Added README

README.md

+# GitLab CI Openstack executor
+
+GitLab CI doesn't support Openstack as an executor but provides the ability to implement your own
+executor by using scripts to provision, run, and clean up CI environment. This repository contains
+such scripts as well as a Containerfile to build and configure a container image with Gitlab Runner
+that uses custom Openstack executor.
+
+## Building
+
+```sh
+git clone https://github.com/RedHatQE/openstack-gitlab-executor.git
+cd openstack-gitlab-executor
+podman build --build-arg GITLAB_RUNNER_VERSION=<version> -f Containerfile -t openstack-gitlab-runner
+```
+
+## Configuration
+
+The container expects the following environment variables:
+
+### Instance variables
+
+`FLAVOR` - Instance flavor reference
+
+`BUILDER_IMAGE` - Image to use for instance provisioning
+
+`NETWORK` - Network name
+
+`KEY_PAIR_NAME` - SSH key pair name
+
+`SECURITY_GROUP` - Security group
+
+`USERNAME` - Username for SSH connection to instances
+
+`PRIVATE_KEY_PATH` - Path to private key of the `KEY_PAIR_NAME` inside the container.
+
+### GitLab Runner variables
+
+`RUNNER_TAG_LIST` - Tag list
+
+`REGISTRATION_TOKEN` - Runner's registration token
+
+`RUNNER_NAME` - Runner name
+
+`CI_SERVER_URL` - Runner URL
+
+### [Openstack variables](https://docs.openstack.org/python-openstackclient/latest/cli/man/openstack.html#environment-variables)
+
+`OS_AUTH_URL` - Openstack authentication URL
+
+`OS_PROJECT_NAME` - Project-level authentication scope (name or ID)
+
+`OS_USERNAME` - Authentication username
+
+`OS_PASSWORD` - Authentication password
+
+`OS_PROJECT_DOMAIN_NAME` - Domain name or ID containing project
+
+`OS_USER_DOMAIN_NAME` - Domain name or ID containing user
+
+`OS_REGION_NAME` - Authentication region name
+
+`OS_IDENTITY_API_VERSION` - Identity API version
+
+`OS_INTERFACE` - Interface type
+
+## Usage
+
+Create an env file with all variables:
+
+```text
+RUNNER_TAG_LIST=<your value>
+REGISTRATION_TOKEN=<your value>
+RUNNER_NAME=<your value>
+CI_SERVER_URL=<your value>
+
+FLAVOR=<your value>
+BUILDER_IMAGE=<your value>
+NETWORK=<your value>
+KEY_PAIR_NAME=<your value>
+SECURITY_GROUP=<your value>
+USERNAME=<your value>
+PRIVATE_KEY_PATH=/mnt/private_key/<private key>
+
+OS_AUTH_URL=<your value>
+OS_PROJECT_NAME=<your value>
+OS_USERNAME=<your value>
+OS_PASSWORD=<your value>
+OS_PROJECT_DOMAIN_NAME=<your value>
+OS_USER_DOMAIN_NAME=<your value>
+OS_REGION_NAME=<your value>
+OS_IDENTITY_API_VERSION=<your value>
+OS_INTERFACE=<your value>
+```
+
+Run a container:
+
+```sh
+podman run -it \
+           --env-file=env \
+           -v <dir with private key>:/mnt/private_key/ \
+           localhost/openstack-gitlab-runner
+```