Woodpecker supports [Docker credentials](https://github.com/docker/docker-credential-helpers) to securely store registry credentials. Install your corresponding credential helper and configure it in your Docker config file passed via [`WOODPECKER_DOCKER_CONFIG`](../10-server.md#docker_config).
By default the docker backend starts the step container without the `--user` flag. This means the step container will use the default user of the container. To change this behavior you can set the `user` backend option to the preferred user/group:
```yaml
steps:
- name: example
image: alpine
commands:
- whoami
backend_options:
docker:
user: 65534:65534
```
The syntax is the same as the [docker run](https://docs.docker.com/engine/reference/run/#user) `--user` flag.
The agent **will not** automatically remove images from the host. This task should be managed by the host system. For example, you can use a cron job to periodically do clean-up tasks for the CI runner.
:::danger
The following commands **are destructive** and **irreversible** it is highly recommended that you test these commands on your system before running them in production via a cron job or other automation.
There is no official support for Podman, but one can try to set the environment variable `DOCKER_HOST` to point to the Podman socket. It might work. See also the [Blog posts](https://woodpecker-ci.org/blog).
Set to the name of an existing network which will be attached to all your pipeline containers (steps). Please be careful as this allows the containers of different pipelines to access each other!
