VyOS 1.3 Configuring Interface causes brief outage


Wondering if this normal behavior because it does not seem it should be. With VyOS 1.3 whenever I make a configuration change on my WAN eth0 interface, no matter what the change is, it causes the interface DHCP (IPv4 and IPv6) to stop/release/restart and causes an brief outage. It does not seem right that configuring, for instance, a description or traffic policy should cause the interface to reset. Shouldn’t that only happen if I’m actually changing the interface addressing?

WAN config:

set interfaces ethernet eth0 address 'dhcp'
set interfaces ethernet eth0 address 'dhcpv6'
set interfaces ethernet eth0 description 'WAN'
set interfaces ethernet eth0 dhcpv6-options pd 0 interface eth1 address '1'
set interfaces ethernet eth0 dhcpv6-options pd 0 interface eth1 sla-id '1'
set interfaces ethernet eth0 dhcpv6-options pd 0 length '60'
set interfaces ethernet eth0 dhcpv6-options rapid-commit

Reproduce issue - Start ping from LAN to something on the WAN ( for example if WAN is the internet) and while ping is running change description or set traffic policy on eth0 interface. Notice ping drops and view logs to see DHCP client releasing/stopping/restarting for eth0 interface.

The “reason” for this unpleasant behavior is that we currently can not change the interface metric on the fly. Thus a service restart is required.

This should be changed as it causes artificial outages which simply suck.

I have filed bug report ⚓ T4203 Reconfigure DHCP client interface causes brief outages


@c-po Thank you for the information and bug report

Is this similar to why OSPF has to restart when bringing up an IP on an interface? I’ve been testing vyos in gns3 to prep for live deployment in our network and noticed that behavior.

@trendal you happen to have a version number you are using for testing? DHCP client fix will be in tomorrows rolling release.

Great news! Thanks for the update!

I’m using this vyos-1.3.0-epa3-amd64.iso in GNS3. Haven’t used DHCP in testing yet.

Just to report I did a new build of VyOS 1.3 and the issue seems to be fixed with DHCP(v4). DHCP client no longer releases/restarts when making non-dhcp related interface changes. The problem still exists with DHCPv6, however. Making non-dhcp interface changes is still causing DHCPv6 client to release and restart.