Re: Slab Unreclaimable is continually growing
Just for reference:
check_mk_agent caused the endlessly growing of SUnreclaim in
/proc/meminfo and similary vm_area_struct in slabtop if the typical
conditions are met in a Debian Buster with check-mk-agent:
- Debian 10 Buster
systemd 241-7~deb10u1 amd64
Kernel 4.19.67-2, but with newer kernels too.
- check-mk-agent
my version is 1.5.0p18, but with newer versions too
- check_mk.socket is active in systemd and used via 6556/tcp
- one or more checks are cached
for example ntp in check_mk_agent or the simple
echo "0 myservice - OK: This is my custom output"
tribe29 as creators of checkmk is aware of this, has observed it only
in Debian Buster and recommends in Buster xinetd for the listening
socket for its agent.
https://lists.mathias-kettner.de/pipermail/checkmk-en/2019-September/028675.html
https://lists.mathias-kettner.de/pipermail/checkmk-en/2019-September/028676.html
Matthias
Am Sa., 27. Juli 2019 um 11:59 Uhr schrieb Matthias Böttcher
<matthias.boettcher@gmail.com>:
>
> On Fri, Jul 26, 2019 at 10:12:20PM +0300, Reco wrote:
> > On Fri, Jul 26, 2019 at 08:55:19PM +0200, Matthias Böttcher wrote:
>
> [...]
>
> > > and additionally I stopped the socket for the Check_MK agent:
> > >
> > > sudo systemctl stop check_mk.socket
> >
> > I do not know this one. What's its purpose? Monitoring, backup,
> > something else? Is there a source available.
>
> Checkmk, formerly Check_MK, is a monitoring software[1].
> I am using the Checkmk Raw Edition (CRE) open-source.
> Per default it gets data from an agent on a host with connect to 6556/tcp
> every 60 seconds. All counters are fetched in one connect,
> nothing is sent to the host. The agent for Linux is one big bash script[2].
>
> The deb with the agent brings systemd integration:
>
> --------------------------------------------
> $ cat "/etc/systemd/system/check_mk@.service"
>
> # systemd service definition file
> [Unit]
> Description=Check_MK
>
> [Service]
> ExecStart=/usr/bin/check_mk_agent
> KillMode=process
>
> User=root
> Group=root
>
> StandardInput=socket
>
> --------------------------------------------
> $ cat /etc/systemd/system/check_mk.socket
>
> # systemd socket definition file
> [Unit]
> Description=Check_MK Agent Socket
>
> [Socket]
> ListenStream=6556
> Accept=true
>
> [Install]
> WantedBy=sockets.target
> --------------------------------------------
>
> With check_mk.socket started, SUnreclaim and vm_area_struct are growing
> endlessly. So I will investigate the checkmk agent.
>
> > Reco
>
> Reco, Thank you for your explanations and bumping me in the right direction.
>
> Matthias
>
> [1] https://checkmk.com/
> [2] https://github.com/tribe29/checkmk/blob/master/agents/check_mk_agent.linux
>
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