Hi everyone. I got placed as Cloud Support Associate at AWS Bangalore in November 2019. I’d like to share my experience of the entire selection process at AWS. I’ll try my best to make it as informative as possible.
First round is Online Test (no negative marking). It was held on campus itself in assigned labs. The test is divided into four main sections:
- Aptitude: This section had 20 MCQ questions based on mathematical aptitude, logical reasoning and general reasoning. Questions on Indiabix website and mock tests held by hashtagplaced are more than enough to prepare for this round. Questions were of easy-moderate difficulty.
- Operating Systems, DBMS and Computer Networks: This section had moderate-difficult level questions based on OS, DBMS, CN and troubleshooting. If you have a good grasp over the subjects then it wont be difficult to ace this round. Geeksforgeeks is the best forum to practice OS and CN questions.
- Coding: This section had 2 questions. One question was easy and could be done in 8-10 minutes, whereas the second question was of moderate difficulty. In order to pass this round one must fully solve at least one of the questions with all test cases being passed. This section had to be completed in 30 minutes.
How I cleared the round: Since I was focusing on many non tech companies as well, I was preparing for aptitude questions. Questions on Indiabix cover almost every topic required. I was confident in around 70-80% of the questions in aptitude. For me revising the class notes and slides of previous semester was more than enough to prepare for OS and CN. The key to ace this section is going with an educated guess.
Among 600 students who gave the online test, 54 were selected for the interviews. We were called for interviews after a week the test was held.
There were four rounds of interviews, all knockout rounds and were held on the same day. It will be a very long day for you, so I suggest you to be prepared.
Interview 1: This interview is based completely on Networking concepts. They expect you to answer in complete depth and be as detailed as possible. It is very normal for interviewer to keep typing on laptop to record your answers while you speak, so speak only what you are sure about, but do not be intimidated by it. A few questions that were asked:
- Suppose I have a brand new laptop and I wish to connect it to the internet. What should I do, and what shall happen in background before the laptop is connected to the internet? (Ans. Manually assigning IP address or DHCP and DORA procedure. They expect you to explain in depth about DHCP and DORA)
- What happens in background when I write www.amazon.com on my web browser and hit enter? (Ans. Complete process starting from how IP address request is sent from browser to OS to the DNS resolver and further, and how IP address is sent back to browser; after which the three-way-handshake procedure to establish TCP connection, and then how a request and response is generated followed by interpretation of HTML and Javascript along with images/sounds. https://medium.com/@maneesha.wijesinghe1/what-happens-when-you-type-an-url-in-the-browser-and-press-enter-bb0aa2449c1a)
- What are few methods of HTTP, what is HTTPs, is the port number different for HTTPs, how is SSL related to HTTPs, explain SSL handshake?
- How is a hub, a router, and a switch different from each other? Explain in terms of broadcast domain.
- As MSS was explained in TCP 3 way handshake, explain what is MTU and compare and contrast MSS and MTU together.
- Explain in depth what is TCP and UDP. Compare and contrast both of them.
- What methods are available to us in flow control and error detection/correction?
- What is public IP? How is it different from private IP? Can I connect to the internet using private IP? What is NAT?
Other important topics for AWS Networking Interview- Subnetting, OSI model with complete details and protocols on each layer, firewall in detail with all types (advantages/disadvantages)
Interview 2: This round was based on Operating Systems and troubleshooting. Just like Interview 1, they expect you to answer in depth. Some of the questions asked were:
- What are different types of memory present in a computer?
- Explain the concept of virtual memory. If it’s not present in hardware, how does it store data? Explain framing, segmentation and paging.
- Explain the entire boot process of windows. (choice was given between Windows and Linux)
- What is cache? What are its different types? Explain the entire process of searching in memory using hit and miss.
- A memory shortage scenario was given and LRU algorithm was asked in a twisted form.
- Troubleshooting: I am not able to connect to the internet. I do not have a spare device with me. Troubleshoot the scenario and figure out where does the issue lie? (Ans. Issue can lie with the device, or the network, or from the server side. This needs to be answered strategically from the most common issue raised first, to the least common possibility addressed last)
- Troubleshooting: My device is heating up very quickly. Troubleshoot the scenario.
- Troubleshooting: I am trying to transfer media over FTP from one device to another. The rate of transfer is very slow. Troubleshoot the scenario.
- Brief questions related to my major project (7th semester) and related technology were asked towards the end of the interview.
Other important topics for AWS Operating Systems and Troubleshooting interview: OS boot process (Win/Linux); Memory management ;Memory pages; Buffer and Caches, Basic commands; System date/time management, network time protocol; Managing Users and groups; File permissions; Managing softwares – installation, uninstallation, upgrade etc; Managing system services and background processes; Remote management of a system – SSH, RDP etc; Network protocols – FTP, HTTP (web servers), SMTP (mail server); System automation – cron, batch jobs, windows startup tasks
How I cracked the tech rounds: I was very well prepared for networking and all of my concepts were strong. I was confident in more than 95% questions asked in Networking interview. However I was not prepared for OS/Troubleshooting at all. The key to crack the interview is be confident and have the right approach towards a question you aren’t certain about. Ask a lot of questions to get a better clarity of the questions, be open to the prompts provided in between your answer by the interviewer. At the end of the interview always ask for a feedback. That is when my interviewer pointed out that I did not brush my concepts of OS very well, however she liked my approach towards the answers.
Interview 3: Managerial Round- A senior manager from AWS will be taking this interview. It was very conversational and was based mostly on CV. All questions were asked in a completely non technical perspective, but had to be answered pertaining to previous professional tech experiences (be it academic, or internship related), and not in a generalised form. A few questions asked were:
- Discuss a time when one of your colleagues struggled and you helped them out. How did it go?
- Was there any time in your life when you received a critical feedback? If yes, how did you react to it and how did you implement it? (Ans. Never answer that this never happened to you, for obvious reasons)
- Why do you want to be a part of AWS and not any analytics firm? (This was asked because I did my summer industrial training in analytics)
Interview 4: HR Round- This round was also based on CV and they were constantly pushing me to answer general questions using past experiences. Never make up a story in this round because they usually ask a lot of details of the story, even if they are not significant. It was a general conversational round and were just checking my emotional quotient. It will be a plus if you prepared for this interview with the 14 leadership principles of Amazon.
The interviewers were very understanding and gave their best to make sure we as students feel a comfortable space. I really liked how all of them ensured I was okay with the room and asked me to take this more as a discussion and less as an interview. All of them gave constructive feedback, upon request of course. Overall it was a great experience.