Supervisord: Don’t start a program before another one is running

You could use sudo in place of your custom script to accomplish the same thing. That is, given the default supervisord configuration, in which only root can run supervisorctl, you could put an entry like this into /etc/sudoers:

alice ALL = (root) NOPASSWD:/usr/bin/supervisorctl restart app1
bob ALL = (root) NOPASSWD:/usr/bin/supervisorctl restart app2

This would allow alice to run sudo /usr/bin/supervisorctl restart app1 as root without having to provide a password, and it would allow bob to restart app2.

Thanks to Mark for the link to that script; here is my working example for CentOS:

#!/bin/bash
# Source: https://confluence.atlassian.com/plugins/viewsource/viewpagesrc.action?pageId=252348917
function shutdown()
{
    date
    echo "Shutting down Tomcat"
    unset CATALINA_PID # Necessary in some cases
    unset LD_LIBRARY_PATH # Necessary in some cases
    unset JAVA_OPTS # Necessary in some cases

    $TOMCAT_HOME/bin/catalina.sh stop
}

date
echo "Starting Tomcat"
export CATALINA_PID=/tmp/$$
export JAVA_HOME=/usr/local/java
export LD_LIBRARY_PATH=/usr/local/apr/lib
export JAVA_OPTS="-Dcom.sun.management.jmxremote.port=8999 -Dcom.sun.management.jmxremote.password.file=/etc/tomcat.jmx.pwd -Dcom.sun.management.jmxremote.access.file=/etc/tomcat.jmxremote.access -Dcom.sun.management.jmxremote.ssl=false -Xms128m -Xmx3072m -XX:MaxPermSize=256m"

# Uncomment to increase Tomcat's maximum heap allocation
# export JAVA_OPTS=-Xmx512M $JAVA_OPTS

. $TOMCAT_HOME/bin/catalina.sh start

# Allow any signal which would kill a process to stop Tomcat
trap shutdown HUP INT QUIT ABRT KILL ALRM TERM TSTP

echo "Waiting for `cat $CATALINA_PID`"
wait `cat $CATALINA_PID`

And here is what I used in /etc/supervisord.conf:

[program:tomcat]
directory=/usr/local/tomcat
command=/usr/local/tomcat/bin/supervisord_wrapper.sh
stdout_logfile=syslog
stderr_logfile=syslog
user=apache

Running, it looks like this:

[root@qa1.qa:~]# supervisorctl start tomcat
tomcat: started
[root@qa1.qa:~]# supervisorctl status
tomcat                           RUNNING    pid 9611, uptime 0:00:03
[root@qa1.qa:~]# ps -ef|grep t[o]mcat
apache    9611  9581  0 13:09 ?        00:00:00 /bin/bash /usr/local/tomcat/bin/supervisord_wrapper.sh start
apache    9623  9611 99 13:09 ?        00:00:10 /usr/local/java/bin/java -Djava.util.logging.config.file=/usr/local/tomcat/conf/logging.properties -Dcom.sun.management.jmxremote.port=8999 -Dcom.sun.management.jmxremote.password.file=/etc/tomcat.jmx.pwd -Dcom.sun.management.jmxremote.access.file=/etc/tomcat.jmxremote.access -Dcom.sun.management.jmxremote.ssl=false -Xms128m -Xmx3072m -XX:MaxPermSize=256m -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djava.endorsed.dirs=/usr/local/tomcat/endorsed -classpath /usr/local/tomcat/bin/bootstrap.jar -Dcatalina.base=/usr/local/tomcat -Dcatalina.home=/usr/local/tomcat -Djava.io.tmpdir=/usr/local/tomcat/temp org.apache.catalina.startup.Bootstrap start

I tried initially to add those environment variables into /etc/supervisord.conf through the environment directive, but ran into trouble with the JAVA_OPTS, with all the spaces and equal signs. Putting it in the wrapper script took care of that.

Hope this helps save someone else some time!