@Override
		protected Properties getExtraProperties(OptionSet options) {
			String containerGroups = options.valueOf(containerGroupsOption);
			Properties props = new Properties();
			if (StringUtils.hasText(containerGroups)) {
				props.put("containerGroups", containerGroups);
			}
			return props;
		}
A custom {@link YarnClusterCreateCommand} adding option for defining
a groups for XD's containers.

@author Janne Valkealahti
spring-xd-yarn/spring-xd-yarn-client/src/main/java/org/springframework/xd/yarn/XdYarnClusterCreateCommand.java