After upgrade to 5.4 redundant corosync ring does not work as expected

[Whatever]

On another cluster I'm facing different issue but again after an upgrade to 5.4
Could you please take a look into: https://forum.proxmox.com/threads/proxmox-cluster-broke-at-upgrade.54182/#post-250102

I'm fully confident that my network switches are configured inline with PVE docs IGMP snooping is enabled and igmp querier is enabled for given VLAN on the switch

What is common in all my setups: bond (LACP) and classic bridge on top of bond

One more thing to be checked: could you provide me an downgraded pve-corosync package from 5.3. Before an upgrade ALL my installs were working smoothly starting from PVE 3.x

 

[fabian]

the corosync packages have not been updated since Oct. 2018 - well before the release of PVE 5.3. all old package versions are available in our repo:
http://download.proxmox.com/debian/pve/dists/stretch/pve-no-subscription/binary-amd64/

 

[Stoiko Ivanov]

One more thing to be checked: could you provide me an downgraded pve-corosync package from 5.3.

AFAIR the corosync version did not change between 5.3 and 5.4 (in both cases you should be running 2.4.4-pve1) (but you can verify with your running 5.3 clusters).
Should you wish to downgrade you can always see which versions are downloadable:
* `apt-cache policy pve-corosync`
And downgrade by running
* `apt install pve-corosync=2.4.2-pve5`

But again - I don't think that this is a corosync issue.

What kind of NICs do you have in your Servers?