mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-28 07:04:00 +08:00
2880984970
Currently building the net_failover docs causes a bunch of warnings to be emitted. These warnings are all related to indentation and correctly highlight missing '::' (for code sections). It looks, from other rst files in Documentation, that the first column should be indented 2 spaces. Add '::' before code snippets and indent all snippets uniformly starting with 2 spaces. Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Tobin C. Harding <me@tobin.cc> Signed-off-by: David S. Miller <davem@davemloft.net>
120 lines
4.3 KiB
ReStructuredText
120 lines
4.3 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0
|
|
|
|
============
|
|
NET_FAILOVER
|
|
============
|
|
|
|
Overview
|
|
========
|
|
|
|
The net_failover driver provides an automated failover mechanism via APIs
|
|
to create and destroy a failover master netdev and mananges a primary and
|
|
standby slave netdevs that get registered via the generic failover
|
|
infrastructrure.
|
|
|
|
The failover netdev acts a master device and controls 2 slave devices. The
|
|
original paravirtual interface is registered as 'standby' slave netdev and
|
|
a passthru/vf device with the same MAC gets registered as 'primary' slave
|
|
netdev. Both 'standby' and 'failover' netdevs are associated with the same
|
|
'pci' device. The user accesses the network interface via 'failover' netdev.
|
|
The 'failover' netdev chooses 'primary' netdev as default for transmits when
|
|
it is available with link up and running.
|
|
|
|
This can be used by paravirtual drivers to enable an alternate low latency
|
|
datapath. It also enables hypervisor controlled live migration of a VM with
|
|
direct attached VF by failing over to the paravirtual datapath when the VF
|
|
is unplugged.
|
|
|
|
virtio-net accelerated datapath: STANDBY mode
|
|
=============================================
|
|
|
|
net_failover enables hypervisor controlled accelerated datapath to virtio-net
|
|
enabled VMs in a transparent manner with no/minimal guest userspace chanages.
|
|
|
|
To support this, the hypervisor needs to enable VIRTIO_NET_F_STANDBY
|
|
feature on the virtio-net interface and assign the same MAC address to both
|
|
virtio-net and VF interfaces.
|
|
|
|
Here is an example XML snippet that shows such configuration.
|
|
::
|
|
|
|
<interface type='network'>
|
|
<mac address='52:54:00:00:12:53'/>
|
|
<source network='enp66s0f0_br'/>
|
|
<target dev='tap01'/>
|
|
<model type='virtio'/>
|
|
<driver name='vhost' queues='4'/>
|
|
<link state='down'/>
|
|
<address type='pci' domain='0x0000' bus='0x00' slot='0x0a' function='0x0'/>
|
|
</interface>
|
|
<interface type='hostdev' managed='yes'>
|
|
<mac address='52:54:00:00:12:53'/>
|
|
<source>
|
|
<address type='pci' domain='0x0000' bus='0x42' slot='0x02' function='0x5'/>
|
|
</source>
|
|
<address type='pci' domain='0x0000' bus='0x00' slot='0x0b' function='0x0'/>
|
|
</interface>
|
|
|
|
Booting a VM with the above configuration will result in the following 3
|
|
netdevs created in the VM.
|
|
::
|
|
|
|
4: ens10: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
|
|
link/ether 52:54:00:00:12:53 brd ff:ff:ff:ff:ff:ff
|
|
inet 192.168.12.53/24 brd 192.168.12.255 scope global dynamic ens10
|
|
valid_lft 42482sec preferred_lft 42482sec
|
|
inet6 fe80::97d8:db2:8c10:b6d6/64 scope link
|
|
valid_lft forever preferred_lft forever
|
|
5: ens10nsby: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel master ens10 state UP group default qlen 1000
|
|
link/ether 52:54:00:00:12:53 brd ff:ff:ff:ff:ff:ff
|
|
7: ens11: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master ens10 state UP group default qlen 1000
|
|
link/ether 52:54:00:00:12:53 brd ff:ff:ff:ff:ff:ff
|
|
|
|
ens10 is the 'failover' master netdev, ens10nsby and ens11 are the slave
|
|
'standby' and 'primary' netdevs respectively.
|
|
|
|
Live Migration of a VM with SR-IOV VF & virtio-net in STANDBY mode
|
|
==================================================================
|
|
|
|
net_failover also enables hypervisor controlled live migration to be supported
|
|
with VMs that have direct attached SR-IOV VF devices by automatic failover to
|
|
the paravirtual datapath when the VF is unplugged.
|
|
|
|
Here is a sample script that shows the steps to initiate live migration on
|
|
the source hypervisor.
|
|
::
|
|
|
|
# cat vf_xml
|
|
<interface type='hostdev' managed='yes'>
|
|
<mac address='52:54:00:00:12:53'/>
|
|
<source>
|
|
<address type='pci' domain='0x0000' bus='0x42' slot='0x02' function='0x5'/>
|
|
</source>
|
|
<address type='pci' domain='0x0000' bus='0x00' slot='0x0b' function='0x0'/>
|
|
</interface>
|
|
|
|
# Source Hypervisor
|
|
#!/bin/bash
|
|
|
|
DOMAIN=fedora27-tap01
|
|
PF=enp66s0f0
|
|
VF_NUM=5
|
|
TAP_IF=tap01
|
|
VF_XML=
|
|
|
|
MAC=52:54:00:00:12:53
|
|
ZERO_MAC=00:00:00:00:00:00
|
|
|
|
virsh domif-setlink $DOMAIN $TAP_IF up
|
|
bridge fdb del $MAC dev $PF master
|
|
virsh detach-device $DOMAIN $VF_XML
|
|
ip link set $PF vf $VF_NUM mac $ZERO_MAC
|
|
|
|
virsh migrate --live $DOMAIN qemu+ssh://$REMOTE_HOST/system
|
|
|
|
# Destination Hypervisor
|
|
#!/bin/bash
|
|
|
|
virsh attach-device $DOMAIN $VF_XML
|
|
virsh domif-setlink $DOMAIN $TAP_IF down
|