We have some percona clusters and always are hesitant to install any patches for it due to possible DB cluster issues with Percona. Our servers all run Mysql 8. We use Oracle Linux 8.7 and also have an older cluster using 7.9 but both percona environments are using Mysql 8 and Percona XtraDB cluster 8. Would I be ok just pushing the patches normally? I assume it treats these just like any other patch for Linux OS as it takes them on the fly and for the most part does not cause any issues. We reboot as needed if pending reboots post patching.
The patching activity would probably operate in a similar manner, but there are a few considerations that should be taken into account.
1.This should be carried out in a rolling fashion, starting with the secondary PXC nodes first. Additionally, the database service should be gracefully stopped before rebooting the entire server if necessary.
After completing the patching activity, it is advisable to always verify the MySQL/PXC logs and OS/kernel logs (e.g., /var/log/messages) for any suspicious warnings or errors.
If using any middleware like ProxySQL its good to put the concerned node in maintenance mode “set global pxc_maint_mode=maintenance;”. This way, ProxySQL will automatically stop sending new traffic to that node.
I see you having a higher PXB(8.0.34) version compared to PXC (8.0.33) Please note that starting from version 8.0.22 compatible versions of XtraBackup and MySQL should match to avoid any hidden compatibility issues. We recommend to having the same version for both (PXC & PXB).
So, going forward we having a latest PXC release (8.0.34-26) as well which you might considering upgrading from these older versions. You can read more about the fixes/changes in the below release notes.
Furthermore, you can refer to the suggestions we provided earlier.