1. A method, comprising: receiving, at a provider network supporting remote configuration of resources of a network-accessible service, a platform approval request comprising an indication of one or more candidate platforms for hosting virtualized resources; performing, in response to the platform approval request, a capability determination operation on a particular candidate platform of the one or more candidate platforms; designating, based at least in part on a result of the capability determination operation, the candidate platform as an approved platform to be used for hosting virtualized resources that are to be configured at least in part via one or more control servers of the provider network; issuing, from a particular control server of the one or more control servers, in response to a resource request from a client, one or more configuration commands to instantiate a particular virtualized resource at the approved platform; and providing, to the client, a reply to the resource request based at least in part on a result of an operation initiated by a remote command executor instantiated at the approved platform in response to the one or more configuration commands, wherein the remote command executor terminates after initiating the operation.