There’s literally not much to say about the scratch container as it’s completely empty! This container is usually only used when creating a base container from an external root filesystem in combination with the ADD command.
A Dockerfile that does this would look like:
ADD rootfs.tar /
The root filesystem can be created outside of Docker or downloaded from a third party. For example when creating a base container using Debian the root filesystem can be created with debootstrap. The ADD command takes the tarball and extracts it into the container.
This week we are going to look at a fairly popular container that is often used as a base for larger images – busybox. We’re also going to look at some of the upsides and downsides of busybox, a somewhat tempestuous project in the free software world.
Continue reading “Container of the Week – busybox”
This post is part of a series where we examine a different container image each week. See previous Containers of the Week here. This week’s image is the official image for the Jenkins project, an open source application for building, deploying and automating software.
Running Jenkins inside a container is a simple task, but I’m going to give you a few tips to improve your Jenkins experience with Docker.
Continue reading “Container of the Week – jenkins”
Welcome to another episode of Container of the Week! This time we are going to look at a utility container that assists you in debugging container operation or just helping to understand what’s going on.
Sometimes testing out a new container or troubleshooting is a simple matter of using “docker logs“. Unfortunately some containers do not log very much to standard output but instead use syslog. The factorish/syslog container can be used to start a simple syslog container in a few seconds to aid troubleshooting a container setup.
Continue reading “Container of the Week – factorish/syslog”
If you are like me then you have probably written the following code a lot as the first command in your Dockerfile:
RUN apt-get update && apt-get install git wget
or maybe you need to build a C program to run in your container and use something like this:
RUN apt-get update && \
apt-get install autoconf automake gcc
It turns out that you can replace both of these scenarios with a base container image from the buildpack-deps
Continue reading “Container of the Week – buildpack-deps”
This week we are going to look at a very simple container, but one that I personally did not know about up until a few days ago. It’s a standard base container, but one with an important property that many users of Docker and Kubernetes are concerned about.
A base container is the container image used in the FROM command of your Dockerfile. Base containers are usually a customised minimal install of a full-sized Linux distribution such as Debian, Ubuntu or CentOS. Read on to find out more about the debian:jessie-slim base container.
This is the first post in an ongoing series looking at container images. Each week I’m going to analyze a particular image and see how it ticks. The one I’m going to look at first is the library/alpine container.
Continue reading “Container of the Week – Alpine Linux”