Adding Containers

Typically, we recommend that people add containers using services as it provides a little more flexibility for the user, but sometimes we understand that you might want to spin up one container.

In the Infrastructure -> Container page, click on Add Container. Any options that docker run supports when creating containers is also supported in Rancher.

  1. Provide a Name and if desired, Description for the container.
  2. Provide the Image to use. You can use any image on DockerHub as well as any registries that have been added to Rancher. The syntax for image name would match any docker run commands.

    Syntax of image names. By default, we pull from the docker registry. If no tag is specified, we will pull the latest tag.


  3. If desired, set up port mapping, which proviedes the ability to access the exposed ports on the container through the host IP. In the Port Map section, you define the public ports that will be used to communicate with the container. You also define the private port that is used to connect to the exposed port of the container.

    Random Port Mapping

    If you would like to take advantage of Rancher’s random port mapping, the public port will be blank and you will need to define the private port. The private port is typically one of exposed ports on the container.

    Note: When ports are exposed in Rancher, it will not show up in docker ps as Rancher manages the iptable rules to make the ports fully dynamic.

  4. In the various tabs, all options available in Docker are available for Rancher. By default, we have set the -i -t.

    If you chose to add the container from the Infrastructure -> Containers page, Rancher will automatically pick a host for you. Otherwise, if you have picked a host to add a container to, the host will be populated in the Security/Host tab.

    There is also the ability to add labels to a container as well as apply scheduling rules. More details about labels and scheduling can be read here.

  5. When you have completed filling out your container options, click Create. If this is the first container on the host to be launched by Rancher, it will automatically deploy a container named Network Agent in the Rancher UI. This container is what Rancher uses to allow containers between different hosts be able to communicate with each other. The Network Agent runs using the rancher/agent-instance image. Rancher will automatically pull the correct version tag for this container.

Editing Containers

From the dropdown of a container, you can select different actions to perform on a container. When viewing containers on a host or service, the dropdown icon can be found by hovering over the container name. In the Infrastructure -> Containers, the dropdown icon is only visible for containers that were created specifically on the hosts. Any containers created through a service will not display its dropdown icon.

You can always click on the container name, which will bring you to the container details page. On that page, the dropdown menu is located in the upper right hand corner next to the state of the container.

When you select Edit from the dropdown menu, you will be only able to change the name and description of the container. Docker containers are immutable (not changeable) after creation. The only things you can edit are things that we store that aren’t really part of the Docker container. This includes restarting, it’s still the same container if you stop and start it. You will need to remove and recreate a container to change anything else.

Note: When ports are exposed in Rancher, it will not show up in docker ps as Rancher manages the iptable rules to make the ports fully dynamic.

You can Clone, which will pre-fill the Add Container screen with all the settings from an existing container. If you forget one thing, you can clone the container, change it, and then delete the old container.

Changing the Container States

When a container is in a Running state, you can Stop the container. This will stop the container on the host, but will not remove it. After the container is in the Stopped state, you can select Start to have the container start running again. Another option is to Restart the container, which will stop and start the container in one step.

You can Delete a container and have it removed from the host.

Executing the Shell

When you select Execute Shell, it brings you into the container shell prompt.

Viewing Logs

It’s always useful to see what is going on with the logs of a container. Clicking View Logs provides the equivalent of docker logs <CONTAINER_ID> on the host.