[CentOS 7.0] Change RunLevel

[1] RunLevel is set with linking to /etc/systemd/system/default.target. For example, the default setting without GUI is like follows.

# show current setting
[root@dlp ~]#systemctl get-default
multi-user.target

[root@dlp ~]#ll /etc/systemd/system/default.target
lrwxrwxrwx. 1 root root 37 Jul 9 06:04 /etc/systemd/system/default.target -> /lib/systemd/system/multi-user.target

[2] For example, if you'd like to change the RunLevel to Graphical-login, set like follows.

[root@dlp ~]#systemctl set-default graphical.target
rm '/etc/systemd/system/default.target'
ln -s '/usr/lib/systemd/system/graphical.target' '/etc/systemd/system/default.target'

# make sute the setting
[root@dlp ~]#systemctl get-default
graphical.target

[root@dlp ~]#ll /etc/systemd/system/default.target
lrwxrwxrwx 1 root root 36 Jul 9 21:55 /etc/systemd/system/default.target -> /lib/systemd/system/graphical.target

[CentOS 7.0] Configure Services

[1] Configure Services of the System.

# list services which are booted (list all includes inactive one with "--all" option)

[root@dlp ~]#systemctl -t service

UNIT                                    LOAD   ACTIVE SUB     DESCRIPTION
auditd.service                      loaded active running Security Auditing Service
avahi-daemon.service         loaded active running Avahi mDNS/DNS-SD Stack
crond.service                       loaded active running Command Scheduler
dbus.service                        loaded active running D-Bus System Message Bus
getty@tty1.service               loaded active running Getty on tty1
...
...
...
systemd-udevd.service                   loaded active running udev Kernel Device Manager
systemd-update-utmp.service             loaded active exited  Update UTMP about System Reboot/Shutdown
systemd-user-sessions.service           loaded active exited  Permit User Sessions
systemd-vconsole-setup.service          loaded active exited  Setup Virtual Console
tuned.service                           loaded active running Dynamic System Tuning Daemon

LOAD   = Reflects whether the unit definition was properly loaded.
ACTIVE = The high-level unit activation state, i.e. generalization of SUB.
SUB    = The low-level unit activation state, values depend on unit type.

37 loaded units listed. Pass --all to see loaded but inactive units, too.
To show all installed unit files use 'systemctl list-unit-files'.

# list boot config of services
[root@dlp ~]#systemctl list-unit-files -t service

UNIT FILE                              STATE
arp-ethers.service                     disabled
auditd.service                         enabled
autovt@.service                        disabled
avahi-daemon.service                   enabled
blk-availability.service               disabled
...
...
...
systemd-user-sessions.service          static
systemd-vconsole-setup.service         static
teamd@.service                         static
tuned.service                          enabled
wpa_supplicant.service                 disabled

124 unit files listed.

[2] Stop and turn OFF auto-start setting for a service if you don'd need it. (it's postfix as an example below)

[root@dlp ~]#systemctl stop postfix

[root@dlp ~]#systemctl disable postfix
rm '/etc/systemd/system/multi-user.target.wants/postfix.service'

[3] There are some SysV services yet. Those are controled by chkconfig like below.

[root@dlp ~]#chkconfig --list


Note: This output shows SysV services only and does not include native
      systemd services. SysV configuration data might be overridden by native
      systemd configuration.

      If you want to list systemd services use 'systemctl list-unit-files'.
      To see services enabled on particular target use
      'systemctl list-dependencies [target]'.

iprdump         0:off   1:off   2:on    3:on    4:on    5:on    6:off
iprinit         0:off   1:off   2:on    3:on    4:on    5:on    6:off
iprupdate       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
network         0:off   1:off   2:on    3:on    4:on    5:on    6:off

# for exmaple, turn OFF auto-start for netconsole

[root@dlp ~]#chkconfig netconsole off

[CentOS 7.0] Configure Networking

[1] Set static IP address to the server. ( Replace the section 'ifcfg-***' to your own interface name )

# install the package below which includes ifconfig, netstat and so on first

[root@dlp ~]#yum -y install net-tools

[root@dlp ~]#vi /etc/sysconfig/network-scripts/ifcfg-eno16777736

HWADDR="00:0C:29:CD:9C:2D"
TYPE="Ethernet"

# change
BOOTPROTO="none"
DEFROUTE="yes"
PEERDNS="yes"
PEERROUTES="yes"
IPV4_FAILURE_FATAL="no"
IPV6INIT="yes"
IPV6_AUTOCONF="yes"
IPV6_DEFROUTE="yes"
IPV6_PEERDNS="yes"
IPV6_PEERROUTES="yes"
IPV6_FAILURE_FATAL="no"
NAME="eno16777736"
UUID="3eb052b5-f8f2-4609-b70b-e44a050f6524"
ONBOOT="yes"
# add like follows
# this server's IP address
IPADDR="10.0.0.30"

# subnet mask
NETMASK="255.255.255.0"

# default gateway
GATEWAY="10.0.0.1"

# DNS server's IP address
DNS1="10.0.0.1"

[root@dlp ~]#systemctl stop NetworkManager

[root@dlp ~]#systemctl disable NetworkManager

rm '/etc/systemd/system/multi-user.target.wants/NetworkManager.service'
rm '/etc/systemd/system/dbus-org.freedesktop.NetworkManager.service'
rm '/etc/systemd/system/dbus-org.freedesktop.nm-dispatcher.service'

[root@dlp ~]#systemctl restart network

[root@dlp ~]#chkconfig network on

[root@dlp ~]#ifconfig

eno16777736: flags=4163  mtu 1500
        inet 10.0.0.30  netmask 255.255.255.0  broadcast 10.0.0.255
        inet6 fe80::20c:29ff:fecd:9c2d  prefixlen 64  scopeid 0x20
        ether 00:0c:29:cd:9c:2d  txqueuelen 1000  (Ethernet)
        RX packets 5978  bytes 7634267 (7.2 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 3256  bytes 287222 (280.4 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10
        loop  txqueuelen 0  (Local Loopback)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0


[2] Disable IPv6 if you do not need it.

[root@dlp ~]#vi /etc/default/grub

# line 6: add
GRUB_CMDLINE_LINUX="ipv6.disable=1 rd.lvm.lv=fedora/swap rd.md=0.....

# reload
[root@dlp ~]#grub2-mkconfig -o /boot/grub2/grub.cfg

[root@dlp ~]#reboot

[3] if you'd like to use the network interface name as ethX, configure like follows.

[root@dlp ~]#vi /etc/default/grub

# line 6: add
GRUB_CMDLINE_LINUX="net.ifnames=0 rd.lvm.lv=fedora/swap rd.md=0.....

# reload
[root@dlp ~]#grub2-mkconfig -o /boot/grub2/grub.cfg

[root@dlp ~]#reboot

[CentOS 7.0] set Time Zone

# show the list of timezones
[root@dlp ~]#timedatectl list-timezones

Asia/Aden
Asia/Almaty
Asia/Amman
Asia/Anadyr
Asia/Aqtau
Asia/Aqtobe
Asia/Ashgabat
...
...
...
Pacific/Rarotonga
Pacific/Saipan
Pacific/Tahiti
Pacific/Tarawa
Pacific/Tongatapu
Pacific/Wake
Pacific/Wallis

# set timezone
[root@dlp ~]#timedatectl set-timezone Asia/Tokyo

# show status
[root@dlp ~]#timedatectl

Local time: Wed 2014-07-09 18:31:16 JST
Universal time: Wed 2014-07-09 09:31:16 UTC
RTC time: Wed 2014-07-09 09:31:15
Timezone: Asia/Tokyo (JST, +0900)
NTP enabled: yes
NTP synchronized: yes
RTC in local TZ: no
DST active: n/a