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DevOps Rapid-Fire Questions & Answers

50 questions for the rapid-fire stage — 33 easy, 17 medium.

About the rapid-fire round

Rapid-fire questions are quick definitions and one-line answers that interviewers fire at the start or end of a round to check your DevOps basics. Aim to answer each in under 20 seconds.

Tips for the rapid-fire round

  • Answer in one or two sentences, then stop.
  • If you don't know, say so quickly and move on; don't guess at length.
  • Revise these the morning of the interview.
  • Practise with a friend who reads them in random order.
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01

What does git cherry-pick do?

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git cherry-pick <hash> applies the changes of one specific commit onto your current branch as a new commit. It is useful to bring a hotfix from main into a release branch without merging everything else. Overusing it creates duplicate commits with different hashes and can cause confusing conflicts later, so prefer merging when you need a whole set of changes.
02

What is the difference between a hard link and a soft link?

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A hard link is another directory entry pointing to the same inode, so the data survives until every hard link is deleted; it cannot cross file systems or point to directories. A soft (symbolic) link is a small file that stores a path to the target; it can cross file systems and point to directories, but it breaks if the target is moved or deleted.
03

What does idempotency mean in Ansible?

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Idempotency means running the same playbook many times gives the same result without unwanted changes. Modules check current state first: the apt module installs a package only if missing and reports ok instead of changed. The shell and command modules are not idempotent by default, so use creates, removes or changed_when conditions, or prefer a dedicated module.
04

What is the difference between CMD and ENTRYPOINT?

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ENTRYPOINT defines the main executable that always runs, while CMD provides default arguments or a default command that can be overridden from docker run. For example, ENTRYPOINT ["python", "app.py"] with CMD ["--port", "8000"] lets users change only the port. Use the exec (JSON array) form so the process runs as PID 1 and receives signals properly.
05

Explain the Kubernetes Service types ClusterIP, NodePort and LoadBalancer.

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A Service gives pods a stable IP and DNS name and load balances across them using label selectors. ClusterIP, the default, is reachable only inside the cluster. NodePort also opens a port, 30000 to 32767, on every node. LoadBalancer additionally asks the cloud provider to create an external load balancer pointing to the service. Each type builds on the previous one.
06

How do an Application Load Balancer and an Auto Scaling group work together?

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The Auto Scaling group launches EC2 instances from a launch template across several Availability Zones and keeps the count between min and max, scaling on policies such as target 60 percent CPU. It registers instances with the ALB's target group. The ALB spreads HTTP traffic across healthy targets, routes by path or host, and health checks let the group replace failed instances.
07

What is an artefact repository and why is it used?

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An artefact repository such as Nexus, JFrog Artifactory or a container registry stores versioned build outputs like JAR files, npm packages and Docker images. The pipeline builds once and promotes the same artefact through dev, staging and production, so what you tested is exactly what you deploy. It also caches public dependencies, speeds up builds and keeps release history for rollbacks.
08

What is the difference between a Pod, a ReplicaSet and a Deployment?

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A Pod is the smallest deployable unit: one or more containers sharing network and storage. A ReplicaSet keeps a specified number of identical pods running. A Deployment manages ReplicaSets and adds rolling updates and rollbacks by creating a new ReplicaSet for each version. In practice you create Deployments and rarely touch ReplicaSets or bare pods directly.
09

What is the difference between git revert and git reset?

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git revert creates a new commit that undoes the changes of an earlier commit, leaving history intact, so it is safe on shared branches like main. git reset moves the branch pointer backwards and removes commits from the branch history, which is fine locally but forces others to deal with rewritten history if already pushed. Use revert for anything already public.
10

Explain stdin, stdout, stderr and what 2>&1 means.

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Every process gets three file descriptors: 0 is stdin, 1 is stdout and 2 is stderr. > redirects stdout to a file, 2> redirects errors, and 2>&1 sends stderr to wherever stdout currently points. So command > out.log 2>&1 captures both normal output and errors in one file. Order matters: 2>&1 placed before > out.log would still print errors to the terminal.
11

Explain Linux file permissions and what chmod 755 means.

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Every file has read (4), write (2) and execute (1) bits for three classes: owner, group and others. chmod 755 gives the owner 7 (read, write, execute) and gives group and others 5 (read, execute). It is typical for scripts and directories that everyone may run or enter but only the owner may change. Use ls -l to see permissions.
12

Explain git reset --soft, --mixed and --hard.

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All three move the current branch pointer to another commit. --soft keeps your changes staged, useful for recombining commits. --mixed, the default, keeps changes in the working directory but unstaged. --hard discards changes in both staging and working directory, so uncommitted work is lost. Lost commits can usually still be found with git reflog for a while.
13

What is git stash and when do you use it?

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git stash saves your uncommitted changes and cleans the working directory, so you can switch branches for an urgent fix. git stash list shows saved entries, git stash pop reapplies the latest and removes it, and git stash apply keeps it. Use git stash -u to include untracked files. It is a short-term tool; for longer work, commit on a branch.
14

Explain Ansible architecture: inventory, modules and playbooks.

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Ansible runs from a control node and connects to managed hosts over SSH, or WinRM for Windows, with no agent needed. The inventory lists hosts and groups. Modules are units of work like apt, copy or service. Playbooks are YAML files containing plays that map host groups to ordered tasks. Variables, templates with Jinja2 and roles organise larger automation.
15

What is a webhook and how does it trigger a build?

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A webhook is an HTTP callback: when an event happens in the Git server, such as a push or pull request, it sends a POST request with event details to a configured URL. Jenkins or another CI tool receives it and starts the matching pipeline immediately. This is better than polling the repository every few minutes, which wastes resources and delays feedback.
16

What is a DaemonSet and when is it used?

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A DaemonSet makes sure one copy of a pod runs on every node, or on a selected group of nodes. When a node joins the cluster, the pod is added automatically. It is used for node-level agents such as log collectors like Fluent Bit, monitoring agents like the Prometheus node exporter, and CNI or storage plugins.
17

What is the difference between kill, kill -15 and kill -9?

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kill sends SIGTERM (15) by default, which asks the process to stop so it can close files, finish requests and clean up. kill -9 sends SIGKILL, which the kernel enforces immediately; the process cannot catch it, so data may be lost and temp files left behind. Always try SIGTERM first and use SIGKILL only when the process does not respond.
18

What is the AWS shared responsibility model?

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AWS is responsible for security of the cloud: physical data centres, hardware, the network and the hypervisor. The customer is responsible for security in the cloud: IAM, data encryption, OS patching on EC2, security groups and application code. The split shifts with the service; for managed services like RDS or Lambda, AWS handles more of the underlying patching.
19

What is the Terraform state file and why is it important?

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terraform.tfstate maps the resources in your code to real resources in the cloud, storing their IDs and attributes. Terraform compares code, state and reality to decide what to create, change or destroy. Without it Terraform would not know what it manages. It may contain secrets in plain text, so store it in a secure remote backend, never in Git.
20

What are zombie and orphan processes?

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A zombie is a process that has exited but whose parent has not yet read its exit status with wait(), so it still holds a PID entry and shows state Z. An orphan is a running process whose parent died; it is adopted by PID 1, which reaps it later. Many zombies indicate a buggy parent; fixing or restarting the parent clears them.
21

What are the typical stages of a CI/CD pipeline?

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A common pipeline is checkout, build or compile, unit tests, static analysis and security scans, packaging into an artefact or container image, pushing to a registry, deploying to a test or staging environment, running integration or smoke tests, an approval gate, and production deployment with monitoring. Fast checks run first so developers get feedback within minutes and slow tests run later.
22

What is Kubernetes and why do companies use it?

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Kubernetes is an open-source container orchestration platform. You declare the desired state, such as five replicas of an API, and it schedules containers across nodes, restarts failed ones, scales them, balances traffic and rolls out updates. Companies use it to run many microservices reliably on shared infrastructure, on any cloud or on-premises, through managed services like EKS, AKS and GKE.
23

What is the difference between a Docker image and a container?

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An image is a read-only template made of layers, containing the application, libraries and configuration, built from a Dockerfile. A container is a running instance of an image with a thin writable layer on top. You can start many containers from one image. Changes made inside a container are lost when it is removed unless they are stored in volumes.
24

Explain the basic Terraform workflow.

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terraform init downloads providers and modules and configures the backend. terraform fmt and validate check style and syntax. terraform plan shows what will be created, changed or destroyed without making changes. terraform apply executes the plan after confirmation. terraform destroy removes all managed resources. In CI, save the plan with -out and apply that exact plan after review.
25

What is the difference between git fetch and git pull?

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git fetch downloads new commits and branches from the remote into remote-tracking branches like origin/main without touching your working files. git pull is fetch followed by merge (or rebase if configured) into your current branch. Fetch is safer when you want to inspect incoming changes first with git log main..origin/main before integrating them.
26

What is the difference between a ConfigMap and a Secret?

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Both inject configuration into pods as environment variables or mounted files, keeping config out of images. ConfigMaps hold non-sensitive data like URLs and feature flags. Secrets hold sensitive values like passwords and tokens; they are only base64 encoded by default, so you should enable encryption at rest, restrict access with RBAC, or use an external secrets manager.
27

What are AWS Regions, Availability Zones and edge locations?

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A Region is a geographic area such as ap-south-1 in Mumbai or ap-south-2 in Hyderabad, fully independent from others. Each Region has multiple Availability Zones, which are separate data centres with independent power and networking, linked by low-latency connections. Edge locations are smaller sites used by CloudFront and Route 53 to cache content and answer DNS close to users.
28

What is the difference between sudo and su?

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su switches to another user, usually root, and needs that user's password, giving a full shell as them. sudo runs a single command with elevated rights using your own password, and is controlled by rules in /etc/sudoers. sudo is preferred in teams because each action is logged against the real user and access can be limited to specific commands.
29

What is the difference between COPY and ADD in a Dockerfile?

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COPY copies local files and directories into the image and does nothing else. ADD can also download from a URL and automatically extracts local tar archives. Because that extra behaviour can be surprising, best practice is to use COPY by default and ADD only when you specifically want tar extraction. For downloads, use curl in a RUN step so you can verify checksums.
30

What is the difference between a process and a thread in Linux?

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A process is a running program with its own address space, file descriptors and PID. A thread is a unit of execution inside a process that shares the same memory and open files with other threads. Creating threads is cheaper and they communicate easily, but a bug in one thread can crash the whole process, while separate processes are isolated from each other.
31

What is an inode in Linux?

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An inode is a data structure that stores a file's metadata: owner, permissions, size, timestamps, link count and pointers to data blocks, but not the file name. Names live in directory entries that map to inode numbers. A file system has a fixed number of inodes, so millions of tiny files can exhaust them while disk space is still free; check with df -i.
32

What is the ELK or EFK stack?

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ELK is Elasticsearch, Logstash and Kibana: Logstash or Beats collect and parse logs, Elasticsearch stores and indexes them, and Kibana provides search and dashboards. EFK replaces Logstash with Fluentd or Fluent Bit, which is common in Kubernetes as a DaemonSet. Centralised logging lets you search across all servers and containers in one place instead of SSH-ing into each.
33

What are the four golden signals, and the RED and USE methods?

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The four golden signals are latency, traffic, errors and saturation. RED, for request-driven services, tracks rate, errors and duration. USE, for resources such as CPU, disks and network, tracks utilisation, saturation and errors. RED tells you whether users are hurting; USE helps find which resource is the bottleneck. Together they give a solid starting set of dashboards and alerts.
34

What is the difference between a container and a virtual machine?

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A virtual machine runs a full guest operating system on a hypervisor, so it is heavier, takes minutes to boot and uses gigabytes. A container shares the host kernel and isolates only the application and its dependencies using namespaces and cgroups, so it starts in seconds and uses far less memory. VMs give stronger isolation; containers give density and portability.
35

What is .gitignore and how do you stop tracking a file that is already committed?

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A .gitignore file lists patterns such as node_modules/, *.log or .env that Git should not track. It only affects untracked files, so a file already committed keeps being tracked. To stop tracking it, run git rm --cached <file>, add it to .gitignore and commit. If it held a secret, the old commits still contain it and the secret must be rotated.
36

What is a multi-stage Docker build and why use it?

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A multi-stage build uses several FROM instructions in one Dockerfile. Early stages contain compilers and build tools to produce the artefact; the final stage starts from a small runtime image and copies only the built output with COPY --from. The result is a much smaller image with fewer vulnerabilities, because build tools, source code and caches never reach production.
37

What is Infrastructure as Code and what are its benefits?

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Infrastructure as Code means defining servers, networks, databases and other resources in version-controlled files instead of clicking in a console. Benefits are repeatable environments, code review for infrastructure changes, history and rollback through Git, fewer manual mistakes, faster provisioning and easy disaster recovery. Common tools are Terraform and OpenTofu for provisioning and Ansible for configuration management.
38

What is Git and how is it different from GitHub?

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Git is a distributed version control system that tracks changes to files; every clone has the full history and works offline. GitHub is a hosting service built around Git that adds remote repositories, pull requests, code review, issues and Actions for CI. Alternatives such as GitLab and Bitbucket offer similar features. You can use Git without GitHub, but not the other way round.
39

Explain liveness, readiness and startup probes.

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A liveness probe checks whether the container is healthy; if it fails, the kubelet restarts it. A readiness probe checks whether it can serve traffic; if it fails, the pod is removed from service endpoints but not restarted. A startup probe gives slow-starting apps time to boot and holds off the other probes until it succeeds. Wrong liveness probes can cause restart loops.
40

What is Site Reliability Engineering, and what is toil?

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SRE, which began at a large search company, applies software engineering to operations: teams own reliability through SLOs, error budgets, automation, incident management and capacity planning. Toil is manual, repetitive, automatable work that grows with scale and adds no lasting value, such as manually restarting services. SRE teams aim to keep toil below about half their time and automate the rest.
41

What is the difference between declarative and imperative IaC, and between Terraform and Ansible?

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Declarative tools describe the end state and the tool works out the steps; imperative tools describe the steps. Terraform is declarative, keeps a state file and is best at provisioning cloud resources. Ansible is procedural with mostly idempotent modules, agentless over SSH, and best at configuring servers and deploying software. Many teams use Terraform to create VMs and Ansible to configure them.
42

Explain IAM users, groups, roles and policies.

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An IAM user is an identity for a person or app with long-term credentials. Groups collect users so permissions are managed together. Policies are JSON documents that allow or deny actions on resources. Roles are identities with temporary credentials that are assumed by services, such as EC2 or Lambda, or by users from other accounts. Prefer roles over access keys wherever possible.
43

What is the difference between monitoring and observability?

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Monitoring tracks known metrics and alerts when they cross thresholds, answering whether something is wrong. Observability is the ability to understand any internal state from outside data, answering why, even for problems you did not predict. It rests on three pillars: metrics for trends, logs for detailed events and traces for following one request across services. Good systems need both.
44

What is Docker Compose?

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Docker Compose defines and runs multi-container applications from a YAML file, usually compose.yaml. You describe services, networks, volumes, environment variables and dependencies, then start everything with docker compose up. It is ideal for local development and testing, for example an API, database and cache together. For production orchestration across many hosts, teams use Kubernetes instead.
45

What are the S3 storage classes and lifecycle policies?

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S3 Standard is for frequently accessed data. Standard-IA and One Zone-IA are cheaper for infrequent access but charge retrieval fees. Intelligent-Tiering moves objects automatically based on access. Glacier Instant, Flexible Retrieval and Deep Archive are for archives with slower, cheaper access. Lifecycle rules move objects between classes after a set age and delete old versions or logs automatically.
46

When do you use a StatefulSet instead of a Deployment?

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Use a StatefulSet for stateful workloads such as databases, Kafka or Elasticsearch that need stable identity. Pods get fixed names like db-0 and db-1, start and stop in order, and each gets its own PersistentVolumeClaim that follows it after rescheduling. A headless service gives each pod a stable DNS name. Deployments treat pods as interchangeable, which suits stateless apps.
47

What are Terraform modules?

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A module is a reusable folder of Terraform files with input variables and outputs, for example a vpc module or an eks-cluster module. The root module calls child modules with different values for each environment. Modules reduce duplication and enforce standards across teams. They can come from local paths, Git or the Terraform Registry and should be pinned to versions.
48

What does set -euo pipefail do in a bash script?

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set -e exits the script when any command fails, set -u treats unset variables as errors, and set -o pipefail makes a pipeline fail if any command in it fails, not just the last. Together they stop a script from silently continuing after an error, which matters in CI and deployment scripts. Commands that may fail on purpose need explicit handling such as || true.
49

What is the difference between continuous integration, continuous delivery and continuous deployment?

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Continuous integration means developers merge small changes often and every merge is automatically built and tested. Continuous delivery goes further: every passing build is packaged and ready to release, but a human approves the production push. Continuous deployment removes that manual step, so every change that passes all checks goes to production automatically. Each stage needs more test confidence than the last.
50

Explain the Kubernetes architecture.

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The control plane has the kube-apiserver, the front door for all requests; etcd, the key-value store holding cluster state; the scheduler, which places pods on nodes; and the controller manager, which runs reconciliation loops. Each worker node runs the kubelet, which starts and monitors pods; kube-proxy, which handles service networking; and a container runtime such as containerd.

Frequently asked questions

What happens in the DevOps rapid-fire round?

Rapid-fire questions are quick definitions and one-line answers that interviewers fire at the start or end of a round to check your DevOps basics. Aim to answer each in under 20 seconds.

How do I clear the rapid-fire round?

Answer in one or two sentences, then stop. If you don't know, say so quickly and move on; don't guess at length. Revise these the morning of the interview.

Which round comes next?

A typical order is online assessment, telephonic screening, one or two technical rounds, a managerial round and HR. Use the other round pages to practise each stage.