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<div>Hello everybody,</div>
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<div>At Facebook we use BGP anycast technology to balance DHCP traffic. To do so we advertise a global VIP via BGP, VIP that then ends up in the rack switch dhcp relayers.</div>
<div>We then receive UDP datagrams that have the VIP IP as the destination IP, therefore we need to bring up tunl0/ip6tnl0 interfaces onto our machines that have the VIP assigned so that applications can get those datagrams destined to the VIP address.</div>
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<div>I’ve been testing kea 0.9.2 in our production environment and I’ve noticed a regression compared to 0.9:</div>
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<div>KEA refuses to listen on tunl0 or ip6tnl0 interfaces.</div>
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<div>I get an error like this:</div>
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<div>2015-11-18 06:09:11.451 WARN [kea-dhcp4.dhcpsrv/650885] DHCPSRV_OPEN_SOCKET_FAIL failed to open socket: the interface tunl0 is down or has no usable IPv4 addresses configured</div>
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<div>Even though I assign an IP to the interface, see:</div>
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<div>$ ip addr show tunl0</div>
<div>9: tunl0: <NOARP> mtu 0 qdisc noop state DOWN</div>
<div> link/ipip 0.0.0.0 brd 0.0.0.0</div>
<div> inet 10.127.255.68/32 scope global tunl0</div>
<div> valid_lft forever preferred_lft forever</div>
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<div>And basically our DICOVERY packets are never seen by the server.</div>
<div>I am currently reading lib/dhcp/iface_mgr.cc but I wanted to give you an heads up...</div>
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<div>-- </div>
<div>Angelo Failla</div>
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<div>Cluster Infrastructure - Dublin</div>
<div>Pallotron@fb.com</div>
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