snapshot（持续更新中）

首先先了解一下官网中提到的如何backup your elasticsearch

https://www.elastic.co/guide/en/elasticsearch/guide/current/backing-up-your-cluster.html

知识点

1.关于repository的几种类型。

（来自官网）To use this functionality, you must first create a repository to save data. There are several repository types that you may choose from:

• Shared filesystem, such as a NAS
• Amazon S3
• HDFS (Hadoop Distributed File System)
• Azure Cloud

下面截图是来自kopf这个插件，url在上面没有提到，其他的都能对上

总结一下：fs---->Shared filesystem

　　　　　s3---->Amazon S3

　　　　　hdfs--->HDFS (Hadoop Distributed File System)

　　　　   azure--->Azure Cloud

下面是google的一篇不错的关于snapshot es的 java 代码。

https://dzone.com/articles/how-use-elasticsearch-snapshot

下面是我自己写的代码

String repositoryPath = "E:\snapshot";
            boolean compress = true;
            String repositoryType = "fs";
            // es 2.4
            Settings setting = Settings.builder()
                    .put("location", repositoryPath)
                    .put("compress", compress).build();
            PutRepositoryResponse putRepositoryResponse = clusterAdminClient.preparePutRepository(defaultRepositoryName)
                    .setType(repositoryType).setSettings(setting)
                    .execute().actionGet();
            if (putRepositoryResponse.isAcknowledged()) {
                System.out.println(defaultRepositoryName + " have been created");
                
                repositoryMetaDataList = clusterAdminClient.prepareGetRepositories(defaultRepositoryName).get().repositories();
                System.out.println(repositoryMetaDataList.size());
            }

Exception in thread "main" RepositoryVerificationException[[hippo_Repository] [VMYox38PS9qXN3hYhf588Q, 'RemoteTransportException[[node-hippo3][10.12.198.242:9300][internal:admin/repository/verify]]; nested: RepositoryVerificationException[[hippo_Repository] a file written by master to the store [/opt/hippo/snapshot/E:snapshot] cannot be accessed on the node [{node-hippo3}{VMYox38PS9qXN3hYhf588Q}{10.12.198.242}{10.12.198.242:9300}{master=true}]. This might indicate that the store [/opt/hippo/snapshot/E:snapshot] is not shared between this node and the master node or that permissions on the store don't allow reading files written by the master node];'], [EZQYXYKcTtuDCgjr17_M6g, 'RemoteTransportException[[node-hippo1][10.12.198.240:9300][internal:admin/repository/verify]]; nested: RepositoryVerificationException[[hippo_Repository] a file written by master to the store [/opt/hippo/snapshot/E:snapshot] cannot be accessed on the node [{node-hippo1}{EZQYXYKcTtuDCgjr17_M6g}{10.12.198.240}{10.12.198.240:9300}{master=false}]. This might indicate that the store [/opt/hippo/snapshot/E:snapshot] is not shared between this node and the master node or that permissions on the store don't allow reading files written by the master node];']]]
    at org.elasticsearch.repositories.RepositoriesService$VerifyingRegisterRepositoryListener$1.onResponse(RepositoriesService.java:440)
    ......

一开始我以为，这个repositoryPath应该是绝对路径，从报错看到设置的应该是相对路径（开头不能是/，直接输入文件夹名字就好了），那么绝对的文件夹位置在哪里设置的，google了一下，发现在elasticsearch.yml中有个变量path.repo，恍然大悟。。。