Managing communications for modified computer networks

A computer-implemented method for managing communications for modified computer networks, the method comprising:

• modifying, by a computing system configured to use mapping information for a first virtual computer network, an outgoing communication sent to a first computing node of multiple computing nodes in the first virtual computer network from another of the multiple computing nodes, the modifying of the outgoing communication including changing a destination of the outgoing communication from a first virtual network address associated with the first computing node to a distinct first substrate network address that corresponds to a location of the first computing node in a substrate network on which the first virtual computer network is overlaid;
• forwarding the modified communication to the first computing node over the substrate network based at least in part on the first substrate network address;
• determining, by the configured red computing system, to move the first computing node to a different location in the substrate network, the different location corresponding to a second substrate network address that is distinct from the first substrate network address, the determining being based at least in part on identifying one or more benefits associated with moving the first computing node;
• managing, by the configured computing system, and after the forwarding of the modified communication, the move of the first computing node to the different location in the substrate network, the moved first computing node retaining the first virtual network address, the managing of the move including updating the mapping information to associate the first computing node with the second substrate network address;
• modifying, by the configured computing system, and after the move of the first computing node, an additional outgoing communication sent to the first computing node from another of the multiple computing nodes, the modifying of the additional outgoing communication including changing a destination of the additional outgoing communication from the first virtual network address to the second substrate network address based at least in part on the updated mapping information;
• and
• forwarding the modified additional outgoing communication to the moved first computing node over the substrate network based at least in part on the second substrate network address.

A non-transitory computer-readable medium whose contents configure a computing system to manage communications for modified computer networks, by performing a method comprising:

• managing one or more sent communications that involve a first of multiple computing nodes of a first virtual computer network and that each specify a virtual network address associated with the first computing node for the first virtual computer network, the managing of each of the one or more sent communications including identifying a distinct substrate network address for the first computing node that is for use in delivering the sent communication to a network location of the first computing node in a physical substrate network interconnecting the multiple computing nodes, the substrate network address being identified based at least in part on a mapping for the first computing node of the associated virtual network address to the substrate network address;
• and
• determining to initiate one or more modifications to the first virtual computer network in such a manner as to enable delivery of additional sent communications that involve the first computing node, the one or more modifications including a change to the first computing node that causes a modification of at least one of the associated virtual network address for the first computing node and of the substrate network address for the first computing node and further including updating the mapping for the first computing node to reflect the change to the first computing node;
• and
• after the managing of the one or more sent communications, managing the delivery of the additional sent communications, the managing of the delivery including modifying the additional sent communications based on the updated mapping.

A system, comprising:

• one or more processors of one or more computing systems;
• and
• one of multiple communication manager modules that manage communications between multiple computing nodes of a first virtual computer network via one or more intermediate physical networks, the one communication manager module being associated with a first group of one or more of the multiple computing nodes that are implemented as virtual machines hosted by one or more computing systems, each of the communication manager modules other than the one communication manager module having a distinct associated group of one or more other of the multiple computing nodes, the one communication manager module being configured to, when executed by at least one of the one or more processors, manage outgoing communications for the computing nodes of the first group by:
• after one of the computing nodes of the first group initiates sending a communication to a destination first computing node that is part of the associated group for a first other of the communication manager modules, determining a destination network address in the one or more intermediate physical networks for use with the communication, the determined destination network address corresponding at least in part to the first other communication manager module, and using the determined destination network address to forward the sent communication to the first computing node via the one or more intermediate physical networks;
• determining to initiate a move of the first computing node to a new location in the one or more intermediate physical networks such that the first computing node becomes part of the associated group for a distinct second other of the communication manager modules;
• after the first computing node is moved to the new location, determining a distinct second destination network address in the one or more intermediate physical networks, the determined destination network address corresponding at least in part to the second other communication manager module, and updating mapping information associated with the first virtual computer network to include an indication of the determined second destination network address for the first computing node;
• and
• after one of the computing nodes of the first group initiates sending a second communication to the first computing node, using the determined second destination network address to forward the second communication to the moved first computing node via the one or more intermediate networks by modifying the second communication to reflect the determined second destination network address, the determined second destination network address being identified based on the updated mapping information.