Intermediate everything in DevOps & Cloud, page 19
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.
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.
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.
CSI Volume Cloning: `cp` for Kubernetes Volumes
Think of volume cloning as cp for your Kubernetes data. It creates a new, independent volume pre-populated with data from an existing one, offloading the copy operation to your storage provider.
Kubernetes Secrets: Encrypting Data at Rest
By default, Kubernetes Secrets are only base64-encoded, not encrypted. Encryption at rest makes the API server encrypt Secret data before saving to etcd, protecting against compromised backups.
Kubernetes Gateway API: The Successor to Ingress
The Gateway API replaces Kubernetes Ingress with a role-oriented model, separating infrastructure from application routing. Use it when different teams need to manage their own traffic rules.
kube-apiserver: The Front Door to Your Kubernetes Cluster
The kube-apiserver is the front door to your Kubernetes control plane. All requests to query or modify the cluster's state must pass through it, from kubectl commands to automated controller actions. The footgun is bypassing it to modify etcd directly.
Kubernetes' Declarative Model: Desired vs. Actual State
The declarative model is like telling Kubernetes your destination, not giving it turn-by-turn directions. You define the desired state in a file, and Kubernetes works to make it a reality. This enables self-healing and GitOps.
Private Container Registry: Own Your Image Pipeline
A private container registry is your own personal Docker Hub, giving you full control over image storage and access. It's crucial for secure, in-house CI/CD pipelines.
Retry and Timeout Policies: Handling Network Flakes
Retries and timeouts are automated patience for network requests. Instead of failing on a glitch, a service waits (timeout) and tries again (retry). This is key for microservice resilience, but beware of "retry storms" that can amplify failures.
Service Mesh Authorization: A Bouncer for Your Microservices
A service mesh authorization policy is a bouncer for your microservices. It moves access control from your app to the mesh, checking service identity and request details like HTTP method and path. Use it for fine-grained, Zero Trust security.
Content-Based Routing: Directing Traffic by Request Details
Content-based routing is a smart traffic cop for your services. It inspects request headers or URIs to direct traffic, enabling canary releases or A/B tests. The footgun is rule order: a broad rule placed first can shadow specific rules below it.
Traffic Splitting: Route Live Traffic Between Service Versions
Traffic splitting directs percentages of live user traffic to different versions of a service. It's key for canary releases, letting you test new code on a small user group before a full rollout.
Mutual TLS (mTLS): When Services Need to Trust Each Other
mTLS is a two-way ID check for services. Both parties exchange certificates to prove their identity before communicating. Service meshes like Istio use it to secure traffic between microservices.
SPIFFE: Cryptographic Identity for Services
SPIFFE gives every service a cryptographic passport instead of a static secret. It's used in zero-trust networks for services to authenticate each other, like in a Kubernetes service mesh.
Kubernetes Finalizers: The 'Do Not Delete Yet' Lock
A finalizer is a pre-deletion lock. It tells Kubernetes to block an object's deletion until a controller cleans up external resources, like a cloud database or storage bucket.
Operator SDK: Build Kubernetes Operators Faster
The Operator SDK is a developer toolkit that scaffolds the boilerplate for building, testing, and packaging Kubernetes Operators. Use it to automate complex application lifecycle management, like deploying a database cluster that can self-heal and perform…
Configuration Drift: When Live State Betrays Git
Configuration drift is when your live system's state no longer matches its Git source of truth. GitOps tools like Argo CD detect this by constantly comparing live resources to Git, flagging any discrepancies.
Helm Templates: Turning Static YAML into Dynamic Manifests
Think of Helm templating as a mail merge for Kubernetes. It combines static YAML templates with dynamic values to generate manifests for different environments. Use it to manage configurations for dev, staging, and prod.
cAdvisor: A Task Manager for Containers
cAdvisor is like a task manager for your containers, giving you a live view of their resource usage. It's used to track performance, historical usage, and network stats for every container on a host.
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