From 9e5a4d74c2fd35d0e87744db0700dd8af165ce3e Mon Sep 17 00:00:00 2001 From: rvrajvyas Date: Wed, 8 Oct 2025 04:29:29 +0530 Subject: [PATCH] feat: added dns-resolution-scenario --- .../dns-resolution-broken/__init__.py | 377 ++++++++++++++++++ 1 file changed, 377 insertions(+) create mode 100644 clouddojo/scenarios/dns-resolution-broken/__init__.py diff --git a/clouddojo/scenarios/dns-resolution-broken/__init__.py b/clouddojo/scenarios/dns-resolution-broken/__init__.py new file mode 100644 index 0000000..8e5d4cd --- /dev/null +++ b/clouddojo/scenarios/dns-resolution-broken/__init__.py @@ -0,0 +1,377 @@ +# scenarios/dns-resolution-broken/__init__.py +""" +DNS Resolution Broken Scenario +A scenario where DNS configuration is broken preventing domain name resolution +""" + +import os +import subprocess +import time +import shutil +from pathlib import Path +from typing import Dict, Any, List, Optional +from clouddojo.base_scenario import BaseScenario +from clouddojo.scenario_metadata import ScenarioMetadata, StoryContext, Hint, CompanyType + +class DNSResolutionBrokenMetadata(ScenarioMetadata): + """Metadata for dns-resolution-broken scenario""" + + def get_story_context(self) -> StoryContext: + return StoryContext( + company_name="GlobalTech Solutions", + company_type=CompanyType.ENTERPRISE, + your_role="Network Administrator", + situation="Multiple applications are failing to connect to external services. Users report they can't access any websites by domain name, but direct IP connections work fine.", + urgency="critical", + stakeholders=["IT Director", "Application Teams", "Support Desk", "End Users"], + business_impact="All external API integrations down. Email services offline. Business operations severely impacted.", + success_criteria="DNS resolution working, all services can resolve domain names" + ) + + def get_hints(self) -> List[Hint]: + return [ + Hint(1, "Test DNS Resolution", + "First, verify that DNS resolution is actually failing.", + "nslookup google.com || dig google.com"), + + Hint(2, "Check DNS Configuration", + "Examine the DNS resolver configuration file.", + "cat /tmp/clouddojo-resolv.conf"), + + Hint(3, "Identify the Problem", + "Look for invalid or unreachable DNS servers in the configuration.", + "ping 192.168.999.1 # This IP is invalid"), + + Hint(4, "Fix DNS Servers", + "Replace with working DNS servers like Google's or Cloudflare's.", + "echo 'nameserver 8.8.8.8' > /tmp/clouddojo-resolv.conf"), + + Hint(5, "Add Secondary DNS", + "Always configure a backup DNS server for redundancy.", + "echo 'nameserver 1.1.1.1' >> /tmp/clouddojo-resolv.conf") + ] + + def get_learning_path(self) -> str: + return "production-sre" + + def get_completion_story(self, time_taken: int) -> str: + time_str = f"{time_taken // 60}m {time_taken % 60}s" if time_taken > 0 else "record time" + return f"DNS resolution restored! All services are back online and external APIs are responding. The IT Director commends your quick diagnosis and the support desk reports all user issues resolved. Resolution time: {time_str}" + +class DNSResolutionBrokenScenario(BaseScenario): + """DNS resolution troubleshooting scenario""" + + def __init__(self, name: str): + super().__init__(name) + self.resolv_conf = Path("/tmp/clouddojo-resolv.conf") + self.backup_resolv = Path("/tmp/clouddojo-resolv.conf.backup") + self.test_domains_file = Path("/tmp/clouddojo-test-domains.txt") + self._metadata = DNSResolutionBrokenMetadata() + + def get_metadata(self) -> Optional[ScenarioMetadata]: + """Return embedded metadata""" + return self._metadata + + @property + def description(self) -> str: + return "DNS configuration is broken with invalid nameservers preventing domain resolution" + + @property + def difficulty(self) -> str: + return "intermediate" + + @property + def technologies(self) -> list: + return ["linux", "dns", "networking", "troubleshooting", "system-administration"] + + def start(self) -> Dict[str, Any]: + """Start the DNS resolution broken scenario""" + try: + # Clean up any existing scenario files + for file_path in [self.resolv_conf, self.backup_resolv, self.test_domains_file]: + if file_path.exists(): + file_path.unlink() + + # Create broken DNS configuration with invalid nameservers + broken_resolv_content = """# CloudDojo DNS Configuration +# WARNING: These DNS servers are misconfigured! + +# Primary DNS - Invalid IP address +nameserver 192.168.999.1 + +# Secondary DNS - Non-existent server +nameserver 10.0.0.999 + +# Tertiary DNS - Local IP that's not a DNS server +nameserver 127.0.0.53 + +# Domain search path (this part is fine) +search clouddojo.local corp.internal +options timeout:2 attempts:3 +""" + self.resolv_conf.write_text(broken_resolv_content) + + # Create a correct version for reference + correct_resolv_content = """# CloudDojo DNS Configuration - FIXED VERSION +# Using public DNS servers + +# Primary DNS - Google +nameserver 8.8.8.8 + +# Secondary DNS - Cloudflare +nameserver 1.1.1.1 + +# Tertiary DNS - Google Secondary +nameserver 8.8.4.4 + +# Domain search path +search clouddojo.local corp.internal +options timeout:2 attempts:3 +""" + self.backup_resolv.write_text(correct_resolv_content) + + # Create test domains file + test_domains = """# Test these domains after fixing DNS +google.com +cloudflare.com +github.com +stackoverflow.com +""" + self.test_domains_file.write_text(test_domains) + + # Save state + self.save_state({ + 'resolv_conf': str(self.resolv_conf), + 'backup_resolv': str(self.backup_resolv), + 'started_at': time.time() + }) + + connection_info = f"""DNS Config File: {self.resolv_conf} +Backup Config: {self.backup_resolv} +Test Domains: {self.test_domains_file} +Test DNS: nslookup google.com""" + + instructions = f"""šŸ”§ TROUBLESHOOTING SCENARIO: DNS Resolution Failure + +šŸ“‹ SITUATION: +DNS resolution is completely broken. No domains can be resolved but direct IP connections work. + +šŸŽÆ YOUR MISSION: +1. Test DNS resolution to confirm the issue: + nslookup google.com + dig cloudflare.com + host github.com + +2. Check the DNS configuration: + cat {self.resolv_conf} + +3. Identify problems with the nameservers: + - Invalid IP addresses (999 is not valid in IPv4) + - Non-responsive servers + - Wrong ports or services + +4. Fix the DNS configuration: + - Use working public DNS servers + - Google DNS: 8.8.8.8, 8.8.4.4 + - Cloudflare DNS: 1.1.1.1, 1.0.0.1 + - OpenDNS: 208.67.222.222, 208.67.220.220 + +5. Verify DNS resolution works: + nslookup google.com + +šŸ’” HINTS: +ā€¢ Valid IPv4 octets range from 0-255 +ā€¢ Always configure multiple DNS servers for redundancy +ā€¢ Common public DNS servers are reliable for testing +ā€¢ Use 'echo' or text editor to modify resolv.conf +ā€¢ Test with multiple domains to ensure it's working + +šŸ SUCCESS CRITERIA: +ā€¢ At least 2 valid nameservers configured +ā€¢ DNS queries successfully resolve +ā€¢ No invalid IP addresses in configuration +ā€¢ Test domains can be resolved + +šŸ’” TIP: Replace the invalid nameservers with working public DNS servers +""" + + return { + "success": True, + "connection_info": connection_info, + "instructions": instructions, + "config_file": str(self.resolv_conf) + } + + except Exception as e: + return {"success": False, "error": f"Failed to start scenario: {str(e)}"} + + def stop(self) -> bool: + """Stop and cleanup the scenario""" + try: + # Clean up files + for file_path in [self.resolv_conf, self.backup_resolv, self.test_domains_file]: + if file_path.exists(): + file_path.unlink() + + self.clear_state() + return True + except Exception: + return False + + def status(self) -> Dict[str, Any]: + """Get current status of the scenario""" + try: + # Check if files exist + files_exist = self.resolv_conf.exists() + + # Read current configuration + current_config = "" + if self.resolv_conf.exists(): + current_config = self.resolv_conf.read_text() + # Count nameservers + nameserver_lines = [l for l in current_config.split('\n') + if l.strip().startswith('nameserver')] + + details = f"""Scenario Status: {'Active' if files_exist else 'Not Running'} +Config File: {'āœ…' if self.resolv_conf.exists() else 'āŒ'} +Backup File: {'āœ…' if self.backup_resolv.exists() else 'āŒ'} +Nameservers Configured: {len(nameserver_lines) if files_exist else 0}""" + + return {"running": files_exist, "details": details} + except Exception as e: + return {"running": False, "details": f"Error: {str(e)}"} + + def check(self) -> Dict[str, Any]: + """Check if DNS resolution has been fixed""" + try: + checks = [] + all_passed = True + + # Check if config file exists + if not self.resolv_conf.exists(): + return { + "passed": False, + "feedback": "āŒ DNS configuration file not found. Please start the scenario first." + } + + # Read configuration + config_content = self.resolv_conf.read_text() + lines = config_content.split('\n') + + # Extract nameserver entries + nameservers = [] + for line in lines: + if line.strip().startswith('nameserver'): + parts = line.strip().split() + if len(parts) >= 2: + nameservers.append(parts[1]) + + # Check: At least 2 nameservers configured + checks.append(("At least 2 nameservers configured", len(nameservers) >= 2)) + if len(nameservers) < 2: + all_passed = False + + # Check: No invalid IP addresses + valid_dns_servers = [ + "8.8.8.8", "8.8.4.4", # Google + "1.1.1.1", "1.0.0.1", # Cloudflare + "208.67.222.222", "208.67.220.220", # OpenDNS + "9.9.9.9", "149.112.112.112", # Quad9 + "4.2.2.1", "4.2.2.2" # Level3 + ] + + invalid_ips = [] + valid_count = 0 + + for ns in nameservers: + # Check if IP is valid format + try: + octets = ns.split('.') + if len(octets) == 4: + for octet in octets: + if not (0 <= int(octet) <= 255): + invalid_ips.append(ns) + break + else: + # Check if it's a known working DNS server + if ns in valid_dns_servers: + valid_count += 1 + elif ns.startswith("127.") or ns.startswith("192.168.999"): + invalid_ips.append(ns) + else: + invalid_ips.append(ns) + except (ValueError, AttributeError): + invalid_ips.append(ns) + + checks.append(("No invalid IP addresses", len(invalid_ips) == 0)) + if len(invalid_ips) > 0: + all_passed = False + + checks.append(("At least one valid public DNS server", valid_count >= 1)) + if valid_count < 1: + all_passed = False + + # Test actual DNS resolution (simulate) + has_working_dns = valid_count >= 1 and len(invalid_ips) == 0 + checks.append(("DNS resolution would work", has_working_dns)) + if not has_working_dns: + all_passed = False + + # Generate feedback + feedback_lines = [] + for check_name, passed in checks: + status = "āœ… PASS" if passed else "āŒ FAIL" + feedback_lines.append(f"{status} {check_name}") + + if invalid_ips: + feedback_lines.append(f"\nāš ļø Invalid nameservers found: {', '.join(invalid_ips)}") + + if all_passed: + feedback_lines.append("\nšŸŽ‰ Excellent! DNS resolution is now properly configured!") + feedback_lines.append(f"āœ… Valid DNS servers configured: {', '.join([ns for ns in nameservers if ns in valid_dns_servers])}") + else: + feedback_lines.append("\nšŸ’” HINTS:") + if len(nameservers) < 2: + feedback_lines.append("ā€¢ Add at least 2 nameservers for redundancy") + if invalid_ips: + feedback_lines.append("ā€¢ Remove or fix invalid IP addresses") + if valid_count < 1: + feedback_lines.append("ā€¢ Use known public DNS servers (8.8.8.8, 1.1.1.1, etc.)") + + return { + "passed": all_passed, + "feedback": "\n".join(feedback_lines) + } + + except Exception as e: + return {"passed": False, "feedback": f"āŒ Error checking solution: {str(e)}"} + + def reset(self) -> bool: + """Reset scenario to broken state""" + try: + # Restore broken DNS configuration + if self.resolv_conf.exists(): + broken_resolv_content = """# CloudDojo DNS Configuration +# WARNING: These DNS servers are misconfigured! + +# Primary DNS - Invalid IP address +nameserver 192.168.999.1 + +# Secondary DNS - Non-existent server +nameserver 10.0.0.999 + +# Tertiary DNS - Local IP that's not a DNS server +nameserver 127.0.0.53 + +# Domain search path (this part is fine) +search clouddojo.local corp.internal +options timeout:2 attempts:3 +""" + self.resolv_conf.write_text(broken_resolv_content) + + return True + except Exception: + return False + +# Export scenario +scenario_class = DNSResolutionBrokenScenario \ No newline at end of file