CI/CD: Continuous Integration / Continuous Delivery: automating the build, test, and deployment pipeline so code ships faster and safer.
Container: A lightweight, isolated package that bundles an application with all its dependencies. Docker is the most popular container runtime.
Docker: An open-source platform for building, shipping, and running containers. It uses a Dockerfile to define images and docker-compose for multi-container apps.
Kubernetes (K8s): An open-source container orchestration system that automates deployment, scaling, and management of containerised workloads across a cluster.
Infrastructure as Code: Managing and provisioning infrastructure through machine-readable config files (e.g. Terraform HCL) instead of manual steps.
Terraform: HashiCorp's open-source IaC tool. You declare the desired state of cloud infrastructure in HCL and Terraform creates, updates, or destroys resources to match.
Pipeline: An automated sequence of steps (build, test, deploy) triggered on every code push. Defined in tools like GitHub Actions, GitLab CI, or Jenkins.
Image: A read-only snapshot of a container's filesystem and metadata. Images are built from Dockerfiles and stored in registries like Docker Hub or ECR.
Registry: A service that stores and distributes container images. Examples: Docker Hub, GitHub Container Registry, Amazon ECR, Google Artifact Registry.
Orchestration: Automated coordination of container lifecycles: scheduling, scaling, load balancing, self-healing, and rolling updates. Kubernetes is the industry standard.
Helm: The package manager for Kubernetes. Helm Charts are templated Kubernetes manifests that make deploying complex apps repeatable and configurable.
GitOps: An operational model where the Git repository is the single source of truth. Changes to infrastructure and applications are made via pull requests, then synced by an agent (e.g. ArgoCD, Flux).
Shift Left: Moving testing, security, and quality checks earlier in the development lifecycle, catching issues when they're cheapest to fix.
SRE: Site Reliability Engineering: applying software engineering practices to operations. SREs define SLOs (Service Level Objectives) and manage error budgets.
Immutable Infrastructure: Rather than patching running servers, new images or containers are built and deployed. Old ones are discarded. Increases reliability and reproducibility.