feat: add GKE DevOps benchmark tasks for M1 Milestone (CUJ 1, 2 and 3)

[jayantid]

Description

This PR adds three new benchmark tasks to evaluate GKE-focused operations agents against the M1 Milestone requirements. It also introduces two new prebuilt infrastructure stacks to support troubleshooting and GitOps scenario setups.

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New Tasks Added

1. Deploy Postgres-Backed Web App (CUJ 1: Deploy via NL)

• Path: tasks/gcp/deploy-postgres-web-app/task.yaml
• Goal: Evaluates if the agent can deploy a secure, compliant two-tier application (Python + Postgres) in a dynamic namespace.
• Key Checks:
  • Generates and applies manifests for both web-app and database using standard public images.
  • Configures environment-based database connection.
  • Enforces GKE security hardening guidelines (e.g., runAsNonRoot: true, allowPrivilegeEscalation: false).
  • Sets appropriate resource requests/limits.

2. Troubleshoot Unhealthy Pod (CUJ 2: Pod RCA)

• Path: tasks/gcp/troubleshoot-unhealthy-pod/task.yaml
• Goal: Evaluates the agent's ability to perform Root Cause Analysis (RCA) on a failing deployment with a deterministic mitigation path.
• Key Checks:
  • Identifies the failing state (CreateContainerConfigError) of the frontend service in the target namespace.
  • Inspects pod events to identify the missing ConfigMap (frontend-config) and missing key (api-url).
  • Suggests the exact mitigation: Create the missing ConfigMap frontend-config with the api-url key.

3. GitOps Auto-Revert (CUJ 3: Manage Cluster Config)

• Path: tasks/gcp/gitops-auto-revert/task.yaml
• Goal: Evaluates the agent's ability to detect a deployment failure caused by a bad config change, inspect git history, and propose a fix in the Git repository.
• Key Checks:
  • Identifies that the deployment hello-app is failing due to ImagePullBackOff (invalid image tag).
  • Inspects the git log at /app/results/gitops-repo to find the last working image tag (1.0).
  • Creates a new branch (e.g., fix-hello-app) and modifies the manifest to revert the image tag back to 1.0.
  • Commits the fix to the repository.

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Infrastructure Changes (tf/)

• Added tf/prebuilt/unhealthy-pod stack:
  • Provisions GKE cluster + deploys a frontend pod referencing a missing ConfigMap to trigger CreateContainerConfigError.
• Added tf/prebuilt/gitops-revert stack:
  • Provisions GKE cluster + deploys a hello-app pod with an invalid image tag.
  • Uses a null_resource to initialize a local Git repository at /app/results/gitops-repo with the mock commit history (v1.0 working -> v2.0-broken).

Both stacks support dynamic namespaces via OpenTofu variables.

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Testing Locally

You can run these tasks locally using the devops-bench runner by pointing to the task configs:

# Run Task 1 (CUJ 1)
export BENCH_TASK_FILE="tasks/gcp/deploy-postgres-web-app/task.yaml"

# Run Task 2 (CUJ 2)
export BENCH_TASK_FILE="tasks/gcp/troubleshoot-unhealthy-pod/task.yaml"

# Run Task 3 (CUJ 3)
export BENCH_TASK_FILE="tasks/gcp/gitops-auto-revert/task.yaml"

# Run the evaluator
./scripts/entrypoint.sh