Creating a container: choose an image, configure and start

Open your project and click on Create container in the top right-hand corner. The wizard consists of three steps: Select image, Configure, and Check & create. In the top right-hand corner, you can see how many containers your plan allows.

Step 1: Select an image

At the very top is our catalogue: selected images with a brief description, source and licence type. You can quickly find the right image using the search box and the categories Web applications, Databases, Runtimes and Tools. Images with at least one startable version are listed first. You can display images whose versions are currently being checked or are locked by selecting ‘Show: … more under review or locked’.

Each card specifies the licence type:

• Free - usage, modification and running of the software without any special conditions.
• Copyleft - if you modify and redistribute the software, you must make the modified source code available under the same licence.
• Restricted - certain usages, such as operating the software as a service for third parties, require a licence from the manufacturer.
• Commercial - you need your own licence or a subscription from the manufacturer to run the software.
• Unclassified - please check the terms and conditions directly with the manufacturer.

Further official images

Below the catalogue you will find the Docker Official Images. You’re free to choose any of them - the selected version is checked when the container is created, after which it starts automatically.

Can’t find your image?

Then you have three options:

• Image by address - any image from the official sources displayed (for example docker.io/library/nginx:1.30). If no version (tag) is specified, latest is used.
• Connect your own registry - for images from your own registry, such as Harbor, GitLab or GitHub. Enter the address (for example registry.muster.de/team), and, if required, your username and password or a token. It is best to use a token with read-only access. Once we have approved it - you will receive an email - the full image address is all you need, for example registry.muster.de/team/app:1.0.
• Request approval - please specify the image address, licence and intended use. Our team will check the origin, security and licence and get back to you.

Step 2: Configure

The default settings are suitable for most cases - only change what you need to. On the right, the ‘What your container will look like’ preview continuously displays the name, image, address, volumes and networks.

• Container name - 2 to 31 characters consisting of lower-case letters, numbers and hyphens, starting with a letter. Other containers will access it using this name, for example as a database host. The name cannot be changed later.
• Version - each version shows its check result. Under ‘Other version’, you can enter your own version if required; it is checked before the container starts.
• Settings for this image - mandatory details such as a database password. Passwords are already marked as Secret (environment variables and secrets).
• How should it be reachable? - internally only, on the web (HTTPS) or via a custom port (TCP or UDP). For a web address, specify the port within the container and, optionally, your own domain (making a container reachable on the web).
• Store data permanently - creates a volume. The wizard suggests the appropriate path from the image.
• Networks - which networks the container is on (networks and firewall).
• Advanced - RAM and CPU for this container (blank means: up to the project limit; 100% CPU corresponds to one core), additional variables, restart behaviour, autostart and a custom start command.

If you have a Docker Compose file, you can import its details at the top via Template from docker-compose (Using a docker-compose template).

Step 3: Check & create

The summary shows all the details and, below that, what happens after creation. On the right, confirm the licence: ‘I am operating this software myself and comply with the manufacturer’s licence terms.’ If the security check has identified high-risk findings, also confirm ‘Start despite high-risk security findings’. Then click on Create container.

Security checks on the images

We automatically check every version of an image for known vulnerabilities before it is launched for the first time. We use the open-source scanner Trivy for this. You can see the result for each version:

• Checked - no high or critical findings; the version will start immediately.
• High-risk findings - can be started, but only after your confirmation. We recommend an update as soon as a newer version has been checked.
• Blocked - critical findings; the version cannot be started.
• Exception approval - approved on an exceptional basis despite critical findings, following review by our team. Here, too, you must confirm the start.
• Being checked - the check is still in progress. The container is being created and will start automatically as soon as the check has been passed.

Versions that have already been verified start in a few seconds; new versions start after verification, which usually takes only a few minutes. You can view the progress in the History tab.