since the first time where I had restart containers that use vswap.
  1. 19.03.2018 18:03:13
  2. # 9
Vladimir Accepted Answer
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Glad to hear that.

Feel free to let me know if you have any further questions or concerns.
  1. 17.04.2018 18:04:06
  2. # 10
Fred Flint Accepted Answer
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Well it just happened again. I rebooted the 2 containers that seemed to be causing the high load and it went away again. I am going to have to upgrade this node to the real kernel and see if that takes care of it.
  1. 17.04.2018 19:04:11
  2. # 11
Vladimir Accepted Answer
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Hello.

We would like to check this problem.
Please submit a ticket to https://cloudlinux.zendesk.com, our techs will check the issue in place.
  1. 17.04.2018 20:04:23
  2. # 12
Fred Flint Accepted Answer
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Hello.

We would like to check this problem.
Please submit a ticket to https://cloudlinux.zendesk.com, our techs will check the issue in place.


You guys already did and said you couldn't find anything. It seems to be hard to reproduce. I see there was one race condition that was fixed in the latest OVZ kernel so maybe that took care of it. It started happening as soon as up updated Kernelcare and I haven's seen this on other nodes not running KernelCare but running the exact same real kernel. So I think the best thing is to run the real kernel in this case.
  1. 19.04.2018 15:04:40
  2. # 13
Vladimir Accepted Answer
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I am sorry, but it's hard to help you without a clear understanding what's going on on that server.
We really would like to check this problem in place. Please submit a ticket to https://cloudlinux.zendesk.com and our techs will investigate it further.
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