Docker Build Process: Dockerfile to Image to Container

    Introduction Docker has revolutionized how we build, ship, and run applications by providing a standardized way to package software with all its dependencies. Understanding the Docker build process is fundamental to modern DevOps practices. This guide visualizes the complete journey from writing a Dockerfile to running a container: Dockerfile Creation: Writing instructions for your application Image Building: Creating a reusable image from the Dockerfile Container Execution: Running instances of your image Multi-Stage Builds: Optimizing image size and security Part 1: The Docker Build Process Flow Complete Build to Run Lifecycle %%{init: {'theme':'dark', 'themeVariables': {'primaryTextColor':'#e5e7eb','secondaryTextColor':'#e5e7eb','tertiaryTextColor':'#e5e7eb','textColor':'#e5e7eb','nodeTextColor':'#e5e7eb','edgeLabelText':'#e5e7eb','clusterTextColor':'#e5e7eb','actorTextColor':'#e5e7eb'}}}%% flowchart TD Start([Developer writes code]) --> CreateDockerfile[Create DockerfileDefine base image,dependencies, commands] CreateDockerfile --> BuildContext[Prepare Build ContextGather files neededfor build] BuildContext --> DockerBuild[Run: docker build -t app:v1 .] DockerBuild --> LayerProcess{Process EachInstruction} LayerProcess --> FROM[FROM instructionPull base image] FROM --> COPY[COPY/ADD instructionsCopy application files] COPY --> RUN[RUN instructionsExecute commandsInstall dependencies] RUN --> ENV[ENV/EXPOSE/WORKDIRSet environment] ENV --> CMD[CMD/ENTRYPOINTDefine startup command] CMD --> CacheCheck{Layer existsin cache?} CacheCheck -->|Yes| UseCache[Use cached layer⚡ Fast build] CacheCheck -->|No| BuildLayer[Build new layer🔨 Execute instruction] UseCache --> NextLayer{Moreinstructions?} BuildLayer --> NextLayer NextLayer -->|Yes| LayerProcess NextLayer -->|No| CreateImage[Create Docker ImageTagged as app:v1Stored in local registry] CreateImage --> DockerRun[Run: docker run -p 8080:8080 app:v1] DockerRun --> CreateContainer[Create Container- Writable layer on top- Network configuration- Volume mounts] CreateContainer --> StartProcess[Start Container ProcessExecute CMD/ENTRYPOINT] StartProcess --> Running[Container Running ✓Application accessibleon port 8080] Running --> Stop{Containerstopped?} Stop -->|No| Running Stop -->|Yes| Cleanup[Container stoppedCan be restartedor removed] style CreateDockerfile fill:#064e3b,stroke:#3b82f6 style CreateImage fill:#1e3a8a,stroke:#3b82f6 style Running fill:#064e3b,stroke:#3b82f6 Image Layer Structure Docker images are built in layers, with each instruction in the Dockerfile creating a new layer: ...

    January 23, 2025 · 9 min · Rafiul Alam

    Kubernetes Pod Lifecycle: Pending → Running → Succeeded

    Introduction Kubernetes Pods are the smallest deployable units in Kubernetes, representing one or more containers that share resources. Understanding the Pod lifecycle is crucial for debugging, monitoring, and managing applications in Kubernetes. This guide visualizes the complete Pod lifecycle: Pod Creation: From YAML manifest to scheduling State Transitions: Pending → Running → Succeeded/Failed Init Containers: Pre-application setup Container Restart Policies: How Kubernetes handles failures Termination: Graceful shutdown process Part 1: Pod Lifecycle Overview Complete Pod State Machine %%{init: {'theme':'dark', 'themeVariables': {'primaryTextColor':'#e5e7eb','secondaryTextColor':'#e5e7eb','tertiaryTextColor':'#e5e7eb','textColor':'#e5e7eb','nodeTextColor':'#e5e7eb','edgeLabelText':'#e5e7eb','clusterTextColor':'#e5e7eb','actorTextColor':'#e5e7eb'}}}%% stateDiagram-v2 [*] --> Pending: Pod created Pending --> Running: All containers started Pending --> Failed: Scheduling failedImage pull failedInvalid config Running --> Succeeded: All containerscompleted successfully(restartPolicy: Never/OnFailure) Running --> Failed: Container failedand won't restartPod deleted during run Running --> Running: Container restarted(restartPolicy: Always/OnFailure) Succeeded --> [*]: Pod cleanup Failed --> [*]: Pod cleanup Running --> Terminating: Delete requestreceived Terminating --> Succeeded: Graceful shutdownsuccessful Terminating --> Failed: Force terminationafter grace period note right of Pending Pod accepted by cluster - Waiting for scheduling - Pulling images - Starting init containers - Creating container runtime end note note right of Running Pod is executing - At least 1 container running - Could be starting/restarting - Application serving traffic - Health checks active end note note right of Succeeded All containers terminated successfully - Exit code 0 - Will not be restarted - Job/CronJob completed end note note right of Failed Pod terminated in failure - Non-zero exit code - OOMKilled - Exceeded restart limit - Node failure end note note right of Terminating Pod shutting down - SIGTERM sent - Grace period active - Endpoints removed - Cleanup in progress end note Pod Creation to Running Flow %%{init: {'theme':'dark', 'themeVariables': {'primaryTextColor':'#e5e7eb','secondaryTextColor':'#e5e7eb','tertiaryTextColor':'#e5e7eb','textColor':'#e5e7eb','nodeTextColor':'#e5e7eb','edgeLabelText':'#e5e7eb','clusterTextColor':'#e5e7eb','actorTextColor':'#e5e7eb'}}}%% flowchart TD Start([kubectl apply -f pod.yaml]) --> APIServer[API ServerValidates YAMLWrites to etcd] APIServer --> Scheduler{Scheduler findssuitable node?} Scheduler -->|No| PendingNoNode[Status: PendingReason: Unschedulable- Insufficient resources- Node selector mismatch- Taints/tolerations] Scheduler -->|Yes| AssignNode[Pod assigned to NodeUpdate: spec.nodeName] AssignNode --> Kubelet[Kubelet on target nodereceives Pod spec] Kubelet --> PullImages{Pull containerimages} PullImages -->|Failed| ImagePullError[Status: PendingReason: ImagePullBackOff- Image doesn't exist- Registry auth failed- Network issues] PullImages -->|Success| InitContainers{Init containersdefined?} InitContainers -->|Yes| RunInit[Run init containerssequentially] InitContainers -->|No| CreateContainers RunInit --> InitSuccess{All initcontainerssucceeded?} InitSuccess -->|No| InitFailed[Status: Init:Erroror Init:CrashLoopBackOff] InitSuccess -->|Yes| CreateContainers[Create main containersSetup networkingMount volumes] CreateContainers --> StartContainers[Start all containersin Pod] StartContainers --> HealthChecks{Startup probedefined?} HealthChecks -->|Yes| StartupProbe[Execute startup probe] HealthChecks -->|No| Running StartupProbe --> StartupResult{Probepassed?} StartupResult -->|No| ProbeFailed[Container not readyIf fails too long:CrashLoopBackOff] StartupResult -->|Yes| Running[Status: Running- Container ready- Liveness probe active- Readiness probe active] Running --> ServingTraffic[Pod receives trafficAdded to Service endpoints] style PendingNoNode fill:#78350f,stroke:#f59e0b style ImagePullError fill:#7f1d1d,stroke:#ef4444 style InitFailed fill:#7f1d1d,stroke:#ef4444 style Running fill:#064e3b,stroke:#10b981 style ServingTraffic fill:#064e3b,stroke:#10b981 Part 2: Pod Creation Sequence API Server to Kubelet Communication %%{init: {'theme':'dark', 'themeVariables': {'primaryTextColor':'#e5e7eb','secondaryTextColor':'#e5e7eb','tertiaryTextColor':'#e5e7eb','textColor':'#e5e7eb','nodeTextColor':'#e5e7eb','edgeLabelText':'#e5e7eb','clusterTextColor':'#e5e7eb','actorTextColor':'#e5e7eb'}}}%% sequenceDiagram participant User as Developer participant API as API Server participant ETCD as etcd participant Sched as Scheduler participant Kubelet as Kubelet (Node) participant Runtime as Container Runtime participant Reg as Container Registry User->>API: kubectl apply -f pod.yaml Note over API: Validate Pod spec- Required fields- Resource limits- Security context API->>ETCD: Write Pod objectStatus: PendingnodeName: ETCD-->>API: Acknowledged API-->>User: Pod created Note over Sched: Watch for unscheduled Pods Sched->>API: List Pods with nodeName="" API-->>Sched: Pod list Note over Sched: Score nodes:- CPU/Memory available- Affinity rules- Taints/TolerationsBest node: node-1 Sched->>API: Bind Pod to node-1 API->>ETCD: Update Pod.spec.nodeName = "node-1" Note over Kubelet: Watch for Pods on node-1 Kubelet->>API: Get Pod specifications API-->>Kubelet: Pod details Kubelet->>Runtime: Pull image: nginx:1.21 Runtime->>Reg: Pull nginx:1.21 Reg-->>Runtime: Image layers Note over Runtime: Extract and cache image Kubelet->>Runtime: Create containerwith Pod spec config Runtime-->>Kubelet: Container created Kubelet->>Runtime: Start container Runtime-->>Kubelet: Container started Kubelet->>API: Update Pod Status:Phase: RunningcontainerStatuses: ready API->>ETCD: Save Pod status Kubelet->>Kubelet: Start health checks- Startup probe- Readiness probe- Liveness probe Note over Kubelet,Runtime: Continuous monitoringand health checking Part 3: Init Containers Init containers run before app containers and must complete successfully before the main containers start. ...

    January 23, 2025 · 11 min · Rafiul Alam

    Multi-Environment Pipeline: Dev → Staging → Production

    Introduction Multi-environment pipelines enable safe, progressive deployment of code changes through isolated environments. Each environment serves a specific purpose in validating changes before they reach production users. This guide visualizes the multi-environment deployment flow: Environment Hierarchy: Dev → Staging → Production Environment Isolation: Separate configs, databases, resources Progressive Promotion: Automated testing at each stage Approval Gates: Manual checkpoints for production Configuration Management: Environment-specific settings Part 1: Multi-Environment Architecture Complete Environment Flow %%{init: {'theme':'dark', 'themeVariables': {'primaryTextColor':'#e5e7eb','secondaryTextColor':'#e5e7eb','tertiaryTextColor':'#e5e7eb','textColor':'#e5e7eb','nodeTextColor':'#e5e7eb','edgeLabelText':'#e5e7eb','clusterTextColor':'#e5e7eb','actorTextColor':'#e5e7eb'}}}%% flowchart TD Dev([👨‍💻 Developer]) --> LocalDev[Local DevelopmentLaptop/Docker DesktopFast iteration] LocalDev --> Push[git push origin feature/new-api] Push --> CI[CI Pipeline TriggeredBuild + Test + Lint] CI --> CIPass{CIPassed?} CIPass -->|No| FixLocal[❌ Fix locallyCheck logsRun tests] FixLocal -.-> LocalDev CIPass -->|Yes| FeatureBranch{Branchtype?} FeatureBranch -->|feature/*| DevEnv[🔧 Dev EnvironmentNamespace: devAuto-deploy on push] FeatureBranch -->|main| StagingEnv[🎯 Staging EnvironmentNamespace: stagingAuto-deploy on merge] subgraph DevEnvironment[Development Environment] DevEnv --> DevConfig[Configuration:- Debug mode ON- Verbose logging- Mock external APIs- Dev database- Minimal replicas: 1] DevConfig --> DevTest[Basic Tests:- Smoke tests- Health checks- Manual QA] DevTest --> DevDone[✅ Dev validatedReady for staging] end DevDone --> MergePR[Merge Pull Requestto main branch] MergePR --> StagingEnv subgraph StagingEnvironment[Staging Environment] StagingEnv --> StagingConfig[Configuration:- Production-like setup- Staging database- Real external APIs test- Replicas: 2-3- Resource limits] StagingConfig --> StagingTest[Comprehensive Tests:- Integration tests- E2E tests- Performance tests- Security scans] StagingTest --> StagingResult{All testspassed?} StagingResult -->|No| StagingFail[❌ Staging failedRollback stagingFix issues] StagingFail -.-> FixLocal StagingResult -->|Yes| StagingMonitor[Monitor staging:- Error rates- Performance metrics- User acceptance testing] StagingMonitor --> StagingReady[✅ Staging validatedReady for production] end StagingReady --> ApprovalGate{ManualApprovalRequired} ApprovalGate --> ReviewTeam[Team Lead Review:- Code changes- Test results- Risk assessment- Deployment timing] ReviewTeam --> Approved{Approved?} Approved -->|No| Rejected[❌ RejectedMore testing neededor wrong timing] Approved -->|Yes| ProdEnv[🚀 Production EnvironmentNamespace: productionManual trigger only] subgraph ProductionEnvironment[Production Environment] ProdEnv --> ProdConfig[Configuration:- Production settings- Production database- High availability- Replicas: 5-10- Strict resource limits- Auto-scaling enabled] ProdConfig --> ProdDeploy[Deployment Strategy:- Blue-green or- Canary or- Rolling update] ProdDeploy --> ProdHealth{Productionhealthy?} ProdHealth -->|No| AutoRollback[🚨 Auto-rollbackRevert to previousAlert on-call team] ProdHealth -->|Yes| ProdMonitor[Monitor Production:- Real user metrics- Error rates- Business KPIs- SLO compliance] ProdMonitor --> ProdStable{Stable for15 minutes?} ProdStable -->|No| AutoRollback ProdStable -->|Yes| Success[✅ Deployment Complete!New version liveMonitor continues] end style DevEnv fill:#064e3b,stroke:#10b981 style StagingEnv fill:#78350f,stroke:#f59e0b style ProdEnv fill:#1e3a8a,stroke:#3b82f6 style Success fill:#064e3b,stroke:#10b981 style StagingFail fill:#7f1d1d,stroke:#ef4444 style AutoRollback fill:#7f1d1d,stroke:#ef4444 style Rejected fill:#7f1d1d,stroke:#ef4444 Part 2: Environment Comparison Environment Characteristics %%{init: {'theme':'dark', 'themeVariables': {'primaryTextColor':'#e5e7eb','secondaryTextColor':'#e5e7eb','tertiaryTextColor':'#e5e7eb','textColor':'#e5e7eb','nodeTextColor':'#e5e7eb','edgeLabelText':'#e5e7eb','clusterTextColor':'#e5e7eb','actorTextColor':'#e5e7eb'}}}%% graph TB subgraph Local[🏠 Local Development] LocalProps[Properties:✓ Fast iteration✓ Developer's laptop✓ Docker Compose✓ Mock services✓ Hot reload enabled] LocalData[Data:- SQLite or local DB- Seed data- No real user data- Quick reset] LocalAccess[Access:- localhost only- No authentication- Debug tools enabled] end subgraph Dev[🔧 Development Environment] DevProps[Properties:✓ Shared team env✓ Kubernetes cluster✓ Continuous deployment✓ Latest features✓ Can be unstable] DevData[Data:- Dev database- Synthetic test data- Reset weekly- No PII] DevAccess[Access:- VPN required- Basic auth- All developers- Debug mode ON] end subgraph Staging[🎯 Staging Environment] StagingProps[Properties:✓ Production mirror✓ Same infrastructure✓ Pre-production testing✓ Stable builds only✓ Performance testing] StagingData[Data:- Staging database- Anonymized prod data- Or realistic test data- Refreshed monthly] StagingAccess[Access:- VPN required- OAuth/SSO- Developers + QA- Debug mode OFF] end subgraph Prod[🚀 Production Environment] ProdProps[Properties:✓ Live customer traffic✓ High availability✓ Auto-scaling✓ Disaster recovery✓ Maximum stability] ProdData[Data:- Production database- Real user data- Encrypted at rest- Regular backups] ProdAccess[Access:- Public internet- Full authentication- Limited admin access- Audit logging enabled] end Local --> |git push feature/*| Dev Dev --> |Merge to main| Staging Staging --> |Manual approval| Prod style Local fill:#064e3b,stroke:#10b981 style Dev fill:#064e3b,stroke:#10b981 style Staging fill:#78350f,stroke:#f59e0b style Prod fill:#1e3a8a,stroke:#3b82f6 Environment Configuration Matrix Aspect Local Dev Staging Production Purpose Development Feature testing Pre-production validation Live users Deployment Manual Auto on push Auto on merge Manual approval Replicas 1 1-2 2-3 5-10+ Database Local SQLite Shared dev DB Staging DB (prod-like) Production DB Resources Minimal Low Medium (prod-like) High Monitoring None Basic Full Full + Alerts Debug Mode Yes Yes No No Logging Level DEBUG DEBUG INFO WARN/ERROR External APIs Mocked Test endpoints Test endpoints Production endpoints Data Seed data Synthetic Anonymized Real user data Access localhost VPN + Basic auth VPN + SSO Public + Full auth Uptime SLA N/A None None 99.9%+ Part 3: Progressive Promotion Pipeline Promotion Flow with Quality Gates %%{init: {'theme':'dark', 'themeVariables': {'primaryTextColor':'#e5e7eb','secondaryTextColor':'#e5e7eb','tertiaryTextColor':'#e5e7eb','textColor':'#e5e7eb','nodeTextColor':'#e5e7eb','edgeLabelText':'#e5e7eb','clusterTextColor':'#e5e7eb','actorTextColor':'#e5e7eb'}}}%% flowchart LR subgraph LocalStage[Local Stage] L1[Write Code] L2[Run Unit Tests] L3[Manual Testing] L1 --> L2 --> L3 end subgraph DevStage[Dev Stage] D1[Auto Deploy] D2[Smoke Tests] D3{TestsPass?} D4[Dev Validated ✓] D1 --> D2 --> D3 D3 -->|Yes| D4 D3 -->|No| D5[❌ Fix] D5 -.-> L1 end subgraph StagingStage[Staging Stage] S1[Auto Deploy] S2[Integration Tests] S3[E2E Tests] S4[Performance Tests] S5{All Pass?} S6[Staging Validated ✓] S1 --> S2 --> S3 --> S4 --> S5 S5 -->|Yes| S6 S5 -->|No| S7[❌ Fix] S7 -.-> L1 end subgraph ApprovalStage[Approval Gate] A1[Create Release] A2[Code Review] A3[Change Advisory] A4{Approved?} A1 --> A2 --> A3 --> A4 A4 -->|No| A5[❌ Rejected] A5 -.-> L1 end subgraph ProdStage[Production Stage] P1[Manual Deploy] P2[Canary 10%] P3{Healthy?} P4[Increase to 50%] P5{Healthy?} P6[Complete 100%] P7[Monitor] P8[Success ✓] P1 --> P2 --> P3 P3 -->|Yes| P4 --> P5 P5 -->|Yes| P6 --> P7 --> P8 P3 -->|No| P9[🚨 Rollback] P5 -->|No| P9 end L3 --> |git push| D1 D4 --> |Merge PR| S1 S6 --> A1 A4 -->|Yes| P1 style L3 fill:#064e3b,stroke:#10b981 style D4 fill:#064e3b,stroke:#10b981 style S6 fill:#064e3b,stroke:#10b981 style P8 fill:#064e3b,stroke:#10b981 style D5 fill:#7f1d1d,stroke:#ef4444 style S7 fill:#7f1d1d,stroke:#ef4444 style P9 fill:#7f1d1d,stroke:#ef4444 Part 4: Environment-Specific Configuration Configuration Management Strategy %%{init: {'theme':'dark', 'themeVariables': {'primaryTextColor':'#e5e7eb','secondaryTextColor':'#e5e7eb','tertiaryTextColor':'#e5e7eb','textColor':'#e5e7eb','nodeTextColor':'#e5e7eb','edgeLabelText':'#e5e7eb','clusterTextColor':'#e5e7eb','actorTextColor':'#e5e7eb'}}}%% flowchart TD Start([Application needs config]) --> Method{ConfigMethod?} Method --> EnvVars[Environment Variables] Method --> ConfigMaps[Kubernetes ConfigMaps] Method --> Secrets[Kubernetes Secrets] EnvVars --> EnvExample[Examples:- NODE_ENV=production- LOG_LEVEL=info- FEATURE_FLAGS=true] ConfigMaps --> CMExample[Examples:- app-config.yaml- nginx.conf- application.properties] Secrets --> SecretExample[Examples:- DATABASE_PASSWORD- API_KEYS- TLS certificates] EnvExample --> Override{Override perenvironment?} CMExample --> Override SecretExample --> Override Override --> DevOverride[Dev Environment:DEBUG=trueDB_HOST=dev-dbREPLICAS=1CACHE_TTL=60s] Override --> StagingOverride[Staging Environment:DEBUG=falseDB_HOST=staging-dbREPLICAS=3CACHE_TTL=300s] Override --> ProdOverride[Production Environment:DEBUG=falseDB_HOST=prod-dbREPLICAS=10CACHE_TTL=600s] DevOverride --> Inject[Inject at deployment:kubectl apply -f k8s/dev/- deployment.yaml- configmap.yaml- secrets.yaml] StagingOverride --> Inject ProdOverride --> Inject style EnvVars fill:#1e3a8a,stroke:#3b82f6 style ConfigMaps fill:#1e3a8a,stroke:#3b82f6 style Secrets fill:#7f1d1d,stroke:#ef4444 Kubernetes Configuration Example # k8s/base/deployment.yaml (Common base) apiVersion: apps/v1 kind: Deployment metadata: name: myapp spec: selector: matchLabels: app: myapp template: metadata: labels: app: myapp spec: containers: - name: myapp image: myapp:latest # Overridden per environment ports: - containerPort: 8080 envFrom: - configMapRef: name: myapp-config - secretRef: name: myapp-secrets resources: # Overridden per environment requests: memory: "128Mi" cpu: "100m" limits: memory: "256Mi" cpu: "200m" --- # k8s/dev/configmap.yaml apiVersion: v1 kind: ConfigMap metadata: name: myapp-config namespace: dev data: NODE_ENV: "development" LOG_LEVEL: "debug" DATABASE_HOST: "postgres.dev.svc.cluster.local" REDIS_HOST: "redis.dev.svc.cluster.local" FEATURE_NEW_UI: "true" FEATURE_BETA_API: "true" --- # k8s/staging/configmap.yaml apiVersion: v1 kind: ConfigMap metadata: name: myapp-config namespace: staging data: NODE_ENV: "staging" LOG_LEVEL: "info" DATABASE_HOST: "postgres.staging.svc.cluster.local" REDIS_HOST: "redis.staging.svc.cluster.local" FEATURE_NEW_UI: "true" FEATURE_BETA_API: "false" --- # k8s/production/configmap.yaml apiVersion: v1 kind: ConfigMap metadata: name: myapp-config namespace: production data: NODE_ENV: "production" LOG_LEVEL: "warn" DATABASE_HOST: "postgres.production.svc.cluster.local" REDIS_HOST: "redis.production.svc.cluster.local" FEATURE_NEW_UI: "false" # Gradual rollout FEATURE_BETA_API: "false" --- # k8s/dev/kustomization.yaml apiVersion: kustomize.config.k8s.io/v1beta1 kind: Kustomization namespace: dev resources: - ../base/deployment.yaml - configmap.yaml - secrets.yaml images: - name: myapp newTag: dev-abc123 replicas: - name: myapp count: 1 patches: - patch: |- - op: replace path: /spec/template/spec/containers/0/resources/requests/memory value: 128Mi - op: replace path: /spec/template/spec/containers/0/resources/limits/memory value: 256Mi target: kind: Deployment name: myapp --- # k8s/production/kustomization.yaml apiVersion: kustomize.config.k8s.io/v1beta1 kind: Kustomization namespace: production resources: - ../base/deployment.yaml - configmap.yaml - secrets.yaml images: - name: myapp newTag: v1.2.3 replicas: - name: myapp count: 10 patches: - patch: |- - op: replace path: /spec/template/spec/containers/0/resources/requests/memory value: 512Mi - op: replace path: /spec/template/spec/containers/0/resources/limits/memory value: 1Gi - op: replace path: /spec/template/spec/containers/0/resources/requests/cpu value: 500m - op: replace path: /spec/template/spec/containers/0/resources/limits/cpu value: 1000m target: kind: Deployment name: myapp Part 5: Database Migration Strategy Multi-Environment Database Flow %%{init: {'theme':'dark', 'themeVariables': {'primaryTextColor':'#e5e7eb','secondaryTextColor':'#e5e7eb','tertiaryTextColor':'#e5e7eb','textColor':'#e5e7eb','nodeTextColor':'#e5e7eb','edgeLabelText':'#e5e7eb','clusterTextColor':'#e5e7eb','actorTextColor':'#e5e7eb'}}}%% sequenceDiagram participant Dev as Developer participant DevDB as Dev Database participant StagingDB as Staging Database participant ProdDB as Production Database participant Migration as Migration Tool Note over Dev: Write migration:001_add_users_table.sql Dev->>DevDB: Run migration locallyCREATE TABLE users... DevDB-->>Dev: Migration applied ✓ Dev->>Dev: Test applicationwith new schema Dev->>Dev: git push feature/add-users Note over DevDB: CI/CD Pipeline triggered Dev->>DevDB: Auto-run migrationsin dev environment DevDB-->>Dev: Dev DB updated ✓ Note over Dev: Create Pull RequestMerge to main Dev->>StagingDB: Trigger staging deployment Note over Migration,StagingDB: Pre-deployment hook Migration->>StagingDB: Backup databasepg_dump > backup.sql Migration->>StagingDB: Run migrations001_add_users_table.sql StagingDB-->>Migration: Migration applied ✓ Note over StagingDB: Deploy applicationTest with new schema alt Migration Failed Migration->>StagingDB: Rollback migrationRestore from backup StagingDB-->>Migration: Rolled back end Note over Dev: Manual approvalfor production Dev->>ProdDB: Trigger production deployment Note over Migration,ProdDB: Pre-deployment steps Migration->>ProdDB: Full database backupSnapshot created Migration->>ProdDB: Check migration statusSELECT version FROM schema_migrations ProdDB-->>Migration: Current version: 000 Migration->>ProdDB: Run migrationsin transaction Note over Migration,ProdDB: BEGIN;CREATE TABLE users;INSERT INTO schema_migrationsVALUES ('001');COMMIT; ProdDB-->>Migration: Migration successful ✓ Note over ProdDB: Deploy new applicationversion alt Production Issues Migration->>ProdDB: Rollback migrationRun down migration:DROP TABLE users; Note over ProdDB: Deploy previousapplication version end Migration->>ProdDB: Verify data integrityCheck constraints ProdDB-->>Migration: All checks passed ✓ Note over Dev,ProdDB: Production updated successfully Part 6: Multi-Environment CI/CD Pipeline Complete Pipeline Configuration # .github/workflows/multi-env-deploy.yml name: Multi-Environment Deployment on: push: branches: - main - develop pull_request: branches: - main env: REGISTRY: ghcr.io IMAGE_NAME: ${{ github.repository }} jobs: # CI - Same for all environments build-and-test: runs-on: ubuntu-latest steps: - uses: actions/checkout@v3 - name: Run linting run: npm run lint - name: Run unit tests run: npm test - name: Build Docker image run: docker build -t $IMAGE_NAME:${{ github.sha }} . - name: Run integration tests run: docker-compose -f docker-compose.test.yml up --abort-on-container-exit - name: Push image run: | echo ${{ secrets.GITHUB_TOKEN }} | docker login ghcr.io -u ${{ github.actor }} --password-stdin docker push $IMAGE_NAME:${{ github.sha }} # Deploy to Dev - Auto on feature branches deploy-dev: needs: build-and-test if: github.ref != 'refs/heads/main' runs-on: ubuntu-latest environment: name: development url: https://dev.example.com steps: - uses: actions/checkout@v3 - name: Deploy to Dev run: | kubectl config set-cluster dev --server="${{ secrets.DEV_K8S_SERVER }}" kubectl config set-credentials admin --token="${{ secrets.DEV_K8S_TOKEN }}" kubectl set image deployment/myapp myapp=$IMAGE_NAME:${{ github.sha }} -n dev kubectl rollout status deployment/myapp -n dev - name: Run smoke tests run: | curl https://dev.example.com/health npm run test:smoke -- --env=dev # Deploy to Staging - Auto on main branch deploy-staging: needs: build-and-test if: github.ref == 'refs/heads/main' runs-on: ubuntu-latest environment: name: staging url: https://staging.example.com steps: - uses: actions/checkout@v3 - name: Run database migrations run: | kubectl exec -n staging deployment/postgres -- \ psql -U postgres -d app -f /migrations/migrate.sql - name: Deploy to Staging run: | kubectl config set-cluster staging --server="${{ secrets.STAGING_K8S_SERVER }}" kubectl config set-credentials admin --token="${{ secrets.STAGING_K8S_TOKEN }}" kubectl apply -k k8s/staging/ kubectl rollout status deployment/myapp -n staging --timeout=5m - name: Run E2E tests run: npm run test:e2e -- --env=staging - name: Run performance tests run: | k6 run --vus 10 --duration 30s tests/performance.js - name: Check staging health run: | curl https://staging.example.com/health | jq '.status' | grep -q "healthy" # Deploy to Production - Manual approval required deploy-production: needs: deploy-staging runs-on: ubuntu-latest environment: name: production url: https://example.com steps: - uses: actions/checkout@v3 - name: Backup production database run: | kubectl exec -n production deployment/postgres -- \ pg_dump -U postgres app > backup-$(date +%Y%m%d-%H%M%S).sql - name: Run database migrations run: | kubectl exec -n production deployment/postgres -- \ psql -U postgres -d app -f /migrations/migrate.sql - name: Deploy to Production (Blue-Green) run: | kubectl config set-cluster prod --server="${{ secrets.PROD_K8S_SERVER }}" kubectl config set-credentials admin --token="${{ secrets.PROD_K8S_TOKEN }}" # Deploy green version kubectl apply -k k8s/production/ kubectl rollout status deployment/myapp-green -n production --timeout=10m # Switch traffic to green kubectl patch service myapp -n production -p '{"spec":{"selector":{"version":"green"}}}' - name: Monitor production metrics run: | sleep 300 # Wait 5 minutes ERROR_RATE=$(curl -s prometheus.example.com/api/v1/query?query=rate5m) if [ "$ERROR_RATE" -gt "0.01" ]; then echo "Error rate too high, rolling back" kubectl patch service myapp -n production -p '{"spec":{"selector":{"version":"blue"}}}' exit 1 fi - name: Notify team if: success() uses: slackapi/slack-github-action@v1 with: payload: | { "text": "✅ Production deployment successful!", "version": "${{ github.sha }}", "deployed_by": "${{ github.actor }}" } Part 7: Best Practices Environment Management Checklist ✅ DO: ...

    January 23, 2025 · 11 min · Rafiul Alam