dist: add workaround to capture coredump during system reboot or shut…

…down

We found that systemd-coredump does not correctly capturing coredump
during system reboot or shutdown.
As a workaround of this issue, set coredump file path to
kernel.core_pattern during system reboot or shutdown.
It will save core to /var/tmp/core.scylla.$PID.$TIMESTAMP.

Fixes scylladb/scylla-machine-image#436

dist/common/scripts/scylla_kill

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+st_jobs=$(systemctl list-jobs --no-pager shutdown.target)
+if [[ ! $st_jobs =~ (^No jobs .*\.$) ]]; then
+    sysctl -w kernel.core_pattern=/var/tmp/core.%e.%p.%t
+fi
+pkill scylla

dist/common/systemd/scylla-server.service

@@ -16,6 +16,7 @@ EnvironmentFile=/etc/sysconfig/scylla-server
 EnvironmentFile=/etc/scylla.d/*.conf
 ExecStartPre=/opt/scylladb/scripts/scylla_prepare
 ExecStart=/usr/bin/scylla $SCYLLA_ARGS $SEASTAR_IO $DEV_MODE $CPUSET $MEM_CONF
+ExecStop=/opt/scylladb/scripts/scylla_kill
 ExecStopPost=/opt/scylladb/scripts/scylla_stop
 TimeoutStartSec=1y
 TimeoutStopSec=900