CentOS 7 Lost NIC

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Hello,

I have a big problem with my servers.

I have 4 NIC on all my KVM Servers but the most time on a start (restart) I
lost one NIC? It is not always the same, but this two are virtio NICs.

with ifup eth0(1) the system say,I have no configured eth0 or eth1 file ?

Can any tell me what I can do?

thank’s for a answer

NetworkManager is disabled.

4 thoughts on - CentOS 7 Lost NIC

  • You haven’t given us much to go on. The output of these commands might be helpful:

    lspci
    “ip addr show” or “ifconfig -a”
    dmesg | grep -i eth ls -l /etc/sysconfig/network/ifcfg-eth*
    cat /etc/sysconfig/network/ifcfg-eth*

  • Hello Am Friday 11 December 2015, 10:13:00 schrieb Gordon Messmer:

    lspci;

    -00:00.0 Host bridge: Intel Corporation 440FX – 82441FX PMC [Natoma] (rev 02)
    00:01.0 ISA bridge: Intel Corporation 82371SB PIIX3 ISA [Natoma/Triton II]
    00:01.1 IDE interface: Intel Corporation 82371SB PIIX3 IDE [Natoma/Triton II]
    00:01.3 Bridge: Intel Corporation 82371AB/EB/MB PIIX4 ACPI (rev 03)
    00:02.0 VGA compatible controller: Red Hat, Inc. QXL paravirtual graphic card
    (rev 04)
    00:03.0 Ethernet controller: Red Hat, Inc Virtio network device
    00:04.0 Ethernet controller: Red Hat, Inc Virtio network device
    00:05.0 Audio device: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family)
    High Definition Audio Controller (rev 01)
    00:06.0 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI
    Controller #1 (rev 03)
    00:06.1 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI
    Controller #2 (rev 03)
    00:06.2 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI
    Controller #3 (rev 03)
    00:06.7 USB controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI
    Controller #1 (rev 03)
    00:07.0 Communication controller: Red Hat, Inc Virtio console
    00:08.0 SCSI storage controller: Red Hat, Inc Virtio block device
    00:09.0 SCSI storage controller: Red Hat, Inc Virtio block device
    00:0a.0 Unclassified device [00ff]: Red Hat, Inc Virtio memory balloon
    00:0b.0 Ethernet controller: Intel Corporation I350 Ethernet Controller Virtual Function (rev 01)
    00:0c.0 Ethernet controller: Intel Corporation I350 Ethernet Controller Virtual Function (rev 01)

    ifconfig;

    ens12: flags=4163 mtu 1500
    inet6 fe80::5054:ff:fe81:e89 prefixlen 64 scopeid 0x20 inet6 2001:15c0:xxxx:xxxx::xxxx prefixlen 64 scopeid 0x0
    ether 52:54:00:81:0e:89 txqueuelen 1000 (Ethernet)
    RX packets 229 bytes 20108 (19.6 KiB)
    RX errors 0 dropped 0 overruns 0 frame 0
    TX packets 140 bytes 12736 (12.4 KiB)
    TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

    eth1: flags=4163 mtu 1500
    inet 192.168.xxx.xxx netmask 255.255.255.0 broadcast 192.168.100.255
    inet6 fe80::5054:ff:fe97:3af2 prefixlen 64 scopeid 0x20 ether 52:54:00:97:3a:f2 txqueuelen 1000 (Ethernet)
    RX packets 1326 bytes 127389 (124.4 KiB)
    RX errors 0 dropped 242 overruns 0 frame 0
    TX packets 299 bytes 27625 (26.9 KiB)

    lo: flags=73 mtu 65536
    inet 127.0.0.1 netmask 255.0.0.0
    inet6 ::1 prefixlen 128 scopeid 0x10
    loop txqueuelen 0 (Lokale Schleife)
    RX packets 184 bytes 14404 (14.0 KiB)
    RX errors 0 dropped 0 overruns 0 frame 0
    TX packets 184 bytes 14404 (14.0 KiB)
    TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
    TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

    ifconfig -a:

    ens11: flags=4098 mtu 1500
    ether 52:54:00:14:78:0e txqueuelen 1000 (Ethernet)
    RX packets 0 bytes 0 (0.0 B)
    RX errors 0 dropped 0 overruns 0 frame 0
    TX packets 0 bytes 0 (0.0 B)
    TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

    ens12: flags=4163 mtu 1500
    inet6 fe80::5054:ff:fe81:e89 prefixlen 64 scopeid 0x20 inet6 2001:15c0:xxxx:xxxx::xxxx prefixlen 64 scopeid 0x0
    ether 52:54:00:81:0e:89 txqueuelen 1000 (Ethernet)
    RX packets 281 bytes 24584 (24.0 KiB)
    RX errors 0 dropped 0 overruns 0 frame 0
    TX packets 165 bytes 14950 (14.5 KiB)
    TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

    eth1: flags=4163 mtu 1500
    inet 192.168.xxx.xxx netmask 255.255.255.0 broadcast 192.168.100.255
    inet6 fe80::5054:ff:fe97:3af2 prefixlen 64 scopeid 0x20 ether 52:54:00:97:3a:f2 txqueuelen 1000 (Ethernet)
    RX packets 1607 bytes 149627 (146.1 KiB)
    RX errors 0 dropped 297 overruns 0 frame 0
    TX packets 327 bytes 31579 (30.8 KiB)
    TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

    eth2: flags=4089 mtu 1500
    ether 52:54:00:e3:1d:5b txqueuelen 1000 (Ethernet)
    RX packets 0 bytes 0 (0.0 B)
    RX errors 0 dropped 0 overruns 0 frame 0
    TX packets 0 bytes 0 (0.0 B)
    TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

    lo: flags=73 mtu 65536
    inet 127.0.0.1 netmask 255.0.0.0
    inet6 ::1 prefixlen 128 scopeid 0x10
    loop txqueuelen 0 (Lokale Schleife)
    RX packets 184 bytes 14404 (14.0 KiB)
    RX errors 0 dropped 0 overruns 0 frame 0
    TX packets 184 bytes 14404 (14.0 KiB)
    TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

    The problem I found now, is I have only a eth0, eth1 configured but I found now a eth2 (??????) and the eth1 is not working next boot I have a eth3 …….

    ls -l /etc/sysconfig/network-scripts/ifcfg-eth*

    -rw-r–r–. 1 root root 227 5. Dez 16:18 /etc/sysconfig/network-scripts/ifcfg-
    eth0
    -rw-r–r–. 1 root root 482 5. Dez 16:25 /etc/sysconfig/network-scripts/ifcfg-
    eth1

    #cat /etc/sysconfig/network-scripts/ifcfg-eth0

    HWADDR=52:54:00:E3:1D:5B
    TYPE=Ethernet BOOTPROTO=none DEFROUTE=no IPV4_FAILURE_FATAL=yes IPV6INIT=no NAME=eth0
    UUID=35fb02e0-74f2-411a-9b76-978a07ebf3c5
    ONBOOT=yes IPADDR=192.168.55.203
    PREFIX=24
    GATEWAY=192.168.55.1
    ZONE=work

    # cat /etc/sysconfig/network-scripts/ifcfg-eth1
    TYPE=”Ethernet”
    BOOTPROTO=none DEFROUTE=”yes”
    IPV4_FAILURE_FATAL=”yes”
    IPV6INIT=”no”
    IPV6_AUTOCONF=”yes”
    IPV6_DEFROUTE=”yes”
    IPV6_PEERDNS=”yes”
    IPV6_PEERROUTES=”yes”
    IPV6_FAILURE_FATAL=”no”
    NAME=”eth1″
    #UUID=”fed939b5-954e-4822-b6cc-553c4a35766a”
    UUID=eb5c2cbd-310f-4132-8bca-498bed1e651c DEVICE=”eth1″
    ONBOOT=”yes”
    DNS1=”192.168.100.221″
    DOMAIN=”xxxxxx.xxx yyyyy.yyyy”
    IPADDR=192.168.100.203
    PREFIX=24
    GATEWAY=192.168.100.220
    DNS2=217.196.154.211
    HWADDR=52:54:00:97:3A:F2
    ZONE=internal

    I have NetworkManager disabled but I mean this is a Problem from NetworkManager?

    after X reboot I have a correct Network :-(.

    dmesg has no output?

    –
    mit freundlichen Gr

  • It wasn’t clear that you were talking about KVM *guests* before.

    Are the ethernet addresses changing between boots? If you run “ifconfig
    -a | grep ether” does the output change from one boot to another?

    What do you get from “virsh dumpxml ” in the KVM host?

  • Am Saturday 12 December 2015, 21:12:08 schrieb Gordon Messmer:

    When the network is not working the virtio NICs are not working?
    When I boot / reboot I have only one from the configured NICs eth0 or eth1 and a not configured NIC eth2 after a broken reboot I have eth1 and eth3 and so on.

    But sometimes after more reboots the network is working again?

    The 2 “hostdev” configured NICs are working always (external)

    OK, I test it.