commands.sh

#!/bin/bash

# Lab 10 - Migration and Rollback Runbook
# Commands executed during the lab

# 1. Update system packages
sudo apt update

# 2. Install required tools
sudo apt install -y postgresql postgresql-contrib git

# 3. Start PostgreSQL service
sudo systemctl start postgresql
sudo systemctl enable postgresql

# 4. Create working directory
mkdir -p ~/migration-lab
cd ~/migration-lab
pwd

# 5. Initialize Git repository
git init
git config user.name "Lab User"
git config user.email "lab@example.com"

# 1. Switch to postgres user and create database
sudo -u postgres psql -c "CREATE DATABASE inventory_db;"
sudo -u postgres psql -c "CREATE USER labuser WITH PASSWORD 'labpass123';"
sudo -u postgres psql -c "GRANT ALL PRIVILEGES ON DATABASE inventory_db TO labuser;"
sudo -u postgres psql -d inventory_db -c "GRANT ALL ON SCHEMA public TO labuser;"

# 2. Create environment configuration file
nano db_config.sh

# Contents of `db_config.sh`
chmod +x db_config.sh
source db_config.sh

# Step 2: Create Migration Directory Structure
mkdir -p migrations/up
mkdir -p migrations/down
mkdir -p migrations/validation
mkdir -p logs

# Step 3: Build Migration Template Script
nano migrate.sh

# Contents of `migrate.sh`
chmod +x migrate.sh

# Step 4: Create Migration Tracking System
nano migrations/up/000_init_tracking.sql

# Contents of `migrations/up/000_init_tracking.sql`
nano migrations/down/000_init_tracking.sql

# Step 5: Create Sample Migration
nano migrations/up/001_create_products.sql

# Contents of `migrations/up/001_create_products.sql`
nano migrations/down/001_create_products.sql

# Step 6: Create Validation Script
nano migrations/validation/001_validate_products.sql

# Step 1: Build Pre-Migration Checklist Script
nano pre_migration_check.sh

# Contents of `pre_migration_check.sh`
chmod +x pre_migration_check.sh

# Step 2: Create Backup and Restore Scripts
nano backup_database.sh

# Contents of `backup_database.sh`
chmod +x backup_database.sh

# Contents of `backup_database.sh`
nano restore_database.sh

# Contents of `restore_database.sh`
chmod +x restore_database.sh

# Step 3: Create Rollback Procedure Document
nano ROLLBACK_RUNBOOK.md

# Step 4: Create Migration Execution Runbook
nano MIGRATION_RUNBOOK.md

# Step 5: Create Validation Test Suite
nano validate_migration.sh

# Contents of `validate_migration.sh`
chmod +x validate_migration.sh

# 1. Test database connection
source db_config.sh
psql -c "SELECT version();"

# 2. Initialize tracking system
psql -f migrations/up/000_init_tracking.sql
psql -c "SELECT * FROM migration_history;"

# 3. Test backup script
./backup_database.sh
ls -lh backups/

# 4. Execute sample migration
psql -f migrations/up/001_create_products.sql
psql -c "\d products"

# 5. Test rollback
psql -f migrations/down/001_create_products.sql
psql -c "\d products"

# 1. Check all files created
ls -R migrations/

# 1. Check all files created
cat MIGRATION_RUNBOOK.md

# Success Criteria
cat ROLLBACK_RUNBOOK.md

# 2. Verify scripts are executable
ls -l *.sh

# 3. Test pre-migration checks
./pre_migration_check.sh

# Run the migration wrapper
./migrate.sh up 001_create_products.sql

# Run validation suite
./validate_migration.sh 001_create_products.sql

# Check migration history after wrapper execution
psql -c "SELECT * FROM migration_history ORDER BY executed_at DESC;"

# Issue: Cannot connect to PostgreSQL
sudo systemctl status postgresql

# Issue: Permission denied on scripts
chmod +x *.sh

# Issue: Permission denied on scripts
ls -l

# Issue: Backup file not created
df -h