Termination policies for scaling compute resources

1. A computer implemented method for scaling compute resources, the method comprising:

receiving a plurality of user-specified termination policies, including an ordering of attributes, that is used to select one or more virtual machine instances from a group of virtual machine instances to de-provision, the group of virtual machine instances having been provisioned for a user on one or more host computing devices and the ordering of attributes determining the order in which virtual machine instances should be de-provisioned;

detecting that at least one virtual machine instance of the group of virtual machine instances should be de-provisioned based on one or more attributes associated with the at least one virtual machine instance;

selecting the at least one virtual machine instance to de-provision based at least in part on applying a user-specified termination policy of the plurality of user-specific termination policies;

applying the plurality of user-specified termination policies in a specified order until at least one virtual machine instance is selected to be de-provisioned; and

de-provisioning the selected at least one virtual machine instance.

2. The computer implemented method of claim 1 , wherein the one or more attributes associated with the at least one virtual machine instance include at least one of:

a virtual machine instance that has been executing for a longest time interval;

a virtual machine instance that has been executing for a shortest time interval;

a virtual machine instance that has an oldest launch configuration; or

a virtual machine instance that is nearest in time to a next billing time interval.

3. The computer implemented method of claim 1 , wherein the plurality of user-specified termination policies have been ranked in the specified order by a user.

4. The computer implemented method of claim 1 , wherein applying the plurality of user-specified termination policies in a specified order further comprises:

determining a subset of the group of virtual machine instances that are associated with a first attribute specified by a first termination policy; and

determining, from the subset of the group of virtual machine instances, at least one virtual machine instance that is associated with a second attribute; and

de-provisioning the at least one virtual machine instance that is associated with the second attribute.

5. A computing device, comprising:

at least one processor; and

memory including instructions that, when executed by the processor, cause the computing device to:

invoke a group of virtual machine instances;

receive a plurality of user-specified termination policies ranked in order of execution that is used to select virtual machine instances in a group of virtual machine instances to de-provision, the group of virtual machine instances having been provisioned for a user on one or more host computing devices;

determine that at least one virtual machine instance in the group of virtual machine instances should be de-provisioned;

identify at least one virtual machine instance that is associated with at least one attribute specified by the user-specified termination policy;

apply the plurality of user-specified termination policies in the order of execution until at least one virtual machine instance is selected for de-provisioning; and

de-provision the at least one virtual machine instance that is associated with the at least one attribute.

6. The computing device of claim 5 , wherein receiving a user-specified termination policy further comprises:

receiving, from an application executing on the group of virtual machine instances, information used to select the at least one virtual machine instance to de-provision; and

selecting the at least one virtual machine instance based at least in part on the information received from the application.

7. The computing device of claim 5 , wherein the at least one attribute specified by the user-specified termination policy is one of:

a launch time of a virtual machine instance;

a configuration version of a virtual machine instance; or

a billing time for use of a virtual machine instance.

8. The computing device of claim 5 , wherein the instructions, when executed, further cause the computing device to:

inspect metadata associated with each virtual machine instance, the metadata including attributes of the virtual machine instances;

execute the user-specified termination policy to identify the at least one attribute specified by the user-specified termination policy; and

select the at least one virtual machine instance to de-provision based on the attributes included in the metadata.

9. A non-transitory computer readable storage medium storing one or more sequences of instructions executed by one or more processors to:

execute a group of virtual machine instances;

receive a plurality of termination policies ranked in an order of execution that are used to select virtual machine instances in a group of virtual machine instances to de-provision, the group of virtual machine instances having been provisioned for a user on one or more host computing devices;

determine that at least one virtual machine instance in the group of virtual machine instances should be de-provisioned;

execute the plurality of termination policies in the order of execution until at least one virtual machine instance that is associated with at least one attribute that is specified by a termination policy of the plurality of termination policies is identified; and

de-provision the at least one virtual machine instance that is associated with the at least one attribute.

10. The non-transitory computer readable storage medium of claim 9 further comprising instructions to:

determine a launch time of each virtual machine instance in the group of virtual machine instances; and

select the at least one virtual machine instance to be de-provisioned based at least in part on the launch time of the at least one virtual machine instance.

11. The non-transitory computer readable storage medium of claim 9 further comprising instructions to:

determine a billing time interval for each virtual machine instance in the group of virtual machine instances; and

select the at least one virtual machine instance to be de-provisioned based at least in part on identifying the virtual machine instance that is nearest in time to a billing time interval.

12. The non-transitory computer readable storage medium of claim 9 further comprising instructions to:

determine a configuration version of each virtual machine instance in the group of virtual machine instances; and

select the at least one virtual machine instance having an oldest configuration version to be de-provisioned.

13. The non-transitory computer readable storage medium of claim 12 , further comprising instructions to:

determine a subset of the group of virtual machine instances that is associated with an attribute specified by a first termination policy;

determine, from the subset of the group of virtual machine instances, at least one virtual machine instance that is associated with an attribute specified by a second termination policy; and

de-provision the at least one virtual machine instance.

14. The non-transitory computer readable medium of claim 9 , wherein the group of virtual machine instances is a group of compute resources hosted on one or more host computing devices, the group of compute resources executing at least one application for a user; and

wherein selecting the at least one virtual machine instance to be de-provisioned is performed by an automatic scaling service configured to de-provision the at least one virtual machine instance based at least in part on one or more operating metrics associated with the virtual machine instances.