Interview questions for Infrastructure engineer

Infrastructure engineers, or IT infrastructure engineers, build, maintain, upgrade, monitor, and coordinate the digital networks and systems that support networked communities. When interviewing infrastructure engineers, suitable candidates will display excellent analytical, problem-solving, and time-management skills, and an in-depth understanding of what is expected of networks and IT systems and how they operate.
You’re designing the routing infrastructure for a large enterprise spread over several campuses, interconnected with a carrier-provided WAN.

1. Would you choose EIGRP or OSPF as the interior gateway routing protocol?

What Most People Say: Most choose one or the other based on their personal preference and experience.
What You Should Say: “Both OSPF and EIGRP are scalable. Both can be configured for equal cost multipath, and both can be tuned for sub-second failover. EIGRP is usually found in heavy Ciscoenvironments. OSPF is found across all networking vendors. However, the choice between OSPF and EIGRP depends on the routing infrastructure requirements and interoperability concerns. I need more information to make a recommendation.

2. May I ask you a few questions?

Why You Should Say It: “This isn’t a multiple choice question even though it sounds like one,” says Banks. “Don’t take the bait. Showcase your design mentality and architectural approach by clarifying the situation before recommending a solution.”

3. Tell me about a time when you influenced the outcome of a project by taking a leadership role.

This question is an opportunity to show the interviewer both your teamwork and leadership skills. Tell the interviewer about a project where your idea was critical to the project’s development or when your team faced a difficult task and it was your idea that enabled your team to complete the task.

“Last summer, I interned at a company that did municipal sewer projects. The community they were working with wanted to obtain funding through a state loan program, and, as you may know, government programs usually have specific requirements for how the requests are put together. Most of the other team members were busy with other work, so I took it upon myself to research the loan requirements and be the primary contact with the state. In the end, the project went wel

4. Why do you think that you will become a Site Reliability Engineer?

I have a practical understanding and working knowledge in DevOps with a deep understanding of:
o The inter-relationship of SRE with DevOps and other popular frameworks
o The underlying principles behind SRE
o Service Level Objectives (SLO’s) and their user focus
o Service Level Indicators (SLI’s) and the modern monitoring landscape
o Error budgets and the associated error budget policies
o Toil and its effect on an organization’s productivity
o Some practical steps that can help to eliminate toil
o Observability as something to indicate the health of a service
o SRE tools, automation techniques, and the importance of security
o Anti-fragility, our approach to failure and failure testing
o The organizational impact that introducing SRE brings

5. Your resume says you’re a Spanning Tree expert. What can you tell me about it?

• What Most People Say: “I don’t know how to describe Spanning Tree. We were running it on our network but the consultants set it up.”
• What You Should Say: “Here’s a high-level overview: Spanning Tree is a loop prevention protocol that detects physical loops in an Ethernet network and blocks links to prevent those loops. It should be configured with specific primary and backup root bridges. Spanning Tree comes in several flavors, including rapid and multiple. Rapid per-VLAN generates a unique Spanning Tree per domain, while multiple maps specific VLANs to specific Spanning Tree instances. Spanning Tree ports can be put in various modes, but not all modes are appropriate for all ports. Spanning Tree has various guards that are used to enforce the spanning-tree topology, including root guard and BPDU guard.

6. Would you like me to explain what these guards do and where they should be placed?

Why You Should Say It: Experts on specific protocols should be able to explain what the protocol is used for and how it should be deployed. Furthermore, they should be able to describe the protocol’s sub-features, how they should be configured and any major concerns related to using the protocol in a production environment. For instance, they should be able to explain point-to-point mode vs. edge mode. Bottom line, says Banks: “Don’t claim to be an expert unless you really are an expert.”

7. Explain Data Structure. Name some data structure?

Data structure is a data organization, management, and storage format that enablesefficient access and modification. More precisely, a data structure is a collection of data values, the relationships among them, and the functions or operations that can be applied to the data.
The types of data structures are listed below:
• Linear: Arrays, lists
• Tree: Binary, heaps
• Graphs: Decision, Acyclic, etc
Hash: Distributed hash table, hash tree, etc

8. How do you find answers to difficult questions?

• What Most People Say: “I go to my technical leader for answers when I’m stumped.”
• What You Should Say: “I love a challenge. So I’ll search the Internet, wikis and dig into books when I encounter a difficult problem. In fact, I’ll research every available resource before escalating a problem to someone else in the organization.”
• Why You Should Say It: Technical leaders have enough on their plates. They’re looking for curious and motivated self-starters who want to learn and grow. “Represent yourself as a contributor to ace the interview,” says Banks. “The ability to solve difficult problems and work independently not only appeals to managers, it increases your value as an engineer.”

9. What activity means Reducing Toil?

Activities that can reduce toil are:
1. Creating external automation
2. Creating internal automation
3. Enhancing the service to not require maintenance intervention.
9. Define Service Level Indicators
A Service Level Indicator (SLI) is a measure of the service level provided by a service provider to a customer. SLIs form the basis of Service Level Objectives (SLOs), which in turn form the basis of Service Level Agreements (SLAs). An SLI can also be called an SLA metric.
Although every system is different in the services provided, common SLIs are used pretty often. Common SLIs include latency, throughput, availability, and error rate; others include durability (in storage systems), end-to-end latency (for complex data processing systems, especially pipelines), and correctness.