82 lines
3.6 KiB
Markdown
82 lines
3.6 KiB
Markdown
# Building images with kaniko and GitLab CI/CD
|
|
|
|
> [Introduced](https://gitlab.com/gitlab-org/gitlab-ce/issues/45512) in GitLab 11.2.
|
|
Requires GitLab Runner 11.2 and above.
|
|
|
|
[kaniko](https://github.com/GoogleContainerTools/kaniko) is a tool to build
|
|
container images from a Dockerfile, inside a container or Kubernetes cluster.
|
|
|
|
kaniko solves two problems with using the
|
|
[docker-in-docker build](using_docker_build.md#use-docker-in-docker-executor) method:
|
|
|
|
1. Docker-in-docker requires [privileged mode](https://docs.docker.com/engine/reference/run/#runtime-privilege-and-linux-capabilities)
|
|
in order to function, which is a significant security concern.
|
|
1. Docker-in-docker generally incurs a performance penalty and can be quite slow.
|
|
|
|
## Requirements
|
|
|
|
In order to utilize kaniko with GitLab, a [GitLab Runner](https://docs.gitlab.com/runner/)
|
|
using either the [Kubernetes](https://docs.gitlab.com/runner/executors/kubernetes.html),
|
|
[Docker](https://docs.gitlab.com/runner/executors/docker.html), or
|
|
[Docker Machine](https://docs.gitlab.com/runner/executors/docker_machine.html)
|
|
executors is required.
|
|
|
|
## Building a Docker image with kaniko
|
|
|
|
When building an image with kaniko and GitLab CI/CD, you should be aware of a
|
|
few important details:
|
|
|
|
- The kaniko debug image is recommended (`gcr.io/kaniko-project/executor:debug`)
|
|
because it has a shell, and a shell is required for an image to be used with
|
|
GitLab CI/CD.
|
|
- The entrypoint will need to be [overridden](using_docker_images.md#overriding-the-entrypoint-of-an-image),
|
|
otherwise the build script will not run.
|
|
- A Docker `config.json` file needs to be created with the authentication
|
|
information for the desired container registry.
|
|
|
|
---
|
|
|
|
In the following example, kaniko is used to build a Docker image and then push
|
|
it to [GitLab Container Registry](../../user/project/container_registry.md).
|
|
The job will run only when a tag is pushed. A `config.json` file is created under
|
|
`/kaniko/.docker` with the needed GitLab Container Registry credentials taken from the
|
|
[environment variables](../variables/README.md#predefined-environment-variables)
|
|
GitLab CI/CD provides. In the last step, kaniko uses the `Dockerfile` under the
|
|
root directory of the project, builds the Docker image and pushes it to the
|
|
project's Container Registry while tagging it with the Git tag:
|
|
|
|
```yaml
|
|
build:
|
|
stage: build
|
|
image:
|
|
name: gcr.io/kaniko-project/executor:debug
|
|
entrypoint: [""]
|
|
script:
|
|
- echo "{\"auths\":{\"$CI_REGISTRY\":{\"username\":\"$CI_REGISTRY_USER\",\"password\":\"$CI_REGISTRY_PASSWORD\"}}}" > /kaniko/.docker/config.json
|
|
- /kaniko/executor --context $CI_PROJECT_DIR --dockerfile $CI_PROJECT_DIR/Dockerfile --destination $CI_REGISTRY_IMAGE:$CI_COMMIT_TAG
|
|
only:
|
|
- tags
|
|
```
|
|
|
|
## Using a registry with a custom certificate
|
|
|
|
When trying to push to a Docker registry that uses a certificate that is signed
|
|
by a custom CA, you might get the following error:
|
|
|
|
```sh
|
|
$ /kaniko/executor --context $CI_PROJECT_DIR --dockerfile $CI_PROJECT_DIR/Dockerfile --no-push
|
|
INFO[0000] Downloading base image registry.gitlab.example.com/group/docker-image
|
|
error building image: getting stage builder for stage 0: Get https://registry.gitlab.example.com/v2/: x509: certificate signed by unknown authority
|
|
```
|
|
|
|
This can be solved by adding your CA's certificate to the kaniko certificate
|
|
store:
|
|
|
|
```yaml
|
|
before_script:
|
|
- echo "{\"auths\":{\"$CI_REGISTRY\":{\"username\":\"$CI_REGISTRY_USER\",\"password\":\"$CI_REGISTRY_PASSWORD\"}}}" > /kaniko/.docker/config.json
|
|
- |
|
|
echo "-----BEGIN CERTIFICATE-----
|
|
...
|
|
-----END CERTIFICATE-----" >> /kaniko/ssl/certs/ca-certificates.crt
|
|
```
|