How many network cards do I need to build 3-server HA system?

[Mayank006]

I learned that we need one Internal IP for HA data transfer and one for public use IP. I am not sure how it works Please suggest.

Do we need two network cards per server? (Dual Port 10GbE for HA and Dual Port 1GbE for other use)

 

[Dunuin]

You want dedicated NICs for a corosync ring (+ optionally for management) as the latency should always be below 1ms so you don't want any other traffic on that NIC/switch that could reduce QoS.
Then a NIC for your guests.
And another NIC for backups/migrations/replication so when those saturate your NIC this wouldn't affect your guests.
When using ceph maye more NICs.