8 Distributed Systems Interview Questions (With Answers)

Updated 19 September 2023

Distributed systems are an important development in information technology and computer science fields. Using distributed systems, professionals can build and enhance stand-alone applications. If you want to work with networking, system security or cloud computing, it is important to be familiar with some commonly asked interview questions to increase your chances of getting hired. In this article, we list various distributed systems interview questions and share sample answers and highlight some tips to help you prepare for your interview.

8 Distributed Systems Interview Questions With Sample Answers

Distributed systems interview questions include a mix of situational, general and technical questions that help hiring managers determine if you are a suitable candidate for the role. They use these questions to determine your understanding of concepts, your professional background and your experience. Here are some examples of responses you can use as a guide:

1. What excites you about distributed systems?

Hiring managers may ask this question to understand your interest in distributed systems. You can share your area of interest, for instance, application protocols for large-scale distributed systems.

Example answer: "Achieving scalability excites me the most when working with distributed systems. Scalable systems help meet users' needs and achieve high reliability and performance. In my last job, I assisted my peers in enhancing scalability by implementing the Byzantine model. The model helped in tackling arbitrary failures from failing nodes."

2. Can you name some security mechanisms used in distributed systems?

Security in distributed systems is of critical importance to protect network components and servers from malicious parties. Interviewers may ask this question to learn if you know the risks and security mechanisms associated with distributed systems. You can share your experience working with automated systems.

Example answer: 'There are various security mechanisms used in distributed systems, ranging from physical and electronic security of system components, access control mechanisms, authentication mechanisms and communication security mechanisms. Two common mechanisms in ensuring communication security include encryption and traffic padding.

A major aspect of computer and communications security is encryption, which encrypts plaintext into ciphertext, which makes the message unreadable and decrypts it back into readable plaintext. A traffic padding technique conceals messages on a communication line by inserting dummy messages to maintain a uniform level of traffic at all times.'

3. What are the challenges in designing a distributed system?

Distributed systems pose several correlating risks. Your interviewer may ask you this question to evaluate your risk management skills. You can share your experience by mentioning the challenges you encountered in your previous job.

Example answer: "As a developer, I know how challenging it is to scale distributed systems. The first challenge when designing a distributed system is the increasing number of users and the amount of data processed. It is essential for a system to function smoothly without experiencing downtime or slowing down. It is also important that the system is fault-tolerant, which enables it to function even if one or more of its components fail. A secure system prevents sensitive data from being compromised. The system also requires to be resilient to unexpected events, like power outages or network issues."

4. How do distributed systems use access control?

Access control is an important security concept for regulating who can access and use computer resources. This question aims to understand your knowledge of access control policies and security risks.

Example answer: 'Attribute-based access control is one of the well-adapted methodologies for distributed systems. It helps control access to objects and processes and manage access rights by evaluating a set of policies, relationships and rules. This dynamic method allows access to resources and users based on attributes such as time of day and location.'

5. What are the different distributed deployments?

Distributed deployments can help enhance the performance and scalability of different systems. Recruiters may ask this question to know your expertise in data collection and the ability to handle spikes and anomalies.

Example answer: 'There are various distributed deployments which include departmental, small enterprise, medium enterprise and large enterprise, depending on the size of the deployment. Organisations can consider other factors apart from size and complexities, which include data centre capacity, computer network size and capacity, requirements for fidelity and availability of data, data consumption, whether they plan on running processes periodically or ad hoc and the number of users accessing the system.'

6. What is the requirement of fault tolerance systems?

Fault tolerance provides three main features to distributed systems, such as reliability, availability and security. Interviewers may ask this question to understand if you can implement fault tolerance techniques on the design, configuration and application of distributed systems.

Example answer: 'Distributed computing requires a fault tolerance system that keeps the system running in the event of failures. A key goal is maintaining the system's functionality even if a part malfunctions or fails. Reliable systems are fault tolerant. There are several useful requirements for a fault tolerance system, including availability, reliability, safety and maintainability.

The availability of a system refers to its readiness to deliver its functions to its users and work at any instant in time. The reliability of a system refers to its ability to operate continuously without failure over time. Systems with high reliability work continuously for longer durations without interruption. Safety refers to when a system cannot perform its function accurately and cannot execute its corresponding process, yet no casualty happens. A highly maintainable system is also highly accessible, especially if it is easy to fix any defects mechanically.'

7. What is the CAP theorem?

The knowledge of the consistence-availability-partition (CAP) tolerance theorem is essential when building cloud applications. A potential employer may ask this question to determine your ability to design shared networks and systems. Below is a sample answer:

Example answer: 'According to the CAP theorem, a distributed system cannot guarantee C, A and P simultaneously. At most, it can provide two out of three guarantees. A database operation requires preserving data consistency after its execution. Availability determines that databases require to be available and responsive at all times, with no downtime. Partition tolerance refers to databases continuing to operate when communication becomes unstable.'

8. Describe the different distributed computing network topologies.

A network topology describes the connection between computer systems and network devices. Knowledge of network topologies shows interviewers you understand how the topologies links end users and data centres.

Example answer: 'Bus topologies, star topologies and ring topologies are the three most common network topologies in distributed computing. Bus topologies connect various nodes in a network to a common bus or main line. The star topology links each node to a central node. The ring topology connects every node together in the network in a loop.'

Tips For The Interview

Here are some tips that can help you during interviews:

Learn more about the company

Researching companies before interviews can help you gain a competitive advantage over other candidates. It can also help you understand the organisational goals and be prepared for the new job role. Go through the company history, defining moments and past successes. You can visit the company site and visit their About Us page, connect with the current employees, understand the company culture and search the competitors. Visit the company site and read their blog, white paper and case studies to understand the company better.

Understand the job role

As a potential employee, it is important to understand the job role and responsibilities before an interview. Make sure that your resume and cover letter include keywords from the job description, since interviewers are often looking for specific qualifications. You can be better prepared for the interview if you have a general understanding of the company's clients and products or services.

Conduct mock interviews

Practise for a job interview to help you get familiarised with the actual interview process, enhance your interview skills and improve your hiring prospects. For instance, you can prepare mixed interview questions and record yourself answering the questions. The topics that you can focus on include distributed system fundamentals, the architecture of large-scale web applications and the design of real-world systems. You can then review your performance based on your body language, posture, choice of words and confidence and make notes on improvement.