Apr 2023

In Kubernetes deployments, there are always a number of virtual interfaces, this isn't an issue until you are trying to look at the details of physical interfaces, and the virtual ones scroll the physical ones off the page. You can use a grep command to hide the virtual interfaces to stop this this though.

Lets say I use an IP command to list the interfaces on a Linux instance.

  ip -br -c a

I will see something similar to the following output.

lo               UNKNOWN        127.0.0.1/8 ::1/128
eth2             UP             11.0.200.2/16 fe80::76fe:48ff:fe45:e65e/64
eth3             DOWN
eth4             UP             12.0.200.4/16 fe80::76fe:48ff:fe45:e660/64
eth5             DOWN
eth0             UP             10.43.30.200/24 fe80::76fe:48ff:fe45:1eee/64
eth1             DOWN
internalk3s0     UNKNOWN        192.168.255.1/24
kube-ipvs0       DOWN           10.1.0.1/32 10.1.58.55/32 10.1.139.197/32 10.1.224.155/32 10.1.15.231/32 10.1.234.150/32 10.1.224.182/32 10.1.82.169/32 10.1.88.39/32 10.1.113.246/32 10.1.0.10/32 10.1.92.105/32 10.1.242.227/32 10.1.136.136/32 10.1.147.213/32 10.1.105.61/32 10.1.14.221/32 10.1.62.150/32 192.168.255.1/32 10.1.142.50/32 10.1.227.44/32 10.1.178.20/32 10.1.37.6/32 10.1.220.215/32 10.1.46.190/32 10.1.188.12/32 10.1.27.143/32 10.1.75.75/32 10.1.45.171/32 10.1.242.58/32 10.1.146.97/32 10.1.119.162/32 10.1.133.120/32 10.1.193.167/32 10.1.44.38/32 10.1.226.76/32 10.1.60.158/32
flannel.1        UNKNOWN        10.0.0.0/32 fe80::c426:bfff:fe61:77b7/64
cni0             UP             10.0.0.1/24 fe80::98df:c5ff:fe4f:e664/64
veth5b959f30@if2 UP             fe80::483d:bcff:fe00:bf49/64
veth1b36bc0e@if2 UP             fe80::a479:9ff:feec:741b/64
vetheafccb8b@if2 UP             fe80::fc7a:eaff:fe49:ade4/64
veth6cab92f8@if2 UP             fe80::80a7:bfff:fe8f:504/64
vetha6ca6c5c@if2 UP             fe80::784a:afff:fe3e:511/64
vetha47d76c5@if2 UP             fe80::94e0:b3ff:fe8f:8b1b/64
veth78d7ae7b@if2 UP             fe80::1083:91ff:fe56:b7ad/64
vethbfbdce9e@if2 UP             fe80::d4a7:13ff:fe38:bb29/64
veth12caaf80@if2 UP             fe80::104e:19ff:fe18:c5bf/64
vethecaec700@if2 UP             fe80::5c86:38ff:fedb:5bfa/64
vethf759469f@if2 UP             fe80::a455:1eff:fed1:d90/64
veth5b8833a6@if2 UP             fe80::cad:7aff:fea3:d84a/64
veth18c2a62d@if2 UP             fe80::40d1:4ff:fe6e:d485/64
veth8e69b358@if2 UP             fe80::f0be:46ff:fee7:fb23/64
veth62243482@if2 UP             fe80::c52:58ff:fe6e:a289/64
veth4def4cbc@if2 UP             fe80::106e:beff:fe82:90d9/64
veth6583da97@if2 UP             fe80::e8dd:3ff:fe64:9071/64
veth30a60131@if2 UP             fe80::5097:44ff:fea9:9783/64
veth17bbb9b4@if2 UP             fe80::4067:f9ff:fe92:3663/64
vetha71f5d6e@if2 UP             fe80::6493:5cff:fef8:aadd/64
veth4171ad7f@if2 UP             fe80::a9:96ff:fe0e:311/64
vethffca2e81@if2 UP             fe80::302f:f9ff:fee5:8f50/64
vethce83eb59@if2 UP             fe80::c0f8:c5ff:fe07:f5e9/64
veth30897d87@if2 UP             fe80::c0ac:bff:fe78:6080/64
vethe9389c32@if2 UP             fe80::d810:1ff:fe14:5285/64
vethde8e4fea@if2 UP             fe80::547d:b0ff:fe0b:1f1c/64
vethc3a4bead@if2 UP             fe80::9c59:dcff:fee7:6f8e/64
veth4f402974@if2 UP             fe80::f490:b3ff:fe57:44e6/64
veth0cdaa299@if2 UP             fe80::283b:a8ff:fe3e:a4de/64
vethb0dc4ed2@if2 UP             fe80::e07f:9aff:fea0:99ea/64
veth1c3166fa@if2 UP             fe80::8c40:cbff:fe20:ec8/64
veth2255cafe@if2 UP             fe80::8df:44ff:feb0:4386/64
vethb12cf176@if2 UP             fe80::48b8:e7ff:fe3e:c539/64
veth931f4dd1@if2 UP             fe80::9cad:31ff:fe6d:b6bf/64
vetha3c59775@if2 UP             fe80::70fe:feff:fe35:d5a7/64
veth2ceb7cf6@if2 UP             fe80::a008:eeff:feb6:4cba/64
veth2199c7d1@if2 UP             fe80::f4c1:e4ff:fefa:465c/64

Unfortunately, the vethxxxxxx interfaces will cause the physical interface details at the top of the list out of the view of the console, so what we really need is a way to filter this result. This can be done using grep and a filter to format our output.

  ip -br -c a |grep -v veth

This will hide anything containing the letters veth.

lo               UNKNOWN        127.0.0.1/8 ::1/128
eth2             UP             11.0.200.2/16 fe80::76fe:48ff:fe45:e65e/64
eth3             DOWN
eth4             UP             12.0.200.4/16 fe80::76fe:48ff:fe45:e660/64
eth5             DOWN
eth0             UP             10.43.30.200/24 fe80::76fe:48ff:fe45:1eee/64
eth1             DOWN
internalk3s0     UNKNOWN        192.168.255.1/24
kube-ipvs0       DOWN           10.1.0.1/32 10.1.58.55/32 10.1.139.197/32 10.1.224.155/32 10.1.15.231/32 10.1.234.150/32 10.1.224.182/32 10.1.82.169/32 10.1.88.39/32 10.1.113.246/32 10.1.0.10/32 10.1.92.105/32 10.1.242.227/32 10.1.136.136/32 10.1.147.213/32 10.1.105.61/32 10.1.14.221/32 10.1.62.150/32 192.168.255.1/32 10.1.142.50/32 10.1.227.44/32 10.1.178.20/32 10.1.37.6/32 10.1.220.215/32 10.1.46.190/32 10.1.188.12/32 10.1.27.143/32 10.1.75.75/32 10.1.45.171/32 10.1.242.58/32 10.1.146.97/32 10.1.119.162/32 10.1.133.120/32 10.1.193.167/32 10.1.44.38/32 10.1.226.76/32 10.1.60.158/32
flannel.1        UNKNOWN        10.0.0.0/32 fe80::c426:bfff:fe61:77b7/64
cni0             UP             10.0.0.1/24 fe80::98df:c5ff:fe4f:e664/64

No our list is much more readable.

We could refine this output with multiple exclusions using the -e switch:

  ip -br -c a |grep -v -e "veth" -e "cni0" -e "flannel" -e "kube" -e "internal" -e"lo"

This give the following output.

eth2             UP             11.0.200.2/16 fe80::76fe:48ff:fe45:e65e/64
eth3             DOWN
eth4             UP             12.0.200.4/16 fe80::76fe:48ff:fe45:e660/64
eth5             DOWN
eth0             UP             10.43.30.200/24 fe80::76fe:48ff:fe45:1eee/64
eth1             DOWN

This is a lot to type/remember, but you could make a script out of it.