Documentation of build environment ( Ubuntu version, RAM memory on build machine, etc )

[Anders Hedberg]

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Summary

Problem:
I set up a virtual machine running Ubuntu 20.04LTS ( released a few months back ). The 3.3.0 version of chirpstack does not build there (fails on "gettext") . If running on Ubuntu 18.04.05LTS it builds just fine.

Clang does not build on 18.04.05 with 16Gb of memory. When allocating 32 Gb of RAM on my virtual build machine it works fine.

The disk also needs to be bigger than 32 Gb to work ( 200 Gb is fine )

What is the use-case?

I run node-red on the full version of chirpstack-gateway-os and need to include it in the build. Thus I need to build the images myself.
We also use a lot of virtual machines for doing builds. Even though I use a physical Vmware ESXi server it is also possible to set up really powerful buildservers on Amazon AWS and just power them on ( and pay ) when doing builds. In order to do this, I need to know how big the disk should be, how much RAM is required, which operating system to use etc.

Implementation description

I hope for a comment in the readme.md under https://github.com/brocaar/chirpstack-gateway-os#building-images "The pre-built images was built on an Ubuntu 18.04.05 Linux with 32 Gbyte of Ram and 512 gb of disk. A complete build took 4 hours."

Can you implement this by yourself and make a pull request?

Yes. I'll try.