chkconfig is a simple command-line tool that helps a Linux administrator configure, maintain, autostart and manage the configuration of the symlinks located in /etc/rc[0-6].d path.
First of all let me show you which are the most used services in a Linux distributuion.
You can find out what services can be started in your server by typing:
chkconfig --list
The output should look something like this:
~ # chkconfig --list
acpid 0:off 1:off 2:on 3:on 4:on 5:on 6:off
cgconfig 0:off 1:off 2:off 3:off 4:off 5:off 6:off
cgred 0:off 1:off 2:off 3:off 4:off 5:off 6:off
cmdavd 0:off 1:off 2:off 3:off 4:off 5:off 6:off
cmdmgd 0:off 1:off 2:off 3:off 4:off 5:off 6:off
crond 0:off 1:off 2:on 3:on 4:on 5:on 6:off
htcacheclean 0:off 1:off 2:off 3:off 4:off 5:off 6:off
httpd 0:off 1:off 2:on 3:on 4:on 5:on 6:off
ip6tables 0:off 1:off 2:on 3:on 4:on 5:on 6:off
iptables 0:off 1:off 2:on 3:on 4:on 5:on 6:off
mailman 0:off 1:off 2:on 3:on 4:on 5:on 6:off
mdmonitor 0:off 1:off 2:on 3:on 4:on 5:on 6:off
mysqld 0:off 1:off 2:on 3:on 4:on 5:on 6:off
named 0:off 1:off 2:on 3:on 4:on 5:on 6:off
netconsole 0:off 1:off 2:off 3:off 4:off 5:off 6:off
netfs 0:off 1:off 2:off 3:on 4:on 5:on 6:off
network 0:off 1:off 2:on 3:on 4:on 5:on 6:off
ntpd 0:off 1:off 2:off 3:off 4:off 5:off 6:off
ntpdate 0:off 1:off 2:off 3:off 4:off 5:off 6:off
portreserve 0:off 1:off 2:on 3:on 4:on 5:on 6:off
psa 0:off 1:off 2:on 3:on 4:on 5:on 6:off
qmail 0:off 1:off 2:on 3:on 4:on 5:on 6:off
rdisc 0:off 1:off 2:off 3:off 4:off 5:off 6:off
restorecond 0:off 1:off 2:off 3:off 4:off 5:off 6:off
rsyslog 0:off 1:off 2:on 3:on 4:on 5:on 6:off
saslauthd 0:off 1:off 2:off 3:off 4:off 5:off 6:off
spamassassin 0:off 1:off 2:on 3:on 4:on 5:on 6:off
squid 0:off 1:off 2:off 3:off 4:off 5:off 6:off
sshd 0:off 1:off 2:on 3:on 4:on 5:on 6:off
xinetd 0:off 1:off 2:on 3:on 4:on 5:on 6:off
xinetd based services:
chargen-dgram: off
chargen-stream: off
daytime-dgram: off
daytime-stream: off
discard-dgram: off
discard-stream: off
echo-dgram: off
echo-stream: off
ftp_psa: on
poppassd_psa: on
rsync: off
smtp_psa: on
smtps_psa: on
submission_psa: on
tcpmux-server: off
time-dgram: off
time-stream: off
The left column contains the name of the process, to the right you have 7 columns, each one represents a Linux runlevel. Usually you will use runlevels 3,4,5. Runlevel 0 and 6 are related to shutdown (0) and reboot (6), so you should never use these.
The “on” and “off” reffer to the fact that a specific service will autostart (on) or will not autostart (off) after a reboot of the server.
The manual of chkconfig can be accesed via the command:
~ # chkconfig --help
chkconfig version 1.3.49.3 - Copyright (C) 1997-2000 Red Hat, Inc.
This may be freely redistributed under the terms of the GNU Public License.usage: chkconfig [--list] [--type ] [name]
chkconfig --add
chkconfig --del
chkconfig --override
chkconfig [--level ] [--type ] <on|off|reset|resetpriorities>
root@nyxware~ #
To autostart a service after each reboot you would use a command like this:
chkconfig --level 345 httpd on
or just
chkconfig httpd on
To stop a process from starting after each reboot enter the command:
chkconfig httpd off
or stop it from running at a specific runlevel:
# chkconfig --level 3 httpd off root@nyxware#
Use grep to see the status of a specific service:
~ # chkconfig --list | grep ssh sshd 0:off 1:off 2:on 3:on 4:on 5:on 6:off root@nyxware ~ #
* replace httpd with your desired service name.