In a virtualized data center environment, which of the following features can be configured to ensure high availability of virtual machines by automatically restarting them on another host in case of a failure?

High Availability (HA) is a core feature in virtualization platforms designed to ensure business continuity. In a cluster of server hosts, HA continuously monitors the health of each host. If a host fails unexpectedly (e.g., due to a hardware issue or power outage), the HA service automatically restarts the virtual machines (VMs) that were running on the failed host onto other available, healthy hosts within the same cluster. This process minimizes downtime for the services running inside the VMs without manual intervention.

A. Virtual LAN (VLAN): This is a networking feature used to logically segment a physical network into multiple broadcast domains for traffic isolation and management, not for VM failover.
B. Port Aggregation Protocol (PAgP): This is a Cisco-proprietary protocol for bundling multiple physical network links into a single logical channel to increase bandwidth and provide network path redundancy. It does not manage VM state.
C. Jumbo Frames: This feature allows for Ethernet frames larger than the standard 1500 bytes to improve network throughput, particularly for storage traffic. It is a performance optimization, not a high availability mechanism for VMs.

1. VMware vSphere Documentation: "vSphere High Availability (HA) provides high availability for virtual machines by pooling them and the hosts they reside on into a cluster. Hosts in the cluster are monitored and in the event of a failure, the virtual machines on a failed host are restarted on alternate hosts."

Source: VMware vSphere 8.0 Documentation, "Creating and Using vSphere HA Clusters," Introduction to vSphere HA.

2. Microsoft Hyper-V Documentation: "With the Failover Clustering feature in Windows Server, you can provide high availability for virtual machines... If a cluster node fails, the clustered role (in this case, the virtual machine) is automatically restarted on another node."

Source: Microsoft Learn, "Deploy a Hyper-V Cluster," Overview section.

3. HPE Technical White Paper: "High availability (HA) is a key component of any virtualization deployment... In the event of a physical server failure, VMware HA automatically restarts the affected VMs on other production servers that have spare capacity."

Source: HPE White Paper, "Implementing VMware vSphere 6.7 on HPE ProLiant and HPE Synergy servers," Page 12, Section: "VMware vSphere High Availability."