Scale Cloud Run worker pools with Workflows

Preview — Cloud Run worker pools

This feature is subject to the "Pre-GA Offerings Terms" in the General Service Terms section of the Service Specific Terms. Pre-GA features are available "as is" and might have limited support. For more information, see the launch stage descriptions.

After you've created a Cloud Run worker pool, you can use Workflows to automate its scaling. This lets you adjust the instance count based on external events, custom logic, or schedules.

Before you begin

The following list describes the requirements when using Workflows to deploy and execute a Cloud Run worker pools workflow:

Sign in to your Google Cloud account. If you're new to Google Cloud, create an account to evaluate how our products perform in real-world scenarios. New customers also get $300 in free credits to run, test, and deploy workloads.

In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

Roles required to select or create a project

• Select a project: Selecting a project doesn't require a specific IAM role—you can select any project that you've been granted a role on.
• Create a project: To create a project, you need the Project Creator role (roles/resourcemanager.projectCreator), which contains the resourcemanager.projects.create permission. Learn how to grant roles.

Note: If you don't plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.

Go to project selector

Verify that billing is enabled for your Google Cloud project.

In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

Roles required to select or create a project

• Select a project: Selecting a project doesn't require a specific IAM role—you can select any project that you've been granted a role on.
• Create a project: To create a project, you need the Project Creator role (roles/resourcemanager.projectCreator), which contains the resourcemanager.projects.create permission. Learn how to grant roles.

Note: If you don't plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.

Go to project selector

Verify that billing is enabled for your Google Cloud project.

1. Enable the Cloud Run Admin API and Workflows APIs.

   Roles required to enable APIs

   To enable APIs, you need the Service Usage Admin IAM role (roles/serviceusage.serviceUsageAdmin), which contains the serviceusage.services.enable permission. Learn how to grant roles.

   Enable the APIs

Required roles

To get the permissions that you need to deploy and execute Cloud Run worker pools with Workflows, ask your administrator to grant you the following IAM roles:

• Cloud Run Admin (roles/run.admin) on the Cloud Run worker pool
• Workflows Editor (roles/workflows.editor) on the project
• Service Account User (roles/iam.serviceAccountUser) on the service identity

To allow Workflows to update the Cloud Run worker pool, the service account that is used to deploy your workflow must have the following role:

• Cloud Run Admin (roles/run.admin)

For a list of IAM roles and permissions that are associated with Cloud Run, see Cloud Run IAM roles and Cloud Run IAM permissions. If your Cloud Run worker pool interfaces with Google Cloud APIs, such as Cloud Client Libraries, see the service identity configuration guide. For more information about granting roles, see deployment permissions and manage access.

Create a Cloud Run worker pool

Create a Cloud Run worker pool if you haven't done so already. You will reference the name of the Cloud Run worker pool when executing your workflow later on.

Create, deploy, and execute the workflow

The following workflow updates the instance count of your Cloud Run worker pool.

1. In your home directory, create a new YAML file for your workflow, such as update-cr-worker-pool.yaml, and copy and paste the following content into your file:

   main:
     params: [args]
     steps:
       - init:
           assign:
             - project: ${sys.get_env("GOOGLE_CLOUD_PROJECT_ID")}
             - region: ${args.region}
             - workerPoolName: ${args.workerPool}
             - instanceCount: ${args.instanceCount}
             - workerPoolUrl: ${"https://run.googleapis.com/v2/projects/" + project + "/locations/" + region + "/workerPools/" + workerPoolName}
       - updateWorkerPool:
           call: http.patch
           args:
             url: ${workerPoolUrl}
             query:
               updateMask: "scaling.manualInstanceCount"
             auth:
               type: OAuth2
             body:
               scaling:
                 manualInstanceCount: ${int(instanceCount)}
           result: updateResult
       - returnOutput:
           return: ${updateResult.body}
   

2. Deploy the workflow and associate it with a specified service account:

   gcloud workflows deploy WORKFLOW_NAME \
       --source=WORKFLOW_NAME.yaml \
       --location=REGION \
       --service-account=SERVICE_ACCOUNT

   Replace the following:

   • WORKFLOW_NAME: the name of your workflow, such as update-worker-pool. The workflow name should match the name of the YAML file you created earlier.
   • REGION: the region your Cloud Run worker pool is deployed in, for example europe-west1.
   • SERVICE_ACCOUNT: the service account email that has been granted the required roles, for example:
     • SERVICE_ACCOUNT_NAME@PROJECT_ID.iam.gserviceaccount.com
     • [e-mail]

3. Execute the workflow with the details of your worker pool and the instance count:

   gcloud workflows execute WORKFLOW_NAME \
       --location=REGION \
       --data='{"region":"REGION", "workerPool":"WORKER_POOL_NAME", "instanceCount":INSTANCE_COUNT}'

   Replace the following:

   • WORKFLOW_NAME: the name of your workflow.
   • REGION: the region your Cloud Run worker pool is deployed in, for example europe-west1.
   • WORKER_POOL_NAME: the name of your worker pool.
   • INSTANCE_COUNT: the modified number of instances for the worker pool, for example 3.

Verify the updates

After you've executed the workflow, you can view the updates in the following places in the Google Cloud console:

• To view the execution status and results, go to the Workflows details page and select your workflow:

  Go to Workflows

  Verify that the manualInstanceCount field has changed in the most recent execution of the workflow.

• To verify the update was successful in Cloud Run, go to the worker pools page:

  Go to Cloud Run

  Verify that the manual scaling count for your worker pool has changed.