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AWS CodeDeploy

Deployment Lifecycle Event Hooks​

EC2/On-Premises Hook Order​

ApplicationStop
     ↓
DownloadBundle
     ↓
BeforeInstall
     ↓
Install
     ↓
AfterInstall
     ↓
ApplicationStart
     ↓
ValidateService     ← Run health checks here

Lambda Hook Order​

BeforeAllowTraffic   ← Run pre-traffic validation Lambda
     ↓
AllowTraffic         ← Traffic shifted to new version
     ↓
AfterAllowTraffic    ← Run post-traffic validation Lambda

Rollback Behavior​

TriggerRollback?
Deployment failure (any hook fails)✅ Automatic
CloudWatch Alarm threshold breached✅ Automatic (if configured)
Manual rollback✅ Manual via console/CLI
tip

CodeDeploy "rollback" redeploys the previous revision, it doesn't reverse the deployment — it deploys the old version again.

appspec.yml — Lambda​

version: 0.0
Resources:
  - MyLambdaFunction:
      Type: AWS::Lambda::Function
      Properties:
        Name: "OrderProcessor"
        Alias: "live"
        CurrentVersion: !Sub "${LambdaVersion1}"
        TargetVersion: !Sub "${LambdaVersion2}"
Hooks:
  - BeforeAllowTraffic: !Sub "arn:aws:lambda:${AWS::Region}:${AWS::AccountId}:function:PreTrafficHook"
  - AfterAllowTraffic: !Sub "arn:aws:lambda:${AWS::Region}:${AWS::AccountId}:function:PostTrafficHook"

Deployment Group​

ConfigDescription
Deployment groupTarget instances (by EC2 tags, ASG, or ECS service)
Deployment configTraffic shifting strategy
Service roleIAM role for CodeDeploy
AlarmsCloudWatch alarms that trigger rollback
TriggersSNS on deployment events

🧪 Practice Questions​

Q1. A CodeDeploy deployment fails during the ValidateService hook. What happens next?

A) Deployment is marked failed but no rollback
B) CodeDeploy rolls back to the previous version
C) CodeDeploy retries the hook 3 times
D) CodeDeploy skips the hook and continues

✅ Answer & Explanation

B — Any hook failure causes CodeDeploy to automatically roll back to the last successful deployment.

Q2. Which CodeDeploy deployment configuration sends 10% of traffic to a new Lambda version, waits 5 minutes monitoring CloudWatch alarms, then shifts 100%?

A) LambdaLinear10PercentEvery1Minute
B) LambdaAllAtOnce
C) LambdaCanary10Percent5Minutes
D) LambdaBlueGreen

✅ Answer & Explanation

C — Canary10Percent5Minutes = shift 10% traffic → monitor for 5 minutes → if healthy, shift remaining 90%.

🔗 Resources​