Intermediate everything in Cloud Platforms, page 3
RDS Multi-AZ versus Read Replicas
Multi-AZ is a synchronous standby for failover, replicas are async for read scaling, combine both when needed.
Shared responsibility model across service tiers
Provider secures the cloud infrastructure; you secure what you put in it; the line shifts with abstraction. For OS patching, you patch IaaS VMs but the provider patches a managed database OS.
Automating a no-public-IP governance rule
Use organization-level policy guardrails (SCP, Azure Policy, Org Policy) to deny public IP attachment before creation, applied across all accounts.
Service-managed vs customer-managed vs BYOK keys
Service-managed keys are automatic but opaque; CMK gives you control over rotation, policy, and revocation in a KMS; BYOK imports your own key material for compliance.
Granting a VM scoped storage access without static keys
Attach a least-privilege role or managed identity to the VM so it gets auto-rotating temporary credentials scoped to the bucket.
CDN caching for static and dynamic content
Cache static assets with long TTLs and versioned filenames; bypass or short-cache dynamic per-user responses; invalidate via fingerprinted URLs not purges.
DNS routing policies for active-passive failover
A failover policy with health checks routes to primary and flips to secondary on failure; keep TTL low; pair with health checks not just policy.
Process running but load balancer says unhealthy
The probe path, port, protocol, or expected status may mismatch; a security group may block the probe; the app may be up but not ready.
Connecting two VPCs privately
VPC peering is simple but non-transitive and full-mesh; a Transit Gateway scales hub-and-spoke; PrivateLink exposes one service narrowly.
Object storage tiers and lifecycle automation
Tiers trade storage price for retrieval cost and latency; automate with lifecycle rules or intelligent tiering.
Protecting object storage from accidental loss
Enable versioning, MFA delete or object lock, cross-region replication, and least-privilege policies.
Shared file system access across many VMs
Use a managed NFS service like EFS or Filestore; watch per-operation latency, throughput modes, and metadata-heavy small-file workloads.
Diagnosing high I/O wait on a database volume
Check IOPS and throughput against the volume limit, look for burst-credit exhaustion, then move to provisioned IOPS or a larger volume.
The instance metadata service explained
A local endpoint exposing instance identity, region, and temporary role credentials.
Managing state across ephemeral instances
Keep instances stateless, externalize sessions to Redis, data to managed databases, files to object storage.
On-Demand vs Reserved vs Spot pricing
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
Front with a load balancer, define a launch template, an auto-scaling group across AZs, and target-tracking policies.
When hybrid cloud beats public or private
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
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
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.
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