VMware vSphere: Install, Configure, Manage [V8] interview questions

A snapshot captures a VM’s disk (and optionally memory) state at a point in time by creating delta files; new writes go to the delta. It is for short-lived rollback (e.g. before patching). It is not a backup: it depends on the original disks, grows and hurts performance over time, and can fill the datastore. Consolidate/delete snapshots promptly and use a real backup product.

Check CPU ready time (VM waiting for CPU), memory ballooning/swapping (host memory pressure), storage latency (datastore/device latency, DAVG/KAVG in esxtop) and network dropped packets. High CPU ready points to contention; swapping points to overcommitted memory; high storage latency points to the storage path. esxtop and vCenter performance charts are the tools.

Be specific and show it is a habit: hands-on labs and home projects, following release notes and a few trusted sources, a certification roadmap, reading other people’s code or post-mortems, and teaching others to cement what you learn. Tie it to this role’s stack. Enthusiasm plus a concrete routine beats a vague "I love learning".

Pick a real failure and own it without blaming others. Describe how you contained the impact, communicated honestly, fixed the root cause (not just the symptom), and added a safeguard — a test, a monitor, a checklist, a runbook — so it cannot recur. Interviewers want accountability and a blameless, learning mindset, not a claim that you never fail.

vSphere uses role-based access control: assign a role (a set of privileges) to a user/group on an inventory object, and it propagates to children. Create or use a role like "Virtual Machine Power User", then assign it to the operator on that VM folder only. Permissions elsewhere are unaffected, enforcing least privilege.

VMFS is a clustered filesystem on block storage (FC/iSCSI/local) that lets multiple hosts share a datastore. vSAN pools the local disks of cluster hosts into a single software-defined, policy-based datastore, removing the need for a separate SAN. vSAN uses storage policies (failures to tolerate, stripe width) applied per VM/disk.

vSphere HA monitors hosts and, if one fails, restarts its VMs on the remaining hosts in the cluster. Admission control reserves enough spare capacity so those restarts can actually happen — if adding a VM would break that guarantee, admission control blocks power-on. You size it by host failures to tolerate, a percentage, or a dedicated failover host.

Use the STAR method: briefly set the Situation and Task, then spend most of your answer on the Action — how you broke the problem down, what you tried, how you tested — and finish with the Result and what you learned. Pick a real example with a measurable outcome (time saved, outage resolved) and show your reasoning, not just the fix.

Protect the business first: a production outage affecting users usually wins. State your rule — impact and urgency over who is shouting loudest — communicate quickly to set expectations, delegate or ask for help, and park or renegotiate the lower-impact items with their owners. Show calm, a clear framework, and that you keep people informed.

ESXi is the bare-metal hypervisor that runs VMs on a physical host. vCenter Server centrally manages many ESXi hosts, providing features like vMotion, DRS and HA. A cluster is a group of hosts managed together so vCenter can balance load (DRS) and restart VMs on failure (HA) across them.

Explain how you gathered the facts you could quickly, identified the biggest risk, made a reversible decision where possible, and set a point to re-evaluate. Note how you communicated the uncertainty and your assumptions. Show judgement and bias for action — making a sound call and adjusting beats waiting for perfect information.

Distributed Resource Scheduler balances CPU and memory load across a cluster by live-migrating (vMotion) VMs. It compares each host’s load to the cluster average and makes recommendations; in fully automated mode it applies them. Migration thresholds and VM/host affinity rules tune how aggressively and where it moves VMs.

Set a cadence and a single source of truth: short, regular updates in plain language with status, impact, next step and ETA — even when the news is "no change yet". Tailor the detail to the audience and never let people find out bad news late. Reliable, proactive communication builds the trust that lets you do the technical work.

A standard switch is configured per host; a distributed switch is configured once in vCenter and spans all hosts, keeping networking consistent. vDS adds features like Network I/O Control, port mirroring, LACP, private VLANs and health checks, and it preserves network state during vMotion. It centralizes and simplifies large deployments.

Show that you separated the person from the problem. Explain how you listened to their reasoning, brought data or a small proof of concept instead of opinions, looked for the shared goal (reliability, deadline, cost), and either reached agreement or disagreed-and-committed to the team’s decision. Avoid blaming; emphasise the outcome and the relationship staying intact.

Lead with the impact in their terms (cost, risk, time, customers affected), not the technical cause. Use a simple analogy, avoid jargon, and offer a clear recommendation with options and trade-offs. Confirm they have understood and tell them what you need from them. The goal is a confident decision, not to show how much you know.

Use vSphere Lifecycle Manager (vLCM). You define a desired image (ESXi version, vendor add-ons, firmware) for the cluster; vLCM checks compliance and remediates hosts to match, coordinating with DRS to evacuate VMs and enter maintenance mode first. It replaces the older baseline-based Update Manager workflow.

Give a concrete example: how you set clear expectations, paired on real work, let them struggle productively before stepping in, gave specific feedback, and gradually handed over ownership. Mention a result — they shipped something, passed a certification, became independent. Leadership is about multiplying others, not doing it all yourself.

Connect your answer to the actual job and company: what about the work, the stack or the mission fits your strengths and goals. For the three-year question, show healthy ambition and direction (deeper expertise, more ownership, perhaps leading) that the company could realistically support, so it reads as commitment, not a stepping stone.

Shared compatibility: a vMotion-enabled VMkernel adapter on both hosts, network connectivity (ideally a dedicated/fast network), CPU compatibility (or Enhanced vMotion Compatibility, EVC, to mask CPU differences), and access to the VM’s files — shared storage, or vMotion can also move storage. The VM must have no host-only devices attached.