At 4:30AM CST on cloud01 a hypervisor [HV09] was listed as offline in the cluster, however it did not terminate and migrate the VM's on it. The VM's and the hypervisor did remain online from 4:30AM to 6:55AM CST. At 6:55AM we initiated a manual failover to remediate the issue with the hypervisor and allow it to migrate the VM's and reboot as it should have done automatically. This caused (5) VM's to go offline during the reboot event. All of the affected VM's are now back online after approximately 5-10 minutes of downtime due in part to the sequencing of VM startups during these types of events. We are aware why the hypervisor did not perfom an automatig failover and remediation and will put in permanent fixes to help prevent this from reoccurring.