[libvirt] [PATCH v2] daemon: Update libvirtd SysV/upstart scripts to avoid confusion

[Peter Krempa]

On some systems init scripts are installed along with upstart . This may
cause trouble if user tries to restart/stop a instance of libvirtd
managed with upstart with init script.

Upstart config file uses "respawn" stanza to ensure that libvirtd is
restarted after a crash/kill. This combined with a

The SysV init script is now able to detect libvirtd managed with upstart
explicitly and notify the user about this. This patch also modifies the
way the PID file is handled. Libvirtd alone removes the pid file on a
successful exit, so now, the init script does not delete it. It's only
deleted while starting libvirtd, when the script detects, that no
libvirtd with pid specified in the pid file is running.

This patch also modifies the upstart configuration file for libvirt.
Same logic as in the SysV script for handling pid files is used. The
upstart script does not explicitly check for a SysV managed instance.
Upstart alone prohibits to stop a not-started instance, so this issue is
handled automaticaly.

https://bugzilla.redhat.com/show_bug.cgi?id=728153
---
initctl_check() in the SysV init file is not strongly required. The purpose
of this is to notify the user of the source of problem the user is experiencing.

It can be left out, but then no (reasonable) notification will be provided
and the user might kill libvirtd managed by upstart (which will thereafter
respawn)

 daemon/libvirtd.init.in |   43 +++++++++++++++++++++++++++++++++++++++++--
 daemon/libvirtd.upstart |   31 ++++++++++++++++++++++++-------
 2 files changed, 65 insertions(+), 9 deletions(-)

diff --git a/daemon/libvirtd.init.in b/daemon/libvirtd.init.in
index 0697a2b..28801d1 100644
--- a/daemon/libvirtd.init.in
+++ b/daemon/libvirtd.init.in
@@ -43,6 +43,8 @@ LIBVIRTD_CONFIG=
 LIBVIRTD_ARGS=
 KRB5_KTNAME=/etc/libvirt/krb5.tab

+INITCTL_PATH=/sbin/initctl
+
 test -f @sysconfdir@/sysconfig/libvirtd && . @sysconfdir@/sysconfig/libvirtd

 export QEMU_AUDIO_DRV
@@ -56,8 +58,45 @@ fi

 RETVAL=0

+# Check if libvirt is managed by upstart and fail if it's the case
+initctl_check() {
+    if [ -x $INITCTL_PATH ]; then
+        #extract status from upstart
+        LIBVIRTD_UPSTART_STATUS=`$INITCTL_PATH status libvirtd | tr "/" " " | cut -d " " -f 2`
+        if [ $LIBVIRTD_UPSTART_STATUS = "start" ]; then
+            logger -t "libvirtd" -s  "libvirtd is managed by upstart and started, use initctl instead"
+            exit 1
+        fi
+    fi
+}
+
+# test if a pidfile exists and if there's a libvirtd process associated with it
+pidfile_check() {
+    #check if libvirtd is running
+    if [ -f "$PIDFILE" ]; then
+        PID=`cat $PIDFILE`
+        if [ -n "$PID" ]; then
+            PROCESSES=`pidof $PROCESS | grep $PID`
+            if [ -n "$PROCESSES" ]; then
+                logger -t "libvirtd" -s "$SERVICE with pid $PID is running";
+                exit 1
+            else
+                # pidfile exists but no running libvirtd found
+                # remove stuck pidfile
+                rm -f $PIDFILE
+            fi
+        else
+            # pidfile is empty
+            rm -f $PIDFILE
+        fi
+    fi
+}
+
 start() {
     echo -n $"Starting $SERVICE daemon: "
+    initctl_check
+    pidfile_check
+
     mkdir -p @localstatedir@/cache/libvirt
     rm -rf @localstatedir@/cache/libvirt/*
     KRB5_KTNAME=$KRB5_KTNAME daemon --pidfile $PIDFILE --check $SERVICE $PROCESS --daemon $LIBVIRTD_CONFIG_ARGS $LIBVIRTD_ARGS
@@ -68,14 +107,13 @@ start() {

 stop() {
     echo -n $"Stopping $SERVICE daemon: "
+    initctl_check

     killproc -p $PIDFILE $PROCESS
     RETVAL=$?
     echo
     if [ $RETVAL -eq 0 ]; then
         rm -f @localstatedir@/lock/subsys/$SERVICE
-        rm -f $PIDFILE
-        rm -rf @localstatedir@/cache/libvirt/*
     else
         exit $RETVAL
     fi
@@ -88,6 +126,7 @@ restart() {

 reload() {
     echo -n $"Reloading $SERVICE configuration: "
+    initctl_check

     killproc -p $PIDFILE $PROCESS -HUP
     RETVAL=$?
diff --git a/daemon/libvirtd.upstart b/daemon/libvirtd.upstart
index fd1d951..c506d45 100644
--- a/daemon/libvirtd.upstart
+++ b/daemon/libvirtd.upstart
@@ -7,6 +7,29 @@ stop on runlevel [!345]

 respawn

+pre-start script
+    PIDFILE=/var/run/libvirtd.pid
+    #check if libvirtd is running
+    if [ -f "$PIDFILE" ]; then
+        PID=`cat $PIDFILE`
+        if [ -n "$PID" ]; then
+            PROCESSES=`pidof libvirtd | grep $PID`
+
+            if [ -n "$PROCESSES" ]; then
+                logger -t "libvirtd" -s "error: libvirtd is already running with pid $PID"
+                stop
+                exit 0
+            else
+                # remove stuck pidfile
+                rm -f $PIDFILE
+            fi
+        else
+            # empty pidfile
+            rm -f $PIDFILE
+        fi
+    fi
+end script
+
 script
     LIBVIRTD_CONFIG=
     LIBVIRTD_ARGS=
@@ -31,16 +54,10 @@ script
         ulimit -c "$DAEMON_COREFILE_LIMIT"
     fi

-    # Clean up a pidfile that might be left around
-    rm -f /var/run/libvirtd.pid
-
+    # No pid file and/or libvirtd not running.
     mkdir -p /var/cache/libvirt
     rm -rf /var/cache/libvirt/*

     exec /usr/sbin/libvirtd $LIBVIRTD_CONFIG_ARGS $LIBVIRTD_ARGS
 end script

-post-stop script
-    rm -f $PIDFILE
-    rm -rf /var/cache/libvirt/*
-end script
-- 
1.7.3.4