In some cases, it is necessary for a job to aquire a port from a pool of predefined ports (eg. for using an independent memcache connection to be able to flush it on each test setup).

Each pool should have a name and an enumerated list of port numbers.

If a job depends on a pool, it is blocked until any of the pool's port gets released.

If a job has finished, it releases the aquired port, just as it is implemented with the fixed port allocation strategy.

Allocating a fixed port should lock that port from getting aquired by another job, that depends on a pool, containing the same port and vice versa.