DevOps on Kaisekukun

Setting Up a Local Dev Environment with Docker

Sun, 21 Jun 2026 11:00:00 +0900

“It works on my machine” is a phrase every developer knows all too well. Docker solves this by packaging your application and its dependencies into portable containers. This article walks through setting up a local development environment with Docker.

The Three Core Concepts

Dockerfile: A blueprint for your container — which base image to use and what to install.
docker-compose.yml: A configuration file for managing multiple containers (web server, database, cache, etc.) together.
Volume mount: Lets the container reference files on your host machine. Essential for hot reload.

Multi-Service Setup with docker-compose

A typical frontend + backend + database setup can be defined in a single docker-compose.yml:

Accelerating GitHub Actions CI/CD workflows using Caching

Wed, 15 Apr 2026 12:00:00 +0900

Optimizing CI/CD workflow times directly impacts developer productivity and reduces computing expenses. This article shows you how to integrate dependency caching in GitHub Actions, helping you slash compilation and package setup times.

We provide YAML workflow templates for Node.js, Python, and Rust, alongside best practices to ensure optimal cache hits.

1. Why Cache Dependencies in CI/CD?

When a CI agent starts without caching, it spins up a clean container and fetches every dependency from package registries. This introduces several drawbacks:

Docker Container Image Security Best Practices

Tue, 10 Mar 2026 12:00:00 +0900

In modern cloud-native development, Docker containers are the default standard for deploying web applications.

However, generic Dockerfiles often yield images containing OS vulnerabilities, unnecessary tooling, or root process privileges. In this guide, we cover the essential best practices to harden your Docker container images for production.

1. Enforce Multi-stage Builds

Leaving build tools, compiler caches, or developer dependencies (like npm or git) inside your final runtime image increases the container size and broadens the attack surface.