Monit fails to start process - bash

Question

I've written a scrip that works fine to start and stop a server.
#!/bin/bash
PID_FILE='/var/run/rserve.pid'
start() {
touch $PID_FILE
eval "/usr/bin/R CMD Rserve"
PID=$(ps aux | grep Rserve | grep -v grep | awk '{print $2}')
echo "Starting Rserve with PID $PID"
echo $PID > $PID_FILE
}
stop () {
pkill Rserve
rm $PID_FILE
echo "Stopping Rserve"
}
case $1 in
start)
start
;;
stop)
stop
;;
*)
echo "usage: rserve {start|stop}" ;;
esac
exit 0
If I start it by running
rserve start
and then start monit it will correctly capture the PID and the server:
The Monit daemon 5.3.2 uptime: 0m
Remote Host 'localhost'
status Online with all services
monitoring status Monitored
port response time 0.000s to localhost:6311 [DEFAULT via TCP]
data collected Mon, 13 May 2013 20:03:50
System 'system_gauss'
status Running
monitoring status Monitored
load average [0.37] [0.29] [0.25]
cpu 0.0%us 0.2%sy 0.0%wa
memory usage 524044 kB [25.6%]
swap usage 4848 kB [0.1%]
data collected Mon, 13 May 2013 20:03:50
If I stop it, it will properly kill the process and unmonitor it. However if I start it again, it won't start the server again:
ps ax | grep Rserve | grep -vc grep
1
monit stop localhost
ps ax | grep Rserve | grep -vc grep
0
monit start localhost
[UTC May 13 20:07:24] info : 'localhost' start on user request
[UTC May 13 20:07:24] info : monit daemon at 4370 awakened
[UTC May 13 20:07:24] info : Awakened by User defined signal 1
[UTC May 13 20:07:24] info : 'localhost' start: /usr/bin/rserve
[UTC May 13 20:07:24] info : 'localhost' start action done
[UTC May 13 20:07:34] error : 'localhost' failed, cannot open a connection to INET[localhost:6311] via TCP
Here is the monitrc:
check host localhost with address 127.0.0.1
start = "/usr/bin/rserve start"
stop = "/usr/bin/rserve stop"
if failed host localhost port 6311 type tcp with timeout 15 seconds for 5 cycles
then restart

Answer 1

I had problem start or stop process via shell too.
One solution might be add "/bin/bash" in the config like this:
start program = "/bin/bash /urs/bin/rserv start"
stop program = "/bin/bash /urs/bin/rserv stop"
It worked for me.

Answer 2

monit is a silent killer. It does not tell you anything. Here are things I would check which monit won't help you identify
Check permissions of all the files you are reading / writing. If you are redirecting output to a file, make sure that file is writable by uid and gid you are using to execute the program
Again check exec permission on the program you are trying to run
Specify full path to any program you are trying to execute ( not strictly necessary, but you don't have to worry about path not being set if you always specify full path )
Make sure you can run the program outside of monit without any error before trying to investigate why monit is not starting.

Answer 3

If the Monit log is displaying
failed to start (exit status -1) -- no output
Then it may be that you're trying to run a script without any of the Bash infrastructure. You can run such a command by wrapping it in /bin/bash -c, like so:
check process my-process
matching "my-process-name"
start program = "/bin/bash -c '/etc/init.d/my-init-script'"

Answer 4

When monit starts it checks for its own pidfile and checks if the process with
matching PID is running already - if it does, then it just wakes up this
process.
in your case, check if this pid is being used by some other process:
ps -ef |grep 4370
if yes, then you need to remove the below file(usually under /run directory) and start monit again:
monit.pid

Answer 5

For me, the issue was that the stop command was not being run, even though I specifically specified "then restart" on the configuration.
The solution was just to change:
start program = "/etc/init.d/.... restart"