Intermediate everything in DevOps & Cloud, page 27
Traffic Shaping for Safer Deployments
In deployments, traffic shaping isn't about network speed, but controlling user exposure. You route a precise percentage of users to a new code version, slowly 'opening the valve' from 1% to 100% to de-risk the release. This is the engine of a canary deploy.
Kubernetes Health Checks: Liveness, Readiness, and Startup Probes
Kubernetes health checks ask your app: "Are you alive?" (liveness), "Ready for traffic?" (readiness), and "Done starting?" (startup). This lets it automate restarts and traffic routing for zero-downtime deployments.
Kubernetes Ingress: The Cluster's Front Door
Kubernetes Ingress is the smart receptionist for your cluster. It routes external HTTP/S requests to internal services based on hostnames or paths, letting you expose multiple apps under one IP.
Helm: The Package Manager for Kubernetes
Helm is the package manager for Kubernetes. It uses a packaging format called Charts to define, install, and upgrade applications, making it the standard way to manage software on a K8s cluster. It is a Cloud Native Computing Foundation (CNCF) project.
Kubernetes Service: A Stable Address for Ephemeral Pods
A Kubernetes Service provides a stable IP address and DNS name for a group of ephemeral Pods. It acts like a load balancer, distributing traffic so you don't have to track individual Pod IPs, which can change at any time.
Kubernetes Deployment: Declarative App Updates
A Kubernetes Deployment is your app's blueprint. You declare the desired state—like '3 replicas of image v2'—and Kubernetes makes it happen. It's the standard for stateless apps like APIs. The footgun: don't manage Pods directly; manage the Deployment.
Kubernetes Pods: The Atomic Unit of Deployment
A Kubernetes Pod is the atomic unit of deployment, a logical host for containers sharing a network and storage. This is ideal for co-locating a main app with a helper "sidecar" container. The footgun: a Pod is not a container; you scale by adding more.
Kubernetes: The Operating System for Your Cluster
Think of Kubernetes as an OS for your entire datacenter. It automates deploying, scaling, and managing containerized applications across a fleet of servers. The footgun is adopting it for simple projects, where its complexity outweighs its benefits.
AWS Secrets Manager: Stop Hardcoding Credentials
AWS Secrets Manager is a digital vault for your app's credentials. Instead of hardcoding API keys or database passwords, your app fetches them at runtime. It's used for storing sensitive data securely, with built-in rotation and auditing.
Configuration Drift: When Servers Go Rogue
Configuration drift is when a server's live settings diverge from your version-controlled 'source of truth.' This happens from manual hotfixes or inconsistent deployments, creating snowflake servers that are hard to debug.
Configuration as Code: Treat Your Settings Like Source Code
Configuration as Code (CasC) treats your settings like source code, storing them in version control. This ensures every environment is identical, with changes automatically tested and deployed via CI/CD.
Ephemeral Environments: A Staging Server for Every PR
Ephemeral environments are disposable, production-like test servers created for every pull request. They let developers test changes in isolation without waiting for a shared staging server, catching integration bugs earlier.
Infrastructure Drift: When Reality and Code Diverge
Infrastructure drift is when live systems no longer match their configuration code. This happens when someone manually changes a cloud resource instead of updating the Terraform file. The footgun: your next terraform apply may destroy your manual changes.
Ansible: Automating Infrastructure with Playbooks
Ansible is like a recipe book for your servers. You write simple "playbooks" describing a desired state, and Ansible makes it happen over SSH without installing agents. It's ideal for configuration management, app deployment, and orchestrating workflows.
Packer: Build Identical Machine Images Everywhere
Packer is a universal recipe for baking machine images. It takes a single template and builds identical images for multiple platforms like AWS or Docker. Use it to create consistent "golden images" for your infrastructure.
Terraform State: The Map to Your Infrastructure
Terraform state is the source of truth mapping your code to real cloud resources. It's used on every plan and apply to determine changes. The footgun: never store state in Git or edit the tfstate file directly; this risks corruption and secret leaks.
Self-Hosted Runners: Bring Your Own CI/CD Hardware
A self-hosted runner is your own machine executing CI/CD jobs, giving you full control over its environment and network. Use it for private network access or custom hardware. The footgun: you are now responsible for all security, updates, and maintenance.
GitHub Composite Actions: Script Your CI Steps
A composite action is a reusable script for your CI workflow, bundling multiple steps into one. It's perfect for DRYing up common sequences like setup and testing, but remember you cannot nest composite actions within each other.
Jenkins Shared Libraries: Don't Repeat Your Pipeline Code
Jenkins Shared Libraries let you centralize and reuse Pipeline code, just like a common function library. Use them to define standard build or deployment stages across many projects.
Secrets Management in CI/CD Pipelines
Treat secrets like temporary keys, not permanent passwords. Your CI/CD pipeline should fetch them just-in-time from a central vault, never storing them in code. The biggest footgun is storing secrets as long-lived environment variables in the CI tool itself.
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