CentOS 7のsystemdサービス管理のメモ。
サービスの稼働状態や自動起動設定の確認・操作。　　

UNITの状態

確認 : 一覧

$ systemctl list-unit

ACTIVE, SUBが実行状態を表している。

# UNITのタイプがServiceのみを確認
$ systemctl list-units -t service
UNIT                 LOAD   ACTIVE SUB     DESCRIPTION
auditd.service       loaded active running Security Auditing Service
chronyd.service      loaded active running NTP client/server
...
● kdump.service      loaded failed failed  Crash recovery kernel arming

確認 : 個別

$ systemctl is-active [UNIT名]

$ systemctl is-active yum-cron
active

確認 : 個別詳細

$ systemctl status [UNIT名]

$ systemctl status yum-cron
● yum-cron.service - Run automatic yum updates as a cron job
   Loaded: loaded (/usr/lib/systemd/system/yum-cron.service; enabled; vendor preset: disabled)
   Active: active (exited) since 火 2016-09-13 16:56:49 JST; 2 days ago
  Process: 644 ExecStart=/bin/touch /var/lock/subsys/yum-cron (code=exited, status=0/SUCCESS)
 Main PID: 644 (code=exited, status=0/SUCCESS)
   CGroup: /system.slice/yum-cron.service

操作（起動・停止・再起動・強制終了）

UNITの操作。
$ sudo systemctl [UNITコマンド] [UNIT名]

自動起動設定

確認 : 一覧

$ systemctl list-unit-files

# UNITのタイプがServiceのみを確認
$ systemctl list-unit-files -t service
UNIT FILE                                   STATE
arp-ethers.service                          disabled
auditd.service                              enabled
chrony-dnssrv@.service                      static
dbus-org.freedesktop.hostname1.service      static
...

# grepへパイプで繋いで「enabled」のみを表示させる
$ systemctl list-unit-files -t service | grep enabled
UNIT FILE                                   STATE
auditd.service                              enabled
chronyd.service                             enabled
...
tuned.service                               enabled
yum-cron.service                            enabled

確認 : 個別

$ sudo systemctl is-enabled [Unit名]

# yum-cronの状態確認
$ sudo systemctl is-active yum-cron
enabled

操作（有効化・無効化）

$ sudo systemctl [UNITコマンド] [UNIT名]