How to put multiple images in image keyword in gitlab-ci - gitlab

Question

I have two jobs build_binary and build deb and I want to combine both of them. But the issue is they both use different images. Former one uses golang:latest and later one uses ubuntu:20.04 as shown:
gitlab-ci.yml
build_binary:
stage: build
image: golang:latest
rules:
- if: '$CI_COMMIT_TAG'
# tags:
# - docker-executor
artifacts:
untracked: true
script:
- echo "Some script"
build deb:
stage: deb-build
rules:
- if: '$CI_COMMIT_TAG'
# tags:
# - docker-executor
image: ubuntu:20.04
dependencies:
- build_binary
script:
- echo "Some script 2"
artifacts:
untracked: true
I have tried in these two ways but it didn't work.
build_binary:
stage: build
image: golang:latest ubuntu:20.04
and
build_binary:
stage: build
image: [golang:latest,ubuntu:20.04]
Any pointers would be very helpful.

Answer 1

It's not about gitlab-ci - for first hand you should understand what is images, what containers (docker) are in it's nature.
You cannot magically get mixed image that will be magically ubuntu:20.04+golang:latest. It's just impossible to make it from gitlab-ci file.
But you can create your own IMAGE.
You can take Dockerfile for ubuntu:20.04, at dockerhub https://hub.docker.com/_/ubuntu
Then you can add commands to it to install golang inside this operation system `
After this you open golang:latest Dockerfile and copy it's installation process to ubuntu Dockerfile with required modifications.
Then you do docker build -t my-super-ubuntu-and-golang - see manual
Then you check it - docker run and check that it's normal ubuntu with golang
If all success you can push it to your own account to dockerhub and in gitlab-ci:
image: your-name/golang-ubuntu-20.04
...
Suggestion to use services is very incorrect - service starts another image and connect it by network, so you can run postgres, rabbit and another services and use it in your tests for example:
image: alpine
services : [ rabbitmq ]
not mean that rabbitmq will be started on alpine - both will started - image of alpine and image of rabbitmq with local HOST name rabbitmq, and your alpine could connect to tcp://rabbitmq:5672 and use it. It's another approach.
P.S.
For example you can look at https://hub.docker.com/r/partlab/ubuntu-golang
I think it's not image you really want but you can see how to make mixed ubuntu-golang image

Answer 2

Using the image and services keywords in your.gitlab-ci.yml file, you may define a GitLab CI/CD job that uses multiple Docker images.
For example, you could use the following configuration to specify a job that uses both a Golang image and an Ubuntu image:
build:
image: golang:latest
services:
- ubuntu:20.04
before_script:
- run some command using Ubuntu
script:
- go build
- run some other command using Ubuntu