# Deployment Process SOP

## Document Information
- **Document ID**: SOP-DEV-002
- **Version**: 1.0
- **Date**: 2025-09-09
- **Author**: DevOps Team
- **Status**: Active

## 1. Purpose and Scope

### 1.1 Purpose
This SOP defines the standardized process for deploying applications to various environments, ensuring consistent, reliable, and secure deployments.

### 1.2 Scope
This procedure applies to:
- All application deployments to staging and production
- Database schema changes
- Configuration updates
- Third-party service integrations
- Emergency hotfix deployments

## 2. Deployment Environments

### 2.1 Environment Hierarchy
```
Development → Staging → Production
     ↓           ↓          ↓
  Local Dev   Integration  Live System
```

### 2.2 Environment Specifications

#### Development Environment
- **Purpose**: Feature development and initial testing
- **Access**: All developers
- **Data**: Synthetic test data
- **Deployment**: Automatic on code push
- **Rollback**: Not required

#### Staging Environment
- **Purpose**: Integration testing and user acceptance testing
- **Access**: QA team, Product owners, Selected stakeholders
- **Data**: Production-like anonymized data
- **Deployment**: Manual approval required
- **Rollback**: Automated rollback available

#### Production Environment
- **Purpose**: Live system serving end users
- **Access**: DevOps team, On-call engineers
- **Data**: Live customer data
- **Deployment**: Change approval board required
- **Rollback**: Immediate rollback capability required

## 3. Pre-Deployment Requirements

### 3.1 Code Readiness Checklist
- [ ] All code reviewed and approved
- [ ] All tests passing (unit, integration, e2e)
- [ ] Security scans completed with no critical issues
- [ ] Performance testing completed
- [ ] Documentation updated
- [ ] Release notes prepared

### 3.2 Infrastructure Readiness
- [ ] Target environment available and healthy
- [ ] Database migrations tested
- [ ] Dependencies updated and verified
- [ ] Configuration files validated
- [ ] Monitoring and alerting configured
- [ ] Backup procedures verified

### 3.3 Approval Requirements

#### Staging Deployment
- [ ] Technical lead approval
- [ ] QA team sign-off
- [ ] Automated test results green

#### Production Deployment
- [ ] Change approval board approval
- [ ] Security team sign-off
- [ ] Business stakeholder approval
- [ ] On-call engineer identified
- [ ] Rollback plan documented

## 4. Deployment Process

### 4.1 Standard Deployment Flow

#### Phase 1: Pre-Deployment
1. **Deployment Preparation**
   - Create deployment branch from approved code
   - Generate deployment artifacts
   - Validate deployment configuration
   - Schedule deployment window

2. **Team Notification**
   - Send deployment notification to stakeholders
   - Update deployment dashboard
   - Confirm on-call coverage
   - Brief support team on changes

3. **Final Verification**
   - Run pre-deployment health checks
   - Verify rollback procedures
   - Confirm monitoring is active
   - Check system capacity

#### Phase 2: Deployment Execution
1. **Deployment Start**
   ```bash
   # Example deployment commands
   ./deploy.sh --environment=production --version=1.2.3
   
   # Deployment steps
   echo "Starting deployment of version 1.2.3"
   echo "Stopping application services..."
   echo "Backing up current version..."
   echo "Deploying new version..."
   echo "Running database migrations..."
   echo "Starting application services..."
   echo "Running health checks..."
   ```

2. **Progressive Deployment** (Production Only)
   - Deploy to single server/container
   - Verify functionality
   - Gradually roll out to all servers
   - Monitor key metrics throughout

3. **Post-Deployment Verification**
   - Run automated smoke tests
   - Verify key functionality
   - Check performance metrics
   - Confirm integrations working

#### Phase 3: Post-Deployment
1. **Monitoring**
   - Monitor application metrics
   - Watch error rates and logs
   - Verify user experience
   - Check system performance

2. **Documentation**
   - Update deployment log
   - Document any issues encountered
   - Record deployment metrics
   - Update system documentation

## 5. Deployment Types

### 5.1 Standard Deployment
**When Used**: Regular feature releases
**Timing**: During maintenance windows
**Process**: Full deployment process
**Rollback**: Standard rollback procedures

### 5.2 Hotfix Deployment
**When Used**: Critical bug fixes
**Timing**: Outside normal hours if necessary
**Process**: Expedited approval process
**Rollback**: Immediate rollback available

### 5.3 Emergency Deployment
**When Used**: Security vulnerabilities, system outages
**Timing**: Immediate
**Process**: Emergency approval only
**Rollback**: Mandatory rollback plan

### 5.4 Blue-Green Deployment
**When Used**: Zero-downtime requirements
**Process**: 
1. Deploy to inactive environment (Green)
2. Test Green environment thoroughly
3. Switch traffic from Blue to Green
4. Keep Blue as immediate rollback option

### 5.5 Canary Deployment
**When Used**: High-risk changes
**Process**:
1. Deploy to small subset of users (5%)
2. Monitor metrics and user feedback
3. Gradually increase traffic (25%, 50%, 100%)
4. Rollback if issues detected

## 6. Database Deployments

### 6.1 Schema Changes
```sql
-- Migration script example
-- Migration: 001_add_user_preferences_table.sql
-- Date: 2025-09-09
-- Author: Developer Name

BEGIN TRANSACTION;

-- Create new table
CREATE TABLE user_preferences (
    id SERIAL PRIMARY KEY,
    user_id INTEGER NOT NULL REFERENCES users(id),
    preference_key VARCHAR(100) NOT NULL,
    preference_value TEXT,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

-- Add indexes
CREATE INDEX idx_user_preferences_user_id ON user_preferences(user_id);
CREATE INDEX idx_user_preferences_key ON user_preferences(preference_key);

-- Update schema version
INSERT INTO schema_versions (version, applied_at) VALUES ('001', CURRENT_TIMESTAMP);

COMMIT;
```

### 6.2 Data Migration Process
1. **Preparation**
   - Backup production database
   - Test migration on staging environment
   - Calculate expected migration time
   - Plan rollback procedure

2. **Execution**
   - Put application in maintenance mode
   - Run migration scripts
   - Verify data integrity
   - Update application configuration

3. **Verification**
   - Run data validation tests
   - Check application functionality
   - Monitor performance metrics
   - Remove maintenance mode

## 7. Configuration Management

### 7.1 Configuration Deployment
```yaml
# Example configuration structure
environments:
  staging:
    database:
      host: staging-db.internal
      port: 5432
      name: app_staging
    api:
      base_url: https://staging-api.company.com
      timeout: 30
    features:
      new_dashboard: true
      beta_features: true
  
  production:
    database:
      host: prod-db.internal
      port: 5432
      name: app_production
    api:
      base_url: https://api.company.com
      timeout: 60
    features:
      new_dashboard: false
      beta_features: false
```

### 7.2 Secret Management
- Use environment variables for secrets
- Store secrets in secure vault (e.g., HashiCorp Vault)
- Rotate secrets regularly
- Never commit secrets to version control
- Use service accounts for application authentication

## 8. Rollback Procedures

### 8.1 Rollback Decision Criteria
Initiate rollback when:
- Error rate exceeds threshold (>1% increase)
- Performance degradation (>20% slower response times)
- Critical functionality broken
- Security vulnerability introduced
- Data corruption detected

### 8.2 Rollback Process
```bash
#!/bin/bash
# Rollback script example

echo "Starting rollback procedure..."

# 1. Stop current version
echo "Stopping current application version..."
sudo systemctl stop application

# 2. Restore previous version
echo "Restoring previous application version..."
sudo rm -rf /opt/app/current
sudo cp -r /opt/app/previous /opt/app/current

# 3. Restore database (if needed)
echo "Checking if database rollback is needed..."
if [ "$DATABASE_ROLLBACK" = "true" ]; then
    echo "Restoring database from backup..."
    pg_restore --clean --create -h localhost -U postgres app_backup.sql
fi

# 4. Start application
echo "Starting application..."
sudo systemctl start application

# 5. Verify rollback
echo "Running post-rollback health checks..."
./health-check.sh

echo "Rollback completed successfully"
```

### 8.3 Rollback Verification
- [ ] Application starts successfully
- [ ] Health checks pass
- [ ] Key functionality verified
- [ ] Performance metrics normal
- [ ] Error logs reviewed
- [ ] Stakeholders notified

## 9. Monitoring and Alerts

### 9.1 Deployment Monitoring
Monitor these metrics during and after deployment:

**Application Metrics:**
- Response time
- Error rate
- Throughput (requests per second)
- Memory and CPU usage
- Database connection pool

**Infrastructure Metrics:**
- Server health
- Network connectivity
- Disk space
- Load balancer status
- CDN performance

### 9.2 Alerting Configuration
```yaml
# Example alert configuration
alerts:
  - name: high_error_rate
    condition: error_rate > 1%
    duration: 5m
    severity: critical
    action: trigger_rollback
    
  - name: slow_response_time
    condition: avg_response_time > 2000ms
    duration: 10m
    severity: warning
    action: notify_team
    
  - name: deployment_failure
    condition: deployment_status == "failed"
    duration: 0s
    severity: critical
    action: notify_oncall
```

## 10. Security Considerations

### 10.1 Deployment Security
- Use secure deployment channels (SSH, VPN)
- Verify deployment artifact integrity
- Apply principle of least privilege
- Audit all deployment activities
- Encrypt sensitive configuration data

### 10.2 Access Control
- Separate deployment credentials per environment
- Use multi-factor authentication
- Implement approval workflows
- Log all deployment actions
- Regular access review and rotation

## 11. Documentation and Communication

### 11.1 Deployment Documentation
**Before Deployment:**
- Deployment plan document
- Risk assessment
- Rollback procedures
- Communication plan

**During Deployment:**
- Real-time status updates
- Issue tracking
- Decision log
- Stakeholder notifications

**After Deployment:**
- Deployment summary report
- Lessons learned
- Performance metrics
- Next steps

### 11.2 Communication Templates

#### Pre-Deployment Notification
```
Subject: [DEPLOYMENT] Production Deployment Scheduled - [Date/Time]

Team,

We have scheduled a production deployment for [Application Name] version [X.Y.Z].

Deployment Details:
- Date: [Date]
- Time: [Start Time - End Time]
- Duration: [Expected Duration]
- Impact: [Expected Impact Description]

Changes Included:
- [Feature 1]
- [Bug Fix 1]
- [Performance Improvement 1]

On-call Engineer: [Name]
Rollback Contact: [Name]

Please reach out with any questions or concerns.

Thanks,
DevOps Team
```

#### Post-Deployment Summary
```
Subject: [DEPLOYMENT COMPLETE] Production Deployment Summary - [Date]

Team,

The production deployment of [Application Name] version [X.Y.Z] has been completed successfully.

Deployment Summary:
- Start Time: [Time]
- End Time: [Time]
- Total Duration: [Duration]
- Status: [Success/Partial Success/Failed]

Key Metrics (24 hours post-deployment):
- Error Rate: [X%]
- Average Response Time: [X ms]
- Uptime: [X%]

Issues Encountered:
- [Issue 1 and resolution]
- [Issue 2 and resolution]

Next Actions:
- [Action 1]
- [Action 2]

Thanks,
DevOps Team
```

## 12. Continuous Improvement

### 12.1 Deployment Metrics
Track monthly:
- Deployment frequency
- Lead time for changes
- Mean time to recovery (MTTR)
- Change failure rate
- Deployment success rate

### 12.2 Process Improvement
- Monthly deployment retrospectives
- Quarterly process reviews
- Annual deployment strategy assessment
- Regular tool evaluation and updates

## 13. Compliance and Audit

### 13.1 Audit Requirements
- Maintain deployment logs for 2 years
- Document all approval decisions
- Track configuration changes
- Monitor access to deployment systems
- Regular compliance reviews

### 13.2 Compliance Checklist
- [ ] Change approval documented
- [ ] Security review completed
- [ ] Backup procedures executed
- [ ] Monitoring configured
- [ ] Rollback plan tested
- [ ] Stakeholder notification sent
- [ ] Post-deployment review conducted

## 14. Revision History

| Version | Date | Author | Changes |
|---------|------|--------|---------|
| 1.0 | 2025-09-09 | DevOps Team | Initial version |