vSAN Health Service - Network Health - All hosts have a vSAN vmknic configured

Products

VMware vSAN

Issue/Introduction

This article explains the purpose of the Network Health - All hosts have a vSAN vmknic configured check in Skyline Health and provides details on why it might report an error.

Symptoms:

Alert from vSAN Health Monitor
- vSAN Health Service - Network Health - All hosts have a vSAN vmknic configured

Environment

VMware vSAN 6.0.x
VMware vSAN 6.x
VMware vSAN 8.0.x
VMware vSAN 7.0.x

Resolution

Q: What does the Network Health - All hosts have a vSAN vmknic configured check do?

To participate in a vSAN cluster, and form a single partition of fully connected ESXi hosts, each ESXi host in a vSAN cluster must have a vmknic (VMkernel NIC or VMkernel adapter) configured for vSAN traffic. This check ensures each ESXi host in the vSAN cluster has a vmknic configured for vSAN traffic.

Note: Even if an ESXi host is part of the vSAN cluster, but is not contributing storage, it must still have a VMkernel NIC configured for vSAN traffic.

Also, this check ensures that there is one vmknic configured for vSAN traffic. While multiple vmknics are supported, this test does not check for a consistent network configuration. (For example: Some ESXi hosts may have 2 vmknics, while others hosts only have 1 vmknic).

Q: What does it mean when it is in an error state?

If this test fails, it means that at least one of the ESXi hosts in the cluster does not have a VMkernel NIC configured for vSAN traffic.

Q: How does one troubleshoot and fix the error state?

Ensure that each ESXi host participating in the vSAN cluster has a vmknic enabled for vSAN traffic. This can be done using the vSphere Web Client, where each ESXi host’s networking configuration can easily be checked. To check the vSAN traffic column and ensure that at least 1 vmknic is Enabled for vSAN traffic, navigate to this menu in the vSphere client:

In vSAN 6.6 and later: Hosts and Clusters > ESXi host > Configure > Networking > VMkernel Adapters
In vSAN 6.5 and earlier: Hosts and Clusters > ESXi host > Manage Networking > VMkernel Adapters

It can also be checked from the CLI using the command:

esxcli vsan network list

For example:

[root@ESXi-h01:~] esxcli vsan network list
Interface
VmkNic Name: vmk2
IP Protocol: IPv4
Interface UUID: 264ed254-5aa5-0647-9cc7-001f29595f9f
Agent Group Multicast Address: 224.2.3.4
Agent Group Multicast Port: 23451
Master Group Multicast Address: 224.1.2.3
Master Group Multicast Port: 12345
Multicast TTL: 5
Traffic Type: vsan

In the preceding output, the VMkernel nic vmk2 is used for vSAN traffic. Confirm that all hosts have a vmk configured for vSAN.

For more information, see the Troubleshooting the vSAN Network .

Workaround:
It can also be checked from the RVC by running this command:

vsan.cluster_info

This displays which VMkernel adapter, if any, is being used on each host for vSAN traffic.

For example:

<<truncated>>
Host: <host-name>
Product: VMware ESXi 6.0.0 build-2391873
VSAN enabled: yes
Cluster info:
Cluster role: agent
Cluster UUID: 529ccbe4-81d2-89bc-7a70-a9c69bd23a19
Node UUID: 545ca9af-ff4b-fc84-dcee-001f29595f9f
Member UUIDs: ["5460b129-4084-7550-46e1-0010185def78", "54196e13-7f5f-cba8-5bac-001517a69c72", "54188e3a-84fd-9a38-23ba-001b21168828", "545ca9af-ff4b-fc84-dcee-001f29595f9f"] (4)
Node evacuated: no
Storage info:
Auto claim: no
Checksum enforced: no
Disk Mappings:
SSD: HP Serial Attached SCSI Disk (naa.xxx) - 186 GB, v2
MD: HP Serial Attached SCSI Disk (naa.xxx) - 136 GB, v2
MD: HP Serial Attached SCSI Disk (naa.xxx) - 136 GB, v2
MD: HP Serial Attached SCSI Disk (naa.xxx) - 136 GB, v2
MD: HP Serial Attached SCSI Disk (naa.xxx) - 136 GB, v2
MD: HP Serial Attached SCSI Disk (naa.xxx) - 136 GB, v2
MD: HP Serial Attached SCSI Disk (naa.xxx) - 136 GB, v2
MD: HP Serial Attached SCSI Disk (naa.xxx) - 136 GB, v2
FaultDomainInfo:
Not configured
NetworkInfo:
Adapter: vmk2 (172.xx.x.x)

<<truncated>>

This provides both the VMkernel NIC used for vSAN traffic and also the IP address of the interface.