vpsAdminOS supports runlevels as suggested by runit documentation. There are three runlevels built-in: single, rescue and default. single starts only gettys, which is useful for maintenance. Runlevel rescue starts gettys, configures network and starts sshd. rescue does not import ZFS pools and does not start osctld. Runlevel default starts all services that handle network configuration, importing of storage pools and starting containers.
Every runit service belongs to one or more runlevels, you can create your own
runlevels by assigning services into it, see options under
The default runlevel can be configured using option
At runtime, runlevels can be switched using
is a utility from vpsAdminOS and
runsvchdir comes with runit. The following
commands are equivalent:
svctl switch single
svctl switch default
It may take several seconds for runit to notice the change and start appropriate services.
Booting into a different runlevel
The default runlevel to boot can be changed using kernel arguments. You can
change these arguments in the bootloader if you have one, or generate config
for netboot. The recognized kernel argument is
runlevel=single can also be written as
To make a persistent change, it should be done in your Nix configuration. If you'd like to make temporary changes on a running system, read on.
Generally, a service is enabled by creating a symlink in the runlevel directory,
which points to the service. To disable a service, the symlink is simply removed.
runit monitors the current runlevel's directory, starts new services and stops
removed services. Runlevel directories are in
/etc/runit/runsvdir and the
enabled services are linked from
/etc/runit/services. For example, to enable
sshd in the current runlevel, you'd do:
ln -s /etc/runit/services/sshd /etc/runit/runsvdir/current/sshd
You could either create and remove these symlinks manually, or you can use
svctl is a tool made for easier service and runlevel management.
You can forget where the services are stored and where the runlevels are.
svctl can list all or enabled services, enable/disable services in selected
runlevels and switch the current runlevel.
When called without any arguments,
svctl lists all available services and the
runlevels they're in:
eudev rescue default
eudev-trigger rescue default
getty-tty1 single rescue default
getty-tty2 single rescue default
getty-tty3 single rescue default
getty-tty4 single rescue default
getty-ttyS0 single rescue default
getty-ttyS1 single rescue default
networking rescue default
nix rescue default
rsyslog rescue default
sshd rescue default
To enable service
sshd in runlevel
single, you'd do:
svctl enable sshd single
Review the change by listing services in runlevel
svctl list-services single
If you do not provide the runlevel's name, it defaults to the currently active
runlevel. So when you've booted in a single user mode, i.e. runlevel
sshd can be enabled just by:
svctl enable sshd