Docker Build

Skaffold supports building with Dockerfile

1. locally
2. in cluster
3. on Google CloudBuild

Dockerfile with Docker locally

If you have Docker installed, Skaffold can be configured to build artifacts with the local Docker daemon.

By default, Skaffold connects to the local Docker daemon using Docker Engine APIs, though it can also use the Docker command-line interface instead, which enables artifacts with BuildKit.

After the artifacts are successfully built, Docker images will be pushed to the remote registry. You can choose to skip this step.

Configuration

To use the local Docker daemon, add build type local to the build section of skaffold.yaml. The following options can optionally be configured:

The docker builder replaces cache references to the artifact image with the tagged image to allow caching from the previously built image.

Example

The following build section instructs Skaffold to build a Docker image gcr.io/k8s-skaffold/example with the local Docker daemon:

build:
  artifacts:
  - image: gcr.io/k8s-skaffold/example
    docker:
      cacheFrom:
      # Local Docker builder replaces cache references to the artifact image with
      # the tagged image reference, useful for caching from the previous build.
      - gcr.io/k8s-skaffold/example
  local: {}

Which is equivalent to:

build:
  artifacts:
  - image: gcr.io/k8s-skaffold/example
  local:
    useDockerCLI: false
    useBuildkit: false

Artifact dependency

You can additionally define dependency on other artifacts using the requires expression:

build:
  artifacts:
  - image: image1
    requires:
      - image: image2
        alias: IMAGE2
  - image: image2
  local: {}

The specified alias IMAGE2 becomes available as a build-arg in the Dockerfile for image1 and its value automatically set to the image built from image2.

Dockerfile in-cluster with Kaniko

Kaniko is a Google-developed open source tool for building images from a Dockerfile inside a container or Kubernetes cluster. Kaniko enables building container images in environments that cannot easily or securely run a Docker daemon.

Skaffold can help build artifacts in a Kubernetes cluster using the Kaniko image; after the artifacts are built, kaniko must push them to a registry.

Configuration

To use Kaniko, add build type kaniko to the build section of skaffold.yaml. The following options can optionally be configured:

Artifact dependency

Similar to the local Docker builder, you can define dependency on other artifacts using the requires expression:

build:
  artifacts:
  - image: image1
    requires:
    - image: image2
      alias: IMAGE2
    kaniko: {}
  - image: image2
  cluster: {}

The specified alias IMAGE2 becomes available as a build-arg in the Dockerfile for image1 and its value automatically set to the image built from image2.

Since Kaniko builds images directly to a registry, it requires active cluster credentials. These credentials are configured in the cluster section with the following options:

To set up the credentials for Kaniko refer to the kaniko docs (Note: Rename the downloaded JSON key to kaniko-secret without appending .json). Alternatively, the path to a credentials file can be set with the pullSecretPath option:

build:
  cluster:
    pullSecretName: pull-secret-in-kubernetes
    # OR
    pullSecretPath: path-to-service-account-key-file

Similarly, when pushing to a docker registry:

build:
  cluster:
    dockerConfig:
      path: ~/.docker/config.json
      # OR
      secretName: docker-config-secret-in-kubernetes

Note that the Kubernetes secret must not be of type kubernetes.io/dockerconfigjson which stores the config json under the key ".dockerconfigjson", but an opaque secret with the key "config.json".

Example

The following build section, instructs Skaffold to build a Docker image gcr.io/k8s-skaffold/example with Kaniko:

build:
  artifacts:
    - image: gcr.io/k8s-skaffold/example
      kaniko: {}
  cluster:
    pullSecretName: YOUR-PULL-SECRET-NAME

Dockerfile remotely with Google Cloud Build

Skaffold can build the Dockerfile image remotely with Google Cloud Build.

Configuration

To configure, add googleCloudBuild to build section to skaffold.yaml. The following options can optionally be configured:

The googleCloudBuild builder replaces cache references to the artifact image with the tagged image to allow caching from the previously built image.

Example

The following build section, instructs Skaffold to build a Docker image gcr.io/k8s-skaffold/example with Google Cloud Build:

build:
  artifacts:
  - image: gcr.io/k8s-skaffold/example
    docker:
      cacheFrom:
      # googleCloudBuild replaces cache references to the artifact image with
      # the tagged image reference, useful for caching from the previous build.
      - gcr.io/k8s-skaffold/example
  googleCloudBuild:
    projectId: YOUR-GCP-PROJECT