Troubleshooting: tooti hui network theek karo

Template yahan se download karo: broken-network.yaml. Yeh site ke folder mein deepdive/scenarios/broken-network.yaml pe bhi hai. Is template ko Lab 1 wala deepdive-ec2-role chahiye.

Neeche ki commands stack banati hain aur uske poora banne ka intezaar karti hain. Phir stack ke outputs ki table dikhayi jaati hai, aur ek loop har output (VPC, IGW, instances, route table, NACL aur SGs ke IDs) ko usi naam ke environment variable mein daal deta hai:

export AWS_DEFAULT_REGION=us-east-1
mkdir -p ~/deepdive/scn9 && cd ~/deepdive/scn9      # yaml file yahan rakho
aws cloudformation create-stack --stack-name broken-network --template-body file://broken-network.yaml
aws cloudformation wait stack-create-complete --stack-name broken-network
aws cloudformation describe-stacks --stack-name broken-network --query 'Stacks[0].Outputs' --output table
for k in VpcId IgwId WebInstanceId AppInstanceId AppPrivateIp PublicRouteTableId PublicNaclId WebSgId AppSgId; do
  export $k=$(aws cloudformation describe-stacks --stack-name broken-network \
    --query "Stacks[0].Outputs[?OutputKey=='$k'].OutputValue" --output text)
done
echo $WebInstanceId $AppInstanceId

• Stack CREATE_COMPLETE ho gaya, aur saare outputs variables mein aa gaye.

Neeche ka analyze function source, destination aur port lekar Reachability Analyzer ka ek path banata hai aur uska analysis shuru karta hai. Analysis khatam hone tak har 5 second mein status check hota hai. Phir function batata hai ki raasta mila ya nahi (PathFound), aur agar nahi mila toh kaunse component ne kis wajah (explanation code) se roka. Function teen raaston pe chalaya jaata hai: internet se web tak, web se internet tak (reply aur bahar jaane ka raasta), aur web se app tak.

analyze() {  # source destination port
  local P A
  P=$(aws ec2 create-network-insights-path --source $1 --destination $2 --protocol tcp --destination-port $3 \
      --query NetworkInsightsPath.NetworkInsightsPathId --output text)
  A=$(aws ec2 start-network-insights-analysis --network-insights-path-id $P \
      --query NetworkInsightsAnalysis.NetworkInsightsAnalysisId --output text)
  until [ "$(aws ec2 describe-network-insights-analyses --network-insights-analysis-ids $A --query 'NetworkInsightsAnalyses[0].Status' --output text)" != running ]; do sleep 5; done
  aws ec2 describe-network-insights-analyses --network-insights-analysis-ids $A \
    --query 'NetworkInsightsAnalyses[0].{PathFound:NetworkPathFound,Why:Explanations[].{Code:ExplanationCode,Component:Component.Id}}' --output json
}
analyze $IgwId $WebInstanceId 80          # internet → web
analyze $WebInstanceId $IgwId 443         # web → internet (return/outbound path)
analyze $WebInstanceId $AppInstanceId 8080  # web → app

Yahi analyses console mein bhi kholo. Wahan graphical raaste mein har component (IGW, route table, NACL, SG aur ENI) hara ya laal dikhta hai. Ek galti theek karo, analysis dobara chalao, aur phir agli galti pe jao. Har finding apne notes mein likhte jao.

• Teeno raaston ka pehla nateeja "PathFound: false" aaya, aur tumne explanation codes note kar liye.

Pehli command web page laati hai, jisme "App reachable: OK" dikhna chahiye. Baaki do commands wahi analyses dobara chalati hain, jo ab paas hone chahiye:

curl -s http://$WEB_IP/          # <h1>Web tier OK</h1><p>App reachable: OK {"service": "app", "status": "ok"}</p>
analyze $IgwId $WebInstanceId 80
analyze $WebInstanceId $AppInstanceId 8080

• Browser ya curl mein "App reachable: OK" dikha.
• Dono analyses mein PathFound: true aaya.
• Tumhare notes mein har galti ka symptom, saboot aur fix likha hai.
• (Bonus) Web server pe Session Manager connect ho gaya.