The Zerofox Syndicate

Why I'm switching back to Docker


Update: turns out, all I needed was --layers flag. If you use buildah bud --layers it acts the same as docker build command. It is also possible to set the environment variable BUILDAH_LAYERS=true to override the default behaviour. You can ignore the rest of this article.

I’ve been using podman and buildah for a while but rebuilds simply take too long. I was recently creating a Dockerfile for the IRC server ngircd. This image typically starts of with downloading a bunch of dependencies.

FROM as ngircdbuilder

RUN apt-get update && apt-get install -y \
    autoconf automake build-essential expect libgnutls28-dev \
    libident-dev libpam-dev pkg-config libwrap0-dev libz-dev telnet

Followed by downloading and building of the ngircd source.

ADD /src
RUN tar -xvzf ngircd-24.tar.gz && \
    cd ngircd-24 chmod +x configure && \
    mkdir /opt/ngircd && \
    ./configure --prefix=/opt/ngircd \
    && make && make install

Each time I run buildah build-using-dockerfile or buildah bud, I will have to wait for 10 minutes. Buildah will execute the installation of the build dependencies and compiling steps each time. Docker on the other hand will skip the installation of the build dependencies during a rebuild. It will download the tarball, only to verify that it is still the same file and skip ahead. This whole process only takes a few seconds, making rebuilds for small Dockerfile changes painless.

No matter how much I like running rootless containers with podman. These rebuilds simply eat too much of my time. Until I’ve got a solution for these rebuild times I’m sticking with Docker.

Tags: containers