Custom System Services
You can also create your own system service in Docker Compose format. After creating your own custom service, you can launch it in RancherOS in a couple of methods. The service could be directly added to the cloud-config, or a
docker-compose.yml file could be saved at a http(s) url location or in a specific directory of RancherOS.
Launching Services through Cloud-Config
If you want to boot RancherOS with a system service running, you can add the service to the cloud-config that is passed to RancherOS. When RancherOS starts, this service will automatically be started.
#cloud-config rancher: services: nginxapp: image: nginx restart: always
Launching Services using local files
If you already have RancherOS running, you can start a system service by saving a
docker-compose.yml file at
nginxapp: image: nginx restart: always
To enable a custom system service from the file location, the command must indicate the file location if saved in RancherOS. If the file is saved at a http(s) url, just use the http(s) url when enabling/disabling.
# Enable the system service saved in /var/lib/rancher/conf $ sudo ros service enable /var/lib/rancher/conf/example.yml # Enable a system service saved at a http(s) url $ sudo ros service enable https://mydomain.com/example.yml
After the custom system service is enabled, you can start the service using
sudo ros service up <serviceName>. The
<serviceName> will be the names of the services inside the
$ sudo ros service up nginxapp # If you have more than 1 service in your docker-compose.yml, add all service names to the command $ sudo ros service up service1 service2 service3
Launching Services from a web repository
The https://github.com/rancher/os-services repository is used for the built-in services, but you can create your own, and configure RancherOS to use it in addition (or to replace) it.
The config settings to set the url in which
ros should look for an
index.yml file is:
core repository url is set when a release is made, and any other
<name> url you add will be listed together when running
ros console list,
ros service list or
ros engine list
For example, in RancherOS v0.7.0, the
core repository is set to
Service development and testing
If you’re building your own services in a branch on GitHub, you can push to it, and then load your service from there.
For example, when developing the zfs service:
rancher@zfs:~$ sudo ros config set rancher.repositories.zfs.url https://raw.githubusercontent.com/SvenDowideit/os-services/zfs-service rancher@zfs:~$ sudo ros service list disabled amazon-ecs-agent disabled kernel-extras enabled kernel-headers disabled kernel-headers-system-docker disabled open-vm-tools disabled amazon-ecs-agent disabled kernel-extras disabled kernel-headers disabled kernel-headers-system-docker disabled open-vm-tools disabled zfs [rancher@zfs ~]$ sudo ros service enable zfs Pulling zfs (zombie/zfs)... latest: Pulling from zombie/zfs b3e1c725a85f: Pull complete 4daad8bdde31: Pull complete 63fe8c0068a8: Pull complete 4a70713c436f: Pull complete bd842a2105a8: Pull complete d1a8c0826fbb: Pull complete 5f1c5ffdf34c: Pull complete 66c2263f2388: Pull complete Digest: sha256:eab7b8c21fbefb55f7ee311dd236acee215cb6a5d22942844178b8c6d4e02cd9 Status: Downloaded newer image for zombie/zfs:latest [rancher@zfs ~]$ sudo ros service up zfs WARN The KERNEL_VERSION variable is not set. Substituting a blank string. INFO Project [os]: Starting project INFO [0/21] [zfs]: Starting INFO [1/21] [zfs]: Started INFO Project [os]: Project started
Beware that there is an overly aggressive caching of yml files - so when you push a new yml file to your repo, you need to
delete the files in
The image that you specify in the service yml file needs to be pullable - either from a private registry, or on the Docker Hub.
Available as of v1.1
RancherOS has a system cron service based on Container Crontab. This can be used to start, restart or stop system containers.
To use this on your service, add a
cron.schedule label to your service’s description:
my-service: image: namespace/my-service:v1.0.0 command: my-command labels: io.rancher.os.scope: "system" cron.schedule: "0 * * * * ?"
For a cron service that can be used with user Docker containers, see the
crontab system service.
Service log rotation
RancherOS provides a built in
logrotate container that makes use of logrotate(8) to rotate system logs. This is called on an hourly basis by the
If you would like to make use of system log rotation for your system service, do the following.
system-volumes to your service description’s
volumes_from section. You could also use a volume group containing
my-service: image: namespace/my-service:v1.0.0 command: my-command labels: io.rancher.os.scope: "system" volumes_from: - system-volumes
Next, add an entry point script to your image and copy your logrotate configs to
/etc/logrotate.d/ on startup.
FROM alpine:latest COPY logrotate-myservice.conf entrypoint.sh / ENTRYPOINT ["/entrypoint.sh"]
Example entrypoint.sh (Ensure that this script has the execute bit set).
#!/bin/sh cp logrotate-myservice.conf /etc/logrotate.d/myservice exec "$@"
Your service’s log rotation config will now be included when the system logrotate runs. You can view logrotate output with
system-docker logs logrotate.
Creating your own Console
Once you have your own Services repository, you can add a new service to its index.yml, and then add a
<service-name>.yml file to the directory starting with the first letter.
To create your own console images, you need to:
1 install some basic tools, including an ssh daemon, sudo, and kernel module tools
docker users and groups with UID and GID’s of
3 add both users to the
4 add both groups into the
/etc/sudoers file to allow password-less sudo
5 configure sshd to accept logins from users in the
docker group, and deny
ENTRYPOINT ["/usr/bin/ros", "entrypoint"]
ros binary, and other host specific configuration files will be bind mounted into the running console container when its launched.
For examples of existing images, see https://github.com/rancher/os-images.
We use labels to determine how to handle the service containers.
||Use this label to have the container deployed in System Docker instead of Docker.|
||Service Names (Comma separated list is accepted)||Used to determine order of when containers should be started.|
||When set to
||When set to
RancherOS uses labels to determine if the container should be deployed in System Docker. By default without the label, the container will be deployed in User Docker.
labels: - io.rancher.os.scope=system
Example of how to order container deployment
foo: labels: # Start foo before bar is launched io.rancher.os.before: bar # Start foo after baz has been launched io.rancher.os.after: baz