Devops
294 bites tagged Devops — interview questions with model answers, and 60-second explainers.
Secrets Management: Beyond Environment Variables
Treat secrets like cattle, not pets: they should be temporary and replaceable. Use a central vault to dynamically inject credentials into apps at runtime, especially in CI/CD and containerized environments.
Configuration as Code: Version Control for Your Settings
Configuration as Code treats your system settings like source code: defined in files, versioned, and automatically applied. It's used to manage app settings or service credentials across environments, preventing manual errors.
Dev Containers: Your Dev Environment as Code
A dev container packages your entire development environment—tools, libraries, and settings—into a single, portable container. Use it to standardize team environments, simplify onboarding, and ensure consistency between local dev and CI.
Docker Bind Mounts: A Portal to Your Host Filesystem
A bind mount is a portal from your host machine's filesystem directly into a container, where changes on either side are reflected instantly. Use it for live code development, but never for production data, as it creates a major security risk.
MLOps vs. DevOps: More Than Just "DevOps for ML"
Think of MLOps as DevOps extended for machine learning. While DevOps automates code deployment, MLOps also handles the unique lifecycle of data and models, including retraining and monitoring for performance decay.
Feature Management: Control Releases After You Deploy
A feature management platform decouples code deploys from feature releases. It centralizes control over who sees what, turning simple code toggles into a powerful system for canary releases, A/B tests, and targeted rollouts, all from a UI.
Terminal User Interfaces (TUIs): GUIs for the Console
A TUI is a graphical interface built from text, offering rich interactivity without leaving the console. Use them for system monitoring (btop), file management, or database clients. The footgun: don't confuse them with CLIs; TUIs are stateful apps.
CI/CD for Flutter: Automate Your Builds and Releases
CI/CD for Flutter is a safety net that automatically builds, tests, and deploys your app. Use it to catch bugs early and ship updates to app stores without manual steps.
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.
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.
The Operator Pattern: A Robot SRE for Your App
The Operator pattern adds a custom, automated "robot SRE" to your Kubernetes cluster. It encodes human operational knowledge for a specific application, like a database, into software that handles complex tasks like upgrades, backups, and failovers…
Helm Post-Rendering: Customize Charts Without Forks
Helm post-rendering lets you modify a chart's Kubernetes manifests just before deployment. It's ideal for applying `kustomize` patches or injecting sidecars without forking a public chart.
Helm Hooks: Running Operations During a Release
Helm Hooks are Kubernetes resources that run at specific moments in a release lifecycle. Use them to run a database migration before an app upgrade or to back up data before a deletion. The footgun: a failing hook Job will block and fail the entire.
Helm Repository: Your Private App Store for Kubernetes
A Helm repository is a private app store for your Kubernetes applications. It's just an HTTP server with a catalog file (`index.yaml`) pointing to your packaged charts. Use it to share reusable app templates across teams without using public registries.
Helm: The Package Manager for Kubernetes
Helm is like apt or Homebrew for Kubernetes. It bundles all your app's YAML files into a single manageable package called a Chart, solving "YAML sprawl." Use it to install complex apps with one command or to package your own for repeatable deployments.
GitOps Principles: Your Repo as the Source of Truth
GitOps treats infrastructure state like code, with your Git repo as the single source of truth. Automated agents pull declarative configs from the repo to reconcile the live system, making it ideal for Kubernetes.
Prometheus Alertmanager: Taming Your Alert Storms
Alertmanager is the traffic controller for your Prometheus alerts, turning a potential flood into actionable notifications. It groups, deduplicates, and routes alerts to services like PagerDuty. The footgun: don't load balance traffic to an HA cluster.
Kubernetes Audit Logging: Your Cluster's Black Box Recorder
Kubernetes audit logging is the security camera for your API server, recording every API call to answer "who did what, and when?". It's essential for security forensics and compliance, but a common footgun is using a weak default or logging everything.
Pod Security Admission: Kubernetes' Built-in Guardrails
Think of Pod Security Admission (PSA) as a bouncer for your namespaces, enforcing security rules before pods can run. It applies security standards (`Privileged`, `Baseline`, `Restricted`) via simple labels.
Pod Security Standards: A Security Checklist for Pods
Pod Security Standards are a built-in security checklist for your pods. You apply a level (`Restricted`, `Baseline`, `Privileged`) to a namespace to prevent risky configurations like running as root.
Pod Priority: Deciding Who Gets Evicted in Kubernetes
Pod Priority is a VIP pass for your critical workloads, telling the scheduler which pods can bump others off a node. This ensures system-critical services run even on a full cluster. The footgun: high-priority pods can cause cascading evictions if not planned.
Node Affinity: Tell Your Pods Where to Go
Node affinity is like giving pods a 'preferred seating' list for nodes. You guide the scheduler to nodes with specific labels, like those with GPUs or in a certain zone. The footgun is confusing 'required' (a hard rule) with 'preferred' (a suggestion).
Dynamic Volume Provisioning: Storage on Demand
Dynamic Volume Provisioning lets you request storage by its type (e.g., "fast-ssd") instead of pre-provisioning a disk. Kubernetes automatically creates a matching volume. This is standard for stateful apps.
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