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"?
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.