public int findPort(Allocation request, String host) {
        String key = request.key();
        if (byKeys.containsKey(key)) {
            int port = byKeys.get(key).port;
            log.log(Level.FINE, () -> "Re-using port "+port+" for allocation " + request + " on " + host);
            return port;
        }
        int port = request.port;
        while (byPorts.containsKey(port)) {
            ++port;
        }
        return port;
    }
force add the given allocation, removing any conflicting ones
config-model/src/main/java/com/yahoo/vespa/model/PortFinder.java