Nutanix AHV Node Failed to detect Network card NICs after Replacement

Are you running Nutanix AHV hypervisor in your environment and want to replace Nutanix AHV host’s network card(s) / NICs or SATADOM cause of some reasons then you might encounter network communication issues.

After replacing Network card(s) the NICs or SATADOM Nutanix AHV host is not able to detect network card / NICs and lose the network connectivity.

Nutanix AHV hypersor having networking error to detect the Network cards / NICs and failed to reach to other AHV host and Nutanix CVM network.

In this case we need to troubleshoot the network issue

Network card Issue Causes

Nutanix AHV host’s network card is not detecting issue might occur due to following reasons

  • Network card(s) / NICs replacement on Nutanix AHV host
  • Duplicate MAC addresses
  • SATADOM replacement

Nutanix AHV Network Troubleshooting

Nutanix native AHV hypervisor failed to detect Network card or NICs and not able to communicate with network.

First we need to determine the network issue on Nutanix AHV host

Step 1 : Log in to through SSH in Nutanix AHV host

Default credential

Userid : root
Password : nutanix/4u

Step 2 : check the name of the interfaces on your system, you may issue one of the following command

root@AHV# ipconfig -a

Result would be like this

root@AHV# ifconfig -a
 br0    Link encap:Ethernet  HWaddr 07:01:20:1A:01:7D  
           inet addr:192.168.5.1  Bcast:192.168.5.255  
           Mask:255.255.255.0
           inet6 addr: fe80::a00:27ff:fe1d:17d/64 Scope:Link
           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
           RX packets:19835 errors:0 dropped:0 overruns:0 frame:0
           TX packets:80091 errors:0 dropped:0 overruns:0 carrier:0
           collisions:0 txqueuelen:1000 
           RX bytes:20385937 (201.5 Mb)  TX bytes:478750 (467.5 Kb)


eth0    Link encap:Ethernet  HWaddr 07:01:20:1A:01:2A  
           inet addr:192.168.0.254  Bcast:192.168.0.255                   
           Mask:255.255.255.0
           inet6 addr: fe80::a00:27ff:fe1d:17a/64 Scope:Link
           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
           RX packets:14737 errors:0 dropped:0 overruns:0 frame:0
           TX packets:7193 errors:0 dropped:0 overruns:0 carrier:0
           collisions:0 txqueuelen:1000 
           RX bytes:30385937 (301.5 Mb)  TX bytes:508750 (527.5 Kb) 

Step 3 : Check network interfaces status ( False | True ) and interface Speed ( 100 | 1000 | 10,000)

Log on to the Nutanix Controller VM ( CVM ), and then list the physical interfaces.

nutanix@cvm$ manage_ovs show_interfaces

Output similar to the following is displayed:

name mode link speed 
eth0 1000 false none 
eth1 1000 false none 
eth2 10000 false none 
eth3 10000 false none

Step 4 : Remove the MAC address entry from ifcfg-eth* file from each Nutanix AHV host

root@AHV# vi /etc/sysconfig/network-script/ifcfg-br0
# cat /etc/sysconfig/network-scripts/ifcfg-br0
DEVICE=eth0
TYPE=Ethernet
NM_CONTROLLED=no
ONBOOT=yes
BOOTPROTO=none
HWADDR=0c:c4:7a:64:ef:c0 <--Remove or comment this HWADDR address line

Step 5 : Delete network persistent rule file from Nutanix AHV host

# rm /etc/udev/rules.d/70-persistent-net.rules

After deleting the file take reboot of AHV host

Note : 70-persistent-net.rules file will be re-created after AHV host reboot

Step 6 : Verify network interfaces status must be Link detected: yes

Network interfaces name would be eth0, eth1, eth2, eth3, eth4, eth5, so on..

root#AHV# ethtool eth0

Result would be

 root#AHV# ethtool eth0 

Settings for eth0:10000baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Advertised auto-negotiation: Yes
Speed: 10000Mb/s
Duplex: Full
Port: Twisted Pair
PHYAD: 1
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: d
Wake-on: d
Current message level: 0x00000007 (7)
Link detected: yes <---NIC is detcted by Nutanix AHV host

Step 7 : Now ping network gateway or other Nutanix AHV host or CVM to check network communication / reach-ability.

Step 8 : Optional If required take restart of network service

root@AHV# service network restart

Now Nutanix AHV host has detected the Network card(s) and communicating in network. Enjoy.!

You can gain more information on ethool network utility right below
It it additional information if you are interested in.

Additional Ethtool Commands

Through ethtool commands you can get more information related to network interfaces and commnunication

Display Netwrok Interface Statistics

root@AHV# ethtool –S eth0

Result would be

NIC statistics:
tx_packets: 1800000
rx_packets: 1900000
tx_errors: 0
rx_errors: 0
rx_missed: 0
align_errors: 0
tx_single_collisions: 0
tx_multi_collisions: 0
unicast: 146180
broadcast: 47311
multicast: 82674
tx_aborted: 0
tx_underrun: 0 

Display Version of Ethtool

root@AHV# ethtool --version
ethtool version 4.1

Display Interface Device Driver

root@AHV# ethtool -i eth0

Result would be

driver: e10000
version: 7.3.21-k8-NAPI
firmware-version:
bus-info: 0000:00:03.0
supports-statistics: yes
supports-test: yes
supports-eeprom-access: yes
supports-register-dump: yes
supports-priv-flags: no

Set Duplex Mode

root@AHV# ethtool -s eth0 speed 10000 duplex full
root@AHV# ethtool -s eth0 speed 10000 duplex half

Linux ethtool utility is very important and having awesome commands helps in network troubleshooting and get detailed information for each network interface.

Conclusion

Nutanix AHV hypervisor uses OVS switch to flow the networking for network communication, in case of Nutanix AHV hypervisor having networking issues in network card / NICs , SATADOM replacement.

Just need to troubleshoot the linux network files only and will take up to 10 minutes.


I hope Hyper Hci Blog helped you to troubleshoot Nutanix AHV networking issue. Follow Hyper Hci Blog on Social media to stay connected with us.

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