I'm getting a different error now:

# dnf install gcc
CentOS Stream 9 - BaseOS 890 B/s | 3.9 kB 00:04
Errors during downloading metadata for repository 'baseos':
- Downloading successful, but checksum doesn't match. Calculated: 4152182febfc572005903a92f9bf890fbf4c89cbb24fa3c2d18aff986b9507e31e783b83c307a9166dea027966b3a24da1f5c292fbe5323373d5efe4c2450553(sha512) Expected: f14c0fffec622123d1d4d7a32b1cad1855c4cb28242298243b0d07dff81bfc085f75c19958b40ad72f013a2209bf208edaca5c6d395b77df7beeff25c6ed1b46(sha512)
Error: Failed to download metadata for repo 'baseos': Cannot download repomd.xml: Cannot download repodata/repomd.xml: All mirrors were tried

This reminds me to an issue we had in the past with mirrors sync?

On Wed, Nov 10, 2021 at 4:46 PM Troy Dawson <tdawson@redhat.com> wrote:

On Wed, Nov 10, 2021 at 7:39 AM Florian Weimer <fweimer@redhat.com> wrote:
* Alfredo Moralejo Alonso:

> I'm having problems installing gcc in CS9:
>
> [root@eba723badadf /]# dnf install gcc
> CentOS Stream 9 - BaseOS 583 kB/s | 1.3 MB 00:02
> CentOS Stream 9 - AppStream 1.3 MB/s | 7.7 MB 00:06
> Error:
> Problem: cannot install the best candidate for the job
> - nothing provides libgcc >= 11.2.1-6.el9 needed by gcc-11.2.1-6.el9.x86_64
> - nothing provides libgomp = 11.2.1-6.el9 needed by gcc-11.2.1-6.el9.x86_64
>
> it seems some subpackages of gcc are missing in the repo?

Try running “dnf update” first. If I recall correctly, “dnf install”
does not upgrade already-installed packages for dependencies.

No, this is a legitimate bug, and there is a bugzilla somewhere for it.
It is being worked on as I write this.

Troy