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I have a VM with an interface on a bridge(e.g. br0). After restarting the bridge(bring down, bring up) VM doesn't see the network and I must do "power cycle"(shutdown and then power on) to get VM see the network. Why it is happening and why reboot didn't help? Sincerely.

Hypervisor is KVM on Ubuntu 16.04

Disova
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  • Can you post the output of `brctl show` both before and after restarting the bridge? – shodanshok Dec 30 '16 at 16:43
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    Probably because the VM's virtual NIC on the host side (e.g. `vnet0`) is not re-added to the bridge when it is recreated. This only happens at VM power on. – Michael Hampton Dec 30 '16 at 19:14

1 Answers1

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When you take the bridge down it disconnects all the attached IFs, when you bring it back up, only the IFs defined in ifcfg files (or whatever ubuntu uses instead) are added automatically. KVM guests have a script that does it, executed at VM start. So it's absolutely logical that you don't get reconnected unless you execute VM start.

dyasny
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