booting perpd with linux oom abatement

booting perpd with linux oom abatement

[Wayne Marshall]

In response to the announcement of the latest perp-2.03 release
on the supervision mailing list, there appeared some interesting
comments regarding the linux "oom killer" as colorfully
described here:

http://lwn.net/Articles/104179/

Evidently, the linux kernel can randomly terminate arbitrary
processes -- even privileged ones -- with SIGKILL.  Astonishing.

In any case, it would certainly be undesirable for the linux
kernel to decide to hit the perpd process with SIGKILL.
Accordingly, attached below is an alternative rc.perp boot
script that will abate the thread of the "dreaded linux oom
killer" on perpd(8).

Simply copy into /etc/perp/.boot/rc.perp, restart your system,
and worry no more.

<script>
#!/bin/sh -e
# rc.perp: perpd startup script for perpboot
# ===

### --- configure ---
PERP_VAR=/var/run/perp
PERPD_OPTS="-a6"

## disable oom killer (linux, since kernel 2.6.11):
## (see also proc(5) manual)
OOM_ADJ="-17"

### --- script ---
MYPID=$$

## note: perpboot defines PERP_BASE on startup
## note: perpd will create PERP_VAR if .control is a dangling
symlink

## setup symlink for runtime control files:
if test ! -h ${PERP_BASE}/.control ; then
  rm -Rf ${PERP_BASE}/.control
  ln -s ${PERP_VAR} ${PERP_BASE}/.control
fi

## disable oom killer (see proc(5), linux):
if test -w /proc/${MYPID}/oom_adj ; then
  echo ${OOM_ADJ} > /proc/${MYPID}/oom_adj
fi

## exec perpd, options as configured above:
exec \
  runlimit -F ./rlimit.conf \
  perpd ${PERPD_OPTS} ${PERP_BASE}

### EOF
</script>

I will also be happy to accept suggestions/contributions for a
new "runnoom(8)" utility to include with the runtools collection
in the next perp release.

Regards,

Wayne
http://b0llix.net/perp/