LINUX-6
SERVICE MANAGEMENT (RHEL-6)
Start | stop | adjust run level of services and their status
Available tools are,
1. Chkconfig
(shell)
2. Ntsysv
(TUI)
3. System-config-services
(GUI)
4. service
CHKCONFIG:
Will list all service installed, with their corresponding run level
settings.
[root@localhost ~]# chkconfig
NetworkManager 0:off 1:off
2:on 3:on 4:on
5:on 6:off
abrt-ccpp 0:off 1:off
2:off 3:on 4:off
5:on 6:off
abrtd 0:off
1:off 2:off 3:on
4:off 5:on 6:off
acpid 0:off 1:off
2:on 3:on 4:on
5:on 6:off
atd 0:off 1:off
2:off 3:on 4:on
5:on 6:off
auditd 0:off 1:off
2:on 3:on 4:on 5:on
6:off
blk-availability
0:off 1:on 2:on
3:on 4:on 5:on
6:off
bluetooth 0:off 1:off
2:off 3:on 4:on
5:on 6:off
cpuspeed 0:off 1:on
2:on 3:on 4:on
5:on 6:off
crond 0:off 1:off
2:on 3:on 4:on
5:on 6:off
dnsmasq 0:off 1:off
2:off 3:off 4:off
5:off 6:off
firstboot 0:off 1:off
2:off 3:on 4:off
5:on 6:off
haldaemon 0:off 1:off
2:off 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:off 3:off 4:off
5:off 6:off
ip6tables 0:off 1:off
2:on 3:on 4:on
5:on 6:off
[root@localhost ~]# chkconfig --list auditd
auditd 0:off 1:off
2:on 3:on 4:on
5:on 6:off
It manages both system services as well as XINETD (extended internet
service daemon) services.
Chkconfig refers to /etc/init.d for service repository and fetch the
info of service from there
[root@localhost ~]# ls -l /etc/rc[2-5].d/*auditd
lrwxrwxrwx. 1 root
root 16 Aug 29 15:18 /etc/rc2.d/S11auditd -> ../init.d/auditd
lrwxrwxrwx. 1 root
root 16 Aug 29 15:18 /etc/rc3.d/S11auditd -> ../init.d/auditd
lrwxrwxrwx. 1 root
root 16 Aug 29 15:18 /etc/rc4.d/S11auditd -> ../init.d/auditd
lrwxrwxrwx. 1 root
root 16 Aug 29 15:27 /etc/rc5.d/S11auditd -> ../init.d/auditd
all run levels are forming a sym link to /etc/rc[2-5].d/*auditd and
update about the status corresponding to particular run levels.
[root@localhost ~]# chkconfig --level 2 auditd on
Now the auditd service is on at RL-2,
Verify it…
[root@localhost ~]# chkconfig --list auditd
auditd 0:off 1:off
2:on 3:on 4:on
5:on 6:off
………
[root@localhost ~]# chkconfig --level 23456 auditd on
[root@localhost ~]#
[root@localhost ~]# chkconfig --list auditd
auditd 0:off 1:off
2:on 3:on 4:on
5:on 6:on
[root@localhost ~]#
[root@localhost ~]# chkconfig --level 23456 auditd off
[root@localhost ~]# chkconfig --list auditd
auditd 0:off 1:off
2:off 3:off 4:off
5:off 6:off
IN CASE OF XINETD SERVICES…
Chkconfig refers to /etc/xinetd.d/
[root@localhost ~]# chkconfig rsync on
[root@localhost ~]#
[root@localhost ~]# ls -l /etc/xinetd.d/
total 4
-rw-r--r--. 1 root root 331 Nov 25 06:12 rsync
[root@localhost ~]#
See the changes,
[root@localhost ~]# cat /etc/xinetd.d/rsync
# default: off
# description: The rsync server is a good addition to an ftp server,
as it \
# allows crc checksumming
etc.
service rsync
{
disable = no
flags = IPv6
socket_type = stream
wait = no
user = root
server = /usr/bin/rsync
server_args = --daemon
log_on_failure += USERID
}
[root@localhost ~]#
[root@localhost ~]# chkconfig rsync off
[root@localhost ~]# cat /etc/xinetd.d/rsync
# default: off
# description: The rsync server is a good addition to an ftp server,
as it \
# allows crc checksumming
etc.
service rsync
{
disable = yes
flags = IPv6
socket_type = stream
wait = no
user = root
server = /usr/bin/rsync
server_args = --daemon
log_on_failure += USERID
}
[root@localhost ~]#
Xinetd controlled services are automatically on|off by chkconfig.
System controlled services are not automatically start|stop by
chkconfig, they need manual intervention like,
#service <service name> start|stop|restart
NTSYSV:
Text userc interface which
works on current run level.
We will ghet a TUI of all services, from there we can enable|disable
service. Which is effective for current run level.
We can do this for particular run levels,
[root@localhost ~]# ntsysv --level 2345
[root@localhost ~]# ntsysv --level 35
If no run level specified, it will go only for current run level.
SERVICE:
[root@localhost ~]# service --status-all
abrt-ccpp hook is
installed
abrtd (pid 2019) is running...
abrt-dump-oops is
stopped
acpid (pid 1798) is running...
atd (pid 2038) is running...
auditd (pid 1685) is running...
Usage:
/etc/init.d/bluetooth {start|stop}
cpuspeed is stopped
crond (pid 2027) is running...
dnsmasq is stopped
firstboot is not
scheduled to run
hald (pid 1807) is running...
htcacheclean is
stopped
httpd is stopped
Table: filter
Chain INPUT (policy
ACCEPT)
num target
prot opt source
destination
1 ACCEPT
all ::/0 ::/0 state RELATED,ESTABLISHED
2 ACCEPT
icmpv6 ::/0 ::/0
3 ACCEPT
all ::/0 ::/0
4 ACCEPT
tcp ::/0 ::/0 state NEW tcp dpt:22
5 REJECT
all ::/0 ::/0 reject-with
icmp6-adm-prohibited
Chain FORWARD
(policy ACCEPT)
num target
prot opt source
destination
1 REJECT
all ::/0 ::/0 reject-with
icmp6-adm-prohibited
[root@localhost ~]# service sshd status
openssh-daemon (pid 1883) is
running...
[root@localhost ~]#
ALL SERVICES AND THEIR OPEN PORTS:
[root@localhost ~]# netstat -tulpn
Active Internet
connections (only servers)
Proto Recv-Q Send-Q
Local Address Foreign
Address State PID/Program name
tcp 0
0 0.0.0.0:22
0.0.0.0:* LISTEN 1883/sshd
tcp 0
0 127.0.0.1:25
0.0.0.0:*
LISTEN 1995/master
tcp 0
0 :::22
:::* LISTEN 1883/sshd
tcp 0
0 ::1:25
:::* LISTEN 1995/master
[root@localhost ~]#
SERVICE COMMAND COMPARISON WITH RHEL7:
Purpose
|
RHEL 6
|
RHEL 7
|
Starts a service.
|
# service sshd start
|
# systemctl start sshd
|
Stops a service.
|
# service sshd stop
|
# systemctl stop sshd
|
Restarts a service.
|
# service sshd restart
|
# systemctl restart
sshd
|
Restarts a service only if it is running.
|
# service sshd
condrestart
|
# systemctl try-restart
sshd
|
Reloads configuration.
|
# service sshd reload
|
# systemctl reload sshd
|
Checks if a service is running.
|
# systemctl status sshd
|
# systemctl status sshd
# systemctl is-active sshd |
Displays the status of all services.
|
# service --status-all
|
# systemctl list-units
--type service --all
|
CHKCONFIG & SYSTEMCTL:
purpose
|
chkconfig
|
systemctl
|
Enables a
service.
|
# chkconfig
sshd on
|
# systemctl
enable sshd
|
Disables a
service
|
# chkconfig
sshd off
|
# systemctl
disable sshd
|
Checks if a
service is enabled
|
# chkconfig
--list sshd
|
# systemctl
status sshd
# systemctl is-enabled sshd |
Lists all
services and checks if
they are enabled |
# chkconfig
--list
|
# systemctl
list-unit-files --type service
|
Lists services
that are ordered to start
before the specified unit |
# chkconfig
--list
|
# systemctl
list-dependencies --after sshd
|
Lists services
that are ordered to
start after the specified unit |
# chkconfig
--list
|
# systemctl
list-dependencies --before sshd
|
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