Docker as a builder, can't install systemd header files

Question

I'm trying to update a Docker image based on the official CentOS7 image. It is used as a builder for Node.js projects.

I need to add the systemd-devel package for compiling some dependencies, but this fails with the following error:

fakesystemd-1-17.el7.centos.noarch has installed conflicts systemd: fakesystemd-1-17.el7.centos.noarch

Thanks

Answer 1

fakesystemd is a special package in the CentOS Docker image that satisfies the dependency to Systemd without actually installing Systemd (after all, you don't usually need an init system within a container). yum info fakesystemd tells a bit more:

Minimal docker-specific package to satisfy systemd Provides: without installing systemd in Docker images. It is intended strictly for use in Docker images/containers. It doesn't provide any functionality from systemd package - it only contains few important directories and files. fakesystemd is definitely not applicable for full bootable operation system!

To install the real systemd in the image you need to run yum swap command in this form:

yum swap -- remove fakesystemd -- install systemd systemd-libs

You need to swap the fakesystemd package with the "real" systemd package, and can then also install systemd-devel:

RUN yum swap -y fakesystemd systemd && \
    yum install -y systemd-devel