How can I list which virtual ethernet pairs are running in the current linux host?
I have a question related to the veth
pair that is used in Linux system. I want to know which veth
pairs are running in the current host, which I mean querying the pairs by using one Linux command or finding the related configuration in some files.
I know that to construct veth
pair, you can simply by using
ip link add name1 type veth name2
But I haven't found an command or file that could be used to query the current running veth pairs.
If you know a way that could find the current running veth
pairs, could you please tell me? This would help me a lot.
Solution 1:
You can get peer ifindex with the following ethtool command.
# ethtool -S veth1
NIC statistics:
peer_ifindex: 7
ifindex is shown with:
# ip link
Ref: http://www.spinics.net/lists/netdev/msg102062.html
Solution 2:
I have an older linux kernel without ip netns so I cobbled this together to get the needed info. Assuming you can ssh into your LXC containers, this might be of use to you. It's a quick hack 8)
MY_VMS="10.0.1.1" # etc... change as needed
for A_VM in $MY_VMS
do
if [ ! -f $A_VM.list ]
then
ssh $A_VM ip link list > $A_VM.list
fi
for i in `ifconfig -a | grep "Link encap" | sed 's/ .*//g'`
do
PEER_IFINDEX=`ethtool -S $i 2>/dev/null | grep peer_ifindex | sed 's/ *peer_ifindex: *//g' `
if [ "$PEER_IFINDEX" = "" ]
then
continue
fi
PEER_IF=`grep "^$PEER_IFINDEX:" $A_VM.list | awk '{print $2}' | sed 's/:.*//g'`
if [ "$PEER_IF" = "" ]
then
continue
fi
printf "%-10s is paired with %-10s on %-20s\n" $i $PEER_IF $A_VM
done
done
Solution 3:
I have just written a command to show the peer veth interface:
https://github.com/hariguchi/veth-peer
Example
$ sudo ip link add foo-bar type veth peer name bar-foo
[sudo] password for XXX:
$ veth-peer foor-bar
bar-foo
$ veth-peer xxx
xxx: Link not found
$ veth-peer lo
lo is not veth.
$ sudo ip link del foo-bar
$ veth-peer bar-foo
bar-foo: Link not found
$