GKE/GitOps Implementation Plan

Executive Summary & ROI

Strategic Plan

This document outlines a strategic plan to implement a robust, secure, and SOC2-compliant CI/CD pipeline on our existing Google Kubernetes Engine (GKE) infrastructure. This initiative transitions our software delivery model to GitOps, leveraging GitLab CI for Continuous Integration and ArgoCD for Continuous Deployment.

The core of this proposal is to establish Git as the single source of truth for all applications (Laravel, React, Java) and infrastructure. This implementation will be executed across our three environments (dev, staging, prod) using a high-isolation model of dedicated ArgoCD instances per environment.

Total Estimated Effort

244

- 304 Hours

Business Benefits & Return on Investment (ROI)

By adopting a GitOps model, we directly address challenges like configuration drift and auditability. The projected ROI is realized through measurable improvements in core DORA metrics.

Business Benefit	Metric (DORA)	Estimated Impact
Increased Velocity	Deployment Frequency	50-75% increase. Teams can deploy smaller changes on-demand.
Improved Stability	Change Failure Rate	40-60% reduction. Eliminating manual changes dramatically reduces errors.
Enhanced Security	Security & Compliance	Fully auditable. Every change is a Git commit. This is a core SOC2 requirement.
Faster Recovery	Mean Time to Recovery (MTTR)	< 15 minutes. Rollbacks are as simple as reverting a Git commit.
Developer Productivity	Reduced Toil	~20% reduction in time spent on deployment/infra tasks.

Proposed Solution Architecture

Core Components & Data Flow

This architecture separates application code from deployment configuration. The flow is triggered by a developer and automated end-to-end.

1. Developer

Pushes to App Repo

→

2. GitLab CI

Tests, scans, builds, pushes image

→

3. Artifact Registry

Stores immutable image

↓

6. GKE Cluster

App is live, monitored by Google Cloud Logging

←

5. ArgoCD

Detects change, syncs cluster to desired state

←

4. Manifest Repo

CI job updates YAML with new image tag

Repository Strategy

Application Repos (N):
One for each app (e.g., `laravel-backend`, `react-frontend`). This is where developers work and where CI pipelines are defined.
Manifest Repository (1):
A single Git repository holding all plain YAML manifests for all apps across all environments. This is the single source of truth for the cluster state.

Multi-Environment Strategy

We will deploy three separate instances of ArgoCD (one for each environment). This is the correct strategy for high security and compliance.

Security & SOC2: A compromise of the `dev` instance has zero impact on `prod`.
Blast Radius: An operator error in `dev` cannot delete a `prod` application.
Stability & Testing: We can test ArgoCD upgrades in `dev` before rolling out to `prod`.
Performance: Distributes the load from CI/CD syncs.

Security & SOC2 Compliance Strategy

This architecture is designed to be SOC2-compliant from the ground up by building controls directly into the workflow.

4.1. Change Management (SOC2 CC8)

The GitOps flow *is* the change management control.

Audit Trail: Every cluster change is 100% traceable to a Git commit.
Approvals: `prod` branches are protected. Changes require a GitLab Merge Request (MR).
SOC2 Evidence: An MR provides the *who, what, when, and who approved* for every change.

4.2. Access Control (SOC2 CC6)

A least-privilege model is enforced at three layers:

GCP IAM: GKE Workload Identity provides granular permissions to pods.
GitLab RBAC: Developers have `write` to app repos; only Leads have `merge` to prod manifests.
ArgoCD `AppProject` RBAC: Segments permissions (e.g., `react-team` can only see `react-app`).

4.3. Secret Management (Google Secret Manager)

We will **never** store plaintext secrets in Git.

All secrets are stored in Google Secret Manager.
The External Secrets Operator (ESO) is installed in GKE.
We create `ExternalSecret` YAMLs (pointers, not secrets) in Git.
ESO securely fetches secrets and creates native Kubernetes `Secret` objects for apps to consume.

4.4. Vulnerability Management (SOC2 CC7.1)

Security is "shifted left" into the CI pipeline.

SAST & DAST: GitLab CI jobs run static analysis and dependency checks.
Container Scanning: Using **Trivy** in the `scan` stage of the CI pipeline.
Policy: The pipeline will *fail* and block the build if "Critical" or "High" vulnerabilities are found.

Implementation Plan

This plan assumes a dedicated team of 2 Cloud Engineers. Explore the plan by phase using the chart and filters.

Hour Estimation by Phase

Filter Tasks by Phase

Task	Hours	Why this is required

Migration Strategy & Disaster Recovery

Application Migration Strategy (Zero Downtime)

This is the most critical phase. We will not have a "big bang" cutover. The migration will be done app-by-app with zero downtime using ArgoCD's `diff` capability.

Phase 1: Manifest Generation & Baseline

Announce "change freeze" on the pilot app.
Generate baseline YAML from `kubectl get ...`.
Clean YAML and store in Manifest Repo.
Convert K8s `Secret` to `ExternalSecret` YAMLs.

Phase 2: Controlled GitOps Takeover

Create ArgoCD `Application` with manual sync.
Run `argocd app diff` to find configuration drift.
Do not sync. Update YAML in Git until `diff` is empty.
Git source of truth now perfectly matches the live state.

Phase 3: Full GitOps Enablement

Enable `syncPolicy: automated: { prune: true, selfHeal: true }`.
Test by making a manual change (ArgoCD should revert it).
Connect the GitLab CI pipeline's `update-manifest` job.
Repeat for `staging` and `prod`.

8.1. Rollback Procedures

This is a major strength of GitOps.

Option 1: The GitOps Way (Preferred)

Action: `git revert ` and `git push`.
Result: ArgoCD detects the change and automatically rolls the application back. Fully audited.

Option 2: The Emergency Way (ArgoCD UI/CLI)

Action: `argocd app rollback react-app-prod `
Result: Immediately applies previous state. Creates *drift* (Git and live state mismatch) which must be fixed with Option 1 after the emergency.

8.2. Disaster Recovery (DR) Plan

Recovery is fast due to the stateless nature of the tools.

GKE Cluster Failure

Low risk, as we use **GKE Regional Clusters** across three zones. In a full regional outage, we can restore the system in minutes.

ArgoCD Instance Failure

Low risk. ArgoCD is 99% stateless. All its configuration is stored *in our Git Manifest Repo*. We simply re-install ArgoCD and point it at the repo; it will re-discover all apps.

Core Pipeline Configuration Details

Conceptual GitLab CI Template

stages:
  - test
  - scan
  - build
  - deploy-manifest

variables:
  IMAGE_TAG: $CI_REGISTRY_IMAGE:$CI_COMMIT_SHORT_SHA
  MANIFEST_REPO_URL: "git@gitlab.com:your-org/gke-manifests.git"
  APP_PATH_IN_MANIFEST_REPO: "dev/react-app"

test:
  stage: test
  script:
    - npm install
    - npm test

scan:
  stage: scan
  script:
    - trivy fs . # Fails on high/critical findings

build:
  stage: build
  script:
    - docker build -t $IMAGE_TAG .
    - docker push $IMAGE_TAG

deploy-manifest:
  stage: deploy-manifest
  only: [ main ]
  script:
    - git clone $MANIFEST_REPO_URL
    - cd gke-manifests
    - yq e -i '.spec.template.spec.containers[0].image = env("IMAGE_TAG")' $APP_PATH_IN_MANIFEST_REPO/deployment.yaml
    - git config user.email "ci-pipeline@your-org.com"
    - git config user.name "GitLab CI"
    - git commit -am "Deploying $IMAGE_TAG"
    - git push

ArgoCD "App of Apps" Pattern (Root App)

# root-app-dev.yaml
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: root-dev
  namespace: argocd-dev
spec:
  project: default
  source:
    repoURL: 'https://github.com/your-org/gke-manifests.git'
    path: dev # This app finds all apps in the 'dev' directory
    targetRevision: HEAD
  destination:
    server: 'https://kubernetes.default.svc'
    namespace: argocd-dev
  syncPolicy:
    automated:
      prune: true
      selfHeal: true

ArgoCD App Definition (Found by Root App)

# gke-manifests/dev/react-app.yaml
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: react-app-dev
  namespace: argocd-dev
spec:
  project: react-team # Use AppProject for RBAC
  source:
    repoURL: 'https://github.com/your-org/gke-manifests.git'
    path: dev/react-app # Points to the *actual* manifests
    targetRevision: HEAD
  destination:
    server: 'https://kubernetes.default.svc'
    namespace: react-dev # Deploys *to* this namespace
  syncPolicy:
    automated:
      prune: true
      selfHeal: true

K8s Deployment (Zero-Downtime)

# gke-manifests/dev/react-app/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: react-app
spec:
  replicas: 3
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 25% # Max % of pods that can be down
      maxSurge: 25%       # Max % of extra pods to create
  template:
    spec:
      containers:
      - name: react-app
        image: gcr.io/your-project/react-app:some-tag
        readinessProbe: # CRITICAL for zero-downtime
          httpGet:
            path: /healthz
            port: 80
          initialDelaySeconds: 5
          periodSeconds: 10