Reconfiguration rate-control

A system, comprising:

• one or more processors;
• and
• memory that stores computer-executable instructions that, if executed, cause the one or more processors to:
• modify individual virtual machines of a group of virtual machines from a first configuration to a second configuration, while limiting, to a threshold number, a number of virtual machines of the group that can concurrently be in the process of being modified, wherein no more than the threshold number of virtual machines are unavailable for use while applying the second configuration to the group during the process of being modified;
• and
• stop modifying the group of virtual machines as a result of determining that at least a threshold number of modification attempts failed.

A non-transitory computer-readable storage medium having stored thereon executable instructions that, as a result of being executed by one or more processors of a computer system, cause the computer system to at least:

• limit, to a first threshold number, a number of computer system instances of a group of computer system instances that can concurrently be in a process of being modified;
• and
• stop modifying the group of computer system instances as a result of determining that at least a second threshold number of modification attempts failed,
• wherein the computer system ensures that no more than the first threshold number of computer system instances are unavailable for use while applying a configuration to the group of computer system instances during the process of being modified.