Use the Docker plugin to build and push Docker images to a registry. The following parameters are used to configure this plugin: * `registry` - authenticates to this registry * `username` - authenticates with this username * `password` - authenticates with this password * `email` - authenticates with this email * `repo` - repository name for the image * `tag` - repository tag for the image * `force_tag` - replace existing matched image tags * `insecure` - enable insecure communication to this registry * `mirror` - use a mirror registry instead of pulling images directly from the central Hub * `bip` - use for pass bridge ip * `storage_driver` - use `aufs`, `devicemapper`, `btrfs` or `overlay` driver * `save` - save image layers to the specified tar file (see [docker save](https://docs.docker.com/engine/reference/commandline/save/)) * `destination` - absolute / relative destination path * `tag` - cherry-pick tags to save (optional) * `load` - restore image layers from the specified tar file The following is a sample Docker configuration in your .drone.yml file: ```yaml publish: docker: username: kevinbacon password: $$DOCKER_PASSWORD email: kevin.bacon@mail.com repo: foo/bar tag: latest file: Dockerfile insecure: false ``` You may want to dynamically tag your image. Use the `$$BRANCH`, `$$COMMIT` and `$$BUILD_NUMBER` variables to tag your image with the branch, commit sha or build number: ```yaml publish: docker: username: kevinbacon password: $$DOCKER_PASSWORD email: kevin.bacon@mail.com repo: foo/bar tag: $$BRANCH ``` Or you may prefer to build an image with multiple tags: ```yaml publish: docker: username: kevinbacon password: $$DOCKER_PASSWORD email: kevin.bacon@mail.com repo: foo/bar tag: - latest - "1.0.1" - "1.0" ``` Note that in the above example we quote the version numbers. If the yaml parser interprets the value as a number it will cause a parsing error. ## Layer Caching The Drone build environment is, by default, ephemeral meaning that you layers are not saved between builds. The below example combines Drone's caching feature and Docker's `save` and `load` capabilities to cache and restore image layers between builds: ```yaml publish: docker: username: kevinbacon password: $$DOCKER_PASSWORD email: kevin.bacon@mail.com repo: foo/bar tag: - latest - "1.0.1" load: docker/image.tar save: destination: docker/image.tar tag: latest cache: mount: - docker/image.tar ``` You might also want to create a `.dockerignore` file in your repo to exclude `image.tar` from Docker build context: ``` docker/* ``` In some cases caching will greatly improve build performance, however, the tradeoff is that caching Docker image layers may consume very large amounts of disk space. ## Troubleshooting For detailed output you can set the `DOCKER_LAUNCH_DEBUG` environment variable in your plugin configuration. This starts Docker with verbose logging enabled. ```yaml publish: docker: environment: - DOCKER_LAUNCH_DEBUG=true ``` ## Known Issues There are known issues when attempting to run this plugin on CentOS, RedHat, and Linux installations that do not have a supported storage driver installed. You can check by running `docker info | grep 'Storage Driver:'` on your host machine. If the storage driver is not `aufs` or `overlay` you will need to re-configure your host machine. This error occurs when trying to use the default `aufs` storage Driver but aufs is not installed: ``` level=fatal msg="Error starting daemon: error initializing graphdriver: driver not supported ``` This error occurs when trying to use the `overlay` storage Driver but overlay is not installed: ``` level=error msg="'overlay' not found as a supported filesystem on this host. Please ensure kernel is new enough and has overlay support loaded." level=fatal msg="Error starting daemon: error initializing graphdriver: driver not supported" ``` This error occurs when using CentOS or RedHat which default to the `devicemapper` storage driver: ``` level=error msg="There are no more loopback devices available." level=fatal msg="Error starting daemon: error initializing graphdriver: loopback mounting failed" Cannot connect to the Docker daemon. Is 'docker -d' running on this host? ``` The above issue can be resolved by setting `storage_driver: vfs` in the `.drone.yml` file. This may work, but will have very poor performance as discussed [here](https://github.com/rancher/docker-from-scratch/issues/20).