.github/gh-actions-self-hosted-runners/arc/README.md

<!--
    Licensed to the Apache Software Foundation (ASF) under one
    or more contributor license agreements.  See the NOTICE file
    distributed with this work for additional information
    regarding copyright ownership.  The ASF licenses this file
    to you under the Apache License, Version 2.0 (the
    "License"); you may not use this file except in compliance
    with the License.  You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
-->

# Actions Runner Controller

# About
Check out the docs at https://github.com/actions/actions-runner-controller/blob/master/docs/about-arc.md

# Installing
1. Create a bucket for terraform state, making sure you disable public access and allow your account to access it. (or reuse existing that is noted in the environment file)

2. Create a Github App in your account and install it in the repo you want to provide runners for.
All is explained in : https://github.com/actions/actions-runner-controller/blob/master/docs/authenticating-to-the-github-api.md

3. In your Google Cloud Project create the secrets for
- Github App ID
- Github App Installation ID
- Github App PEM key
All are created in the step before

4. Create a file called `environment_name.env` in the folder `environments` with the following contents:
```
project_id = "PROJECT_ID"                                     # google PROJECT_ID that you want to deploy in
region = "gcp_region"                                         # GCP region for the network
zone = "europe-west3-c"                                       # GCP zone for the nodes
main_runner = {
    name = "main-runner"                                      # Main runner pool name
    machine_type = "e2-standard-16"                           # Main runner pool machine type
    min_node_count = "1"                                      # Main runner pool minimal node count
    max_node_count = "5"                                      # Main runner pool maximal node count
    min_replicas = "5"                                        # Min number of runner PODs in the main pool . Do not confuse with Nodes
    max_replicas = "20"                                       # Max number of runner PODs in the main pool . Do not confuse with Nodes
    webhook_scaling = true                                    # Enable webhook scaling for main pool
}
environment = "environment_name"                              # Name of the environment. Used as a prefix like dev- stag- anything-
ingress_domain = "fqdn"                                       # FQDN for webhook ingress
organization = "org"                                          # Github Organization to use runners in
repository = "repo"                                           # Repository to use runners in
github_app_id_secret_name = "app_id_secret_name"              # Google secret name for app id
github_app_install_id_secret_name = "install_id_secret_name"  # Google secret name for install_id
github_private_key_secret_name = "pem_file_secret_name"       # Google secret name for pem file
deploy_webhook = "false"                                      # Terraform to deploy the scaling webhook
#state_bucket_name = "state_bucket_name"                      # Not used by terraform. This is just to reference what bucket is used for others
```
If you want to create additonal pools you can use the `additional_runner_pools` which is a list of objects. Example:
```
additional_runner_pools = [
{
name = "test-runner"                      # Pool name
machine_type = "e2-standard-2"            # Macihne type for the pool
min_node_count = 1                        # Minimal node count
max_node_count = 2                        # Maximal node count
min_replicas = 1                          # Minimal replica count
max_replicas = 2                          # Maximal replica count
webhook_scaling = true                    # Enable webhook based scaling
runner_image = "gcr.io/someimage:sometag" # Image to use
labels = ["self-hosted", "testrunner"]    # Label set for runner pool. Used in `on`
enable_selector = "true"                  # Enables NodeSelector, forcing runners to this pool
enable_taint = "true"                     # Enables Taints. Prevents other runner pods to run in this pool.
requests = {                              # K8s cpu and memory requests
  cpu = "500m"                            #
  memory = "500mi"}                       #
limits = {                                # K8s cpu and memory limits
    cpu = "2"                             #
    memory = "2Gi"}}]                     #

```



5. Make sure you set the bucket name in the comment in the environment file for documentation purposes

6.  From this directory, login to your gcloud account that you created the bucket with and  init terraform with:
```
gcloud auth login
gcloud auth application-default login
terraform init -backend-config="bucket=bucket_name"
```
7. Terraform apply
```
terraform apply -var-file=environments/environment_name.env
```

# Updating
If you need to update the configuration (e.g. upgrading the github runner image, changing resource settings, etc), follow the steps below:

1. From this directory, login to your gcloud account that you created the bucket with and init terraform. Replace bucket_name with the bucket for storing terraform state, e.g. `beam-arc-state`.
```
gcloud auth login
gcloud auth application-default login
terraform init -backend-config="bucket=bucket_name"
```

2. Terraform plan. Replace environment_name.env with the file under environments, e.g. `beam.env`. Fix config problems if any.
```
terraform plan -var-file=environments/environment_name.env
```

3. Terraform apply. Replace environment_name.env with the file under environments, e.g. `beam.env`.
```
terraform apply -var-file=environments/environment_name.env
```

# Maintanance

- To access the ARC k8s cluster call the `get_kubeconfig_command` terraform output and run the command