1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
|
---
stage: Verify
group: Runner
info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/product/ux/technical-writing/#assignments
type: concepts, howto
---
# Run your CI/CD jobs in Docker containers **(FREE)**
You can run your CI/CD jobs in separate, isolated Docker containers.
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.
1. Specify which container to run the jobs in. Do this by specifying an image in your `.gitlab-ci.yml` file.
1. Optional. Run other services, like MySQL, in containers. Do this by specifying [services](../services/index.md)
in your `.gitlab-ci.yml` file.
## Register a runner that uses the Docker executor
To use GitLab Runner with Docker you need to [register a runner](https://docs.gitlab.com/runner/register/)
that uses the Docker executor.
This example shows how to set up a temporary template to supply services:
```shell
cat > /tmp/test-config.template.toml << EOF
[[runners]]
[runners.docker]
[[runners.docker.services]]
name = "postgres:latest"
[[runners.docker.services]]
name = "mysql:latest"
EOF
```
Then use this template to register the runner:
```shell
sudo gitlab-runner register \
--url "https://gitlab.example.com/" \
--registration-token "PROJECT_REGISTRATION_TOKEN" \
--description "docker-ruby:2.6" \
--executor "docker" \
--template-config /tmp/test-config.template.toml \
--docker-image ruby:2.6
```
The registered runner uses the `ruby:2.6` Docker image and runs two
services, `postgres:latest` and `mysql:latest`, both of which are
accessible during the build process.
## What is an image
The `image` keyword is the name of the Docker image the Docker executor
uses to run CI/CD jobs.
By default, the executor pulls images from [Docker Hub](https://hub.docker.com/).
However, you can configure the registry location in the `gitlab-runner/config.toml` file.
For example, you can set the [Docker pull policy](https://docs.gitlab.com/runner/executors/docker.html#how-pull-policies-work)
to use local images.
For more information about images and Docker Hub, see
the [Docker overview](https://docs.docker.com/get-started/overview/).
## Define `image` in the `.gitlab-ci.yml` file
You can define an image that's used for all jobs, and a list of
services that you want to use during runtime:
```yaml
default:
image: ruby:2.6
services:
- postgres:11.7
before_script:
- bundle install
test:
script:
- bundle exec rake spec
```
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 registry
other 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`:
```yaml
image: "registry.example.com/my/image:latest"
services:
- postgresql:14.3
- redis:latest
```
- A map for `image` and `services`. The `image:name` is
required:
```yaml
image:
name: "registry.example.com/my/image:latest"
services:
- name: postgresql:14.3
- name: redis:latest
```
## 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.
### Override the entrypoint of an image
> Introduced in GitLab and GitLab Runner 9.4. Read more about the [extended configuration options](../docker/using_docker_images.md#extended-docker-configuration-options).
Before explaining the available entrypoint override methods, let's describe
how the runner starts. It uses a Docker image for the containers used in the
CI/CD jobs:
1. The runner starts a Docker container using the defined entrypoint. The default
from `Dockerfile` that may be overridden in the `.gitlab-ci.yml` file.
1. The runner attaches itself to a running container.
1. The runner prepares a script (the combination of
[`before_script`](../yaml/index.md#before_script),
[`script`](../yaml/index.md#script),
and [`after_script`](../yaml/index.md#after_script)).
1. The runner sends the script to the container's shell `stdin` and receives the
output.
To override the entrypoint of a Docker image,
define an empty `entrypoint` in the `.gitlab-ci.yml` file, so the runner does not start
a 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.
The syntax of `image:entrypoint` is similar to [Dockerfile `ENTRYPOINT`](https://docs.docker.com/engine/reference/builder/#entrypoint).
Let's assume you have a `super/sql:experimental` image with a SQL database
in it. You want to use it as a base image for your job because you
want to execute some tests with this database binary. Let's also assume that
this image is configured with `/usr/bin/super-sql run` as an entrypoint. When
the container starts without additional options, it runs
the database's process. The runner expects that the image has no
entrypoint or that the entrypoint is prepared to start a shell command.
With the extended Docker configuration options, instead of:
- Creating your own image based on `super/sql:experimental`.
- Setting the `ENTRYPOINT` to a shell.
- Using the new image in your CI job.
You can now define an `entrypoint` in the `.gitlab-ci.yml` file.
**For Docker 17.06 and later:**
```yaml
image:
name: super/sql:experimental
entrypoint: [""]
```
**For Docker 17.03 and earlier:**
```yaml
image:
name: super/sql:experimental
entrypoint: ["/bin/sh", "-c"]
```
## Define image and services in `config.toml`
Look for the `[runners.docker]` section:
```toml
[runners.docker]
image = "ruby:latest"
services = ["mysql:latest", "postgres:latest"]
```
The image and services defined this way are added to all jobs run by
that runner.
## Access an image from a private Container Registry
To access private container registries, the GitLab Runner process can use:
- [Statically defined credentials](#use-statically-defined-credentials). That is, a username and password for a specific registry.
- [Credentials Store](#use-a-credentials-store). For more information, see [the relevant Docker documentation](https://docs.docker.com/engine/reference/commandline/login/#credentials-store).
- [Credential Helpers](#use-credential-helpers). For more information, see [the relevant Docker documentation](https://docs.docker.com/engine/reference/commandline/login/#credential-helpers).
To define which option should be used, the runner process reads the configuration in this order:
- A `DOCKER_AUTH_CONFIG` [CI/CD variable](../variables/index.md).
- A `DOCKER_AUTH_CONFIG` environment variable set in the runner's `config.toml` file.
- A `config.json` file in `$HOME/.docker` directory of the user running the process.
If the `--user` flag is provided to run the child processes as unprivileged user,
the home directory of the main runner process user is used.
### Requirements and limitations
- Available for [Kubernetes executor](https://docs.gitlab.com/runner/executors/kubernetes.html)
in GitLab Runner 13.1 and later.
- [Credentials Store](#use-a-credentials-store) and [Credential Helpers](#use-credential-helpers)
require binaries to be added to the GitLab Runner `$PATH`, and require access to do so. Therefore,
these features are not available on shared runners, or any other runner where the user does not
have access to the environment where the runner is installed.
### Use statically-defined credentials
There are two approaches that you can take to access a
private registry. Both require setting the CI/CD variable
`DOCKER_AUTH_CONFIG` with appropriate authentication information.
1. Per-job: To configure one job to access a private registry, add
`DOCKER_AUTH_CONFIG` as a [CI/CD variable](../variables/index.md).
1. Per-runner: To configure a runner so all its jobs can access a
private registry, add `DOCKER_AUTH_CONFIG` as an environment variable in the
runner'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:latest`
image. This image is private and requires you to sign in to a private container
registry.
Let's also assume that these are the sign-in credentials:
| Key | Value |
|:---------|:----------------------------|
| registry | `registry.example.com:5000` |
| username | `my_username` |
| password | `my_password` |
Use one of the following methods to determine the value for `DOCKER_AUTH_CONFIG`:
- Do a `docker login` on your local machine:
```shell
docker login registry.example.com:5000 --username my_username --password my_password
```
Then copy the content of `~/.docker/config.json`.
If you don't need access to the registry from your computer, you
can do a `docker logout`:
```shell
docker logout registry.example.com:5000
```
- In some setups, it's possible the Docker client uses the available system key
store to store the result of `docker login`. In that case, it's impossible to
read `~/.docker/config.json`, so you must prepare the required
base64-encoded version of `${username}:${password}` and create the Docker
configuration JSON manually. Open a terminal and execute the following command:
```shell
# The use of printf (as opposed to echo) prevents encoding a newline in the password.
printf "my_username:my_password" | openssl base64 -A
# Example output to copy
bXlfdXNlcm5hbWU6bXlfcGFzc3dvcmQ=
```
Create the Docker JSON configuration content as follows:
```json
{
"auths": {
"registry.example.com:5000": {
"auth": "(Base64 content from above)"
}
}
}
```
#### Configure a job
To configure a single job with access for `registry.example.com:5000`,
follow these steps:
1. Create a [CI/CD variable](../variables/index.md) `DOCKER_AUTH_CONFIG` with the content of the
Docker configuration file as the value:
```json
{
"auths": {
"registry.example.com:5000": {
"auth": "bXlfdXNlcm5hbWU6bXlfcGFzc3dvcmQ="
}
}
}
```
1. You can now use any private image from `registry.example.com:5000` defined in
`image` or `services` in your `.gitlab-ci.yml` file:
```yaml
image: registry.example.com:5000/namespace/image:tag
```
In the example above, GitLab Runner looks at `registry.example.com:5000` for the
image `namespace/image:tag`.
You can add configuration for as many registries as you want, adding more
registries to the `"auths"` hash as described above.
The full `hostname:port` combination is required everywhere
for the runner to match the `DOCKER_AUTH_CONFIG`. For example, if
`registry.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 should
set up registry access at the runner level. This
allows pipeline authors to have access to a private registry just by
running a job on the appropriate runner. It also helps simplify registry
changes and credential rotations.
This means that any job on that runner can access the
registry with the same privilege, even across projects. If you need to
control access to the registry, you need to be sure to control
access to the runner.
To add `DOCKER_AUTH_CONFIG` to a runner:
1. Modify the runner's `config.toml` file as follows:
```toml
[[runners]]
environment = ["DOCKER_AUTH_CONFIG={\"auths\":{\"registry.example.com:5000\":{\"auth\":\"bXlfdXNlcm5hbWU6bXlfcGFzc3dvcmQ=\"}}}"]
```
- The double quotes included in the `DOCKER_AUTH_CONFIG`
data must be escaped with backslashes. This prevents them from being
interpreted as TOML.
- The `environment` option is a list. Your runner may
have existing entries and you should add this to the list, not replace
it.
1. Restart the runner service.
### Use a Credentials Store
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 `$PATH`.
1. Make GitLab Runner use it. There are two ways to accomplish this. Either:
- Create a
[CI/CD variable](../variables/index.md)
`DOCKER_AUTH_CONFIG` with the content of the
Docker configuration file as the value:
```json
{
"credsStore": "osxkeychain"
}
```
- Or, if you're running self-managed runners, add the above JSON to
`${GITLAB_RUNNER_HOME}/.docker/config.json`. GitLab Runner reads this configuration file
and 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:latest`
image. This image is private and requires you to sign in to 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`](https://github.com/awslabs/amazon-ecr-credential-helper) is available in the GitLab Runner `$PATH`.
1. Have any of the following [AWS credentials setup](https://github.com/awslabs/amazon-ecr-credential-helper#aws-credentials).
Make sure that GitLab Runner can access the credentials.
1. Make GitLab Runner use it. There are two ways to accomplish this. Either:
- Create a [CI/CD variable](../variables/index.md)
`DOCKER_AUTH_CONFIG` with the content of the
Docker configuration file as the value:
```json
{
"credHelpers": {
"<aws_account_id>.dkr.ecr.<region>.amazonaws.com": "ecr-login"
}
}
```
This configures Docker to use the Credential Helper for a specific registry.
Instead, you can configure Docker to use the Credential Helper for all Amazon Elastic Container Registry (ECR) registries:
```json
{
"credsStore": "ecr-login"
}
```
- Or, if you're running self-managed runners,
add the previous JSON to `${GITLAB_RUNNER_HOME}/.docker/config.json`.
GitLab Runner reads this configuration file and uses the needed helper for this
specific repository.
1. You can now use any private image from `<aws_account_id>.dkr.ecr.<region>.amazonaws.com` defined in
`image` and/or `services` in your `.gitlab-ci.yml` file:
```yaml
image: <aws_account_id>.dkr.ecr.<region>.amazonaws.com/private/image:latest
```
In the example, GitLab Runner looks at `<aws_account_id>.dkr.ecr.<region>.amazonaws.com` for the
image `private/image:latest`.
You can add configuration for as many registries as you want, adding more
registries to the `"credHelpers"` hash.
### Use checksum to keep your image secure
We recommend using the image checksum in your job definition in your `.gitlab-ci.yml` file to verify the integrity of the image. A failed image integrity verification prevents you from using a modified container.
To use the image checksum you have to append the checksum at the end:
```yaml
image: ruby:2.6.8@sha256:d1dbaf9665fe8b2175198e49438092fdbcf4d8934200942b94425301b17853c7
```
To get the image checksum, on the image `TAG` tab, view the `DIGEST` column.
For example, view the [Ruby image](https://hub.docker.com/_/ruby?tab=tags).
The checksum is a random string, like `6155f0235e95`.
You can also get the checksum of any image on your system with the command `docker images --digests`:
```shell
❯ docker images --digests
REPOSITORY TAG DIGEST (...)
gitlab/gitlab-ee latest sha256:723aa6edd8f122d50cae490b1743a616d54d4a910db892314d68470cc39dfb24 (...)
gitlab/gitlab-runner latest sha256:4a18a80f5be5df44cb7575f6b89d1fdda343297c6fd666c015c0e778b276e726 (...)
```
|