Never mind, I have found the reason. When libvirtd started, it will create bridge virbr0 and then write 1 to /proc/sys/net/ipv4/ip_forward (0 in default). Set ip_forward from 0 to 1 will cause ixgbe driver reset NIC, so the network broke for a while.
> -----Original Messages----- > From: "Genghuang Wang" <wangtianjiao.wang...@gmail.com> > Sent Time: 2018-02-24 14:34:16 (Saturday) > To: "CentOS mailing list" <firstname.lastname@example.org> > Cc: > Subject: Re: [CentOS] Network broke for a while when libvirtd start > > Hello > > > When start service libvirtd by > > > > service libvirtd start > > > > > OS: CentOS 6.5 > > libvirt: libvirt-daemon-1.2.5-1.mira1.x86_64 > > https://www.redhat.com/mailman/listinfo/libvirt-users > is the official mailing list for the libvirt daemon, maybe you can ask > in there and get better support. > > > Does anyone know the reason? > > This mailing list is for the general usage of the CentOS system, I am > afraid that not many experts about libvert could be found here. > > If you ask in the most appropriate mailing list, you may get the > quickest and the most helpful assistance. > _______________________________________________ > CentOS mailing list > CentOS@centos.org > https://lists.centos.org/mailman/listinfo/centos _______________________________________________ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos