Commit a7115a81 authored by Cody West's avatar Cody West Committed by Suzanne Selhorn

Docs: Changes heading levels and builds more structure

Updated the doc so it's easier to see which options are available.
parent c946f083
......@@ -19,7 +19,7 @@ GitLab Runner to support `docker` commands.
To enable Docker commands for your CI/CD jobs, you can use:
- [The shell executor](#use-the-shell-executor)
- [The Docker executor with the Docker image (Docker-in-Docker)](#use-the-docker-executor-with-the-docker-image-docker-in-docker)
- [Docker-in-Docker](#use-docker-in-docker)
- [Docker socket binding](#use-docker-socket-binding)
If you don't want to execute a runner in privileged mode,
......@@ -78,54 +78,29 @@ You can now use `docker` commands (and install `docker-compose` if needed).
When you add `gitlab-runner` to the `docker` group, you are effectively granting `gitlab-runner` full root permissions.
Learn more about the [security of the `docker` group](https://blog.zopyx.com/on-docker-security-docker-group-considered-harmful/).
### Use the Docker executor with the Docker image (Docker-in-Docker)
### Use Docker-in-Docker
"Docker-in-Docker" (`dind`) means:
- Your registered runner uses the [Docker executor](https://docs.gitlab.com/runner/executors/docker.html).
- Your registered runner uses the [Docker executor](https://docs.gitlab.com/runner/executors/docker.html) or the [Kubernetes executor](https://docs.gitlab.com/runner/executors/kubernetes.html).
- The executor uses a [container image of Docker](https://hub.docker.com/_/docker/), provided
by Docker, to run your CI/CD jobs.
The Docker image has all of the `docker` tools installed and can run
the job script in context of the image in privileged mode.
We recommend you use [Docker-in-Docker with TLS enabled](#docker-in-docker-with-tls-enabled),
We recommend you use Docker-in-Docker with TLS enabled,
which is supported by [GitLab.com shared runners](../runners/index.md).
You should always specify a specific version of the image, like `docker:19.03.12`.
If you use a tag like `docker:stable`, you have no control over which version is used.
Unpredictable behavior can result, especially when new versions are released.
#### Limitations of Docker-in-Docker
#### Use the Docker executor with Docker-in-Docker
Docker-in-Docker is the recommended configuration, but is
not without its own challenges:
You can use the Docker executor to run jobs in a Docker container.
- **The `docker-compose` command**: This command is not available in this configuration by default.
To use `docker-compose` in your job scripts, follow the `docker-compose`
[installation instructions](https://docs.docker.com/compose/install/).
- **Cache**: Each job runs in a new environment. Concurrent jobs work fine,
because every build gets its own instance of Docker engine and they don't conflict with each other.
However, jobs can be slower because there's no caching of layers.
- **Storage drivers**: By default, earlier versions of Docker use the `vfs` storage driver,
which copies the file system for each job. Docker 17.09 and later use `--storage-driver overlay2`, which is
the recommended storage driver. See [Using the OverlayFS driver](#use-the-overlayfs-driver) for details.
- **Root file system**: Because the `docker:19.03.12-dind` container and the runner container don't share their
root file system, you can use the job's working directory as a mount point for
child containers. For example, if you have files you want to share with a
child container, you might create a subdirectory under `/builds/$CI_PROJECT_PATH`
and use it as your mount point. For a more detailed explanation, view [issue
#41227](https://gitlab.com/gitlab-org/gitlab-foss/-/issues/41227).
```yaml
variables:
MOUNT_POINT: /builds/$CI_PROJECT_PATH/mnt
script:
- mkdir -p "$MOUNT_POINT"
- docker run -v "$MOUNT_POINT:/mnt" my-docker-image
```
#### Docker-in-Docker with TLS enabled
##### Docker-in-Docker with TLS enabled in the Docker executor
> Introduced in GitLab Runner 11.11.
......@@ -219,7 +194,72 @@ To use Docker-in-Docker with TLS enabled:
- docker run my-docker-image /script/to/run/tests
```
#### Docker-in-Docker with TLS enabled in Kubernetes
##### Docker-in-Docker with TLS disabled in the Docker executor
Sometimes you might have legitimate reasons to disable TLS.
For example, you have no control over the GitLab Runner configuration
that you are using.
Assuming that the runner's `config.toml` is similar to:
```toml
[[runners]]
url = "https://gitlab.com/"
token = TOKEN
executor = "docker"
[runners.docker]
tls_verify = false
image = "docker:19.03.12"
privileged = true
disable_cache = false
volumes = ["/cache"]
[runners.cache]
[runners.cache.s3]
[runners.cache.gcs]
```
You can now use `docker` in the job script. Note the inclusion of the
`docker:19.03.12-dind` service:
```yaml
image: docker:19.03.12
variables:
# When using dind service, you must instruct docker to talk with the
# daemon started inside of the service. The daemon is available with
# a network connection instead of the default /var/run/docker.sock socket.
#
# The 'docker' hostname is the alias of the service container as described at
# https://docs.gitlab.com/ee/ci/docker/using_docker_images.html#accessing-the-services
#
# If you're using GitLab Runner 12.7 or earlier with the Kubernetes executor and Kubernetes 1.6 or earlier,
# the variable must be set to tcp://localhost:2375 because of how the
# Kubernetes executor connects services to the job container
# DOCKER_HOST: tcp://localhost:2375
#
DOCKER_HOST: tcp://docker:2375
#
# This instructs Docker not to start over TLS.
DOCKER_TLS_CERTDIR: ""
services:
- docker:19.03.12-dind
before_script:
- docker info
build:
stage: build
script:
- docker build -t my-docker-image .
- docker run my-docker-image /script/to/run/tests
```
#### Use the Kubernetes executor with Docker-in-Docker
You can use the Kubernetes executor to run jobs in a Docker container.
##### Docker-in-Docker with TLS enabled in Kubernetes
> [Introduced](https://gitlab.com/gitlab-org/charts/gitlab-runner/-/issues/106) in GitLab Runner Helm Chart 0.23.0.
......@@ -287,66 +327,34 @@ To use Docker-in-Docker with TLS enabled in Kubernetes:
- docker run my-docker-image /script/to/run/tests
```
#### Docker-in-Docker with TLS disabled
Sometimes you might have legitimate reasons to disable TLS.
For example, you have no control over the GitLab Runner configuration
that you are using.
Assuming that the runner's `config.toml` is similar to:
```toml
[[runners]]
url = "https://gitlab.com/"
token = TOKEN
executor = "docker"
[runners.docker]
tls_verify = false
image = "docker:19.03.12"
privileged = true
disable_cache = false
volumes = ["/cache"]
[runners.cache]
[runners.cache.s3]
[runners.cache.gcs]
```
You can now use `docker` in the job script. Note the inclusion of the
`docker:19.03.12-dind` service:
```yaml
image: docker:19.03.12
variables:
# When using dind service, you must instruct docker to talk with the
# daemon started inside of the service. The daemon is available with
# a network connection instead of the default /var/run/docker.sock socket.
#
# The 'docker' hostname is the alias of the service container as described at
# https://docs.gitlab.com/ee/ci/services/#accessing-the-services
#
# If you're using GitLab Runner 12.7 or earlier with the Kubernetes executor and Kubernetes 1.6 or earlier,
# the variable must be set to tcp://localhost:2375 because of how the
# Kubernetes executor connects services to the job container
# DOCKER_HOST: tcp://localhost:2375
#
DOCKER_HOST: tcp://docker:2375
#
# This instructs Docker not to start over TLS.
DOCKER_TLS_CERTDIR: ""
#### Limitations of Docker-in-Docker
services:
- docker:19.03.12-dind
Docker-in-Docker is the recommended configuration, but is
not without its own challenges:
before_script:
- docker info
- **The `docker-compose` command**: This command is not available in this configuration by default.
To use `docker-compose` in your job scripts, follow the `docker-compose`
[installation instructions](https://docs.docker.com/compose/install/).
- **Cache**: Each job runs in a new environment. Concurrent jobs work fine,
because every build gets its own instance of Docker engine and they don't conflict with each other.
However, jobs can be slower because there's no caching of layers.
- **Storage drivers**: By default, earlier versions of Docker use the `vfs` storage driver,
which copies the file system for each job. Docker 17.09 and later use `--storage-driver overlay2`, which is
the recommended storage driver. See [Using the OverlayFS driver](#use-the-overlayfs-driver) for details.
- **Root file system**: Because the `docker:19.03.12-dind` container and the runner container don't share their
root file system, you can use the job's working directory as a mount point for
child containers. For example, if you have files you want to share with a
child container, you might create a subdirectory under `/builds/$CI_PROJECT_PATH`
and use it as your mount point. For a more detailed explanation, view [issue
#41227](https://gitlab.com/gitlab-org/gitlab-foss/-/issues/41227).
build:
stage: build
```yaml
variables:
MOUNT_POINT: /builds/$CI_PROJECT_PATH/mnt
script:
- docker build -t my-docker-image .
- docker run my-docker-image /script/to/run/tests
```
- mkdir -p "$MOUNT_POINT"
- docker run -v "$MOUNT_POINT:/mnt" my-docker-image
```
### Use Docker socket binding
......@@ -359,87 +367,50 @@ If you bind the Docker socket and you are
you can no longer use `docker:19.03.12-dind` as a service. Volume bindings
are done to the services as well, making these incompatible.
To make Docker available in the context of the image:
1. Install [GitLab Runner](https://docs.gitlab.com/runner/install/).
1. From the command line, register a runner with the `docker` executor and share `/var/run/docker.sock`:
```shell
sudo gitlab-runner register -n \
--url https://gitlab.com/ \
--registration-token REGISTRATION_TOKEN \
--executor docker \
--description "My Docker Runner" \
--docker-image "docker:19.03.12" \
--docker-volumes /var/run/docker.sock:/var/run/docker.sock
```
This command registers a new runner to use the
`docker:19.03.12` image provided by Docker. The command uses
the Docker daemon of the runner itself. Any containers spawned by Docker
commands are siblings of the runner rather than children of the runner.
This may have complications and limitations that are unsuitable for your workflow.
Your `config.toml` file should now have an entry like this:
#### Use the Docker executor with Docker socket binding
```toml
[[runners]]
url = "https://gitlab.com/"
token = REGISTRATION_TOKEN
executor = "docker"
[runners.docker]
tls_verify = false
image = "docker:19.03.12"
privileged = false
disable_cache = false
volumes = ["/var/run/docker.sock:/var/run/docker.sock", "/cache"]
[runners.cache]
Insecure = false
```
1. Use `docker` in the job script. You don't need to
include the `docker:19.03.12-dind` service, like you do when you're using
the Docker-in-Docker executor:
```yaml
image: docker:19.03.12
before_script:
- docker info
To make Docker available in the context of the image, you will need to mount
`/var/run/docker.sock` into the launched containers. To do this with the Docker
executor, you need to add `"/var/run/docker.sock:/var/run/docker.sock"` to the
[Volumes in the `[runners.docker]` section](https://docs.gitlab.com/runner/configuration/advanced-configuration.html#volumes-in-the-runnersdocker-section).
build:
stage: build
script:
- docker build -t my-docker-image .
- docker run my-docker-image /script/to/run/tests
```
Your configuration should look something like this:
This method avoids using Docker in privileged mode. However,
the implications of this method are:
```toml
[[runners]]
url = "https://gitlab.com/"
token = RUNNER_TOKEN
executor = "docker"
[runners.docker]
tls_verify = false
image = "docker:19.03.12"
privileged = false
disable_cache = false
volumes = ["/var/run/docker.sock:/var/run/docker.sock", "/cache"]
[runners.cache]
Insecure = false
```
- By sharing the Docker daemon, you are effectively disabling all
the security mechanisms of containers and exposing your host to privilege
escalation, which can lead to container breakout. For example, if a project
ran `docker rm -f $(docker ps -a -q)` it would remove the GitLab Runner
containers.
- Concurrent jobs may not work; if your tests
create containers with specific names, they may conflict with each other.
- Sharing files and directories from the source repository into containers may not
work as expected. Volume mounting is done in the context of the host
machine, not the build container. For example:
You can also do this while registering your runner by providing the following options:
```shell
docker run --rm -t -i -v $(pwd)/src:/home/app/src test-image:latest run_app_tests
```
```shell
sudo gitlab-runner register -n \
--url https://gitlab.com/ \
--registration-token REGISTRATION_TOKEN \
--executor docker \
--description "My Docker Runner" \
--docker-image "docker:19.03.12" \
--docker-volumes /var/run/docker.sock:/var/run/docker.sock
```
#### Enable registry mirror for `docker:dind` service
##### Enable registry mirror for `docker:dind` service
When the Docker daemon starts inside of the service container, it uses
the default configuration. You may want to configure a [registry
mirror](https://docs.docker.com/registry/recipes/mirror/) for
performance improvements and to ensure you don't reach Docker Hub rate limits.
##### The service in the `.gitlab-ci.yml` file
###### The service in the `.gitlab-ci.yml` file
You can append extra CLI flags to the `dind` service to set the registry
mirror:
......@@ -450,7 +421,7 @@ services:
command: ["--registry-mirror", "https://registry-mirror.example.com"] # Specify the registry mirror to use
```
##### The service in the GitLab Runner configuration file
###### The service in the GitLab Runner configuration file
> [Introduced](https://gitlab.com/gitlab-org/gitlab-runner/-/issues/27173) in GitLab Runner 13.6.
......@@ -487,7 +458,7 @@ Kubernetes:
command = ["--registry-mirror", "https://registry-mirror.example.com"]
```
##### The Docker executor in the GitLab Runner configuration file
###### The Docker executor in the GitLab Runner configuration file
If you are a GitLab Runner administrator, you can use
the mirror for every `dind` service. Update the
......@@ -520,7 +491,7 @@ picked up by the `dind` service.
volumes = ["/opt/docker/daemon.json:/etc/docker/daemon.json:ro"]
```
##### The Kubernetes executor in the GitLab Runner configuration file
###### The Kubernetes executor in the GitLab Runner configuration file
> [Introduced](https://gitlab.com/gitlab-org/gitlab-runner/-/issues/3223) in GitLab Runner 13.6.
......@@ -569,6 +540,45 @@ The configuration is picked up by the `dind` service.
sub_path = "daemon.json"
```
##### Limitations of Docker socket binding
When you use Docker socket binding, you avoid running Docker in privileged mode. However,
the implications of this method are:
- By sharing the Docker daemon, you are effectively disabling all
the security mechanisms of containers and exposing your host to privilege
escalation, which can lead to container breakout. For example, if a project
ran `docker rm -f $(docker ps -a -q)` it would remove the GitLab Runner
containers.
- Concurrent jobs may not work; if your tests
create containers with specific names, they may conflict with each other.
- Any containers spawned by Docker commands are siblings of the runner rather
than children of the runner. This may have complications and limitations that
are unsuitable for your workflow.
- Sharing files and directories from the source repository into containers may not
work as expected. Volume mounting is done in the context of the host
machine, not the build container. For example:
```shell
docker run --rm -t -i -v $(pwd)/src:/home/app/src test-image:latest run_app_tests
```
You don't need to include the `docker:19.03.12-dind` service, like you do when
you're using the Docker-in-Docker executor:
```yaml
image: docker:19.03.12
before_script:
- docker info
build:
stage: build
script:
- docker build -t my-docker-image .
- docker run my-docker-image /script/to/run/tests
```
## Authenticate with registry in Docker-in-Docker
When you use Docker-in-Docker, the
......@@ -831,13 +841,13 @@ After you've built a Docker image, you can push it up to the built-in
### `docker: Cannot connect to the Docker daemon at tcp://docker:2375. Is the docker daemon running?`
This is a common error when you are using
[Docker-in-Docker](#use-the-docker-executor-with-the-docker-image-docker-in-docker)
[Docker-in-Docker](#use-docker-in-docker)
v19.03 or later.
This issue occurs because Docker starts on TLS automatically.
- If this is your first time setting it up, read
[use the Docker executor with the Docker image](#use-the-docker-executor-with-the-docker-image-docker-in-docker).
[use the Docker executor with the Docker image](#use-docker-in-docker).
- If you are upgrading from v18.09 or earlier, read our
[upgrade guide](https://about.gitlab.com/blog/2019/07/31/docker-in-docker-with-docker-19-dot-03/).
......
......@@ -13,7 +13,7 @@ type: howto
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-the-docker-executor-with-the-docker-image-docker-in-docker)
[Docker-in-Docker build](using_docker_build.md#use-docker-in-docker)
method:
- Docker-in-Docker requires [privileged mode](https://docs.docker.com/engine/reference/run/#runtime-privilege-and-linux-capabilities)
......
......@@ -299,7 +299,7 @@ is set to `always`.
To use your own Docker images for Docker-in-Docker, follow these steps
in addition to the steps in the
[Docker-in-Docker](../../../ci/docker/using_docker_build.md#use-the-docker-executor-with-the-docker-image-docker-in-docker) section:
[Docker-in-Docker](../../../ci/docker/using_docker_build.md#use-docker-in-docker) section:
1. Update the `image` and `service` to point to your registry.
1. Add a service [alias](../../../ci/services/index.md#available-settings-for-services).
......@@ -329,7 +329,7 @@ error during connect: Get http://docker:2376/v1.39/info: dial tcp: lookup docker
To use your own Docker images with Dependency Proxy, follow these steps
in addition to the steps in the
[Docker-in-Docker](../../../ci/docker/using_docker_build.md#use-the-docker-executor-with-the-docker-image-docker-in-docker) section:
[Docker-in-Docker](../../../ci/docker/using_docker_build.md#use-docker-in-docker) section:
1. Update the `image` and `service` to point to your registry.
1. Add a service [alias](../../../ci/services/index.md#available-settings-for-services).
......
......@@ -63,7 +63,7 @@ on your code by using GitLab CI/CD and [sitespeed.io](https://www.sitespeed.io)
using Docker-in-Docker.
1. First, set up GitLab Runner with a
[Docker-in-Docker build](../../../ci/docker/using_docker_build.md#use-the-docker-executor-with-the-docker-image-docker-in-docker).
[Docker-in-Docker build](../../../ci/docker/using_docker_build.md#use-docker-in-docker).
1. Configure the default Browser Performance Testing CI/CD job as follows in your `.gitlab-ci.yml` file:
```yaml
......
......@@ -67,7 +67,7 @@ the merge request's diff view displays an indicator next to lines with new Code
This example shows how to run Code Quality on your code by using GitLab CI/CD and Docker.
- Using shared runners, the job should be configured For the [Docker-in-Docker workflow](../../../ci/docker/using_docker_build.md#use-the-docker-executor-with-the-docker-image-docker-in-docker).
- Using shared runners, the job should be configured For the [Docker-in-Docker workflow](../../../ci/docker/using_docker_build.md#use-docker-in-docker).
- Using private runners, there is an [alternative configuration](#set-up-a-private-runner-for-code-quality-without-docker-in-docker) recommended for running Code Quality analysis more efficiently.
In either configuration, the runner must have enough disk space to handle generated Code Quality files. For example on the [GitLab project](https://gitlab.com/gitlab-org/gitlab) the files are approximately 7 GB.
......@@ -226,7 +226,7 @@ are configured with `privileged=true`, and they do not expose `docker.sock` into
the job container. As a result, socket binding cannot be used to make `docker` available
in the context of the job script.
[Docker-in-Docker](../../../ci/docker/using_docker_build.md#use-the-docker-executor-with-the-docker-image-docker-in-docker)
[Docker-in-Docker](../../../ci/docker/using_docker_build.md#use-docker-in-docker)
was chosen as an operational decision by the runner team, instead of exposing `docker.sock`.
### Disabling the code quality job
......
......@@ -103,7 +103,7 @@ job.
An example configuration workflow:
1. Set up GitLab Runner to run Docker containers, like the
[Docker-in-Docker workflow](../../../ci/docker/using_docker_build.md#use-the-docker-executor-with-the-docker-image-docker-in-docker).
[Docker-in-Docker workflow](../../../ci/docker/using_docker_build.md#use-docker-in-docker).
1. Configure the default Load Performance Testing CI/CD job in your `.gitlab-ci.yml` file.
You need to include the template and configure it with CI/CD variables:
......
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