1. Currently, it is impossible to balance/bind several ports to the same virtual server (if not use fwmark)
Marking is unsuitable in some cases and does not allow flexible virtual-server ---> real-server port matching.
Example of current configuration:
```
set high-availability virtual-server 203.0.113.1 algorithm 'source-hashing'
set high-availability virtual-server 203.0.113.1 port '8080'
set high-availability virtual-server 203.0.113.1 real-server 192.0.2.11 port '8081'
set high-availability virtual-server 203.0.113.1 real-server 192.0.2.12 port '8082'
```
So if we need to balance also and port `8888` it will overwrite the current port `8080`
The proposed change is to set the `virtual-server` as `<tag>` and use `address` to set the address explicit
Proposed new CLI
```
set high-availability virtual-server my_first_server address 203.0.113.1
set high-availability virtual-server my_first_server port 8080
set high-availability virtual-server my_first_server real-server 192.0.2.11 port '8881'
set high-availability virtual-server my_first_server real-server 192.0.2.12 port '8882'
set high-availability virtual-server my_second_server address 203.0.113.1
set high-availability virtual-server my_second_server port 8888
set high-availability virtual-server my_second_server real-server 192.0.2.111 port '8883'
set high-availability virtual-server my_second_server real-server 192.0.2.112 port '8883'
```
Expected keepalived configuration:
```
# Virtual-server configuration
# Vserver my_first_server
virtual_server 203.0.113.1 8080 {
delay_loop 10
lb_algo sh
lb_kind NAT
persistence_timeout 300
protocol TCP
real_server 192.0.2.11 8881 {
weight 1
TCP_CHECK {
}
}
real_server 192.0.2.12 8882 {
weight 1
TCP_CHECK {
}
}
}
# Vserver my_second_server
virtual_server 203.0.113.1 8888 {
delay_loop 10
lb_algo sh
lb_kind NAT
persistence_timeout 300
protocol TCP
real_server 192.0.2.111 8883 {
weight 1
TCP_CHECK {
}
}
real_server 192.0.2.112 8883 {
weight 1
TCP_CHECK {
}
}
}
```
2. `Virtual-server port` should be optional. If we don't set the virtual-server port we don't expect ports and for real-server