<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-elasticsearch</artifactId>
        </dependency>

spring.data.elasticsearch.cluster-name=es
spring.data.elasticsearch.cluster-nodes=10.17.12.158:9300
spring.data.elasticsearch.repositories.enabled=true

集群方式

failed to load elasticsearch nodes : 
org.elasticsearch.client.transport.NoNodeAvailableException:
None of the configured nodes are available:
[{#transport#-1}{HiXBU0PNRV6j7QDw9ZcyNw}{10.17.12.158}{10.17.12.158:9300}, {#transport#-2}{fA87OUrESfCfixlGYDQF3Q}{10.17.12.159}{10.17.12.159:9300}, {#transport#-3}{f7qINyogSoqUf6pv4Gt3Mw}{10.17.12.160}{10.17.12.160:9300}]

单节点

failed to load elasticsearch nodes : org.elasticsearch.client.transport.NoNodeAvailableException: None of the configured nodes are available: [{#transport#-1}{av8BbMdQSe-Ys7hGal7LDw}{10.17.12.158}{10.17.12.158:9300}]

初步判定，应该是spring-boot-starter-data-elasticsearch与Elasticsearch 7.x版本不兼容造成的。

通过测试发现，将Elasticsearch降级到6.x版本，即可解决。

【2019-08-22】更新

最新版本

<!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-data-elasticsearch -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-elasticsearch</artifactId>
    <version>2.1.7.RELEASE</version>
</dependency>

由https://mvnrepository.com网页可知，spring-boot-starter-data-elasticsearch编译依赖于spring-boot-starter和 spring-data-elasticsearch，进一步知道spring-data-elasticsearch的最新版本时3.1.10

通过github网址：https://github.com/spring-projects/spring-data-elasticsearch
可知当前最新发布版是3.1版本，对应Elasticsearch版本时6.2.2，尚不支持Elasticsearch 7.x版本

解决办法

2019年11月6日更新
springboot 2.2整合elasticsearch 7.x请参考
https://blog.csdn.net/chengyuqiang/article/details/102938266