This is a common occurrence on my KVM server and is frustrating because just messing with networking on the server fixes the issue and I have no idea how it gets fixed.
Last night power outage from strong storms prompted this instance of it. The power went off, which means my server went down because it does not have it's redundant power supply plugged in, because it wouldn't make a difference. It's on the same circuit in my basement and is just my fun nerdy server that I host personal services on. Now, the kvm guests cannot reach the Internet normally because dns fails. One positive is that they can ping by IP address, but that doesn't help too much unfortunately.
I have most kvm servers on the br0 bridge and route the traffic rather than routing it so I can assign them static IPs on my internal network and port forward them. I have included 'ip r', and 'ip a' configuration from my kvm host, and the kvm xmldump of my unreliable as of yet mailserver.
I appreciate any help or troubleshooting directions anyone can give me. Thank you!!
default via 192.168.86.1 dev br0 169.254.0.0/16 dev br0 scope link metric 1008 172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 192.168.86.0/24 dev br0 proto kernel scope link src 192.168.86.254 192.168.100.0/24 dev virbr0 proto kernel scope link src 192.168.100.1 192.168.122.0/24 dev defaultbr proto kernel scope link src 192.168.122.1 1: lo: mtu 65536 qdisc noqueue state UNKNOWN qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: enp3s0f0: mtu 1500 qdisc mq master br0 state UP qlen 1000 link/ether b4:99:ba:05:39:22 brd ff:ff:ff:ff:ff:ff inet6 fe80::b699:baff:fe05:3922/64 scope link valid_lft forever preferred_lft forever 3: enp3s0f1: mtu 1500 qdisc noop state DOWN qlen 1000 link/ether b4:99:ba:05:39:24 brd ff:ff:ff:ff:ff:ff 4: enp4s0f0: mtu 1500 qdisc noop state DOWN qlen 1000 link/ether b4:99:ba:05:39:26 brd ff:ff:ff:ff:ff:ff 5: enp4s0f1: mtu 1500 qdisc noop state DOWN qlen 1000 link/ether b4:99:ba:05:39:28 brd ff:ff:ff:ff:ff:ff 6: ib0: mtu 4092 qdisc noop state DOWN qlen 256 link/infiniband 80:00:02:08:fe:80:00:00:00:00:00:00:00:16:35:ff:ff:bf:fb:f5 brd 00:ff:ff:ff:ff:12:40:1b:ff:ff:00:00:00:00:00:00:ff:ff:ff:ff 7: ib1: mtu 4092 qdisc noop state DOWN qlen 256 link/infiniband 80:00:02:09:fe:80:00:00:00:00:00:00:00:16:35:ff:ff:bf:fb:f6 brd 00:ff:ff:ff:ff:12:40:1b:ff:ff:00:00:00:00:00:00:ff:ff:ff:ff 8: br0: mtu 1500 qdisc noqueue state UP qlen 1000 link/ether b4:99:ba:05:39:22 brd ff:ff:ff:ff:ff:ff inet 192.168.86.254/24 brd 192.168.86.255 scope global br0 valid_lft forever preferred_lft forever inet6 fe80::b699:baff:fe05:3922/64 scope link valid_lft forever preferred_lft forever 9: defaultbr: mtu 1500 qdisc noqueue state DOWN qlen 1000 link/ether 52:54:00:02:c8:49 brd ff:ff:ff:ff:ff:ff inet 192.168.122.1/24 brd 192.168.122.255 scope global defaultbr valid_lft forever preferred_lft forever 10: defaultbr-nic: mtu 1500 qdisc pfifo_fast master defaultbr state DOWN qlen 1000 link/ether 52:54:00:02:c8:49 brd ff:ff:ff:ff:ff:ff 11: virbr0: mtu 1500 qdisc noqueue state UP qlen 1000 link/ether 52:54:00:f8:4c:be brd ff:ff:ff:ff:ff:ff inet 192.168.100.1/24 brd 192.168.100.255 scope global virbr0 valid_lft forever preferred_lft forever 12: virbr0-nic: mtu 1500 qdisc pfifo_fast master virbr0 state DOWN qlen 1000 link/ether 52:54:00:f8:4c:be brd ff:ff:ff:ff:ff:ff 13: vnet0: mtu 1500 qdisc pfifo_fast master br0 state UNKNOWN qlen 1000 link/ether fe:54:00:3f:08:1f brd ff:ff:ff:ff:ff:ff inet6 fe80::fc54:ff:fe3f:81f/64 scope link valid_lft forever preferred_lft forever 14: docker0: mtu 1500 qdisc noqueue state UP link/ether 02:42:22:11:f5:ab brd ff:ff:ff:ff:ff:ff inet 172.17.0.1/16 scope global docker0 valid_lft forever preferred_lft forever inet6 fe80::42:22ff:fe11:f5ab/64 scope link valid_lft forever preferred_lft forever 18: veth776aca1@if17: mtu 1500 qdisc noqueue master docker0 state UP link/ether da:8a:e2:11:8a:6f brd ff:ff:ff:ff:ff:ff link-netnsid 0 inet6 fe80::d88a:e2ff:fe11:8a6f/64 scope link valid_lft forever preferred_lft forever 35: vnet1: mtu 1500 qdisc pfifo_fast master br0 state UNKNOWN qlen 1000 link/ether fe:54:00:c5:0f:38 brd ff:ff:ff:ff:ff:ff inet6 fe80::fc54:ff:fec5:f38/64 scope link valid_lft forever preferred_lft forever 36: vnet2: mtu 1500 qdisc pfifo_fast master br0 state UNKNOWN qlen 1000 link/ether fe:54:00:3c:a8:3c brd ff:ff:ff:ff:ff:ff inet6 fe80::fc54:ff:fe3c:a83c/64 scope link valid_lft forever preferred_lft forever 37: vnet3: mtu 1500 qdisc pfifo_fast master virbr0 state UNKNOWN qlen 1000 link/ether fe:54:00:a8:a2:1e brd ff:ff:ff:ff:ff:ff inet6 fe80::fc54:ff:fea8:a21e/64 scope link valid_lft forever preferred_lft forever 38: vnet4: mtu 1500 qdisc pfifo_fast master virbr0 state UNKNOWN qlen 1000 link/ether fe:54:00:48:fa:1f brd ff:ff:ff:ff:ff:ff inet6 fe80::fc54:ff:fe48:fa1f/64 scope link valid_lft forever preferred_lft forever 39: vnet5: mtu 1500 qdisc pfifo_fast master br0 state UNKNOWN qlen 1000 link/ether fe:54:00:20:c2:ce brd ff:ff:ff:ff:ff:ff inet6 fe80::fc54:ff:fe20:c2ce/64 scope link valid_lft forever preferred_lft forever zimbra-centos7 aacb9a74-d5f9-48c0-8d26-481cd573bcfd 8392704 8392704 2 /machine hvm Westmere destroy restart restart /usr/libexec/qemu-kvm system_u:system_r:svirt_t:s0:c340,c568 system_u:object_r:svirt_image_t:s0:c340,c568 +107:+107 +107:+107