Feature/lab7

.github/pull_request_template.md

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+# Goal
+
+# Changes
+- 
+
+# Testing
+- [ ] Unit tests passed
+- [ ] Manual testing done
+- [ ] No tests (explain why): 
+
+# Checklist
+- [ ] PR title is clear and descriptive
+- [ ] Code is formatted/linted (if applicable)
+- [ ] Documentation updated (if applicable)

current-state.txt

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+version: 1.0
+app: myapp
+replicas: 3

desired-state.txt

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+version: 1.0
+app: myapp
+replicas: 3

health.log

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+Mon Mar  9 12:59:33 +03 2026 - ✅ OK: States synchronized
+Mon Mar  9 13:01:00 +03 2026 - ❌ CRITICAL: State mismatch detected!
+  Desired MD5: a15a1a4f965ecd8f9e23a33a6b543155
+  Current MD5: 48168ff3ab5ffc0214e81c7e2ee356f5
+Mon Mar  9 13:02:16 +03 2026 - ✅ OK: States synchronized
+Mon Mar  9 13:03:45 +03 2026 - ✅ OK: States synchronized
+Mon Mar  9 13:03:48 +03 2026 - ✅ OK: States synchronized
+Mon Mar  9 13:03:51 +03 2026 - ✅ OK: States synchronized
+Mon Mar  9 13:03:54 +03 2026 - ✅ OK: States synchronized
+Mon Mar  9 13:03:57 +03 2026 - ✅ OK: States synchronized
+Mon Mar  9 13:04:00 +03 2026 - ✅ OK: States synchronized
+Mon Mar  9 13:04:03 +03 2026 - ✅ OK: States synchronized
+Mon Mar  9 13:04:06 +03 2026 - ✅ OK: States synchronized

healthcheck.sh

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+#!/bin/bash
+# healthcheck.sh - Monitor GitOps sync health
+
+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 detected!" | tee -a health.log
+    echo "  Desired MD5: $DESIRED_MD5" | tee -a health.log
+    echo "  Current MD5: $CURRENT_MD5" | tee -a health.log
+else
+    echo "$(date) - ✅ OK: States synchronized" | tee -a health.log
+fi

labs/submission7.md

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+# GitOps Fundamentals
+
+
+
+## Task 1 — Git State Reconciliation
+
+### Create Desired State (Source of Truth):
+
+```bash
+echo "version: 1.0" > desired-state.txt
+echo "app: myapp" >> desired-state.txt
+echo "replicas: 3" >> desired-state.txt
+cat desired-state.txt
+```
+
+```bash
+version: 1.0
+app: myapp
+replicas: 3
+```
+
+### Simulate Current Cluster State:
+
+```bash
+cp desired-state.txt current-state.txt
+echo "Initial state synchronized"
+```
+
+```bash
+Initial state synchronized
+```
+
+### Create a file named `reconcile.sh`:
+
+```bash
+#!/bin/bash
+# reconcile.sh - GitOps reconciliation loop
+
+DESIRED=$(cat desired-state.txt)
+CURRENT=$(cat current-state.txt)
+
+if [ "$DESIRED" != "$CURRENT" ]; then
+    echo "$(date) - ⚠️  DRIFT DETECTED!"
+    echo "Reconciling current state with desired state..."
+    cp desired-state.txt current-state.txt
+    echo "$(date) - ✅ Reconciliation complete"
+else
+    echo "$(date) - ✅ States synchronized"
+fi
+```
+
+### Simulate Manual Drift:
+
+```bash
+echo "version: 2.0" > current-state.txt
+echo "app: myapp" >> current-state.txt
+echo "replicas: 5" >> current-state.txt
+cat current-state.txt
+```
+
+```bash
+version: 2.0
+app: myapp
+replicas: 5
+```
+
+### Run Reconciliation Manually:
+
+```bash
+./reconcile.sh
+diff desired-state.txt current-state.txt
+```
+
+```bash
+Mon Mar  9 12:45:35 +03 2026 - ✅ States synchronized
+```
+
+### Verify Drift Was Fixed:
+
+```bash
+cat current-state.txt
+```
+
+```bash
+version: 1.0
+app: myapp
+replicas: 3
+```
+
+### Start Continuous Reconciliation Loop:
+
+```bash
+watch -n 5 ./reconcile.sh
+```
+
+```bash
+Every 5.0s: ./reconcile.sh in 0.026s (0)
+Mon Mar  9 12:49:04 +03 2026 - ✅ States synchronized
+Mon Mar  9 12:51:24 +03 2026 - ✅ Reconciliation complete
+```
+
+**Analysis:** GitOps uses a reconciliation loop, a mechanism in which a controller constantly compares the desired state of the system described in the Git repository with the actual state of the infrastructure.
+
+**Advantages:** 
+
+- Reproducibility
+- Version control
+- Automation
+- Preventing configuration drift
+- Transparency and audit
+
+
+
+## Task 2 — GitOps Health Monitoring
+
+### Create a file named `healthcheck.sh`:
+
+```bash
+#!/bin/bash
+# healthcheck.sh - Monitor GitOps sync health
+
+DESIRED_MD5=$(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 detected!" | tee -a health.log
+    echo "  Desired MD5: $DESIRED_MD5" | tee -a health.log
+    echo "  Current MD5: $CURRENT_MD5" | tee -a health.log
+else
+    echo "$(date) - ✅ OK: States synchronized" | tee -a health.log
+fi
+```
+
+### Test Healthy State:
+
+```bash
+./healthcheck.sh
+cat health.log
+```
+
+```bash
+Mon Mar  9 12:59:33 +03 2026 - ✅ OK: States synchronized
+
+Mon Mar  9 12:59:33 +03 2026 - ✅ OK: States synchronized
+```
+
+### Test Healthy State:
+
+```bash
+echo "unapproved-change: true" >> current-state.txt
+cat current-state.txt
+```
+
+```bash
+version: 1.0
+app: myapp
+replicas: 3
+unapproved-change: true
+```
+
+### Run Health Check on Drifted State:
+
+```bash
+./healthcheck.sh
+cat health.log
+```
+
+```bash
+Mon Mar  9 13:01:00 +03 2026 - ❌ CRITICAL: State mismatch detected!
+  Desired MD5: a15a1a4f965ecd8f9e23a33a6b543155
+  Current MD5: 48168ff3ab5ffc0214e81c7e2ee356f5
+
+Mon Mar  9 12:59:33 +03 2026 - ✅ OK: States synchronized
+Mon Mar  9 13:01:00 +03 2026 - ❌ CRITICAL: State mismatch detected!
+  Desired MD5: a15a1a4f965ecd8f9e23a33a6b543155
+  Current MD5: 48168ff3ab5ffc0214e81c7e2ee356f5
+```
+
+### Fix Drift and Verify:
+
+```bash
+./reconcile.sh
+./healthcheck.sh
+cat health.log
+```
+
+```bash
+Mon Mar  9 13:01:53 +03 2026 - ⚠️  DRIFT DETECTED!
+Reconciling current state with desired state...
+Mon Mar  9 13:01:54 +03 2026 - ✅ Reconciliation complete
+
+Mon Mar  9 13:02:16 +03 2026 - ✅ OK: States synchronized
+
+Mon Mar  9 12:59:33 +03 2026 - ✅ OK: States synchronized
+Mon Mar  9 13:01:00 +03 2026 - ❌ CRITICAL: State mismatch detected!
+  Desired MD5: a15a1a4f965ecd8f9e23a33a6b543155
+  Current MD5: 48168ff3ab5ffc0214e81c7e2ee356f5
+Mon Mar  9 13:02:16 +03 2026 - ✅ OK: States synchronized
+```
+
+### Create a file named `monitor.sh`:
+
+```bash
+#!/bin/bash
+# monitor.sh - Combined reconciliation and health monitoring
+
+echo "Starting GitOps monitoring..."
+for i in {1..10}; do
+    echo "\n--- Check #$i ---"
+    ./healthcheck.sh
+    ./reconcile.sh
+    sleep 3
+done
+```
+
+### Run Monitoring Loop:
+
+```bash
+./monitor.sh
+```
+
+```bash
+Starting GitOps monitoring...
+\n--- Check #1 ---
+Mon Mar  9 13:03:45 +03 2026 - ✅ OK: States synchronized
+Mon Mar  9 13:03:45 +03 2026 - ✅ States synchronized
+\n--- Check #2 ---
+Mon Mar  9 13:03:48 +03 2026 - ✅ OK: States synchronized
+Mon Mar  9 13:03:48 +03 2026 - ✅ States synchronized
+\n--- Check #3 ---
+Mon Mar  9 13:03:51 +03 2026 - ✅ OK: States synchronized
+Mon Mar  9 13:03:51 +03 2026 - ✅ States synchronized
+...
+```
+
+### Review Complete Health Log:
+
+```bash
+cat health.log
+```
+
+```bash
+Mon Mar  9 12:59:33 +03 2026 - ✅ OK: States synchronized
+Mon Mar  9 13:01:00 +03 2026 - ❌ CRITICAL: State mismatch detected!
+  Desired MD5: a15a1a4f965ecd8f9e23a33a6b543155
+  Current MD5: 48168ff3ab5ffc0214e81c7e2ee356f5
+Mon Mar  9 13:02:16 +03 2026 - ✅ OK: States synchronized
+Mon Mar  9 13:03:45 +03 2026 - ✅ OK: States synchronized
+Mon Mar  9 13:03:48 +03 2026 - ✅ OK: States synchronized
+Mon Mar  9 13:03:51 +03 2026 - ✅ OK: States synchronized
+...
+```
+
+**Analysis:** Checksums create a unique hash for the file contents. If even one byte of the configuration changes, the MD5 value will also change. Therefore, you can quickly compare the hashes of the current and expected configuration and determine if changes have occurred.
+
+**Comparison:** GitOps tools like ArgoCD use a similar principle. They compare the state of resources in Git with the state in the cluster. If there are differences, ArgoCD shows the OutOfSync status. When the states match, the status becomes Synced. This is similar to the checksum comparison — both mechanisms detect changes between two configuration versions.

monitor.sh

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+#!/bin/bash
+# monitor.sh - Combined reconciliation and health monitoring
+
+echo "Starting GitOps monitoring..."
+for i in {1..10}; do
+    echo "\n--- Check #$i ---"
+    ./healthcheck.sh
+    ./reconcile.sh
+    sleep 3
+done

reconcile.sh

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+#!/bin/bash
+# reconcile.sh - GitOps reconciliation loop
+
+DESIRED=$(cat desired-state.txt)
+CURRENT=$(cat current-state.txt)
+
+if [ "$DESIRED" != "$CURRENT" ]; then
+    echo "$(date) - ⚠️  DRIFT DETECTED!"
+    echo "Reconciling current state with desired state..."
+    cp desired-state.txt current-state.txt
+    echo "$(date) - ✅ Reconciliation complete"
+else
+    echo "$(date) - ✅ States synchronized"
+fi