Centos7 - link up, but no DCHP, unable to bring up next working interface

Question

I have following configuration: server has two network interfaces, both are attached to switch (and will become LOWER_UP after been made up). One of those interfaces will have DHCP server with a lease. Other interface will not provide me with leases.

I need such configuration for CentOS 7, that it will receive IP regardless of interface used for DHCP.

I've tried to make both interfaces BOOTPROTO="dhcp", ONBOOT="yes" and IPV4_FAILURE_FATAL="no". But there is a catch: If CentOS detects link on eno1, it will continue to try to bring up eth0, without trying DHCP on eth2. I couldn't disable eno1, because by random chance DHCP may be on eno1 (or eno2).

Is here a way to say CentOS "try to bring up all those interfaces"?

You certainly can't get an IP address from a DHCP server when the Ethernet cable is disconnected! What is really going on here? — Michael Hampton, Mar 22 '17 at 13:50
Interface eno1 is connected to switch, but there is no DHCP server on that net in 50% of cases. — George Shuklin, Mar 22 '17 at 16:45

score 0 · Answer 1 · answered Mar 22 '17 at 16:47

0

After some debugging I reduced dhcp timeouts to 10 seconds (/etc/dhcp/dhclient.conf). It helped. Now eno1 failing fast enough to allow eno2 to find lease before global network timeout happens.

answered Mar 22 '17 at 16:47

George Shuklin

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Centos7 - link up, but no DCHP, unable to bring up next working interface

1 Answers1