protected void pullImage(RegistryService registryService, ImageConfiguration imageConfig,
                             String pullRegistry) throws MojoExecutionException, DockerAccessException {
        String imageName = imageConfig.getName();
        RunImageConfiguration runConfiguration = imageConfig.getRunConfiguration();
        ImagePullManager pullManager = getImagePullManager(determinePullPolicy(runConfiguration), autoPull);
        RegistryConfig registryConfig = getRegistryConfig(pullRegistry);
        registryService.pullImageWithPolicy(imageName, pullManager, registryConfig, imageConfig.getBuildConfiguration());
    }
Get all volumes which are defined separately from the images

@return defined volumes
src/main/java/io/fabric8/maven/docker/AbstractDockerMojo.java