CI/CD &amp; Automation

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.

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.

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.

Pipeline Templates: Reusable CI/CD Building Blocks

Think of pipeline templates as versioned, shareable functions for your CI/CD. Instead of copy-pasting YAML, you import a standardized block of logic for tasks like security scanning or deployment.

Dynamic Pipelines: Parent-Child vs. Multi-Project

Break up monolithic CI/CD pipelines into smaller, independent ones. Use parent-child pipelines for dynamic jobs in one project (like a monorepo), or multi-project pipelines to coordinate across repos. The footgun: the parent pipeline doesn't wait by default.

Policy as Code in CI/CD with OPA

Treat pipeline rules as code using Open Policy Agent (OPA) to automate guardrails. Instead of scripts, write declarative policies to check test coverage or validate dependency licenses.

Terraform: Manage Infrastructure as Code

Terraform lets you define cloud infrastructure—servers, databases, networks—in a text file, like a blueprint. It reads this file and builds everything for you, making setups on AWS, GCP, or Azure repeatable.

AWS CloudFormation: Your AWS Infrastructure as a Blueprint

AWS CloudFormation is your infrastructure's blueprint. Declare AWS resources in a YAML/JSON file, and AWS builds it. This is perfect for creating repeatable, version-controlled environments.

Vagrant: Your Dev Environment as Code

Vagrant is a scriptable remote for virtual machines, defining a dev environment in one text file. It ensures teams have identical, isolated setups, solving "it works on my machine" problems.

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.

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.

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.

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.

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.

Pulumi: Infrastructure as Code with Real Programming Languages

Pulumi is Infrastructure as Code using real languages like Python or TypeScript, not a special DSL. This lets you use loops, functions, and classes to define resources. The main footgun is writing overly complex, clever code that becomes unmaintainable.

advanced1 min read

Terragrunt: A Thin Wrapper for DRY Terraform

Terragrunt is a thin wrapper for Terraform/OpenTofu that automates common tasks. Just add an empty terragrunt.hcl file to get features like automatic init.

Open Policy Agent (OPA): Centralized Policy as Code

OPA decouples policy decisions from your app's code. Instead of scattering if statements, you query a central engine: 'Is this allowed?' It enforces rules in Kubernetes, CI/CD, and API gateways. A common footgun is only using it for yes/no decisions.

Cloud-Init: Bootstrapping Cloud Instances

Cloud-init is the script that runs on a generic VM's first boot to turn it into *your* server. It's used by cloud providers to apply your user-data (like SSH keys and startup scripts) at launch. The biggest footgun: it only runs once on first boot.

Environment Variables: Configuration Outside Code

Environment variables are settings passed to your app from the outside world, letting you change behavior without touching code. Use them for API keys or database URLs. The biggest footgun is committing secrets to version control instead of using variables.