面对多集群的企业级复杂架构，准备一套备份集群显得非常重要，备份集群在平时不参与读写操作，但是始终包含业务集群的所有数据，在有业务集群不能使用的时候，可以直接通过切换Elasticsearch来完成灾备效果，这篇文章写的是跨集群实现数据迁移和数据灾备
一．Snapshot And Restore说明
快照是从正在运行的Elasticsearch集群中获取的备份。您可以获取单个索引或整个集群的快照，并将其存储在共享文件系统的存储库中。
快照可以通过restore API恢复到正在运行的集群中。
二．首先，你需要一个仓库
vim conf/elasticsearch.yml path.repo /data/backup
注意：这个目录必须是一个网络共享盘，如Nfs,Samba等
三．告诉Elasticsearch仓库在哪里
PUT /_snapshot/my_backup #使用_snapshot API指定仓库名称
{
"type": "fs",
"settings": {
"location": "my_backup_location" #指定仓库位置
"compress": true #压缩Mappings和settings,不能压缩数据
}
}
GET /_snapshot/my_backup #获取仓库位置
四．准备好了就开始备份
PUT /_snapshot/my_backup/kuaizhao1?wait_for_completion=true
#wait_for_completion等待快照完成后再返回
1.返回如下字符串为成功
{"snapshot":{"snapshot":"kuaizhao1,"uuid":"x3AXRHavTySEe2BpBhU_FQ","version_id":5060199,"version":"5.6.1","indices":["test-aop-2014.04","test-xtx-2020.05","test2-newlis-2020.05","test-xtx-2014.04"],"state":"
SUCCESS","start_time":"2020-05-28T06:58:09.818Z","start_time_in_millis":1590649089818,"end_time":"2020-05-28T06:58:10.258Z",
"end_time_in_millis":1590649090258,"duration_in_millis":440,"failures":[],"shards":{"total":8,"failed":0,"successful":8}}}
2.在备份仓库/data/backup中生成如下文件
-rw-rw-r-- 1 elk elk 29 May 28 11:09 incompatible-snapshots -rw-rw-r-- 1 elk elk 275 May 28 11:03 index-0 -rw-rw-r-- 1 elk elk 8 May 28 11:03 index.latest drwxrwxr-x 6 elk elk 4096 May 28 11:03 indices -rw-rw-r-- 1 elk elk 698 May 28 11:03 meta-RUiiWfeISgWFNrVfQ80sGw.dat -rw-rw-r-- 1 elk elk 232 May 28 11:03 snap-RUiiWfeISgWFNrVfQ80sGw.dat
五．增量备份，其实就是在仓库里再建一个快照
PUT /_snapshot/my_backup/kuaizhao2?wait_for_completion=true
#自动识别仓库中其他的快照信息，只对新增或更新的索引进行快照
六．把包含快照数据的网盘挂到另一套集群的任一节点
开始恢复快照
1.这是一套新的集群，上面没有其他索引，没有重名索引
POST _snapshot/my_backup/kuaizhao1/_restore
2.之前恢复过快照，或者上面有重名索引
POST test-xtx-2020.05/_close #先把要还原的索引关闭 POST _snapshot/my_backup/kuaizhao2/_restore GET _cat/shards #还原成功后自动打开索引
七. 错误排查
RepositoryVerificationException[[backup5.28] a file written by master to the store [/data/backup] cannot be accessed on the node [{test1-2}{OZKGLppLRgy1cFdhiVrVGw}{5CgnmLyaS_yGLnxFx1Wrxg}{10.1.5.13}{10.1.5.13:9300}]. This might indicate that the store [/data/backup] 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]
快照仓库不能是本地目录，只能是网络共享盘
location [/data/backup] doesn't match any of the locations specified by path.repo because this setting is empty
要先在elasticsearch.yml中配置仓库重启后才能继续