Master Docker & Jenkins: From Container Basics to Cloud‑Native CI/CD with K8s

With Docker’s widespread adoption, the cloud‑native era has arrived, giving developers tighter control over application environments and reducing operational costs. Integrating Docker into DevOps accelerates continuous integration, makes deployments simpler, and enables scalable infrastructure.

Course Overview

The session covers Docker server architecture, download acceleration, key points for project containerization, and a practical DevOps demo using Jenkins to build Docker images.

IaaS, PaaS, SaaS Explained

IaaS provides virtualized servers for ops teams, PaaS offers managed software services for developers, and SaaS delivers ready‑to‑use applications for end users. Combining these models with self‑built components often leads to higher maintenance overhead.

Why Containers Over Traditional VMs

Docker implements OS‑level virtualization (containers) that share a single Linux kernel, offering isolation with performance superior to heavyweight VMs like VirtualBox. Containers prevent conflicts between projects on the same host and dramatically lower server costs.

Scaling with Cluster Managers

For large‑scale deployments, tools such as Kubernetes (K8s) and Docker Swarm manage clusters, providing automatic scaling and high availability.

Installation Challenges in China

Docker’s default CDN is Cloudflare, which can be slow or blocked in mainland China. Using domestic mirrors (e.g., 163.com) speeds up image pulls and package downloads.

Containerizing a Project

Developers write a Dockerfile based on an official language image, add required libraries, and debug with docker run to identify slow steps (e.g., apt update). Accelerated mirrors should be used for both apt and Composer.

Domestic acceleration for all package sources.

Handle HTTPS/SSL outside the container, using load balancers.

Store persistent files in cloud storage, not inside the container.

Send logs to STDOUT / STDERR and collect them with log‑aggregation tools.

Example: Laravel Demo

The Laravel project is containerized by selecting an appropriate base image (PHP‑Apache), removing local dependencies, mounting the source code, installing missing packages (e.g., zip), and ensuring logs are output to the console.

CI/CD with Jenkins

Jenkins builds the Docker image using the same Dockerfile, pushes it to a private registry, and triggers deployment to a K8s cluster. The pipeline should filter branches (e.g., build only master) and store registry credentials as a K8s secret.

Benefits of the Cloud‑Native Approach

Deploying Docker images on K8s incurs minimal cost, supports elastic scaling, and avoids downtime by rolling updates. The required services are continuous integration, a private Docker registry, and a K8s cluster—ideally provided as managed PaaS to reduce maintenance effort.