Get Your CertDOP-C02PlayCompete
‹ All DOP-C02 questions

DOP-C02 Practice Question 21: CodeDeploy ApplicationStop Previous Revision

AWS Certified DevOps Engineer – Professional (DOP-C02) · Test 3 · question 1 of 10

SDLC Automationhard

A team deploys a web application to an Amazon EC2 fleet with AWS CodeDeploy in-place deployments. During an incident, an engineer manually cleaned up disk space on a subset of the instances and deleted files under the CodeDeploy deployment root directory. Every deployment since then fails on exactly those instances during the ApplicationStop lifecycle event with "Script does not exist at specified location", even though the new revision bundle contains the script and the same revision deploys successfully to every other instance in the deployment group.

What explains the failure, and what is the most direct way to get deployments working again?

Select one answer
Show answer and explanation

Answer:

  • C. ApplicationStop runs the AppSpec file and scripts from the *last successfully deployed* revision, which the manual cleanup removed. Create the deployment with the option to continue even if ApplicationStop fails, after which the new revision's scripts become the ones that run

ApplicationStop fires before the new revision is even downloaded, so it cannot use the new revision's files. The CodeDeploy documentation is explicit: "The AppSpec file and scripts used for this deployment lifecycle event are from the previous successfully deployed application revision." The agent finds that revision through the {{deployment-group-id}}_last_successful_install file under the deployment root. Deleting files there leaves a pointer to scripts that no longer exist, so the hook fails on those instances and only those instances. Creating the deployment with the option to ignore ApplicationStop failures lets the deployment get past the stale revision; once it succeeds, the newly installed revision becomes the "last successful" one and future ApplicationStop hooks come from it.

Option A blames the new revision, but the new revision's AppSpec file is not consulted at ApplicationStop at all, which is also why the identical bundle deploys cleanly to the untouched instances. Fixing a path there changes nothing for this event.

Option B misreads the symptom. An agent version mismatch would fail consistently across the deployment group and would not produce a missing-file error tied to the instances an engineer cleaned up by hand.

Option D addresses what happens *after* a failure, not the failure. Automatic rollback redeploys the last known good revision, the very revision whose scripts are missing, so the rollback would hit the same ApplicationStop problem. It never changes which revision supplies the hook.

Reference: AppSpec 'hooks' section

Practice Test 3 ›

Study guides for DOP-C02

AWS Service Control Policies Explained: SCPs and DenialsAWS service control policies explained: how SCPs cap permissions, why admins still get access denied, inheritance, deny vs allow lists and the exam traps.
How AI Is Changing Software Jobs: Where to PrepareHow AI is changing software jobs: what history shows, the evidence on junior developers, what Klarna learned, new AI roles and five domains to prepare for.
How AWS Certification Exams Work: Scoring and RenewalHow AWS certification exams work: levels, booking, question types, unscored questions, scaled scores, pass marks, validity and how recertification works.
What Is Amazon RDS? Multi-AZ, Read Replicas and BackupsWhat is Amazon RDS? Engines, Multi-AZ, read replicas, backups, RDS Proxy, Aurora and pricing explained, with the traps that AWS exams set around each one.
Best DevOps certification: AWS, Azure, Google or CKAThe best DevOps certification for your stack: AWS DOP-C02, Azure AZ-400, Google Cloud DevOps Engineer and CKA compared on cost, level and prerequisites.
What Is AWS Lambda? Triggers, Concurrency and Cold StartsWhat is AWS Lambda? How functions run, cold starts, triggers vs event source mappings, concurrency, layers, aliases, pricing and the exam traps.
AWS CloudOps Engineer Associate (SOA-C03) exam guideAWS Certified CloudOps Engineer – Associate (SOA-C03) replaced SysOps Administrator. Format, cost, the five domains, what changed and how to prepare.
Which AWS certification should you get? 2026 roadmapWhich AWS certification to get first, by role and experience, with each exam's status in October 2026, what is changing, and prices in USD and INR.
What Is Amazon EC2? Instances, AMIs, EBS and Auto ScalingAmazon EC2 explained: instances, AMIs, instance types, security groups, EBS, Auto Scaling groups and pricing options, with the traps AWS exams set.
SQS vs SNS vs EventBridge on AWSWhen to use an SQS queue, an SNS topic or an EventBridge bus, plus fan-out, FIFO ordering, visibility timeouts and dead-letter queues for AWS exams.