Maintaining high availability of a group of virtual machines using heartbeat messages

A method comprising:

• transmitting, by a subordinate host, a heartbeat message to a master host, wherein the transmitted heartbeat message indicates that the subordinate host is operative at a current time;
• storing, by the subordinate host, heartbeat data in a datastore, wherein the stored heartbeat data indicates that the subordinate host is operative at the current time;
• and
• storing, by the subordinate host, a power-on list in the datastore, wherein the power-on list indicates software application instances for a master host to restart at a host other than the subordinate host if the subordinate host becomes inoperative.

The method of 8, wherein the subordinate host is a first host, the method further comprising:

• receiving, by the subordinate host, from a management server a host list that includes a version number, a plurality of host identifiers, and one or more heartbeat datastores associated with each host identifier of the plurality of host identifiers;
• transmitting the version number to a second host, wherein the second host transmits to the subordinate host a request for the host list when the transmitted version number is greater than a version number included in a host list stored by the second host;
• and
• transmitting the host list from the subordinate host to the second host in response to the request.

One or more computer-readable storage media having computer-executable components comprising:

• a datastore selection component that when executed causes at least one processor to:
• identify a plurality of datastores to which a subordinate host has read-write access;
• select from the plurality of datastores a first heartbeat datastore and a second heartbeat datastore based on a quantity of hosts that have access to the first and second heartbeat datastores;
• and
• associate the first and second heartbeat datastores with the host;
• and
• a heartbeat publication component that when executed causes at least one processor to:
• transmit to a master host a heartbeat message indicating that the subordinate host is operative at a current time;
• and
• store in the first and second heartbeat datastores heartbeat data indicating that the subordinate host is operative at the current time.