[release/5.0] Checklist update to confirm that repos were updated. (#2339)

* Checklist update to confirm that repos were updated.

* Address review comment.

Author: crummel

.github/ISSUE_TEMPLATE/releases/release_checklist.md

@@ -38,6 +38,18 @@
         - [ ] Verify that the `PrivateSourceBuiltArtifactsPackageVersion` in `eng/Versions.props` matches N-1 release artifacts.
         - [ ] Update the `global.json` SDK version to N-1: the latest released "3.1.XYY" SDK version, where "3.1.X" matches the SDK we're building.
         - [ ] Update the `eng/Versions.props` with the latest product versions.
+        - [ ] Verify that all repos that are not pinned were updated, except for these which we expect to be fairly stable:
+          - Arcade
+          - SourceLink
+          - aspnet-xdt
+          - cliCommandLineParser
+          - Xliff-tasks
+          - Newtonsoft.Json
+          - Humanizer
+          - Roslyn (except for feature band updates)
+          - MSBuild (except for feature band updates)
+          - NuGet-client (except for feature band updates)
+          - FSharp (except for feature band updates)
 1.  - [ ] [2.1] Fetch internal git data for submodules.
       1.  Run `git submodule update --init --recursive` and see errors due to missing commits.
       1.  Run `fetch-vsts-commits.sh` with a PAT to automatically fetch internal refs.
@@ -103,6 +115,7 @@
         - [ ] CentOS 8 - dseefeld
         - [ ] Debian - dagood
 1.  - [ ] [Internal] Download the artifacts from the green PR validation build onto a machine with Bash.
+      - In 5.0, the base tarball leg will produce a platform-independent tarball and smoke-test-prereqs to use.
       - We may require only a subset of the artifacts for certain releases: refer to the previous release email thread corresponding to 2.1 vs. 3.1 vs. 5.0 build.
       - Can use <https://github.com/dotnet/source-build/blob/release/3.1/scripts/fetch-azdo-artifact-tarball.sh> as a library.
         - E.g. download the tarballs with `download_tarball`, and fix them up with `fix_azdo_tarball` if necessary.

Documentation/rhel-machine-setup-and-ci.md

@@ -0,0 +1,23 @@
+# Red Hat machine setup and internal CI machines
+
+## Machine setup
+
+### RHEL 7
+
+- It's usually easiest to install the server or minimal workloads and add needed stuff from there.
+- You will need a RHEL developer account (https://developers.redhat.com/register).
+- You will need to install the [EPEL](https://www.redhat.com/en/blog/whats-epel-and-how-do-i-use-it) and [rhel-server-rhscl-7-rpms](https://access.redhat.com/solutions/472793) repos.
+- The build prereqs are mostly the same as the [Fedora docker image](https://github.com/dotnet/dotnet-buildtools-prereqs-docker/blob/main/src/fedora/32/amd64/Dockerfile).
+  - Clang and LLVM are pretty old in the default repos.  The easiest way to get a version that will work with both release/3.1 and release/5.0 is to install llvm-toolset-6.0 and devtoolset-8 from the RHSCL repo.  Then you can run `scl enable devtoolset-8 llvm-toolset-6.0 bash` to get a shell with the updated Clang and LLVM available.
+
+### RHEL 8
+
+- See RHEL 7, but you shouldn't need the RHSCL repo - the Clang and LLVM versions are already good enough.
+
+
+## CI Machines
+
+- Our RHEL CI machines are dnsb-rhel7-1, dnsb-rhel7-2, dnsb-rhel8-1, and dnsb-rhel8-2 in the DotNet-SourceBuild-Internal pool.
+- These can only be remoted into from a REDMOND-joined machine.  The username is dotnet-bot and the password can be found in Keyvault as usual.
+- The most common operation needed is to clean up their source directories.  Typically this is when we get the "object reference is not a tree" or "missing submodule MessagePack" errors in CI and the cause is not missing commits.
+  - Log in to the machines, go to the agent work directory (/data/a/_work), and delete \*/s/\* (this will be 1/s/\*, 2/s/\*, etc).  You may have to sudo to do it.