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Using an SR-IOV Network Interface in a Proxmox LXC

For fun I was trying to work out how I could use an SR-IOV Interface for my LanCache container. Since it would let me run it with very low disk overhead, compared to a VM, and low network overhead compared to a virtual bridge; I am aware that this probably doesn’t affect much though. Also, after running an iperf, it still isn’t as fast as on the host, or a VM with PCIe passthrough, but it’s seems slightly faster than a virtual bridge.

Firstly you need to have SR-IOV enabled and working, and also have the VF’s showing up on the host, eg. interfaces similar to ens6f0v2 showing up in ip a.

Since as you may have noticed, proxmox doesn’t support this in the UI so you’re going to have to add these to the LXC’s config (nano /etc/pve/lxc/<ct-id>.conf).

lxc.net.0.type: phys
lxc.net.0.link: ens6f0v32  # Replace with your VF interface
lxc.net.0.flags: up
lxc.net.0.ipv4.address: 192.168.0.111/24  # Replace with your IP
lxc.net.0.ipv4.gateway: 192.168.0.1  # Replace with your Gateway
lxc.net.0.name: eth0  # Not needed, but it makes things easier
# lxc.net.0.mtu: 9000  # Enable Jumbo Frames, doesn't work on my NIC

Depending if you’ve already got a network interface in the container, you may need to change the lxc.net.0 to lxc.net.1 or higher. Then you can start the container and your interface should show up in the container’s ip a:

root@lancache:~# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
299: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 0a:5b:a7:31:6d:4c brd ff:ff:ff:ff:ff:ff
    altname enp129s0f0v32
    inet 192.168.0.111/24 brd 0.0.0.255 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 2001:<removed>/64 scope global dynamic mngtmpaddr 
       valid_lft 49244sec preferred_lft 49244sec
    inet6 fe80::85b:a7ff:fe31:6d4c/64 scope link 
       valid_lft forever preferred_lft forever

Sources:

Thanks for reading!
Steve.

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