I've created a init.d script called rmCluster which is supposed to execute a simple python script at shutdown which uses boto to shutdown a particular cluster of servers, with 755 perms, located in
/etc/init.d/rmCluster written as:
#!/bin/sh # # chkconfig: 0 1 1 # description: My service # # Author: Me # # ### BEGIN INIT INFO # Provides: rmCluster # Required-Start: # Required-Stop: # Default-Start: 0 # Default-Stop: 0 # Short-Description: My service # Description: My service ### END INIT INFO case $1 in start) python /usr/local/sbin/instanceStopper.py & touch /tmp/theScriptWorks ;; esac exit 0
I have also created a symlink at
/etc/rc0.d/S00rmCluster which points to the above. Note that I am touching a file in /tmp which is successfully occurring.
The python script also has 755 permissions and is written as:
#!/usr/bin/env python import boto.ec2 import subprocess conn=boto.ec2.connect_to_region("us-west-2") reservations = conn.get_all_instances() cluster =  inst_id = subprocess.Popen(["wget", "-q", "-O", "-", "http://169.254.169.254/latest/meta-data/instance-id"], stdout=subprocess.PIPE).communicate() for res in reservations: for inst in res.instances: if inst_id in inst.tags["Name"] and "cloudformation" not in inst.tags: cluster.append( "%s" %(inst.id) ) conn.terminate_instances(cluster)
Note that the python script works perfectly fine when called directly and it also works fine when run the init.d script directly. I've also attempted to remove the shebang in the python script and specifying the path to python within init.d call and it still doesn't work.
My initial though is that perhaps the python libraries are not longer available during this runtime so the script fails, but I'm not sure how to check that. Also, I've contemplated that perhaps it needs to be placed somewhere else in the rc.x dirs. Currently I have set to at S00 and it is the only S00. Killall I moved to S01 and halt I moved to S02; these are the only three "S" scripts within rc.0/
I do appreciated the help
The solution was a combination of input from the response of @Jayan and @Kjetil Joergensen.
The final working version of the init.d script is as follows:
#!/bin/bash # # chkconfig: 2345 99 1 # description: My service # # Author: me # # ### BEGIN INIT INFO # Provides: rmCluster # Required-Start: # Required-Stop: # Default-Start: 0 # Default-Stop: 0 # Short-Description: My service # Description: My service ### END INIT INFO case "$1" in start) touch /var/lock/subsys/rmCluster ;; stop) /usr/bin/python /usr/local/sbin/instanceStopper.py ;; esac exit 0
The major changes were:
- Moving the 'start)' portion into a 'stop)' portion
- Touching the lock file in the 'start)' portion
- Modifying the 'chkconfig:' parameter so that it 'starts' with normal services and get's killed with them as well, thus preventing the script from trying to execute post 'networking' shutdown as noticed by @Kjetil Joergensen
Note: The python script was not changed.
Two caveats, one is that it requires to run
service start rmCluster in order for it to be shutdown during runlevel 0 and 6. For me this was acceptable since it is getting set up during cloudformation provisioning so it is trivial to add this step into EC2 User Data. The second is that the script executes during reboots as well which may not be ideal for every use case. I'll have to do further investigation to see how to make such that only runlevel 0 actually runs 'stop' on this script.
Thank you both for the help.