Yum is complaining that the 64-bit and 32-bit versions of the RPM for systemd-libs in your system do not match.
You'll see that it has version 219-30.el7_3.7 for x86_64 (64-bit) and version 219-30.el7_3.6 for i686 (32-bit).
You can check the version of the package for each architecture in your system with this command:
$ rpm -q systemd-libs
systemd-libs-219-30.el7_3.6.i686
systemd-libs-219-30.el7_3.7.x86_64
See if you see some anomaly there, such as having two versions of systemd-libs for i686...
If the versions match, then the problem might be that yum is trying to upgrade the x86_64 version, but leaving the i686 version behind.
It's possible that your --skip-broken is triggering this somehow, if the i686 version of the package is somehow "broken" to yum...
It's also possible that your system was reconfigured to only consider 64-bit packages and no longer try to install (or maintain) 32-bit ones...
You can try some utilities from the yum-utils package to troubleshoot this.
Can you install it?
$ sudo yum install yum-utils
If you do, try this command to complete yum transactions that were interrupted (which might have caused the issue in the first place):
$ sudo yum-complete-transaction
You can also use the package-cleanup command. For instance, if it seems you have duplicate packages (multiple versions installed for the 32-bit one), try this:
$ sudo package-cleanup --cleandupes
I hope this helps!
Best Answer
If RHEL binary compatibility is not strictly required and if using in-tree kernel modules only (i.e.: no out-of-tree kmods are required), CentOS Stream should remain a viable option.
Otherwise you can use one of the new RHEL clones, such as AlmaLinux, RockyLinux or even Oracle Unbreakable Linux (in this case, be sure to select the RHEL-compatible kernel rather than its own customized kernel). Personal note: I am using RockyLinux with no issues at all (I migrated from a CentOS 8 box with the
migrate2rockyscript) but, as always, your mileage may vary.Finally, if you are sure to need fewer than 16 RHEL instances, you can use plain simple Red Hat Enterprise Linux from Red Hat's free tier (with no support, obviously).
EDIT: as wisely suggested in other answers, migrating to a different distributions as Debian, Ubuntu, etc. is a very reasonable approach. I did the same (rebuilding with latest Ubuntu LTS) in environments where RHEL compatibility was not required. Debian and Ubuntu officially support in-place upgrade paths while most RHEL clones only have unofficial support - RHEL itself and Oracle Unbreakable Linux being the exceptions, with fully supported
leappupgrades - but things are changing now.