{"id":3722,"date":"2014-11-16T11:26:37","date_gmt":"2014-11-16T03:26:37","guid":{"rendered":"http:\/\/rmohan.com\/?p=3722"},"modified":"2015-12-30T15:52:24","modified_gmt":"2015-12-30T07:52:24","slug":"centos-7-systemctl","status":"publish","type":"post","link":"https:\/\/mohan.sg\/?p=3722","title":{"rendered":"Centos 7 SYSTEMCTL && Run level && hostname"},"content":{"rendered":"

Centos 7 SYSTEMCTL && Run level && hostname <\/strong><\/p>\n

Centos 7 SYSTEMCTL && Run level && hostname<\/p>\n

systemctl start httpd.service (service httpd start)<\/p>\n

systemctl stop httpd.service ( service httpd stop)<\/p>\n

systemctl restart httpd.service ( service httpd stop)<\/p>\n

systemctl status httpd.service ( service httpd status)<\/p>\n

systemctl enable httpd.service (chkconfig httpd on)<\/p>\n

systemctl disable httpd.service (chkconfig httpd off)<\/p>\n

job chkconfig?service systemctl
\nService boot from the start chkconfig –level 3 httpd on systemctl enable httpd
\nService does not boot from the start chkconfig –level 3 httpd off systemctl disable httpd<\/p>\n

Service Status service httpd status systemctl status HTTP d (service details)<\/p>\n

systemctl is-active httpd<\/p>\n

Start the status of all services chkconfig –list systemctl list-units –type=service
\nStart Service service httpd start systemctl start httpd
\nOut of service service httpd stop systemctl stop httpd
\nRestart the service service httpd restart systemctl restart httpd<\/p>\n

[root@keeplive ~]# cat \/etc\/inittab
\n# inittab is no longer used when using systemd.
\n#
\n# ADDING CONFIGURATION HERE WILL HAVE NO EFFECT ON YOUR SYSTEM.
\n#
\n# Ctrl-Alt-Delete is handled by \/etc\/systemd\/system\/ctrl-alt-del.target
\n#
\n# systemd uses ‘targets’ instead of runlevels. By default, there are two main targets:
\n#
\n# multi-user.target: analogous to runlevel 3
\n# graphical.target: analogous to runlevel 5
\n#
\n# To set a default target, run:
\n#
\n# ln -sf \/lib\/systemd\/system\/.target \/etc\/systemd\/system\/default.target<\/p>\n

From the command-line switch to the window level level command unchanged: init 5 or startx<\/p>\n

Level by the window switch to the command line level commands unchanged: init 3<\/p>\n

The new version of the run level is defined in the \/lib\/systemd\/system:<\/p>\n

[root@keeplive ~]# ls -ltr \/lib\/systemd\/system\/runlevel*.target
\nlrwxrwxrwx. 1 root root 15 Nov 13 08:46 \/lib\/systemd\/system\/runlevel0.target -> poweroff.target
\nlrwxrwxrwx. 1 root root 13 Nov 13 08:46 \/lib\/systemd\/system\/runlevel1.target -> rescue.target
\nlrwxrwxrwx. 1 root root 17 Nov 13 08:46 \/lib\/systemd\/system\/runlevel2.target -> multi-user.target
\nlrwxrwxrwx. 1 root root 17 Nov 13 08:46 \/lib\/systemd\/system\/runlevel4.target -> multi-user.target
\nlrwxrwxrwx. 1 root root 17 Nov 13 08:46 \/lib\/systemd\/system\/runlevel3.target -> multi-user.target
\nlrwxrwxrwx. 1 root root 16 Nov 13 08:46 \/lib\/systemd\/system\/runlevel5.target -> graphical.target
\nlrwxrwxrwx. 1 root root 13 Nov 13 08:46 \/lib\/systemd\/system\/runlevel6.target -> reboot.target<\/p>\n

You can set different run levels for different needs:<\/p>\n

init 3<\/p>\n

[root@keeplive ~]# ln -svf \/lib\/systemd\/system\/runlevel3.target \/etc\/systemd\/system\/default.target
\n\u2018\/etc\/systemd\/system\/default.target\u2019 -> \u2018\/lib\/systemd\/system\/runlevel3.target\u2019
\n[root@keeplive ~]# ln -svf \/lib\/systemd\/system\/multi-user.target \/etc\/systemd\/system\/default.target
\n\u2018\/etc\/systemd\/system\/default.target\u2019 -> \u2018\/lib\/systemd\/system\/multi-user.target\u2019
\n[root@keeplive ~]# systemctl set-default multi-user.target
\nrm ‘\/etc\/systemd\/system\/default.target’
\nln -s ‘\/usr\/lib\/systemd\/system\/multi-user.target’ ‘\/etc\/systemd\/system\/default.target’
\n[root@keeplive ~]#<\/p>\n

INIT5<\/p>\n

[root@keeplive ~]# ln -svf \/lib\/systemd\/system\/runlevel5.target \/etc\/systemd\/system\/default.target
\n\u2018\/etc\/systemd\/system\/default.target\u2019 -> \u2018\/lib\/systemd\/system\/runlevel5.target\u2019
\n[root@keeplive ~]# ln -svf \/lib\/systemd\/system\/graphical.target \/etc\/systemd\/system\/default.target
\n\u2018\/etc\/systemd\/system\/default.target\u2019 -> \u2018\/lib\/systemd\/system\/graphical.target\u2019
\n[root@keeplive ~]# systemctl set-default graphical.target
\nrm ‘\/etc\/systemd\/system\/default.target’
\nln -s ‘\/usr\/lib\/systemd\/system\/graphical.target’ ‘\/etc\/systemd\/system\/default.target’<\/p>\n

Modify the system run level:
\n1, systemd use than run the target level sysvinit more liberal alternative. Run Level 3 replaced by multi-user.target. Run Level 5 replaced by graphical.target. runlevel3.target and runlevel5.target are directed multi-user.target and graphical.target symbolic links.
\nYou can use the following command to switch to “run level 3”:
\nmulti-user.target systemctl isolate or systemctl isolate runlevel3.target<\/p>\n

You can use the following command to switch to the “Run Level 5”:
\nsystemctl isolate graphical.target or systemctl isolate runlevel5.target<\/p>\n

2, how to change the default runlevel?
\nsystemd use links to point to the default run level. Before creating a new link, can use the following command to remove the presence of link: rm \/etc\/systemd\/system\/default.target
\ndefault startup run level 3:
\nln -sf \/lib\/systemd\/system\/multi-user.target \/etc\/systemd\/system\/default.target<\/p>\n

ln -sf \/lib\/systemd\/system\/graphical.target \/etc\/systemd\/system\/default.target<\/p>\n

systemd does not use \/etc\/inittab file.<\/p>\n

Modify CentOS 7 hostname<\/p>\n

In CentOS, there are three definitions hostname: static (static), transient (transient), and flexible (pretty). “Static” host name is also called kernel hostname, is the system at boot time from \/etc\/hostname
\nautomatic initialization of the host name. “Transient” host name is in the system is running temporarily assigned host name, for example, assigned by DHCP or mDNS server.
\nStatic hostname and transient hostname comply with the same character as the Internet domain restriction rules. On the other hand, a “flexible” is allowed to use
\nthe hostname of free-form (including special \/ whitespace) host name, to show to the end user (eg Linuxidc).<\/p>\n

In CentOS 7, a man named hostnamectl command-line tool that allows you to view or modify the host name associated with the configuration.<\/p>\n

[root@keeplive ~]# hostnamectl
\nStatic hostname: keeplive
\nIcon name: computer
\nChassis: n\/a
\nMachine ID: 2b48dba259f2428ca8038f7aeb1d7f15
\nBoot ID: 57772bec11854cd08ee72db54a1441d3
\nVirtualization: vmware
\nOperating System: CentOS Linux 7 (Core)
\nCPE OS Name: cpe:\/o:centos:centos:7
\nKernel: Linux 3.10.0-123.9.3.el7.x86_64
\nArchitecture: x86_64
\n[root@keeplive ~]# hostnamectl status
\nStatic hostname: keeplive
\nIcon name: computer
\nChassis: n\/a
\nMachine ID: 2b48dba259f2428ca8038f7aeb1d7f15
\nBoot ID: 57772bec11854cd08ee72db54a1441d3
\nVirtualization: vmware
\nOperating System: CentOS Linux 7 (Core)
\nCPE OS Name: cpe:\/o:centos:centos:7
\nKernel: Linux 3.10.0-123.9.3.el7.x86_64
\nArchitecture: x86_64
\n[root@keeplive ~]# hostnamectl –static
\nkeeplive
\n[root@keeplive ~]# hostnamectl –transient
\nkeeplive
\n[root@keeplive ~]# hostnamectl –pretty<\/p>\n

 
\n[root@rhel7 ~]# systemctl list-unit-files|grep enabled
\ncups.path enabled
\nabrt-ccpp.service enabled
\nabrt-oops.service enabled
\nabrt-vmcore.service enabled
\nabrt-xorg.service enabled
\nabrtd.service enabled
\naccounts-daemon.service enabled
\natd.service enabled
\nauditd.service enabled
\navahi-daemon.service enabled
\nbluetooth.service enabled
\nchronyd.service enabled
\ncrond.service enabled
\ncups.service enabled
\ndbus-org.bluez.service enabled
\ndbus-org.fedoraproject.FirewallD1.service enabled
\ndbus-org.freedesktop.Avahi.service enabled
\ndbus-org.freedesktop.ModemManager1.service enabled
\ndbus-org.freedesktop.NetworkManager.service enabled
\ndbus-org.freedesktop.nm-dispatcher.service enabled
\ndisplay-manager.service enabled
\ndmraid-activation.service enabled
\nfirewalld.service enabled
\nfirstboot-graphical.service enabled
\ngdm.service enabled
\ngetty@.service enabled
\nhypervkvpd.service enabled
\nhypervvssd.service enabled
\nirqbalance.service enabled
\niscsi.service enabled
\nksm.service enabled
\nksmtuned.service enabled
\nlibstoragemgmt.service enabled
\nlibvirtd.service enabled
\nlvm2-monitor.service enabled
\nmdmonitor.service enabled
\nmicrocode.service enabled
\nModemManager.service enabled
\nmultipathd.service enabled
\nNetworkManager-dispatcher.service enabled
\nNetworkManager.service enabled
\nnfs-lock.service enabled
\npackagekit-offline-update.service enabled
\npostfix.service enabled
\nrhsmcertd.service enabled
\nrngd.service enabled
\nrpcbind.service enabled
\nrsyslog.service enabled
\nrtkit-daemon.service enabled
\nsmartd.service enabled
\nspice-vdagentd.service enabled
\nsshd.service enabled
\nsysstat.service enabled
\nsystemd-readahead-collect.service enabled
\nsystemd-readahead-drop.service enabled
\nsystemd-readahead-replay.service enabled
\ntuned.service enabled
\nvmtoolsd.service enabled
\navahi-daemon.socket enabled
\ncups.socket enabled
\ndm-event.socket enabled
\niscsid.socket enabled
\niscsiuio.socket enabled
\nlvm2-lvmetad.socket enabled
\nrpcbind.socket enabled
\ndefault.target enabled
\ngraphical.target enabled
\nnfs.target enabled
\nremote-fs.target enabled<\/p>\n

[root@rhel7 ~]# systemctl stop firewalld.service
\n[root@rhel7 ~]# systemctl disable firewalld.service
\n[root@rhel7 ~]# systemctl status firewalld.service
\nfirewalld.service \u2013 firewalld \u2013 dynamic firewall daemon
\nLoaded: loaded (\/usr\/lib\/systemd\/system\/firewalld.service; disabled)
\nActive: inactive (dead)<\/p>\n

DEC 29 22:25:43 rhel7 systemd[1]: Started firewalld \u2013 dynamic firewall daemon.
\nDEC 29 22:43:29 rhel7 systemd[1]: Stopping firewalld \u2013 dynamic firewall daemon\u2026
\nDEC 29 22:43:29 rhel7 systemd[1]: Stopped firewalld \u2013 dynamic firewall daemon.
\nDEC 29 22:44:14 rhel7 systemd[1]: Stopped firewalld \u2013 dynamic firewall daemon.
\nDEC 29 22:44:15 rhel7 systemd[1]: Stopped firewalld \u2013 dynamic firewall daemon.
\nDEC 29 22:44:19 rhel7 systemd[1]: Starting firewalld \u2013 dynamic firewall daemon\u2026
\nDEC 29 22:44:19 rhel7 systemd[1]: Started firewalld \u2013 dynamic firewall daemon.
\nDEC 29 22:44:21 rhel7 systemd[1]: Stopping firewalld \u2013 dynamic firewall daemon\u2026
\nDEC 29 22:44:21 rhel7 systemd[1]: Stopped firewalld \u2013 dynamic firewall daemon.
\nDEC 29 22:44:32 rhel7 systemd[1]: Stopped firewalld \u2013 dynamic firewall daemon.<\/p>\n

systemctl start firewalld.service
\nsystemctl stop firewalld.service
\nsystemctl restart firewalld.service
\nsystemctl status firewalld.service
\nsystemctl enable firewalld.service
\nsystemctl disable firewalld.service
\nsystemctl is-enabled firewalld.service;echo $?
\nsystemctl list-unit-files|grep enabled<\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

Centos 7 SYSTEMCTL && Run level && hostname <\/p>\n

Centos 7 SYSTEMCTL && Run level && hostname<\/p>\n

systemctl start httpd.service (service httpd start)<\/p>\n

systemctl stop httpd.service ( service httpd stop)<\/p>\n

systemctl restart httpd.service ( service httpd stop)<\/p>\n

systemctl status httpd.service ( service httpd status)<\/p>\n

systemctl enable httpd.service (chkconfig httpd on)<\/p>\n

systemctl disable httpd.service (chkconfig httpd […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5,73,4],"tags":[],"_links":{"self":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/3722"}],"collection":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3722"}],"version-history":[{"count":3,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/3722\/revisions"}],"predecessor-version":[{"id":5518,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/3722\/revisions\/5518"}],"wp:attachment":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3722"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3722"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3722"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}