Hi Stephen,

A parallel question about packet-flow between VFs of the same PF when VFs are assigned to different containers on the same host server

Create 2 SRIOV-VFs of a PF in the host and assign them to 2 containers (one VF per container)

send IP packet from container-1 to container-2 (SRC_MAC address in this ethernet frame = container1 VF’s MAC address, DST_MAC address = container2 VF’s MAC address),

container-1 sends packet by calling rte_eth_tx_burst()

container-2 is polling for packets from its VF by calling rte_eth_rx_burst()

Will the packet in above scenario leave the host server, go the switch and then come back to the same host machine for entering container-2 ?

Or, is the SRIOV in PF-NIC smart to identify that SRC_MAC and DST_MAC of the ethernet frame are its own VFs and hence it routes the packet locally within the NIC (packet doesn’t reach the switch at all) ?

Regards,

Purnima

From: Stephen Hemminger <stephen@networkplumber.org>
Sent: Wednesday, November 20, 2024 3:34 AM
To: Thea Corinne Rossman <thea.rossman@cs.stanford.edu>
Cc: users@dpdk.org
Subject: Re: Containernet (Docker/Container Networking) with DPDK?

On Tue, 19 Nov 2024 13:39:38 -0800

Thea Corinne Rossman <thea.rossman@cs.stanford.edu> wrote:

> This is SO helpful -- thank you so much.

>

> One follow-up question regarding NICs: can multiple containers on the same

> host share the same PCI device? If I have a host NIC with (say) VFIO driver

> binding, do I have to split it with some kind of SR-IOV so that each

> container has its own "NIC" binding? Or, when running DPDK's "devbind"

> script, can I set up each one with the same PCI address?

Totally depends on what container system you are using.

If you have two containers sharing same exact PCI device, chaos would ensue.

You might be able to make two VF's on host and pass one to each container;

that would make more sense.