Common Interview Question Candidates get Wrong: High Availability (Yes, really!)


Hello Reader,

Not all questions are equal in interviews and real-world projects. There are some questions that you simply can't mess up, because these concepts are so fundamental, they are used in almost ALL projects.

One such concept is high availability. Surprisingly, I hear wrong answers on this all the time. In this edition, let's go over the common bad answers, a good answer, and then some!

Question: What is High Availability?

Bad Answers

  • Even if a component fails, application should still be up
  • The application should fall back to another region in case of a disaster
  • In case of a failure, application should be able to serve traffic at same rate

Now, the important part to understand is why are these bad answers:

  • Interviewer is looking to see if you know the distinction between different redundancy and failover mechanisms
  • These are not specific and general broad answer

Let's take a look at a good answer and get our concepts cleared.

Good Answer

  • The term "High Availability" itself hints at the correct concept. "Availability" is tied to Availability Zones (AZ).
  • And High Availability simply means in the unlikely event of an Availability Zone failure, your application should still be up and running

BUT, though this is a good answer, we aim for DELIGHT. Many candidates will give the above answer, but in this competitive market, you have to set yourself apart.

Delightful Answer

Explain what High Availability means from the "Good Answer". Then add, "Let me give you an example. You have a three-tier app running in ALB to EC2 to ALB to EC2 to DynamoDB."

"The ALB and DynamoDB are inherently highly available. Now, to make this whole application highly available, we need to provision another EC2 in another Availability Zone. And now, even if one AZ goes down, application will still be up and running"

Be honest - did you guess the answer correctly, or were your concepts little fuzzy 😉? There are many such questions, where you simply can NOT falter, else you'd get rejected. Check out those questions, bad answers, why are they bad, and delighful answers in this video:

video preview

Make sure to knock out these answers out of the park. Onwards and upwards 🙌🚀

If you have found this newsletter helpful, and want to support me 🙏:

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Keep learning and keep rocking 🚀,

Raj

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