Host prevents entering Maintenace Mode: There are insufficient memory resource on standby hosts
In a vSphere 8 – 2-Node Cluster Update I have had to deal with the following message during the Check Compliance process:
High Availability (HA) Admission Control is enabled and set to specify a failover host, which is reserved for HA failover purposes. However, in a 2-node cluster you ultimately only have the 2nd host and if the resources on this host are not sufficient, you are getting automatically stopped by HA in an Compliance Check Process.
Please note that if a host is reserved for HA failover, it cannot be used to host any other virtual machines.
To get rid of this obstacle, we have to switch off Admission Control for the time of the update/upgrade, especially in a 2-node cluster.
- Right-click the cluster in vCenter Server and choose Settings.
- In Configure tab, Select “vSphere Availability” Click EDIT for vSphere HA.
- Select Admission Control.
- Select “Disabled” for define host failover capacity by
There are two more options in this KB:
https://knowledge.broadcom.com/external/article/322172/esxesxi-error-the-host-does-not-have-suf.html
After we have deactivated Admission Control, we run another compliance check and lo and behold, the message is gone. Hardware compatibility is another matter. 🙂
This ist it from this Blog Post, if you have any questions please use the comment section below.