More in DevOps & Cloud — page 17
Diagnosing high I/O wait on a database volume
WHAT IT TESTS: storage performance diagnosis. OUTLINE: check IOPS and throughput against the volume limit, look for burst-credit exhaustion, then move to provisioned IOPS or a larger volume.
Serving user images securely from object storage
WHAT IT TESTS: object storage plus secure delivery. OUTLINE: store images in a private bucket, serve via a CDN with origin access control, use signed URLs for private content.
Object vs block vs file storage
WHAT IT TESTS: storage fundamentals. OUTLINE: object stores flat keyed blobs over HTTP, block gives raw volumes for one VM, file offers a shared hierarchical mount.
Cost-effective fault-tolerant batch processing
WHAT IT TESTS: batch architecture and cost-fault trade-offs. OUTLINE: Spot fleets across types, a durable work queue, idempotent checkpointed tasks, retries.
Optimizing low-latency VM-to-VM networking
WHAT IT TESTS: networking performance depth. OUTLINE: cluster placement groups, enhanced networking and SR-IOV, larger instances for more bandwidth. RED FLAG: ignoring that tight placement concentrates instances in one AZ, trading availability for latency.
The instance metadata service explained
WHAT IT TESTS: cloud-native configuration and credential handling. OUTLINE: a local endpoint exposing instance identity, region, and temporary role credentials.
Managing state across ephemeral instances
WHAT IT TESTS: stateless design discipline. OUTLINE: keep instances stateless, externalize sessions to Redis, data to managed databases, files to object storage. RED FLAG: storing durable state on local instance disks that vanish when an instance is replaced.
On-Demand vs Reserved vs Spot pricing
WHAT IT TESTS: cost-optimization judgment. OUTLINE: On-Demand for unpredictable bursty work, Reserved or Savings Plans for steady baseline, Spot for interruptible fault-tolerant jobs.
Designing an auto-scaling web tier
WHAT IT TESTS: horizontal scaling design. OUTLINE: front with a load balancer, define a launch template, an auto-scaling group across AZs, and target-tracking policies. RED FLAG: scaling stateful instances or scaling without a load balancer and health checks.
What a machine image is and why it matters
WHAT IT TESTS: understanding of immutable, reproducible infrastructure. OUTLINE: an image is a frozen template of OS, software, and config; it makes launches identical and fast. RED FLAG: confusing an image with a running instance or a live backup snapshot.
Launching a virtual machine in the cloud
WHAT IT TESTS: foundational fluency with cloud compute. OUTLINE: pick image, instance type, network placement and security, attached storage, and access keys. RED FLAG: leaving the instance open to the world or ignoring the security group and key pair.
Hybrid cloud bursting from a VMware footprint
WHAT IT TESTS: hybrid architecture and networking depth. OUTLINE: evaluate VMware Cloud on AWS, Azure Arc, Outposts; address connectivity, identity, and data gravity.
Designing for portability across two clouds
WHAT IT TESTS: portability versus lock-in judgment. OUTLINE: abstract via containers, Terraform, and open standards; avoid proprietary managed services. RED FLAG: chasing portability for its own sake while ignoring the velocity and cost penalty it imposes.
When hybrid cloud beats public or private
WHAT IT TESTS: justifying hybrid with a concrete case. OUTLINE: give a scenario like regulated data plus bursty compute; keep sensitive data and legacy systems on-prem, run scalable or customer-facing workloads in public cloud.
Scalability vs elasticity in the cloud
WHAT IT TESTS: a precise distinction often blurred. OUTLINE: scalability is the ability to handle more load by adding capacity; elasticity is automatically adding AND removing capacity in real time to match demand.
IaaS vs PaaS for first cloud migration
WHAT IT TESTS: matching a service model to team maturity. OUTLINE: IaaS (lift-and-shift) gives control with high ops overhead; PaaS lowers ops but may need refactoring; for a monolith with limited expertise, IaaS lift-and-shift is the lower-risk first step.
CapEx vs OpEx in cloud migration
WHAT IT TESTS: the financial shift cloud enables. OUTLINE: CapEx is large upfront asset spend, OpEx is ongoing pay-as-you-go cost; cloud shifts spending from CapEx to OpEx, trading ownership for flexibility.
Publish/Subscribe Pattern
Publish/subscribe decouples senders from receivers: publishers emit messages to a topic without knowing who consumes them, and subscribers receive messages from topics they care about.
Persistent Volume and Persistent Volume Claim
Kubernetes separates storage provisioning from consumption. A PersistentVolume is a cluster storage resource an admin or driver provisions; a PersistentVolumeClaim is a pod's request for storage.
Dynamically generate CI/CD pipelines
WHAT IT TESTS: designing pipeline-as-code that adapts to a repo. OUTLINE: a detection step scans for marker files and maps them to reusable stage templates assembled at runtime; trade off convention/DRY against reduced transparency and harder debugging.