Download Postgresql Docker Image

You can run your CI/CD jobs in separate, isolated Docker containers.

Head to this link and click the Get Docker link to download the installer. The above creates a container named PostgresData based on the Alpine image. Please refer to my previous article (here) for additional information on how to download. The command below will pull the PostgreSQL image from Docker.

If you run Docker on your local machine, you can run tests in the container,rather than testing on a dedicated CI/CD server.

To run CI/CD jobs in a Docker container, you need to:

  1. Register a runner so that all jobs run in Docker containers. Do this by choosing the Docker executor during registration.
  2. Specify which container to run the jobs in. Do this by specifying an image in your .gitlab-ci.yml file.
  3. Optional. Run other services, like MySQL, in containers. Do this by specifying servicesin your .gitlab-ci.yml file.

Register a runner that uses the Docker executor

To use GitLab Runner with Docker you need to register a runnerthat uses the Docker executor.

This example shows how to set up a temporary template to supply services:

Then use this template to register the runner:

The registered runner uses the ruby:2.6 Docker image and runs twoservices, postgres:latest and mysql:latest, both of which areaccessible during the build process.

What is an image

The image keyword is the name of the Docker image the Docker executoruses to run CI/CD jobs.

By default, the executor pulls images from Docker Hub.However, you can configure the registry location in the gitlab-runner/config.toml file.For example, you can set the Docker pull policyto use local images.

For more information about images and Docker Hub, seethe Docker Fundamentals documentation.

Define image in the .gitlab-ci.yml file

You can define an image that's used for all jobs, and a list ofservices that you want to use during runtime:

The image name must be in one of the following formats:

  • image: <image-name> (Same as using <image-name> with the latest tag)
  • image: <image-name>:<tag>
  • image: <image-name>@<digest>

Extended Docker configuration options

Introduced in GitLab and GitLab Runner 9.4.

You can use a string or a map for the image or services entries:

  • Strings must include the full image name(including the registry, if you want to download the image from a registryother than Docker Hub).
  • Maps must contain at least the name option,which is the same image name as used for the string setting.

For example, the following two definitions are equal:

  • A string for image and services:

  • A map for image and services. The image:name isrequired:

Download Postgresql Docker Image

Where scripts are executed

When a CI job runs in a Docker container, the before_script, script, and after_script commands run in the /builds/<project-path>/ directory. Your image may have a different default WORKDIR defined. To move to your WORKDIR, save the WORKDIR as an environment variable so you can reference it in the container during the job's runtime.

Available settings for image

Introduced in GitLab and GitLab Runner 9.4.

SettingRequiredDescription
nameYes, when used with any other option.Full name of the image. It should contain the registry part if needed.
entrypointNo.Command or script to execute as the container's entrypoint. It's translated to Docker's --entrypoint option while creating the container. The syntax is similar to Dockerfile's ENTRYPOINT directive, where each shell token is a separate string in the array.

Overriding the entrypoint of an image

Introduced in GitLab and GitLab Runner 9.4. Read more about the extended configuration options.

Before explaining the available entrypoint override methods, let's describehow the runner starts. It uses a Docker image for the containers used in theCI/CD jobs:

  1. The runner starts a Docker container using the defined entrypoint. The defaultfrom Dockerfile that may be overridden in the .gitlab-ci.yml file.
  2. The runner attaches itself to a running container.
  3. The runner prepares a script (the combination ofbefore_script,script,and after_script).
  4. The runner sends the script to the container's shell stdin and receives theoutput.

To override the entrypoint of a Docker image,define an empty entrypoint in the .gitlab-ci.yml file, so the runner does not starta useless shell layer. However, that does not work for all Docker versions.

  • For Docker 17.06 and later, the entrypoint can be set to an empty value.
  • For Docker 17.03 and earlier, the entrypoint can be set to/bin/sh -c, /bin/bash -c, or an equivalent shell available in the image.
Docker

The syntax of image:entrypoint is similar to Dockerfile's ENTRYPOINT.

Let's assume you have a super/sql:experimental image with a SQL databasein it. You want to use it as a base image for your job because youwant to execute some tests with this database binary. Let's also assume thatthis image is configured with /usr/bin/super-sql run as an entrypoint. Whenthe container starts without additional options, it runsthe database's process. The runner expects that the image has noentrypoint or that the entrypoint is prepared to start a shell command.

With the extended Docker configuration options, instead of:

Download postgresql docker image example
  • Creating your own image based on super/sql:experimental.
  • Setting the ENTRYPOINT to a shell.
  • Using the new image in your CI job.
ImageDownload Postgresql Docker Image

You can now define an entrypoint in the .gitlab-ci.yml file.

For Docker 17.06 and later:

For Docker 17.03 and earlier:

Define image and services in config.toml

Look for the [runners.docker] section:

The image and services defined this way are added to all jobs run bythat runner.

Define an image from a private Container Registry

To access private container registries, the GitLab Runner process can use:

  • Statically defined credentials. That is, a username and password for a specific registry.
  • Credentials Store. For more information, see the relevant Docker documentation.
  • Credential Helpers. For more information, see the relevant Docker documentation.

To define which option should be used, the runner process reads the configuration in this order:

  • A DOCKER_AUTH_CONFIG variable provided as either:
    • A CI/CD variable in the .gitlab-ci.yml file.
    • A project's variables stored on the project's Settings > CI/CD page.
  • A DOCKER_AUTH_CONFIG variable provided as environment variable in the runner's config.toml file.
  • A config.json file in $HOME/.docker directory of the user running the process.If the --user flag is provided to run the child processes as unprivileged user,the home directory of the main runner process user is used.

The runner reads this configuration only from the config.toml file and ignores it ifit's provided as a CI/CD variable. This is because the runner uses onlyconfig.toml configuration and does not interpolate any CI/CD variables atruntime.

Requirements and limitations

  • Available for Kubernetes executorin GitLab Runner 13.1 and later.
  • Credentials Store and Credential Helpersrequire binaries to be added to the GitLab Runner $PATH, and require access to do so. Therefore,these features are not available on shared runners, or any other runner where the user does nothave access to the environment where the runner is installed.

Use statically-defined credentials

There are two approaches that you can take to access aprivate registry. Both require setting the CI/CD variableDOCKER_AUTH_CONFIG with appropriate authentication information.

  1. Per-job: To configure one job to access a private registry, addDOCKER_AUTH_CONFIG as a job variable.
  2. Per-runner: To configure a runner so all its jobs can access aprivate registry, add DOCKER_AUTH_CONFIG to the environment in therunner's configuration.

See below for examples of each.

Determine your DOCKER_AUTH_CONFIG data

As an example, let's assume you want to use the registry.example.com:5000/private/image:latestimage. This image is private and requires you to sign in to a private containerregistry.

Let's also assume that these are the sign-in credentials:

KeyValue
registryregistry.example.com:5000
usernamemy_username
passwordmy_password

Use one of the following methods to determine the value of DOCKER_AUTH_CONFIG:

  • Do a docker login on your local machine:

    Then copy the content of ~/.docker/config.json.

    If you don't need access to the registry from your computer, youcan do a docker logout:

  • In some setups, it's possible the Docker client uses the available system keystore to store the result of docker login. In that case, it's impossible toread ~/.docker/config.json, so you must prepare the requiredbase64-encoded version of ${username}:${password} and create the Dockerconfiguration JSON manually. Open a terminal and execute the following command:

    Create the Docker JSON configuration content as follows:

Configure a job

To configure a single job with access for registry.example.com:5000,follow these steps:

  1. Create a CI/CD variableDOCKER_AUTH_CONFIG with the content of theDocker configuration file as the value:

  2. You can now use any private image from registry.example.com:5000 defined inimage or services in your .gitlab-ci.yml file:

    In the example above, GitLab Runner looks at registry.example.com:5000 for theimage namespace/image:tag.

You can add configuration for as many registries as you want, adding moreregistries to the 'auths' hash as described above.

The full hostname:port combination is required everywherefor the runner to match the DOCKER_AUTH_CONFIG. For example, ifregistry.example.com:5000/namespace/image:tag is specified in the .gitlab-ci.yml file,then the DOCKER_AUTH_CONFIG must also specify registry.example.com:5000.Specifying only registry.example.com does not work.

Configuring a runner

If you have many pipelines that access the same registry, you shouldset up registry access at the runner level. Thisallows pipeline authors to have access to a private registry just byrunning a job on the appropriate runner. It also helps simplify registrychanges and credential rotations.

This means that any job on that runner can access theregistry with the same privilege, even across projects. If you need tocontrol access to the registry, you need to be sure to controlaccess to the runner.

To add DOCKER_AUTH_CONFIG to a runner:

  1. Modify the runner's config.toml file as follows:

    • The double quotes included in the DOCKER_AUTH_CONFIGdata must be escaped with backslashes. This prevents them from beinginterpreted as TOML.
    • The environment option is a list. Your runner mayhave existing entries and you should add this to the list, not replaceit.
  2. Restart the runner service.

Use a Credentials Store

Download Postgresql Docker Image Example

To configure a Credentials Store:

  1. To use a Credentials Store, you need an external helper program to interact with a specific keychain or external store.Make sure the helper program is available in the GitLab Runner $PATH.

  2. Make GitLab Runner use it. There are two ways to accomplish this. Either:

    • Create aCI/CD variableDOCKER_AUTH_CONFIG with the content of theDocker configuration file as the value:

    • Or, if you're running self-managed runners, add the above JSON to${GITLAB_RUNNER_HOME}/.docker/config.json. GitLab Runner reads this configuration fileand uses the needed helper for this specific repository.

credsStore is used to access all the registries.If you use both images from a private registry and public images from Docker Hub,pulling from Docker Hub fails. Docker daemon tries to use the same credentials for all the registries.

Use Credential Helpers

Introduced in GitLab Runner 12.0.

As an example, let's assume that you want to use the aws_account_id.dkr.ecr.region.amazonaws.com/private/image:latestimage. This image is private and requires you to log in into a private container registry.

To configure access for aws_account_id.dkr.ecr.region.amazonaws.com, follow these steps:

  1. Make sure docker-credential-ecr-login is available in the GitLab Runner $PATH.

  2. Have any of the following AWS credentials setup.Make sure that GitLab Runner can access the credentials.

  3. Make GitLab Runner use it. There are two ways to accomplish this. Either:

    • Create a CI/CD variableDOCKER_AUTH_CONFIG with the content of theDocker configuration file as the value:

      This configures Docker to use the Credential Helper for a specific registry.

      Instead, you can configure Docker to use the Credential Helper for all Amazon Elastic Container Registry (ECR) registries:

    • Or, if you're running self-managed runners,add the previous JSON to ${GITLAB_RUNNER_HOME}/.docker/config.json.GitLab Runner reads this configuration file and uses the needed helper for thisspecific repository.

  4. You can now use any private image from aws_account_id.dkr.ecr.region.amazonaws.com defined inimage and/or services in your .gitlab-ci.yml file:

    In the example, GitLab Runner looks at aws_account_id.dkr.ecr.region.amazonaws.com for theimage private/image:latest.

Docker Image Vs Container

You can add configuration for as many registries as you want, adding moreregistries to the 'credHelpers' hash.