I cannot install yum in my docker container

Question

I have a docker container which was built by a keycloak image.

I want to install vim in the container but I found that I need to have yum in order to install the vim. I tried to download yum from the internet and use rpm to install it, but the container didn't have sudo to let me change the file permission.

Following is my linux version:

NAME="Red Hat Enterprise Linux"
VERSION="8.0 (Ootpa)"
ID="rhel"
ID_LIKE="fedora"
VERSION_ID="8.0"
PLATFORM_ID="platform:el8"
PRETTY_NAME="Red Hat Enterprise Linux 8.0 (Ootpa)"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:redhat:enterprise_linux:8.0:GA"
HOME_URL="https://www.redhat.com/"
BUG_REPORT_URL="https://bugzilla.redhat.com/"

REDHAT_BUGZILLA_PRODUCT="Red Hat Enterprise Linux 8"
REDHAT_BUGZILLA_PRODUCT_VERSION=8.0
REDHAT_SUPPORT_PRODUCT="Red Hat Enterprise Linux"
REDHAT_SUPPORT_PRODUCT_VERSION="8.0" 

How can I get any text editor installed in the container?

Answer 1

Minimal RHEL 8 containers do not contain Yum (or DNF) because that requires Python, which inflates the size of an image quite a bit. However, it contains microdnf which is written in C and which has limited capabilities.

You should be able to do

microdnf install vim

or

microdnf install yum

Answer 2

• connect as a root to your container:

docker exec -u root -it <container> bash

*then install vim (or what you need) with

microdnf install vim

Answer 3

I ran into the same problem and found a solution. In your Dockerfile, Try:

FROM jboss/keycloak:8.0.1
USER root
RUN microdnf install <whatever>

HTH.