Difference between load-balancing reverse-proxy and high-availability virtual-server

General questions
1

Can someone explain me the difference between load-balancing reverse-proxy and high-availability virtual-server. When should I use which and also what are the technical differences?

And also if I try to configure high-availability virtual-server like:
set high-availability virtual-server 192.168.100.50 algorithm ‘source-hashing’
set high-availability virtual-server 192.168.100.50 delay-loop ‘10’
…

I’m getting the error:
Either address or fwmark is required but not set for virtual-server
“192.168.100.50”

But 192.168.100.50 has been configured in a vrrp group as address.

2

Virtual-server foo address x.x.x.x

The difference the same as between haproxy and lvs

3

OK, thanks for your answer.

So, “load-balancing reverse-proxy” is realised with haproxy and “high-availability virtual-server” with lvs. Correct? Then AI could help me with the differnences and I know what to use in my case.

Perhaps the documentation for the virtual-server should be adapted. I assume that the first example is not correct.
High availability — VyOS 1.4.x (sagitta) documentation

set high-availability virtual-server 203.0.113.1 algorithm ‘source-hashing’
set high-availability virtual-server 203.0.113.1 delay-loop ‘10’
set high-availability virtual-server 203.0.113.1 forward-method ‘nat’
set high-availability virtual-server 203.0.113.1 persistence-timeout ‘180’
set high-availability virtual-server 203.0.113.1 port ‘8280’
set high-availability virtual-server 203.0.113.1 protocol ‘tcp’
set high-availability virtual-server 203.0.113.1 real-server 192.0.2.11 port ‘80’
set high-availability virtual-server 203.0.113.1 real-server 192.0.2.12 port ‘80’

Instead of “203.0.113.1” a name (foo) and add a address-command like:

set high-availability virtual-server foo address 203.0.113.1