[PVE-User] Newbie in cluster - architecture questions

[Demetri A. Mkobaranov]

Hello,

I'm approaching clustering technology with the final aim to learn HA 
architectures. My preparation on this is zero.

My biggest difficulty at the moment is to understand which technology is 
for and what problem solves.

I'm reading Proxmox documentation and it seems to imply this as 
background knowledge but I don't have it.

Googling is very hard in this realm due to the vastness of the topic and 
the number of technologies "replaced" over the time or competing at the 
current time so I'd be grateful is someone can back me a up a little in 
this learning process.

Questions:

1) From the Proxmox manual it seems like a cluster, without HA, offers 
just the ability to migrate a guest from a node to another one. Is this 
correct?

1B) Basically the configuration of one node is replicated (like /etc/pve 
via pmxcfs) on other nodes so that they are all aware of the guests and 
then corosync makes each node aware of the status of any other node and 
probably triggers the synchronization via pmxcfs. Right? Nothing more 
(unless further configuration) ?

2) Can I have nodes belonging to one cluster but living in different 
countries? Or in this case a multi-cluster is required (like 3 nodes in 
one datacenter and a cluster in another datacenter somehow linked 
together) ?


Thank you for your time and efforts

Demetri