Easy everything in Cloud Platforms
Lift-and-shift versus replatforming migration
Rehosting moves apps unchanged for speed and low risk; replatforming makes targeted optimizations for cloud benefits; explain the speed-versus-value trade-off.
Explain the Well-Architected Framework pillars
Name the pillars, operational excellence, security, reliability, performance efficiency, cost optimization, and sustainability, and explain each briefly.
Feeding large object-store data into training
Stream data instead of copying it all to disk, use streaming/pipe modes, shard and prefetch in parallel, and pack many small images into larger files.
Pre-built AI service vs custom model
Choose a managed service for speed, no ML expertise, and common tasks; build custom for domain-specific needs, control, or cost at scale.
CSV vs JSON vs Parquet for analytics
CSV and JSON are row-based, human-readable, and bulky; columnar Parquet/ORC compress well and read only needed columns; choose columnar for analytics.
ETL versus ELT in cloud data platforms
ETL transforms before loading into the target; ELT loads raw first then transforms in the warehouse, leveraging cheap storage and elastic compute.
Data lake versus data warehouse
Lakes store raw, schema-on-read data of any type cheaply; warehouses store curated, schema-on-write structured data for fast SQL; choose a lake for varied raw data and ML.
On-Demand vs Reserved vs Spot pricing models
On-Demand is flexible but priciest, Reserved trades a 1-3 year commitment for discounts, Spot is cheapest but interruptible.
Attribute cloud costs to teams
Tag resources with team and project metadata, activate them as cost-allocation tags, group the cost report by that tag, and enforce tagging with policy.
Automate patching across a VM fleet
Use a patch or config tool to target by tag, roll out in canaried waves with health checks, and prefer immutable golden images long term.
What is Infrastructure as Code?
IaC defines infra in version-controlled files, giving repeatability, peer review, and drift-free consistency, unlike error-prone console clicks.
Purpose and setup of a Dead-Letter Queue
A DLQ captures messages that repeatedly fail so they neither block the queue nor get lost; configure a redrive policy with a max receive count and alarm on it.
Serverless cold starts and how to mitigate them
A cold start is the latency to provision and initialize a fresh environment; mitigate with provisioned concurrency, smaller packages, and lighter runtimes.
Kubernetes Deployment versus Pod
A Pod is the smallest disposable unit, a Deployment maintains a desired replica count, self-heals, and rolls out updates.
Writing a Dockerfile for a web app
FROM a base, set WORKDIR, install dependencies before app code for cache reuse, EXPOSE the port, CMD the start command.
Deploying to Heroku via Git
Push to the remote, a buildpack detects the language, builds a slug, and runs the Procfile process.
Why not store uploads on local PaaS disk?
PaaS instances are ephemeral and unshared, so local files vanish on restart and are invisible to peers; store uploads in object storage.
The cloud shared responsibility model
The provider secures the cloud (hardware, OS, runtime), you secure what runs in it (code, data, config, access).
How does caching reduce database load?
Cache-aside reads, RAM-speed lookups, TTL plus invalidation.
Read replicas in managed relational databases
A read replica is an async copy of the primary that serves read-only queries, offloading the primary and scaling read-heavy workloads; expect replication lag.
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