public PortMapping createPortMapping(RunImageConfiguration runConfig, Properties properties) {
        try {
            return new PortMapping(runConfig.getPorts(), properties);
        } catch (IllegalArgumentException exp) {
            throw new IllegalArgumentException("Cannot parse port mapping", exp);
        }
    }
Create port mapping for a specific configuration as it can be used when creating containers

@param runConfig the cun configuration
@param properties properties to lookup variables
@return the portmapping
src/main/java/io/fabric8/maven/docker/service/RunService.java