Efficient port management for a distributed network address translation

A method for allocating ports to endpoints of a tenant application being hosted by a hosting environment, the tenant application being assigned a virtual IP (VIP) address and the endpoints being assigned a direct IP (DIP) address corresponding with the VIP address, the method comprising:

• initially pre-allocating ports to the endpoints of the tenant application during initial configuration of the tenant application;
• receiving a first request for additional ports from a first endpoint of the tenant application;
• assigning a first set of additional ports to the first endpoint in response to the first request;
• persisting state information for the first set of additional ports in storage;
• configuring a host device hosting the first endpoint and a network address translation device (NAT) device with information regarding the first set of additional ports assigned to the first endpoint;
• receiving a second request for additional ports from the first endpoint;
• determining if the second request is within a threshold period of time following the first request;
• if the second request is not within the threshold period of time following the first request, assigning a second set of additional ports that has the same number or lower number of ports as the first set of additional ports;
• if the second request is within the threshold period of time following the first request, assigning a second set of additional ports that has a greater of ports than the first set of additional ports;
• persisting state information for the second set of additional ports in storage;
• and
• configuring a host device hosting the first endpoint and the NAT device with information regarding the second set of additional ports assigned to the first endpoint.

A system for allocating ports to endpoints of a tenant application being hosted by a hosting environment, the tenant application being assigned a virtual IP (VIP) address and the endpoints being assigned a direct IP (DIP) address corresponding with the VIP address, the system comprising:

• a plurality of host devices hosting the endpoints of the tenant application, each host device comprising a host-plug-in facilitating configuration of ports for endpoints for NAT purposes;
• a NAT device providing NAT functionality;
• a central NAT manager having a processor and being configured to (1) pre-allocate ports to the endpoints, wherein pre-allocating ports comprises allocating the ports to the endpoints during initial configuration of the tenant application, in advance of any connection attempts via the endpoints and wherein the ports are designated to be excluded from automatic release of the ports even when the ports are unused;
• and
• (2) persisting state information in storage, the state information mapping the at least one VIP address to the DIP addresses for the endpoints and mapping the DIP addresses for the endpoints to the ports pre-allocated to the endpoints;
• wherein the central NAT manager is further configured for:
• receiving a dynamic port allocation request from an endpoint that was pre-allocated one or more ports;
• determining a port allocation size for the endpoint;
• wherein determining the port allocation size for the endpoint comprises:
• determining the dynamic port allocation request from the endpoint is a subsequent port allocation request following a previous port allocation request from the endpoint;
• determining whether the dynamic port allocation request is within a threshold period of time following the previous port allocation request;
• if the dynamic port allocation request is not within the threshold period of time following the previous port allocation request, using a pre-determined port allocation size;
• if the dynamic port allocation request is within the threshold period of time following the previous port allocation request, increasing the port allocation size from the previous port allocation size.