GCE Provision Backend Service

The GCE Provision Backend Service step creates or updates a backend service in Google Cloud. This is a utility step that can be used to provision any backend service within GCP, not limited to MIG deployments.

Prerequisites

This step must be added within a Container Step Group. The step runs as a containerized task and requires the container infrastructure configuration provided by the step group.
A Download Harness Store or Git Clone step must be added before this step to fetch the backend service configuration file from the Harness File Store or a Git repository.

Deployment flow

Download Harness Store: Fetches the backend service configuration JSON file from the Harness File Store and makes it available for the next step. When configuring this step, specify the Download Directory Path (e.g., /harness) where the file will be downloaded.

GCE Provision Backend Service: Reads the configuration file and creates or updates the backend service in the specified GCP project and region. The Config File Path in this step must match the download directory from the previous step (e.g., /harness/backendservice.json).

What this step does

Creates a new backend service in GCP if it doesn't exist
Updates an existing backend service if it already exists
Configures load balancing, health checks, and backend groups based on the configuration file

Step parameters

Parameter	Description	Required
GCP Connector	Harness connector for authenticating to GCP. This connector provides access to create and manage backend services.	Yes
Project	The GCP project ID where the backend service will be created (e.g., `my-project`).	Yes
Region	The GCP region for the backend service (e.g., `us-central1`).	Yes
Backend Service	The name of the backend service to create or update (e.g., `prod-backend-service`).	Yes
Config File Path	Path to the backend service configuration JSON file. This path must match the Download Directory Path configured in the Download Harness Store step, combined with the filename (e.g., if download directory is `/harness` and filename is `backendservice.json`, use `/harness/backendservice.json`).	Yes
Timeout	Maximum time allowed for the step to complete (default: `10m`).	No

Container configuration

Parameter	Description
Container Registry	Harness connector for authenticating to your container registry. This connector pulls the deployment plugin image.
Image	The deployment plugin container image. Use the official Harness image: `harness/gce-provision-backend-service:0.0.1-linux-amd64`

Backend service configuration file

The configuration file defines the backend service properties in JSON format. Store this file in the Harness File Store and reference it using the Download Harness Store step.

{
  "name": "my-backend-service",
  "loadBalancingScheme": "INTERNAL_SELF_MANAGED",
  "protocol": "HTTP",
  "portName": "http",
  "sessionAffinity": "NONE",
  "timeoutSec": 30,
  "connectionDraining": {
    "drainingTimeoutSec": 300
  },
  "healthChecks": [
    "projects/PROJECT_ID/global/healthChecks/HEALTH_CHECK_NAME"
  ],
  "backends": [
    {
      "group": "projects/PROJECT_ID/zones/ZONE/instanceGroups/MIG_NAME",
      "balancingMode": "UTILIZATION",
      "maxUtilization": 0.8,
      "capacityScaler": 1.0
    }
  ]
}

Using expressions for dynamic values

You can use Harness expressions in the configuration file to dynamically reference values from other pipeline steps. This is useful when the MIG name or other values are generated during pipeline execution.

For example, to reference a MIG name from a previous deployment step, use an expression like:

<+pipeline.stages.STAGE_ID.spec.execution.steps.STEP_GROUP_ID.steps.DEPLOY_STEP_ID.output.outputVariables.MIG_NAME>

The exact expression path depends on your pipeline structure—replace STAGE_ID, STEP_GROUP_ID, and DEPLOY_STEP_ID with the actual identifiers from your pipeline configuration.

For more information on using expressions, see Use Harness expressions.

Pipeline YAML

- stepGroup:
    name: MIG
    identifier: MIG
    steps:
      - step:
          type: DownloadHarnessStore
          name: DownloadHarnessStore
          identifier: DownloadHarnessStore
          spec:
            files:
              - /mig_config/backendservice.json
      - step:
          type: GCEProvisionBackendService
          name: GCEProvisionBackendService
          identifier: GCEProvisionBackendService
          spec:
            project: PROJECT_ID
            backendService: my-backend-service
            gcpConnectorRef: GCP_CONNECTOR_ID
            configFilePath: /harness/backendservice.json
            connectorRef: account.harnessImage
            image: harness/gce-provision-backend-service:0.0.1-linux-amd64
            region: us-central1
          timeout: 10m
    stepGroupInfra:
      type: KubernetesDirect
      spec:
        connectorRef: K8S_CONNECTOR_ID

Deployment flow​

What this step does​

Step parameters​

Container configuration​

Backend service configuration file​

Using expressions for dynamic values​

Pipeline YAML​