nspawn

How to create nspawn container:

1. you have to have pretty new template (systemd >= 209)

Create, start nspawn ct:

• download precreated template and unpack it to /var/lib/machines/<ct name>
• machinectl start <cr name>
• machinectl or machinectl list shows running ct, machinectl login to enter container

Login and logout nspawn ct:

• login: machinect login
• logout: ctrl + ]]] (within 1s)

How to enable CT starting after boot:

• systemctl enable machines.target
• systemctl enable systemd-nspawn@<containername>.service

When some override to particular CT is needed, just run this and overrride default settings:

• systemctl edit systemd-nspawn v(e) antispam.service

How to overrride system service
Systemd default systemd-nspawn@.service is not enough for us. To override service, use command "systemctl edit systemd-nspawn@.service" and undefine and define appropriate lines like:

[Service]
ExecStart=
ExecStart=/usr/bin/systemd-nspawn --quiet --keep-unit --boot --link-journal=try-guest --machine=%I

Use the same procedure to edit particular nspawn, like add NET_ADMIN capabilities for particular nspawn: "systemctl edit systemd-nspawn v(e) openport.service":

[Service]
ExecStart=
ExecStart=/usr/bin/systemd-nspawn --quiet --keep-unit --boot --link-journal=try-guest --capability=CAP_NET_ADMIN --machine=%I

Known problems

• cannot start new container: Have to create machine-id - systemd-machine-id-setup --root=/var/lib/machines/<container_name> OR, use next procedure (ugly):

• failed first start: If there is some problems on start template, try to run ct by invoking "systemd-nspawn --capability=CAP_NET_ADMIN -bD /var/lib/machines/netserv/" Terminate container with ctrl + ]]]. Second and another starts should be OK.

• cannot login: edit /etc/securetty and add to the end of file "pts/0" Otherwise, user login to conteiner will not be able.

• cannot start new container: Have to create machine-id - systemd-machine-id-setup --root=/var/lib/machines/<container_name>

Useful commands:

• systemctl list-machines
• ps ax -eo pid,machine,args
• systemctl start|stop machines.target - starts or stop all machines together
• systemctl start systemd-nspawn@<machine name> - start or stop particular machine