To launch RancherOS, we have built-in system services. They are defined in the Docker Compose format, and can be found in the default system config file, /usr/share/ros/os-config.yml
. You can add your own system services or override services in the cloud-config.
Read more about image preloading.
During this service, networking is set up, e.g. hostname, interfaces, and DNS.
It is configured by hostname
and rancher.network
settings in cloud-config.
Runs ntpd
in a System Docker container.
This service provides the RancherOS user interface by running sshd
and getty
. It completes the RancherOS configuration on start up:
If the rancher.password=<password>
kernel parameter exists, it sets <password>
as the password for the rancher
user.
If there are no host SSH keys, it generates host SSH keys and saves them under rancher.ssh.keys
in cloud-config.
Runs cloud-init -execute
, which does the following:
.ssh/authorized_keys
in /home/rancher
and /home/docker
from cloud-config and metadata.write_files
cloud-config setting.rancher.resize_device
cloud-config setting.mounts
cloud-config setting.rancher.sysctl
cloud-config setting.If user-data contained a file that started with #!
, then a file would be saved at /var/lib/rancher/conf/cloud-config-script
during cloud-init and then executed. Any errors are ignored.
Runs /opt/rancher/bin/start.sh
if it exists and is executable. Any errors are ignored.
Runs /etc/rc.local
if it exists and is executable. Any errors are ignored.
This system service runs the user docker daemon. Normally it runs inside the console system container by running docker-init
script which, in turn, looks for docker binaries in /opt/bin
, /usr/local/bin
and /usr/bin
, adds the first found directory with docker binaries to PATH and runs dockerlaunch docker daemon
appending the passed arguments.
Docker daemon args are read from rancher.docker.args
cloud-config property (followed by rancher.docker.extra_args
).