Netplan and high availability

[Harald Weidner]

Hello,

> Currently netplan removes interfaces it does not manage on any
> change (netplan apply).
> 
> Please point me to some recommendations for implementing a high
> availability cluster or pair in Bionic with IP fail over.

I think the easiest solution is to replace Netplan by ifupdown(2)
or systemd-networkd.

That said, ifupdown2's "ifreload -a" leaves all interface untouched,
unless you changed anything regarding this interface.

If, for example, an interface eth0 has IP address X, managed by
ifupdown2, and your cluster (Pacemaker or Keepalived) adds a virtual
IP address Y to the same interface, as soon as you change the IP address
X to Z in /etc/network/interface (or do any other modification to the
eth0 interface there), "ifreload -a" will rearrange eth0, thus deleting
the VIP Y.

But this is better than Netplan dropping unrelated interface
configurations.

Regards,
Harald