# Systemd * [systemctl](#systemctl) * [Units](#units) * [target](#target) * [Config](#config) * [add](#add) * [debug](#debug) * [journald](#journald) * [systemd-networkd.service](#systemd-networkdservice) * [systemd.netdev](#systemdnetdev) * [Kind](#kind) * [Examples](#examples) * [bridge.netdev](#bridgenetdev) * [dummy.netdev](#dummynetdev) * [vlan1.netdev](#vlan1netdev) * [macvtap.netdev](#macvtapnetdev) * [systemd.network](#systemdnetwork) * [static.network](#staticnetwork) * [dhcp.network](#dhcpnetwork) * [A bridge with two enslaved links](#a-bridge-with-two-enslaved-links) * [bridge-slave-interface-vlan.network](#bridge-slave-interface-vlannetwork) * [macvtap.network](#macvtapnetwork) * [systemd.link](#systemdlink) ## systemctl ``` systemctl --all systemctl list-dependencies systemctl list-dependencies libvirtd --all systemctl status [___.service] systemctl | grep ssh systemctl --failed systemctl daemon-reload # scanning for new or changed units systemctl enable unit # start on boot systemctl mask unit # make it impossible to start sudo systemd-analyze plot > /tmp/systemd-startup.svg fbi /tmp/systemd-startup.svg ``` ## Units * .service: default * : instances of a template unit， actually 'instance\_identifier\@.service * .mount, E.g.: `/home` is equivalent to `home.mount` * .device, E.g.: `/dev/sda2` is equivalent to `dev-sda2.device` * .socket * .slice More: ``` # when running in system mode (--system) ls -l /run/systemd/system # Runtime units ls -l /usr/lib/systemd/system # Units of installed packages ls -l /etc/systemd/system # Local configuration, by SA ``` ## target ``` SysV Runlevel systemd Target Notes 0 runlevel0.target, poweroff.target Halt the system. 1, s, single runlevel1.target, rescue.target Single user mode. 2, 4 runlevel2.target, runlevel4.target, multi-user.target User-defined/Site-specific runlevels. By default, identical to 3. 3 runlevel3.target, multi-user.target usually login via multiple consoles or network. 5 runlevel5.target, graphical.target Multi-user, graphical. 6 runlevel6.target, reboot.target Reboot emergency emergency.target Emergency shell systemctl isolate multi-user.target # switch to target systemctl get-default # current target systemctl set-default multi-user.target ``` ## Config /etc/systemd/system/foobar.service.d/\*.conf # override settings ``` systemctl cat unit systemctl edit --full ssh systemctl edit --force new [Unit] Description=new [Service] ExecStart=/usr/sbin/new-daemon [Install] WantedBy=multi-user.target ``` ### add ``` cp -pv foo.service /etc/systemd/system/ systemctl daemon-reload systemctl enable foo systemctl start foo systemctl status foo ``` ## debug ``` /etc/systemd/system.conf LogLevel=debug LogTarget=syslog-or-kmsg ``` ## journald ``` # http://man7.org/linux/man-pages/man5/journald.conf.5.html sudo mkdir -p /var/log/journal # persistent storage journalctl -u unit SYSTEMD_LESS="FRXMK" journalctl -u docker -n 100 -S, --since=, -U, --until= ``` ## systemd-networkd.service /usr/lib/systemd/systemd-networkd\ ``` systemctl status systemd-networkd.service systemctl restart systemd-networkd.service # networkctl list IDX LINK TYPE OPERATIONAL SETUP 1 lo loopback carrier unmanaged 2 enp3s0 ether no-carrier unmanaged 3 eno1 ether degraded unmanaged 4 eno2 ether degraded configured 7 docker0 ether routable unmanaged 9 vethec09cbe ether degraded unmanaged 11 veth5185e04 ether degraded unmanaged 12 zt0 ether routable unmanaged 13 br0 ether routable configured 14 macvtap0 ether degraded unmanaged 15 vnet0 ether degraded unmanaged 16 br8 ether off unmanaged 18 macvtap1 ether degraded unmanaged 19 vnet1 ether degraded unmanaged ``` ## systemd.netdev ``` ls /etc/systemd/network # local administration network directory ls /usr/lib/systemd/network # system network directory ls /run/systemd/network # volatile runtime network directory `/run` is temporary and `/usr/lib` is for vendors symlink with the same name pointing to `/dev/null` disables the configuration file entirely ``` ### Kind ``` `bridge` A bridge device is a software switch, and each of its slave devices and the bridge itself are ports of the switch. `tap` A persistent Level 2 tunnel between a network device and a device node. `tun` A persistent Level 3 tunnel between a network device and a device node. `veth` An Ethernet tunnel between a pair of network devices. `sit` An IPv6 over IPv4 tunnel. `vti` An IPv4 over IPSec tunnel. ``` ### Examples #### bridge.netdev ``` [NetDev] Name=bridge0 Kind=bridge [Match] Virtualization=no ``` #### dummy.netdev ``` [NetDev] Name=dummy-test Kind=dummy MACAddress=12:34:56:78:9a:bc ``` #### vlan1.netdev ``` [NetDev] Name=vlan1 Kind=vlan [VLAN] Id=1 ``` #### macvtap.netdev ``` [NetDev] Name=macvtap-test Kind=macvtap ``` Compare with macvtap.network below. ## systemd.network ### static.network ``` [Match] Name=enp2s0 [Network] Address=192.168.0.15/24 Gateway=192.168.0.1 ``` ### dhcp.network ``` [Match] Name=en* [Network] DHCP=yes ``` ### A bridge with two enslaved links ``` # /etc/systemd/network/25-bridge-static.network [Match] Name=bridge0 [Network] ... # /etc/systemd/network/25-bridge-slave-interface-1.network [Match] Name=enp2s0 [Network] Bridge=bridge0 # /etc/systemd/network/25-bridge-slave-interface-x.network ``` ### bridge-slave-interface-vlan.network ``` [Match] Name=enp2s0 [Network] Bridge=bridge0 [BridgeVLAN] VLAN=1-32 PVID=42 EgressUntagged=42 [BridgeVLAN] VLAN=100-200 [BridgeVLAN] EgressUntagged=300-400 VLAN= The VLAN ID allowed on the port. EgressUntagged= The VLAN ID specified here will be used to untag frames on egress. Configuring EgressUntagged= implicates the use of VLAN= above and will enable the VLAN ID for ingress as well. PVID= The Port VLAN ID specified here is assigned to all untagged frames at ingress. PVID= can be used only once. Configuring PVID= implicates the use of VLAN= above and will enable the VLAN ID for ingress as well. ``` ### macvtap.network ``` [Match] Name=enp0s25 [Network] MACVTAP=macvtap-test ``` ## systemd.link Network link configuration is performed by the net\_setup\_link udev builtin.\ udev (userspace /dev) is a device manager for the Linux kernel. As the successor of devfsd and hotplug, udev primarily manages device nodes in the /dev directory. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. 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