Auto Start MySQL and Apache

Question

How does one get certain daemons to automatically startup on a restart of the server?

I found this post on Server Fault but I am looking of a more in depth explanation of how getting a daemon to auto start works.

I am using CentOS v5.8 and I am trying to get MySQL and Apache to start by default after a restart of the system. Does it involve changing a configuration file?

Answer 1

A daemon is a background process - often called service, too.

Which services are started at what runlevel is defined in directories and links located at /etc/init.d.

The cli-frontend for managing these services is chkconfig.

If you look into the header of some scripts located at /etc/init.d you see some numbers. Some define the runlevel, where the services should be started, other the order-number when - within that level - it should be started and another when it should be stopped. The rc scripts (called via init and its configuration file /etc/inittab) do the magic calls of theses scripts when reaching/changing runlevels.

Answer 2

If you installed both MySQL and Apache from the CentOS 5 repository, they should have installed start/stop scripts under /etc/init.d. You use chkconfig to manage which services are started after the system boots.

# chkconfig --list httpd
httpd           0:off   1:off   2:off   3:off   4:off   5:off   6:off
# chkconfig httpd on
# chkconfig --list httpd
httpd           0:off   1:off   2:on    3:on    4:on    5:on    6:off

The numbers correspond to the different runlevels.