Comment 0 for bug 1776228

I'm facing issues with OpenStack VMs built from Ubuntu 18.04 cloud image and configured with multiple NICs. I have a solution working on 16.04, which doesn't do any more since the introduction of netplan.

Requirements:

 - Multiple interfaces connected to different networks.
 - All NICs configured via DHCP to ensure IP address, but also parameters like MTU adapt to the environment automatically.
 - Default route is supposed to use one specific NIC and network.

The solution on 16.04 was customization of /etc/dhcp/dhclient.conf, such that all unique parameters are retrieved from only that interface. Example with ens3 being the intended authoritative interface:

  option rfc3442-classless-static-routes code 121 = array of unsigned integer 8;
  send host-name = gethostname();
  request subnet-mask, broadcast-address, time-offset,
          netbios-name-servers, netbios-scope, interface-mtu,
          rfc3442-classless-static-routes;
  interface "ens3" { request routers, domain-name, domain-name-servers, domain-search, host-name,
                     dhcp6.name-servers, dhcp6.domain-search, dhcp6.fqdn, dhcp6.sntp-servers, ntp-servers; }

This does no longer work with netplan. I couldn't figure any netplan properties to configure DHCP client to that granularity. And /etc/dhcp/dhclient.conf no longer seems to be honored. As I can see in VM startup console log, each interface is getting default route assigned and the system remains unresponsive most of the times.

How am I supposed to solve this on a netplan managed system?