.How to pass the AWS Developer Associate DVA-C02 exam

Certification is an important step for every developer who uses AWS. It proves the ability to use various AWS services in accordance with best architecture practices. What is worth even more - it aggregates the latest knowledge required to operate in AWS on a certain level. On February 28th 2023 the Developer Associate exam was updated and has a version DVA-C02 from that day on. I passed this version of the exam and in this blogpost will share my insights on how the exam is structured as well as some tips that helped in my preparation.

General structure

As the name suggests, the main topic you will be tested in is Development. In the following table you can see all the domains an exam will cover as well as the "weight" of each topic in percentages.

Detailed description of skills, domains and other useful info can be found on this link.

The exam has a time limit of 130 minutes and consists of 65 questions which is referred to as "exam form". Results of the exam are scored on a scale from 100 to 1000 with the passing score of 720. Exam forms might slightly differ on difficulty level. That is why scoring is "scaled", which in practice means that an applicant with a more difficult exam form will have to answer fewer questions correctly in order to receive the same score as an applicant with a less difficult one. Each question can be:

• Multiple Choice (1 correct response among 4 options).
• Multiple Response (2 or more correct responses among 5 or more options).

Fun fact - among 65 questions there are 15 unscored ones that are used for collecting data by AWS and in future might be included as scored. An applicant does not know which questions are scored and which aren't.

Questions

Let's get to the heart of the exam - questions. They differ in size and difficulty greatly: from one-liners with a single word for an answer, up to scenario-based, very verbose ones that can occupy a significant portion of your screen. Those "biggies" could be intimidating at first glance, especially with a clock ticking in the corner of your screen mercilessly. Here I will share some tips, that helped me to deal with difficult ones better:

• Work backwards - read the last line first and, with that information, read from the start. It will help you to make sense of the question faster by figuring out what is important and what is just a distraction.
• Look for the keywords - there might be several viable options for a single question, but the keyword could help you find the correct one. For example, if "serverless" is present in a question, you will very likely have to exclude EC2 - based answers.
• Use process of elimination - usually there are some options that are definitely wrong, by eliminating those right away you simplify a task greatly and also save time for future questions.

Example question

Let's dissect an example question from official AWS Developer Associate sample questions.

A company is migrating a legacy application to Amazon EC2 instances. The application uses a user name and password that are stored in the source code to connect to a MySQL database. The company will migrate the database to an Amazon RDS for MySQL DB instance. As part of the migration, the company needs to implement a secure way to store and automatically rotate the database credentials.

Which solution will meet these requirements?

A) Store the database credentials in environment variables in an Amazon Machine Image (AMI). Rotate the credentials by replacing the AMI.

B) Store the database credentials in AWS Systems Manager Parameter Store. Configure Parameter Store to automatically rotate the credentials.

C) Store the database credentials in environment variables on the EC2 instances. Rotate the credentials by relaunching the EC2 instances.

D) Store the database credentials in AWS Secrets Manager. Configure Secrets Manager to automatically rotate the credentials.

Let's apply our tips. Reading through the last sentence we find our keywords "automatically rotate database credentials". With this information we read from the start and find that we have to store credentials for "Amazon RDS for MySQL", and that would be our additional keywords. With this information in mind let's go through the answers:

• A) AMI (Amazon Machine Image) has nothing to do with environment variables. It is just a specific value of an EC2 instance's image, that can be used in AWS. This option is obviously incorrect.
• B) AWS Systems Parameter Store is used for storing credentials, parameters, variables, etc. However in order to implement automatic secrets rotation it is necessary to write a custom function. This option is better, but not perfect.
• C) It is possible to store Database credentials in EC2 environment variables, but it is a bad practice, since it involves security risks. Anyone with access to EC2 could have an access to these credentials. This option is incorrect.
• D) AWS Secrets Manager is used for storing credentials, it has an automatic secrets rotation option and has a direct integration with Amazon RDS. These factors make this answer a best possible, therefore correct option.

Preparation

Before I started my preparation I had an opportunity to work on a project serverless solution in AWS for 2 months. It gave me practical perspective on development in AWS. After that, it took me just over 2 weeks of full-time studying to get ready for the exam. It worked well, but in future I would take it slower and give myself more time to prepare. Considering that you have less than a year experience with AWS services, if you spend 2 hours per day, it would take 2-3 months to get ready for the exam.

Here are some tips and useful links, that I used in my preparation:

• Build in AWS. Problem-solving and repetition make you remember things better than any existing course.
• Good theoretical preparation is still very important. Therefore, in order to solidify my knowledge I went through the following:
  • AWS official practice questions test.
  • Stephane Maarek's course on Udemy - he knows how to explain complex ideas in a simple way, the material is precise, hands-on parts are on point.
  • Tutorials Dojo practice exam - very well-composed questions with detailed explanation of correct and incorrect answers.
  • Examtopics community-driven library of exam questions: DVA-C01 (huge set of still applicable questions) and DVA-C02 (smaller but growing set of the newest questions).

Conclusion

Exams and tests are often considered a nuisance, not too valuable part of one's job, that you have to get over with ASAP in order to do the real work. In case of AWS exams, I will challenge this statement. It is definitely important to balance your time between work and learning, but those two should go hand in hand. In my experience, you can learn a great deal and prepare yourself for a real-life scenarios, while studying for the exam. And the cherry on top will be a certificate that validates your skills.