61 lines
2.7 KiB
Markdown
61 lines
2.7 KiB
Markdown
# Building images with kaniko and GitLab CI/CD
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> [Introduced](https://gitlab.com/gitlab-org/gitlab-ce/issues/45512) in GitLab 11.2.
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Requires GitLab Runner 11.2 and above.
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[kaniko](https://github.com/GoogleContainerTools/kaniko) is a tool to build
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container images from a Dockerfile, inside a container or Kubernetes cluster.
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kaniko solves two problems with using the
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[docker-in-docker build](using_docker_build.md#use-docker-in-docker-executor) method:
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1. Docker-in-docker requires [privileged mode](https://docs.docker.com/engine/reference/run/#runtime-privilege-and-linux-capabilities)
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in order to function, which is a significant security concern.
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1. Docker-in-docker generally incurs a performance penalty and can be quite slow.
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## Requirements
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In order to utilize kaniko with GitLab, a [GitLab Runner](https://docs.gitlab.com/runner/)
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using either the [Kubernetes](https://docs.gitlab.com/runner/executors/kubernetes.html),
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[Docker](https://docs.gitlab.com/runner/executors/docker.html), or
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[Docker Machine](https://docs.gitlab.com/runner/executors/docker_machine.html)
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executors is required.
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## Building a Docker image with kaniko
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When building an image with kaniko and GitLab CI/CD, you should be aware of a
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few important details:
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- The kaniko debug image is recommended (`gcr.io/kaniko-project/executor:debug`)
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because it has a shell, and a shell is required for an image to be used with
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GitLab CI/CD.
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- The entrypoint will need to be [overridden](using_docker_images.md#overriding-the-entrypoint-of-an-image),
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otherwise the build script will not run.
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- A Docker `config.json` file needs to be created with the authentication
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information for the desired container registry.
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---
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In the following example, kaniko is used to build a Docker image and then push
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it to [GitLab Container Registry](../../user/project/container_registry.md).
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The job will run only when a tag is pushed. A `config.json` file is created under
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`/root/.docker` with the needed GitLab Container Registry credentials taken from the
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[environment variables](../variables/README.md#predefined-variables-environment-variables)
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GitLab CI/CD provides. In the last step, kaniko uses the `Dockerfile` under the
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root directory of the project, builds the Docker image and pushes it to the
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project's Container Registry while tagging it with the Git tag:
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```yaml
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build:
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stage: build
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image:
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name: gcr.io/kaniko-project/executor:debug
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entrypoint: [""]
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script:
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- mkdir -p /root/.docker
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- echo "{\"auths\":{\"$CI_REGISTRY\":{\"username\":\"$CI_REGISTRY_USER\",\"password\":\"$CI_REGISTRY_PASSWORD\"}}}" > /root/.docker/config.json
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- /kaniko/executor --context $CI_PROJECT_DIR --dockerfile $CI_PROJECT_DIR/Dockerfile --destination $CI_REGISTRY_IMAGE:$CI_COMMIT_TAG
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only:
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- tags
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```
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