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Tag: windows

Private DNS for Native Windows Docker Container

Docker Windows containers have a number of shortcomings, particularly around networking. One showstopper is that it doesn’t use the DNS of its host server. The expected behaviour in (Linux) Docker containers is that the Docker engine creates a virtual DNS for containers. The Docker DNS resolves containers by name (for Docker Swarm / Docker Compose) or delegates to the host DNS configuration. There are options to override this behaviour if necessary.

Native Windows containers don’t do this. Docker for Windows will resolve container names from the Swarm and will then use the default external DNS (Google DNS on to resolve external addresses. It will not use the host machine DNS settings nor can its behaviour be overridden with the --dns flag. This is a serious problem if your container depends on services within a private / corporate network.

This appears to be an issue with the Docker Windows images (nanoserver / windowservercore) rather than with the engine. Microsoft might get round to fixing it but given its half-hearted support for Docker, it might not.

Spring Boot as a Windows Service

The documentation provided by Spring on deploying a Spring Boot application as a Windows Service is a little sparse. Indeed, here it is in full:

Spring Boot application can be started as Windows service using winsw.

A sample maintained separately to the core of Spring Boot describes step-by-step how you can create a Windows service for your Spring Boot application.

— From Spring Boot Reference Guide (version 1.4.3), section 56.2: Microsoft Windows Services

As the official reference guide is lacking detail, here is a step by step guide to building and deploying a Spring Boot application as a Windows Service.

Migrating from SVN to Git

The Spanners demo project is now available on GitHub: Feel free to fork!

I wanted to migrate the Spanners demo from SVN to Git, partly so I could take advantage of GitHub to host it (yes, I know I could host a SVN project on GitHub but where’s the fun in that?). I also wanted to start using a Distributed Source Control Management (DSCM) system and Git is certainly the most popular of these. Even though I’m (currently) the sole contributor to the Spanners demo project, it’s useful to understand how a DSCM system differs from a ‘traditional’ centralized server based SCM such as SVN and CVS.