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scripts: systemd-autofs-restart.sh added

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This script restarts systemd autofs services to workaround a problem, when
systemd doesn't consider autofs mount as own after restore (alien device ID
problem)

v4:
Environment variable NS_PID was renamed to CRTOOLS_INIT_PID

v2:
1) Added different checks: for process with pid, active service, systemd based
container.

Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
This commit is contained in:
Stanislav Kinsburskiy
2016-04-12 12:48:00 +03:00
committed by Pavel Emelyanov
parent 4635b53846
commit 10ffc78dfb
1 changed files with 58 additions and 0 deletions
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58
scripts/systemd-autofs-restart.sh Executable file
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#!/bin/bash
#
# This script can be used as a workaround for systemd autofs mount migration.
# The problem is that systemd is a clever guy: before mounting of actual file
# system on top of autofs mount, it first checks that device number of autofs
# mount is equal to the one, stored in sytemd internals. If they do not match,
# systemd ignores kernel request.
# The problem happens each time autofs is restored (new device number for
# autofs superblock) and can't be properly solved without some kind of "device
# namespaces", where device number can be preseved.
# But some of systemd services can be painlessly restarted. Like
# proc-sys-fs-binfmt_misc.
#
# Usage:
# criu restore <options> --action-script $(pwd)/scripts/systemd-autofs-restart.sh
#
[ "$CRTOOLS_SCRIPT_ACTION" == "post-resume" ] || exit 0
if [ ! -n "$CRTOOLS_INIT_PID" ]; then
echo "CRTOOLS_INIT_PID environment variable is not set"
exit 1
fi
if [ ! -d "/proc/$CRTOOLS_INIT_PID" ]; then
echo "Process with CRTOOLS_INIT_PID=$CRTOOLS_INIT_PID doesn't exist"
exit 1
fi
NS_ENTER=/usr/nsenter
[ ! -x $NSENTER ] || NS_ENTER=/usr/bin/nsenter
if [ ! -x $NS_ENTER ]; then
echo "$NS_ENTER binary not found"
exit 2
fi
JOIN_CT="$NS_ENTER -t $CRTOOLS_INIT_PID -m -u"
# Skip container, if it's not systemd based
[ $($JOIN_CT basename -- $(readlink /proc/1/exe)) == "systemd" ] || exit 0
AUTOFS_SERVICES="proc-sys-fs-binfmt_misc.automount"
for service in $AUTOFS_SERVICES; do
status=$($JOIN_CT systemctl is-active $service)
if [ $status == "active" ]; then
$JOIN_CT systemctl restart $service
if [ $? -ne 0 ]; then
echo "Failed to restart $service service"
exit 2
fi
echo "$service restarted"
else
echo "$service skipped ($status)"
fi
done
exit 0