[GHA] [DOCS] Docker images document

docs/dev/ci/github_actions/docker_images.md

@@ -1,5 +1,78 @@
 # Overview of the Docker Images used in the OpenVINO GitHub Actions CI
 
+Most of the workflows in the OpenVINO GHA CI are using [self-hosted machines with dynamically spawned runners](./runners.md) to execute jobs. 
+
+To avoid corruption of the runners and machines, the workflows utilize various Docker images that introduce a layer of protection for the self-hosted machines.
+
+The Docker images are specified for each job using the `container` key. See the [GHA documentation](https://docs.github.com/en/actions/using-jobs/running-jobs-in-a-container) for the syntax reference.
+
+An example `Build` job from the `linux.yml` workflow:
+```yaml
+Build:
+  ...
+  container:
+    image: openvinogithubactions.azurecr.io/dockerhub/ubuntu:20.04
+    volumes:
+      - /mount:/mount
+  ...
+```
+
+The `openvinogithubactions.azurecr.io/dockerhub/ubuntu:20.04` Docker image is used for this job.
+
+Additionally, it is possible to make the caches available in the Docker containers using the `volumes` key. 
+Read more about the available caches and how to choose one [here](./caches.md).
+
 ## Available Docker Images
 
+The jobs in the workflows utilize appropriate Docker images based on a job's needs. 
+
+As the self-hosted machines are hosted in [Microsoft Azure](https://azure.microsoft.com/en-us), 
+it is optimal to use the Docker images hosted in an instance of [Azure Container Registry (ACR)](https://azure.microsoft.com/en-us/products/container-registry).
+
+The ACR used for the OpenVINO GHA CI is `openvinogithubactions.azurecr.io`.
+
+Some pros and cons of having own container registry are:
+* pros:
+  * No pull limits for the images
+    * There are [limits](https://docs.docker.com/docker-hub/download-rate-limit/) for the pulls from Docker Hub
+  * Fast pulling speeds
+* cons:
+  * The registry should be populated with needed images before usage
+    * The registry does not mirror the images available on Docker Hub automatically
+    * The needed images should be added manually to the registry
+
+As the number of enable workflows grew, so did the number of available Docker images.
+
+The available Docker images are using the following pattern for their names: `openvinogithubactions.azurecr.io/dockerhub/<image-name>:<image-tag>`.
+
+Most of the images on the OpenVINO ACR are mirrors of the images with the same names on Docker Hub.
+
+The examples:
+* `openvinogithubactions.azurecr.io/dockerhub/ubuntu:20.04` corresponds to `ubuntu:20.04` from Docker Hub
+* `openvinogithubactions.azurecr.io/dockerhub/ubuntu:22.04` corresponds to `ubuntu:22.04` from Docker Hub
+* `openvinogithubactions.azurecr.io/dockerhub/nvidia/cuda:11.8.0-runtime-ubuntu20.04` corresponds to `nvidia/cuda:11.8.0-runtime-ubuntu20.04` from Docker Hub
+
 ## How to choose an Image
+
+The Docker image required for a job stems from the nature of the job and configuration that is being tested.
+
+An example `Build` job from the `linux.yml` workflow:
+```yaml
+Build:
+  ...
+  container:
+    image: openvinogithubactions.azurecr.io/dockerhub/ubuntu:20.04
+    volumes:
+      - /mount:/mount
+  ...
+```
+
+The `openvinogithubactions.azurecr.io/dockerhub/ubuntu:20.04` Docker image is used for this job and **for other jobs in the workflow**.
+Usually, if one Docker image is used for the building job, the other jobs would use the same image for testing. 
+
+If the tests do not require any specific OS or distribution, it would be best to use the already available images: e.g., `openvinogithubactions.azurecr.io/dockerhub/ubuntu:20.04`.
+
+If the plan is to test some specific OS or distribution (e.g., `fedora`), 
+the Docker image for this flavour should be first uploaded to the OpenVINO ACR and only then used in a workflow. 
+
+Contact someone from the CI team for assistance with the image uploading.