Jeff’s Note #
Unlike generic exam dumps, ADH analyzes this scenario through the lens of a Real-World Lead Developer.
For DVA-C02 candidates, the confusion often lies in understanding which Elastic Beanstalk deployment types affect existing instances versus only new ones. In production, this is about knowing exactly how your deployment impacts running environments and user sessions, and minimizing downtime. Let’s drill down.
The Certification Drill (Simulated Question) #
Scenario #
TechWave Solutions develops and manages several web applications hosted on AWS Elastic Beanstalk, running on Amazon EC2 instances. A lead developer needs to deploy configuration changes that must only be applied to new EC2 instances launched after the deployment. Existing instances should remain untouched during this rollout.
The Requirement: #
Identify which Elastic Beanstalk deployment types can be used to deploy changes only to new instances, without impacting existing ones.
The Options #
- A) All at once
- B) Immutable
- C) Rolling
- D) Blue/green
- E) Rolling with additional batch
Google adsense #
leave a comment:
Correct Answer #
B) Immutable
D) Blue/green
Quick Insight: The Developer Imperative #
- Immutable and Blue/Green deployments create new instances with updated configurations, avoiding in-place upgrades on existing instances.
- Rolling and All at once deployments update existing instances directly, which can cause downtime or service disruption.
- Rolling with additional batch mitigates impact somewhat but still updates existing instances incrementally.
Content Locked: The Expert Analysis #
You’ve identified the answer. But do you know the implementation details that separate a Junior from a Senior?
The Expert’s Analysis #
Correct Answer #
Options B (Immutable) and D (Blue/green)
The Winning Logic #
- Immutable Deployment: Elastic Beanstalk launches a full set of new EC2 instances with the updated application version or configuration behind a temporary environment. Once healthy, traffic switches to the new instances, and old instances are terminated. This ensures zero downtime with new instances only touched.
- Blue/Green Deployment: Similar concept, but uses two separate Elastic Beanstalk environments (blue = current, green = new). You deploy changes to the green environment first, then swap production traffic from blue to green, ensuring that only new instances receive changes without disturbing existing ones.
Neither method modifies existing running instances directly, perfectly matching the requirement.
The Trap (Distractor Analysis): #
- A) All at once: Deploys updates by stopping and replacing all instances simultaneously, affecting existing instances immediately; not suitable.
- C) Rolling: Updates batches of running instances sequentially, altering existing instances partially during deployment. Does not meet “new instances only” criteria.
- E) Rolling with additional batch: Adds capacity so more instances remain healthy during rollout, but still updates existing instances; not purely deploying to new instances.
The Technical Blueprint #
# Example CLI command to initiate an immutable deployment via EB CLI
eb deploy --strategy immutable
# Blue/Green deployment usually done by creating a clone environment and swapping CNAMEs
eb clone my-app-env --clone_name my-app-green-env
# Deploy to the new environment
eb deploy my-app-green-env
# Swap environment URLs in the console or CLI
eb swap my-app-env my-app-green-env
The Comparative Analysis #
| Option | API Complexity | Performance Impact | Use Case |
|---|---|---|---|
| A) All at once | Low | High downtime | Fast but disruptive |
| B) Immutable | Medium | Minimal downtime | Safe zero-downtime deployments |
| C) Rolling | Medium | Partial downtime | Gradual rollout, partial impact |
| D) Blue/green | High | Minimal downtime | Full environment swap |
| E) Rolling with addition | Medium-High | Reduced downtime | Safer than rolling but still in-place |
Real-World Application (Practitioner Insight) #
Exam Rule #
For the exam, always pick Immutable or Blue/Green when the question specifies no changes to existing instances only to new ones.
Real World #
In production, developers often prefer Immutable deployments when cost isn’t a constraint, because it guarantees clean, isolated environments. Blue/Green is preferred for complex scenarios involving manual traffic shifting or extended testing.
(CTA) Stop Guessing, Start Mastering #
Disclaimer
This is a study note based on simulated scenarios for the AWS DVA-C02 exam.