systemd技巧

原文地址：http://www.freedesktop.org/wiki/Software/systemd/TipsAndTricks

 

Tips & Tricks

 

Also check out the Frequently Asked Questions!

Listing running services

 

$ systemctlUNIT                       LOAD   ACTIVE SUB     JOB DESCRIPTIONaccounts-daemon.service    loaded active running     Accounts Serviceatd.service                loaded active running     Job spooling toolsavahi-daemon.service       loaded active running     Avahi mDNS/DNS-SD Stackbluetooth.service          loaded active running     Bluetooth Managercolord-sane.service        loaded active running     Daemon for monitoring attached scanners and registering them with colordcolord.service             loaded active running     Manage, Install and Generate Color Profilescrond.service              loaded active running     Command Schedulercups.service               loaded active running     CUPS Printing Servicedbus.service               loaded active running     D-Bus System Message Bus...

 

Showing runtime status

 

$ systemctl status udisks2.serviceudisks2.service - Storage Daemon          Loaded: loaded (/usr/lib/systemd/system/udisks2.service; static)          Active: active (running) since Wed, 27 Jun 2012 20:49:25 +0200; 1 day and 1h ago        Main PID: 615 (udisksd)          CGroup: name=systemd:/system/udisks2.service                  └ 615 /usr/lib/udisks2/udisksd --no-debugJun 27 20:49:25 epsilon udisksd[615]: udisks daemon version 1.94.0 startingJun 27 20:49:25 epsilon udisksd[615]: Acquired the name org.freedesktop.UDisks2 on the system message bus

 

cgroup tree

 

$ systemd-cgls└ system  ├ 1 /usr/lib/systemd/systemd --system --deserialize 18  ├ ntpd.service  │ └ 8471 /usr/sbin/ntpd -u ntp:ntp -g  ├ upower.service  │ └ 798 /usr/libexec/upowerd  ├ wpa_supplicant.service  │ └ 751 /usr/sbin/wpa_supplicant -u -f /var/log/wpa_supplicant.log -c /etc/wpa_supplicant/wpa_supplicant.conf -u -f /var/log/wpa_supplicant.log -P /var/run/wpa_supplicant.pid  ├ nfs-idmap.service  │ └ 731 /usr/sbin/rpc.idmapd  ├ nfs-rquotad.service  │ └ 753 /usr/sbin/rpc.rquotad  ├ nfs-mountd.service  │ └ 732 /usr/sbin/rpc.mountd  ├ nfs-lock.service  │ └ 704 /sbin/rpc.statd  ├ rpcbind.service  │ └ 680 /sbin/rpcbind -w  ├ postfix.service  │ ├   859 /usr/libexec/postfix/master  │ ├   877 qmgr -l -t fifo -u  │ └ 32271 pickup -l -t fifo -u  ├ colord-sane.service  │ └ 647 /usr/libexec/colord-sane  ├ udisks2.service  │ └ 615 /usr/lib/udisks2/udisksd --no-debug  ├ colord.service  │ └ 607 /usr/libexec/colord  ├ prefdm.service  │ ├ 567 /usr/sbin/gdm-binary -nodaemon  │ ├ 602 /usr/libexec/gdm-simple-slave --display-id /org/gnome/DisplayManager/Display1  │ ├ 612 /usr/bin/Xorg :0 -br -verbose -auth /var/run/gdm/auth-for-gdm-O00GPA/database -seat seat0 -nolisten tcp  │ └ 905 gdm-session-worker [pam/gdm-password]  ├ systemd-ask-password-wall.service  │ └ 645 /usr/bin/systemd-tty-ask-password-agent --wall  ├ atd.service  │ └ 544 /usr/sbin/atd -f  ├ ksmtuned.service  │ ├  548 /bin/bash /usr/sbin/ksmtuned  │ └ 1092 sleep 60  ├ dbus.service  │ ├ 586 /bin/dbus-daemon --system --address=systemd: --nofork --systemd-activation  │ ├ 601 /usr/libexec/polkit-1/polkitd --no-debug  │ └ 657 /usr/sbin/modem-manager  ├ cups.service  │ └ 508 /usr/sbin/cupsd -f  ├ avahi-daemon.service  │ ├ 506 avahi-daemon: running [epsilon.local]  │ └ 516 avahi-daemon: chroot helper  ├ system-setup-keyboard.service  │ └ 504 /usr/bin/system-setup-keyboard  ├ accounts-daemon.service  │ └ 502 /usr/libexec/accounts-daemon  ├ systemd-logind.service  │ └ 498 /usr/lib/systemd/systemd-logind  ├ crond.service  │ └ 486 /usr/sbin/crond -n  ├ NetworkManager.service  │ ├  484 /usr/sbin/NetworkManager --no-daemon  │ └ 8437 /sbin/dhclient -d -4 -sf /usr/libexec/nm-dhcp-client.action -pf /var/run/dhclient-wlan0.pid -lf /var/lib/dhclient/dhclient-903b6f6aa7a1-46c8-82a9-7f637dfbb3e4-wlan0.lease -cf /var/run/nm-d...  ├ libvirtd.service  │ ├ 480 /usr/sbin/libvirtd  │ └ 571 /sbin/dnsmasq --strict-order --bind-interfaces --pid-file=/var/run/libvirt/network/default.pid --conf-file= --except-interface lo --listenaddress 192.168.122.1 --dhcp-range 192.168.122.2,1...  ├ bluetooth.service  │ └ 479 /usr/sbin/bluetoothd -n  ├ systemd-udev.service  │ └ 287 /usr/lib/systemd/systemd-udevd  └ systemd-journald.service    └ 280 /usr/lib/systemd/systemd-journald

 

ps with cgroups

 

$ alias psc='ps xawf -eo pid,user,cgroup,args'$ psc  PID USER     CGROUP                              COMMAND...    1 root     name=systemd:/systemd-1             /bin/systemd systemd.log_target=kmsg systemd.log_level=debug selinux=0  415 root     name=systemd:/systemd-1/sysinit.service /sbin/udevd -d  928 root     name=systemd:/systemd-1/atd.service /usr/sbin/atd -f  930 root     name=systemd:/systemd-1/ntpd.service /usr/sbin/ntpd -n  932 root     name=systemd:/systemd-1/crond.service /usr/sbin/crond -n  935 root     name=systemd:/systemd-1/auditd.service /sbin/auditd -n  943 root     name=systemd:/systemd-1/auditd.service  \_ /sbin/audispd  964 root     name=systemd:/systemd-1/auditd.service      \_ /usr/sbin/sedispatch  937 root     name=systemd:/systemd-1/acpid.service /usr/sbin/acpid -f  941 rpc      name=systemd:/systemd-1/rpcbind.service /sbin/rpcbind -f  944 root     name=systemd:/systemd-1/rsyslog.service /sbin/rsyslogd -n -c 4  947 root     name=systemd:/systemd-1/systemd-logger.service /lib/systemd/systemd-logger  950 root     name=systemd:/systemd-1/cups.service /usr/sbin/cupsd -f  955 dbus     name=systemd:/systemd-1/messagebus.service /bin/dbus-daemon --system --address=systemd: --nofork --systemd-activation  969 root     name=systemd:/systemd-1/getty@.service/tty6 /sbin/mingetty tty6  970 root     name=systemd:/systemd-1/getty@.service/tty5 /sbin/mingetty tty5  971 root     name=systemd:/systemd-1/getty@.service/tty1 /sbin/mingetty tty1  973 root     name=systemd:/systemd-1/getty@.service/tty4 /sbin/mingetty tty4  974 root     name=systemd:/user/lennart/2        login -- lennart      1824 lennart  name=systemd:/user/lennart/2         \_ -bash  975 root     name=systemd:/systemd-1/getty@.service/tty3 /sbin/mingetty tty3  988 root     name=systemd:/systemd-1/polkitd.service /usr/libexec/polkit-1/polkitd  994 rtkit    name=systemd:/systemd-1/rtkit-daemon.service /usr/libexec/rtkit-daemon...

 

Changing the Default Boot Target

 

$ ln -sf /usr/lib/systemd/system/multi-user.target /etc/systemd/system/default.target

 

This line makes the multi user target (i.e. full system, but no graphical UI) the default target to boot into. This is kinda equivalent to setting runlevel 3 as the default runlevel on Fedora/sysvinit systems.

$ ln -sf /usr/lib/systemd/system/graphical.target /etc/systemd/system/default.target

 

This line makes the graphical target (i.e. full system, including graphical UI) the default target to boot into. Kinda equivalent to runlevel 5 on fedora/sysvinit systems. This is how things are shipped by default.

What other units does a unit depend on?

 

For example, if you want to figure out which services a target like multi-user.target pulls in, use something like this:

$ systemctl show -p "Wants" multi-user.targetWants=rc-local.service avahi-daemon.service rpcbind.service NetworkManager.service acpid.service dbus.service atd.service crond.service auditd.service ntpd.service udisks.service bluetooth.service cups.service wpa_supplicant.service getty.target modem-manager.service portreserve.service abrtd.service yum-updatesd.service upowerd.service test-first.service pcscd.service rsyslog.service haldaemon.service remote-fs.target plymouth-quit.service systemd-update-utmp-runlevel.service sendmail.service lvm2-monitor.service cpuspeed.service udev-post.service mdmonitor.service iscsid.service livesys.service livesys-late.service irqbalance.service iscsi.service netfs.service

 

Instead of "Wants" you might also try "WantedBy", "Requires", "RequiredBy", "Conflicts", "ConflictedBy", "Before", "After" for the respective types of dependencies and their inverse.

What would get started if I booted into a specific target?

 

If you want systemd to calculate the "initial" transaction it would execute on boot, try something like this:

$ systemd --test --system --unit=foobar.target

 

for a boot target foobar.target. Note that this is mostly a debugging tool that actually does a lot more than just calculate the initial transaction, so don't build scripts based on this.