deployment-strategies

# Deployment Strategies Skill

Patterns for deploying applications safely.

## Strategy Comparison

| Strategy | Downtime | Risk | Rollback | Complexity |
|----------|----------|------|----------|------------|
| Recreate | Yes | High | Slow | Low |
| Rolling | No | Medium | Medium | Low |
| Blue-Green | No | Low | Instant | Medium |
| Canary | No | Low | Fast | High |
| A/B Testing | No | Low | Fast | High |

## Rolling Deployment

### Kubernetes Configuration

```yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: app
spec:
  replicas: 5
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1        # Extra pods during update
      maxUnavailable: 0  # No downtime
  template:
    spec:
      containers:
        - name: app
          image: app:v2
          readinessProbe:
            httpGet:
              path: /health
              port: 8080
            initialDelaySeconds: 5
            periodSeconds: 5
```

### Rollout Commands

```bash
# Start rollout
kubectl set image deployment/app app=app:v2

# Watch rollout progress
kubectl rollout status deployment/app

# Pause rollout
kubectl rollout pause deployment/app

# Resume rollout
kubectl rollout resume deployment/app

# Rollback
kubectl rollout undo deployment/app
```

## Blue-Green Deployment

### Architecture

```
                    ┌─────────────┐
                    │   Router    │
                    │ (Service)   │
                    └──────┬──────┘
                           │
           ┌───────────────┴───────────────┐
           │                               │
           ▼                               ▼
    ┌─────────────┐                 ┌─────────────┐
    │    Blue     │                 │   Green     │
    │   (v1.0)    │                 │   (v1.1)    │
    │   Active    │                 │   Standby   │
    └─────────────┘                 └─────────────┘
```

### Implementation

```yaml
# Blue deployment (current)
apiVersion: apps/v1
kind: Deployment
metadata:
  name: