Systemctl 安装及基础操作

01、首先检查系统上是否安装了systemd以及当前安装的Systemd的版本是什么？

# systemd --version

systemd 215

+PAM +AUDIT +SELINUX +IMA +SYSVINIT +LIBCRYPTSETUP +GCRYPT +ACL +XZ -SECCOMP -APPARMOR

从上面的例子可以清楚地看出，我们已经安装了systemd 215版本。

02.检查systemd和systemctl的二进制文件和库的安装位置。

# whereis systemd 

systemd: /usr/lib/systemd /etc/systemd /usr/share/systemd /usr/share/man/man1/systemd.1.gz

# whereis systemctl

systemctl: /usr/bin/systemctl /usr/share/man/man1/systemctl.1.gz

03.检查systemd是否正在运行。

# ps -eaf | grep [s]ystemd

root 1 0 0 16:27 ? 00:00:00 /usr/lib/systemd/systemd --switched-root --system --deserialize 23

root 444 1 0 16:27 ? 00:00:00 /usr/lib/systemd/systemd-journald

root 469 1 0 16:27 ? 00:00:00 /usr/lib/systemd/systemd-udevd

root 555 1 0 16:27 ? 00:00:00 /usr/lib/systemd/systemd-logind

dbus 556 1 0 16:27 ? 00:00:00 /bin/dbus-daemon --system --address=systemd: --nofork --nopidfile --systemd-activation

注意：systemd作为父守护进程运行（PID = 1）。 在上面的命令ps中使用（-e）选择所有进程，（ a）选择除会话前导之外的所有进程和（-f）选择完整格式列表（即-eaf）。

另请注意上面示例中的方括号以及其他示例。 Square Bracket表达式是grep的字符类模式匹配的一部分。

04.分析systemd启动过程

# systemd-analyze

Startup finished in 487ms (kernel) + 2.776s (initrd) + 20.229s (userspace) = 23.493s

05.分析每个进程在引导时花费的时间

# systemd-analyze blame

8.565s mariadb.service

7.991s webmin.service

6.095s postfix.service

4.311s httpd.service

3.926s firewalld.service

3.780s kdump.service

3.238s tuned.service

1.712s network.service

1.394s lvm2-monitor.service

1.126s systemd-logind.service

....

06.分析启动时的关键链

# systemd-analyze critical-chain

The time after the unit is active or started is printed after the "@" character.

The time the unit takes to start is printed after the "+" character.

multi-user.target @20.222s

└─mariadb.service @11.657s +8.565s

└─network.target @11.168s

└─network.service @9.456s +1.712s

└─NetworkManager.service @8.858s +596ms

└─firewalld.service @4.931s +3.926s

└─basic.target @4.916s

└─sockets.target @4.916s

└─dbus.socket @4.916s

└─sysinit.target @4.905s

└─systemd-update-utmp.service @4.864s +39ms

└─auditd.service @4.563s +301ms

└─systemd-tmpfiles-setup.service @4.485s +69ms

└─rhel-import-state.service @4.342s +142ms

└─local-fs.target @4.324s

└─boot.mount @4.286s +31ms

└─systemd-fsck@dev-disk-by/x2duuid-79f594ad/x2da332/x2d4730/x2dbb5f/x2d85d19608096

└─dev-disk-by/x2duuid-79f594ad/x2da332/x2d4730/x2dbb5f/x2d85d196080964.device @4

重要：Systemctl接受服务（.service），挂载点（.mount），套接字（.socket）和设备（.device）作为单位。

07、列出所有可用的单位

# systemctl list-unit-files

UNIT FILE STATE 

proc-sys-fs-binfmt_misc.automount static 

dev-hugepages.mount static 

dev-mqueue.mount static 

proc-sys-fs-binfmt_misc.mount static 

sys-fs-fuse-connections.mount static 

sys-kernel-config.mount static 

sys-kernel-debug.mount static 

tmp.mount disabled

brandbot.path disabled

.....

08、列出所有运行单元

# systemctl list-units

UNIT LOAD ACTIVE SUB DESCRIPTION

proc-sys-fs-binfmt_misc.automount loaded active waiting Arbitrary Executable File Formats File Syste

sys-devices-pc...0-1:0:0:0-block-sr0.device loaded active plugged VBOX_CD-ROM

sys-devices-pc...:00:03.0-net-enp0s3.device loaded active plugged PRO/1000 MT Desktop Adapter

sys-devices-pc...00:05.0-sound-card0.device loaded active plugged 82801AA AC97 Audio Controller

sys-devices-pc...:0:0-block-sda-sda1.device loaded active plugged VBOX_HARDDISK

sys-devices-pc...:0:0-block-sda-sda2.device loaded active plugged LVM PV Qzyo3l-qYaL-uRUa-Cjuk-pljo-qKtX-VgBQ8

sys-devices-pc...0-2:0:0:0-block-sda.device loaded active plugged VBOX_HARDDISK

sys-devices-pl...erial8250-tty-ttyS0.device loaded active plugged /sys/devices/platform/serial8250/tty/ttyS0

sys-devices-pl...erial8250-tty-ttyS1.device loaded active plugged /sys/devices/platform/serial8250/tty/ttyS1

sys-devices-pl...erial8250-tty-ttyS2.device loaded active plugged /sys/devices/platform/serial8250/tty/ttyS2

sys-devices-pl...erial8250-tty-ttyS3.device loaded active plugged /sys/devices/platform/serial8250/tty/ttyS3

sys-devices-virtual-block-dm/x2d0.device loaded active plugged /sys/devices/virtual/block/dm-0

sys-devices-virtual-block-dm/x2d1.device loaded active plugged /sys/devices/virtual/block/dm-1

sys-module-configfs.device loaded active plugged /sys/module/configfs

...

09、列出所有失败的单元

# systemctl --failed

UNIT LOAD ACTIVE SUB DESCRIPTION

kdump.service loaded failed failed Crash recovery kernel arming

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.

1 loaded units listed. Pass --all to see loaded but inactive units, too.

To show all installed unit files use systemctl list-unit-files.

10、检查单元(cron.service)是否启用?

# systemctl is-enabled crond.service

enabled

11.检查单元或服务是否正在运行？

 systemctl status firewalld.service

firewalld.service - firewalld - dynamic firewall daemon

Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled)

Active: active (running) since Tue 2018-04-28 16:27:55 IST; 34min ago

Main PID: 549 (firewalld)

CGroup: /system.slice/firewalld.service

└─549 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopid

Apr 28 16:27:51 tecmint systemd[1]: Starting firewalld - dynamic firewall daemon...

Apr 28 16:27:55 tecmint systemd[1]: Started firewalld - dynamic firewall daemon.

原创文章，作者：ItWorker，如若转载，请注明出处：https://blog.ytso.com/59181.html