Everything in Cloud Platforms, page 6
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.
How cloud DNS resolves a URL to an IP
Recursive resolver queries root, then TLD, then your authoritative cloud DNS zone; the matching record returns an IP, cached per TTL.
Layer 4 vs Layer 7 load balancers
Layer 4 load balancers route transport connections using addresses, ports and protocol information. Layer 7 balancers can route HTTP requests by host, path or headers. Choose for the protocols and routing rules you need; Layer 7 is not always an upgrade.
Public and private subnet VPC design
Web server in a public subnet routed to an internet gateway, database in a private subnet with no inbound from the internet, NAT for outbound.
Block storage availability across AZ failure
Block volumes are AZ-bound, so use snapshots, synchronous replication, or app-level replication, trading cost for lower RTO/RPO.
Object store vs NFS consistency models
S3 gives strong read-after-write per object with no partial updates; NFS offers close-to-open with shared mutable files.
Maximizing object-store throughput for small files
Spread keys across prefixes for partition parallelism, batch small files, parallelize and use multipart uploads.
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.
Serving user images securely from object storage
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
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
Spot fleets across types, a durable work queue, idempotent checkpointed tasks, retries.
Optimizing low-latency VM-to-VM networking
Cluster placement groups, enhanced networking and SR-IOV, larger instances for more bandwidth.
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.
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