docker-local-development-rhel-6-10

Dockerfiles and settings for local development on Rhel 6.10 images via Ansible (mainly)

Since Rhel 6.10 is out of support getting things to work on it (specifically Python 3.x) and Ansible is quite painful

There are also some "gotcha's" to keep in mind when using M1 macs and when trying to avoid using Docker-Desktop which has now been properly monetised

There's also a dockerfile-centos-7 version in here as a bit of a contrast which can be connected to via VSCode.

Installing Docker without Docker-Desktop

Make sure Docker-Desktop is no longer installed
brew install docker docker-compose
There will likely be instructions to link these two as docker-compose is now a plugin for docker so follow those instructions
You need a docker runtime for macs - use Colima
you'll need to run colima start to start the docker runtime

Considerations for M1 macs

docker build will freak out without the correct settings as you're no longer on an intel/amd platform

Either run all docker tasks with

--platform linux/amd64 flag
export DOCKER_DEFAULT_PLATFORM=linux/amd64 to environment
add FROM --platform=linux/amd64 <dockerimage>:<version> to all dockerfiles

Making life easier with Portainer

Follow these installation instructions You'll want to use the community edition

Docker commands

Build

docker build --platform linux/amd64 -t <dockerimage>:<version> .

Build rhel7.9 container

docker built -f dockerfile-centos-7 -t <dockerimage>:<version> .

Run

docker run -t -i -d --platform linux/amd64 -v /<local_folder_path>:/<container_folder <dockerimage>:<version>

Connecting to your local file system (i.e. VSCode)

If the docker image has the relevant glibc and other libraries available then VSCode will be able to connect to the file system for you without having to mount a volume.

Docker exec

docker exec -it <container_id> /bin/bash

Portainer gui

http://localhost:9443 > Containers > Select container > Console

If you haven't set the run -i flag you won't be able to easily do this. You can still do it with docker exec -it <container_id> /bin/bash but you'll need to know the container id

Things to avoid

Don't run build commands from the VSCode terminal. It seems pretty slow and will sometimes randomly timeout getting things from repositories...
Due to the lack of GCLIB versions in Centos 6.10 you won't be able to connect your VSCode directly to the running container (I tried but something fails, even if you follow the VSCode workaround).

Sources

https://www.getpagespeed.com/server-setup/how-to-fix-yum-after-centos-6-went-eol

https://danieleriksson.net/2017/02/08/how-to-install-latest-python-on-centos/

robertsweetman/docker-local-development-rhel-6-rhel-7