vSAN health alarm ‘Hosts disconnected from VC’ – Solved

In this blog, we will guide you to fix VMware vSAN issues on vSAN Health. The error message vSphere shows in under the cluster is vSAN Health Alarm ‘Hosts Disconnected From VC’.

What does it means with this error and how can you fix this?

As the error message is showing ‘Host Disconnected From VC‘, Here VC stands for vCenter Server, It means one or more host from the vSAN Cluster is in a degraded state or down and hosts not participating in the Cluster activity. As you can see in the above picture.

This is a kind of very critical issue and you need to fix it as soon as possible by looking at the Logs in vCenter or iLO/IMM/iDRAC server manager. This issue also can be due to any planned maintenance. In the case of planned maintenance on the host, it should be put in maintenance mode.

If an ESXi host that is part of a vSAN cluster is disconnected from vCenter or not responding, it could cause operational issues. This could be due to a power outage or some other event. vSAN still considers the host as a member of the cluster. There could also be any network outage.

It means that vSAN is unable to use the capacity or resources available on this ESXi host, and it may also imply that components residing on the disks on this ESXi host are now in an ABSENT state, placing virtual machines at risk should another failure occur in the cluster. However, because it is disconnected from vCenter, the overall state of this ESXi host is not known.

Solution

An administrator should immediately check why an ESXi host that is part of the vSAN cluster is no longer connected to vCenter. One option is to manually try to reconnect the host to vCenter Server via the vSphere web client UI.

You could first check the management network between VC and host and make sure that is well connected. If the problem is still there, you could connect to the host via SSH and check the vSAN management daemon status with the following command:

/etc/init.d/vsanmgmtd status

To restart the vSAN daemon, use below command:

/etc/init.d/vsanmgmtd restart

If you see any hardware failure on the host, put it into the maintenance mode, reboot and replace the faulty part as soon as possible.

If there any network issues, you can check the vmnic(VMKernal Network Adapter) status by pinging the vmnic IP by manually logging to one of the hosts.

To ping the VMKernal Adapter use below commands:

vmkping -I vmk1 -s 10.0.2.14

Where vmk1 is your VMKernal Net adapter and 10.0.2.14 is the IP of VMKernal depending on your configuration.

To know more on vSAN troubleshooting guide, please refer the VMware KB Article Guide.

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