Virtual computing instance migration

A computer-implemented method for migrating a virtual machine instance, comprising:

• under the control of one or more computer systems configured with executable instructions,
• instantiating the virtual machine instance to result in an instantiated virtual machine instance in a first computer system, the first computer system comprising one or more components that do not conform, at the time of instantiation of the virtual machine instance, to a preference for one or more hardware specifications for instantiating a virtual machine instance that indicates an optionally specifiable hardware preference for instantiating a virtual machine instance, the preference received via an interface through which one or more requests for instantiation of a virtual machine instance from a plurality of virtual machine instance types can be submitted, one or more of the plurality of virtual machine instance types being capable of being requested with the optionally specifiable hardware preference;
• generating for the instantiated virtual machine instance a metadata flag that identifies that the instantiated virtual machine instance should be migrated to a physical host computer system that conforms to the preference if capacity within a conforming physical host computer system becomes available;
• detecting, as a result of the metadata flag, and after instantiation of and during execution of the virtual machine instance, a condition within a second host computer system that conforms to the preference;
• and
• migrating, as a result of the metadata flag, the virtual machine instance from the first computer system to the second host computer system due at least in part to having detected the condition within the second host computer system.

A computer system, comprising:

• an interface through which one or more requests for instantiation of a virtual machine instance from a plurality of virtual machine instance types can be submitted, one or more of the plurality of virtual machine instance types being capable of being requested with an optionally specifiable hardware preference;
• one or more host computer systems comprising hardware components collectively configured to instantiate a virtual machine instance;
• and
• a management sub-system configured to process a request received through the interface, wherein:
• the virtual machine instance is instantiated in a first host computer system from the one or more host computer systems to result in an instantiated virtual machine instance, the first computer system comprising one or more components that do not conform, at the time of instantiation of the virtual machine instance, to the optionally specifiable hardware preference for one or more hardware specifications for instantiating the virtual machine instance that indicates a hardware component for instantiating a virtual machine instance;
• a metadata flag is associated with the instantiated virtual machine instance that identifies that the instantiated virtual machine instance should be migrated to a host computer system that conforms to the set of preferences if capacity within a conforming physical host computer system becomes available;
• and
• the virtual machine instance is migrated, as a result of the metadata flag and after instantiation of and during execution of the virtual machine instance, from the first host computer system to a second host computer system that conforms to the optionally specifiable hardware preference.

One or more non-transitory computer-readable storage media having collectively stored therein instructions that, when executed by one or more processors of a computer system, cause the computer system to fulfill a set of preferences that includes one or more hardware specifications for instantiating a virtual machine instance that indicates an optionally specifiable hardware preference for instantiating a virtual machine instance by causing the computer system to at least:

• implement, for an amount of time, the virtual machine instance to result in an instantiated virtual machine instance using a first host computer system that fails to conform to the one or more hardware specifications at the time of instantiation of the virtual machine instance;
• generate in the instantiated virtual machine a metadata flag that identifies that the instantiated virtual machine instance should be migrated to a host computer system that conforms to the set of preferences if capacity within a conforming host computer system becomes available;
• and
• migrate the virtual machine instance, as a result of the metadata flag and after instantiation of and during execution of the virtual machine instance, from the first host computer system to a second host computer system that conforms to the one or more hardware specifications,
• wherein the set of preferences are received via an interface through which one or more requests for instantiation of a virtual machine instance from a plurality of virtual machine instance types can be submitted, one or more of the plurality of virtual machine instance types being capable of being requested with the optionally specifiable hardware preference.