Azure Host Servicing

This section describes detailed instructions for Azure Host Servicing.

The Azure Accelerated Networking support for Virtual Edges on Azure adds the DPDK failsafe/TAP/MLX PMD model. When Azure host maintenance is performed, the SR-IOV VFs might be temporarily removed and added back later.

Reference the following for more information: https://learn.microsoft.com/en-us/azure/virtual-network/accelerated-networking-how-it-works#azure-host-servicing

The events are logged by the kernel and can be viewed in the output of dmesg. They can also be viewed in /var/log/messages:

edge:b3-edge1:~# egrep 'VF registering|VF unregistering' /var/log/messages

2023-07-25T22:06:11.903 INFO   kern   kernel:[   11.091250] hv_netvsc 000d3a92-2dba-000d-3a92-2dba000d3a92 eth1: VF registering: eth5

2023-07-25T22:06:12.049 INFO   kern   kernel:[   11.237233] hv_netvsc 000d3a92-245f-000d-3a92-245f000d3a92 eth2: VF registering: eth6

2023-07-25T22:06:12.208 INFO   kern   kernel:[   11.396127] hv_netvsc 000d3a92-2178-000d-3a92-2178000d3a92 eth3: VF registering: eth7

2023-07-25T22:06:12.362 INFO   kern   kernel:[   11.549624] hv_netvsc 000d3a92-218a-000d-3a92-218a000d3a92 eth4: VF registering: eth8

2023-07-25T22:30:09.188 INFO   kern   kernel:[ 1448.376507] hv_netvsc 000d3a92-2178-000d-3a92-2178000d3a92 eth3-hv: VF unregistering: eth7

2023-07-25T22:30:14.390 INFO   kern   kernel:[ 1453.577954] hv_netvsc 000d3a92-218a-000d-3a92-218a000d3a92 eth4-hv: VF unregistering: eth8

2023-07-25T22:30:19.380 INFO   kern   kernel:[ 1458.568168] hv_netvsc 000d3a92-2dba-000d-3a92-2dba000d3a92 eth1-hv: VF unregistering: eth5

2023-07-25T22:30:26.555 INFO   kern   kernel:[ 1465.742626] hv_netvsc 000d3a92-245f-000d-3a92-245f000d3a92 eth2-hv: VF unregistering: eth6

The HOTPLUG OUT events are reported on the VMware SD-WAN Orchestrator, as shown in the image below.

The Edge continues running during the Azure Host maintenance and the Paths stay up.

When the SR-IOV VFs are added back after Azure host maintenance is complete, the events can be viewed in the output of dmesg or in /var/log/messages.

edge:b3-edge1:~# egrep 'VF registering|VF unregistering' /var/log/messages

...

2023-07-25T22:31:23.137 INFO   kern   kernel:[ 1522.324791] hv_netvsc 000d3a92-2dba-000d-3a92-2dba000d3a92 eth1-hv: VF registering: eth5

2023-07-25T22:31:28.381 INFO   kern   kernel:[ 1527.568576] hv_netvsc 000d3a92-2178-000d-3a92-2178000d3a92 eth3-hv: VF registering: eth6

2023-07-25T22:31:33.416 INFO   kern   kernel:[ 1532.604181] hv_netvsc 000d3a92-245f-000d-3a92-245f000d3a92 eth2-hv: VF registering: eth7

2023-07-25T22:31:38.468 INFO   kern   kernel:[ 1537.656531] hv_netvsc 000d3a92-218a-000d-3a92-218a000d3a92 eth4-hv: VF registering: eth8

The HOTPLUG IN events are reported on the VMware SD-WAN Orchestrator.