Documentation/networking/net_failover.rst

1 .. SPDX-License-Identifier: GPL-2.0
21 it is available with link up and running.
28 virtio-net accelerated datapath: STANDBY mode
31 net_failover enables hypervisor controlled accelerated datapath to virtio-net
32 enabled VMs in a transparent manner with no/minimal guest userspace changes.
35 feature on the virtio-net interface and assign the same MAC address to both
36 virtio-net and VF interfaces.
47     <link state='down'/>
49     <alias name='ua-backup0'/>
56     <teaming type='transient' persistent='ua-backup0'/>
59 In this configuration, the first device definition is for the virtio-net
62 required attribute type having value 'persistent'. The link state for the
63 virtio-net device is set to 'down' to ensure that the 'failover' netdev prefers
64 the VF passthrough device for normal communication. The virtio-net device will
69 periodically be unplugged. A second attribute - 'persistent' is provided and
70 points to the alias name declared for the virtio-net device.
77       link/ether 52:54:00:00:12:53 brd ff:ff:ff:ff:ff:ff
80       inet6 fe80::97d8:db2:8c10:b6d6/64 scope link
83       link/ether 52:54:00:00:12:53 brd ff:ff:ff:ff:ff:ff
85       link/ether 52:54:00:00:12:53 brd ff:ff:ff:ff:ff:ff
88 virtio-net interface, and ens11 is the slave 'primary' VF passthrough interface.
91 like systemd-networkd, ifupdown, etc, do not understand the 'net_failover'
98 Below is the patch snippet used with 'cloud-ifupdown-helper' script found on
102   @@ -27,6 +27,8 @@ do_setup() {
106   +    if [ -d "/sys/class/net/${INTERFACE}/master" ]; then exit 0; fi
108        if ifup --no-act "$INTERFACE" > /dev/null 2>&1; then
109            # interface is already known to ifupdown, no need to generate cfg
113 Live Migration of a VM with SR-IOV VF & virtio-net in STANDBY mode
117 with VMs that have direct attached SR-IOV VF devices by automatic failover to
133     <teaming type='transient' persistent='ua-backup0'/>
139   DOMAIN=vm-01
143   TAP_IF=vmtap01        # virtio-net interface in the VM.
149   # Set the virtio-net interface up.
150   virsh domif-setlink $DOMAIN $TAP_IF up
153   virsh detach-device --live --config $DOMAIN $VF_XML
155   ip link set $PF vf $VF_NUM mac $ZERO_MAC
158   # the VF -> br0 -> vnet interface path.
163   virsh migrate --live --persistent $DOMAIN qemu+ssh://$REMOTE_HOST/system
174 completes, and it reattaches the VF to the VM and brings down the virtio-net
178   # reattach-vf.sh
183   virsh attach-device --config --live vm01 vf.xml
184   virsh domif-setlink vm01 vmtap01 down