Oliver,

Thanks for this changeset and i think this is getting closer but over the past few months there have been a few changes that I don't think this series takes into account. 

A few comments i hope we can address quickly (since 18.04 is going offline tomorrow).

1. Can the whole block at https://github.com/tianocore/edk2/blob/dd3ba82d31a6d3cc4564dc83c9229e13773b55da/.pytool/CISettings.py#L172 be removed.  The only reason these exist is to pick up and download the compilers. 

2. what about supporting the loongarch64 compiler? Can we add to container?

3. If loongarch64 is included in container should you delete this file too: edk2/gcc_loongarch64_unknown_linux_ext_dep.yaml at master · tianocore/edk2 (github.com)

4.  Patch 4 has changes in multiple packages.  I believe it is a requirement in edk2 to only change a single package per commit.  It makes reviews and cherry-picking/bisection easier. 

5. Since only Core CI as controlled by  file .azurepipelines/Ubuntu_GCC5.yml why not use the base container instead of test container?  The Core CI Process will not use qemu.  The platform Ci files have their own yml with container specifier. 

6. what about removing the steps for installing node and cspell from the container build?  Since these are managed in the container they should be skipped. 

Thanks

Sean

-18.04 vm_image since this will no longer be available
  after Dec 1st.  Use ubuntu-latest instead.