GitOps Fundamentals Lab

This lab teaches core GitOps principles by simulating key workflows using only Linux command-line tools. Students will:

1. Practice declarative configuration management
2. Implement automated reconciliation
3. Build self-healing systems
4. Monitor state synchronization health

No Kubernetes or GitOps tools required!

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Task 1: Git State Reconciliation

Objective: Simulate how GitOps operators continuously synchronize cluster state with Git

Why This Matters:

• Understand the core reconciliation loop in GitOps
• Learn why declarative configuration > imperative commands
• See how automation prevents configuration drift

Tools Used:

git | watch | diff | cp

1. Initialize repository:

   mkdir gitops-lab && cd gitops-lab
   git init
   

2. Create desired state:

   echo "version: 1.0" > desired-state.txt
   git add . && git commit -m "Initial state"
   

3. Simulate live cluster:

   cp desired-state.txt current-state.txt
   

4. Create reconciliation script:

   #!/bin/bash
   # reconcile.sh
   DESIRED=$(cat desired-state.txt)
   CURRENT=$(cat current-state.txt)
   
   if [ "$DESIRED" != "$CURRENT" ]; then
   echo "$(date) - DRIFT DETECTED! Reconciling..."
   cp desired-state.txt current-state.txt
   fi
   

5. Trigger manual drift:

   echo "version: 2.0" > current-state.txt # Simulate manual cluster change
   

6. Run reconciliation:

   chmod +x reconcile.sh
   ./reconcile.sh # Should detect and fix drift
   

7. Automate reconciliation:

   watch -n 5 ./reconcile.sh # Runs every 5 seconds
   

8. Documentation:

   • Create a submission7.md file.
   • Provide the output.

Expected Output

Mon Jul 3 14:30:00 UTC 2023 - DRIFT DETECTED! Reconciling...

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Task 2: GitOps Health Monitoring

Objective: Implement health checks for configuration synchronization

Why This Matters:

• Learn to validate system state consistency
• Detect configuration drift before it causes failures
• Build proactive monitoring for GitOps systems

Tools Used:

md5sum | cron | echo | date

1. Create health check script:

   #!/bin/bash
   # healthcheck.sh
   DESIRED_MD5=$(md5sum desired-state.txt | awk '{print $1}')
   CURRENT_MD5=$(md5sum current-state.txt | awk '{print $1}')
   
   if [ "$DESIRED_MD5" != "$CURRENT_MD5" ]; then
   echo "$(date) - CRITICAL: State mismatch!" >> health.log
   else
   echo "$(date) - OK: States synchronized" >> health.log
   fi
   

2. Make executable:

   chmod +x healthcheck.sh
   

3. Simulate healthy state:

   ./healthcheck.sh
   cat health.log# Should show "OK"
   

4. Create drift:

   echo "unapproved change" >> current-state.txt
   

5. Run health check:

   ./healthcheck.sh
   cat health.log# Now shows "CRITICAL"
   

6. Documentation:

   • Provide the output in a submission7.md file.

Expected Output in health.log

Mon Jul 3 14:35:00 UTC 2023 - OK: States synchronized
Mon Jul 3 14:36:00 UTC 2023 - CRITICAL: State mismatch!

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Lab Guidelines

• Use proper Markdown formatting and structure for the documentation files.
• Organize the files within the lab folder using appropriate naming conventions.
• Create a Pull Request to the main branch of the repository with your completed lab assignment.

1. Key Concepts Demonstrated:

   Task	GitOps Principle	Real-World Equivalent
   1	Continuous Reconciliation	Argo CD/Flux sync loops
   2	Health Monitoring	Kubernetes operator status checks

"These simulations mirror how real GitOps operators work - just at human speed instead of computer speed!"