I am running a web server on an AWS EC2 micro instance. The instance has ~630MB of RAM. With time, I have several httpd processes and very little free RAM. When I restart the httpd service, I end up freeing about 350MB of RAM.
I thought of having this automated every 12 hours using a cron job under root. My script includes code as
service httpd restart
service mysqld restart
ps aux
free -m
This is the first time I am attempting cron scripts.
I receive an email with the expected output for ps aux and free -m, but
./scriptName.sh: line 1: service: command not found
./scriptName.sh: line 2: service: command not found
for the restarts commands.
The script did run as root. I am afraid that using sudo may cause the script to hang. The relevant lines from the output of ps –
root 14664 0.0 0.2 142200 1720 ? S 22:41 0:00 CROND
root 14665 0.0 0.2 9296 1236 ? Ss 22:41 0:00 /bin/sh -c ./scriptName.sh
smmsp 14667 0.0 0.6 76020 4244 ? R 22:41 0:00 /usr/sbin/sendmail -FCronDaemon -i -odi -oem -oi -t -f root
root 14669 0.0 0.1 11244 1008 ? R 22:41 0:00 ps aux
What is the right thing to do to have a successful restart of services?
Is it even advisable to do something like this?
The primary problem is that there is no proper $PATH defined in the run environment of cron, so you need to use the full path to service for this to work.
You can find out this path with the command which service, which should print something like /usr/sbin/service.
The secondary problem: I wouldn’t do that, just blindly restarting services on a production system is never a good idea. Do you have an actual memory/performance problem or might it be that your RAM is just used up by buffers and the like (see http://www.linuxatemyram.com/)?
Please add the output of free -m after a few hours to your question.
Check more discussion of this question.