Concepts in DevOps & Cloud, page 31
Pod Topology Spread: Spreading Pods for High Availability
Pod Topology Spread Constraints prevent putting all your pods in one basket. They instruct the scheduler to distribute a service's pods evenly across nodes or zones, improving availability. The main footgun is that it's a soft preference by default.
Cloud Disaster Recovery: Planning for Failure
Cloud DR isn't about backups; it's a business continuity plan defining acceptable downtime (RTO) and data loss (RPO). It's for when a whole region fails or a bad deploy corrupts data. The footgun is having a plan but never testing it, creating false security.
Shift Left Security: Treat Security Like a Bug
Treat security vulnerabilities like bugs by finding them early in the development cycle, not as a final gate before release. This means running automated security scans in CI/CD pipelines and even in your IDE.
Kappa Architecture Unifies Batch and Stream
Kappa treats batch as a special case of streaming: store every event in an immutable log, compute views in real time, and replay the log when logic changes. It removes Lambda's dual codebase but forces you to pay for infinite retention and replay costs.
End-to-End Testing: Simulate Real User Paths
End-to-end testing exercises the full stack through user flows, catching integration fractures unit tests miss. Run it in staging before releases to verify behavior. The trap is using it for fast feedback; it is slow, brittle, so never abandon unit tests.
OPA Gatekeeper: Enforce Kubernetes Policies as Code
OPA Gatekeeper is a Kubernetes admission controller using OPA to enforce policies on resources. Use it to mandate labels or block insecure images. The footgun is thinking it's just OPA; Gatekeeper adds K8s-native CRDs, auditing, and mutation capabilities.
Dependency Resolution: The Build's Constraint Solver
Dependency resolution finds compatible package versions across transitive requirements. It runs whenever npm, Maven, or pip installs in CI. The footgun is trusting ranges without a lock file; tomorrow's resolve can silently install different code.
Kubebuilder: Build Kubernetes APIs the Canonical Way
Kubebuilder is a framework for scaffolding custom Kubernetes APIs, letting you define your own resources like MyWebApp. Use it to extend Kubernetes with declarative APIs, making your app a first-class citizen.
Container Images Are Stacked Deltas
Images stack read-only layers like transparent sheets, one per Dockerfile step, topped by a thin writable layer. This enables cache reuse and fast pulls. The footgun: removing a file in a later layer hides but does not delete it; those bytes still ship.
GitLab CI/CD: Pipeline as Code
Your .gitlab-ci.yml file turns your repo into an assembly line. Pushes trigger build and test jobs across runners. One missing rules clause can spawn jobs on every branch and explode compute costs.
Docker Content Trust: Signed Image Verification
Docker Content Trust is a cryptographic tamper-evident seal for image tags. It lets you verify who published an image before pulling from any registry. The footgun is that without DOCKER_CONTENT_TRUST=1, unsigned tags pull silently with no warning.
Terraform Modules: Reusable Infrastructure Blueprints
A Terraform module is a reusable container for related resources, letting you stamp out infrastructure from one blueprint instead of copying HCL. Teams share VPC patterns or tagging standards with them.
Vault: Centralized Secrets with Dynamic Leasing
Vault is a secrets firewall: it centralizes credentials and issues short-lived leases instead of static keys. Use it when apps need DB passwords not hardcoded. The footgun is using Vault without audit logs, leaving secrets unmonitored.
Dynamic Secrets: Temporary On-Demand Credentials
Dynamic secrets are temporary credentials minted on demand, not static passwords living in config files. A CI job requests a 15-minute database lease instead of a long-lived env var.
Container Image Security Scanning
A container image is a frozen filesystem; scanning unpacks layers to flag known CVEs before deployment. Run it in CI/CD after every build and continuously in production registries. Scanning only at build time misses new CVEs in running images.
IAST: Inside-Out Runtime Security Scanning
IAST is an inside-out security scanner: an agent in your running app watches data flow to catch vulnerabilities with few false positives. It runs during functional tests, giving precise line-of-code findings. If your tests skip a route, IAST stays blind to it.
Security Champions: Embedded Team Defense
A security champions program embeds trained developers inside teams to catch risks early. It scales AppSec without hiring a specialist for every squad. The footgun is treating champions as free labor instead of investing in their training and time.
Backstage: The Developer Portal Framework
Backstage is a framework for building a developer portal, not a ready-made dashboard. It centralizes ownership, docs, and tooling when microservice sprawl hides context. The footgun is treating it as a product you deploy without upkeep; the catalog rots.
Platform Orchestrator: Infrastructure's Travel Agent
A platform orchestrator is infrastructure's travel agent: describe an app and it provisions compute, databases, and caches across clouds automatically. It shines once teams outgrow per-service Terraform. Adopt it too early and it becomes a bottleneck.
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