數據備份是一個必須要考慮的問題，官網提供了 snapshot 接口來備份和恢復數據。
先來看看官方說明：
如果ES是集群，那么需要使用共享存儲，支持的存儲有：
a、shared file system
b、S3
c、HDFS
我使用的是第一種，NFS共享文件系統。這里要說一下權限問題，ES一般是使用 elasticsearch 用戶啟動的，要保證共享目錄對 elasticsearch 用戶有讀寫權限，要不然創建倉庫和快照的時候會報訪問拒絕500錯誤。
在nfs-server上導出共享目錄的權限配置，這里將所有連接用戶都壓縮為root權限：
# vim /etc/exports
/data02/es 192.168.3.56(rw,sync,all_squash,anonuid=0,anongid=0,no_subtree_check) 192.168.3.57(rw,sync,all_squash,anonuid=0,anongid=0,no_subtree_check) 192.168.3.49(rw,sync,all_squash,anonuid=0,anongid=0,no_subtree_check)
# /etc/init.d/nfs-kernel-server reload
1、創建掛載目錄，並給予權限
# mkidr -pv /nh/esbk/my_backup
# chmod 755 /nh/esbk/
# chown elasticsearch.elasticsearch /nh/esbk/
2、掛載共享目錄
# vim /etc/fstab
192.168.3.97:/data02/es /nh/esbk/my_backup nfs defaults 0 0
# mount -a
# df -hT
3、修改ES的配置文件，添加倉庫路徑，重啟服務
# vim /etc/elasticsearch/elasticsearch.yml
path.repo: ["/nh/esbk"]
# /etc/init.d/elasticsearch restart
4、注冊快照倉庫到ES，這里是在 kibana 的 Dev Tools 上操作的，也可以使用 curl 發起請求。
Before any snapshot or restore operation can be performed, a snapshot repository should be registered in Elasticsearch.
After all nodes are restarted, the following command can be used to register the shared file system repository with the name my_backup.
PUT /_snapshot/my_backup
{
"type": "fs",
"settings": {
"compress": true,
"location": "/nh/esbk/my_backup"
}
}
5、查看倉庫信息
GET /_snapshot/my_backup
# curl -u elastic -XGET 'http://192.168.3.49:9200/_snapshot/my_backup?pretty'
{
"my_backup" : {
"type" : "fs",
"settings" : {
"compress" : "true",
"location" : "/nh/esbk/my_backup"
}
}
}
6、創建快照
A repository can contain multiple snapshots of the same cluster.
Snapshots are identified by unique names within the cluster.
A snapshot with the name snapshot_1 in the repository my_backup can be created by executing the following command.
PUT /_snapshot/my_backup/snapshot_1
這里發起請求后，會立馬返回 true，並在后台執行操作。
如果想等待執行完成之后再返回，可以加一個參數：
PUT /_snapshot/my_backup/snapshot_1?wait_for_completion=true
7、查看剛才創建的快照的信息
Once a snapshot is created information about this snapshot can be obtained using the following command.
GET /_snapshot/my_backup/snapshot_1
{
"snapshots": [
{
"snapshot": "snapshot_1",
"uuid": "xSMRNVMIRHmx_qlhX5fqfg",
"version_id": 5040199,
"version": "5.4.1",
"indices": [
".monitoring-kibana-2-2017.07.05",
".monitoring-kibana-2-2017.07.11",
"zixun-nginx-access-2017.07.12",
".monitoring-logstash-2-2017.07.07",
".monitoring-kibana-2-2017.07.07",
"filebeat-2017.07.07",
".watcher-history-3-2017.07.04",
".watcher-history-3-2017.07.07",
".monitoring-es-2-2017.07.05",
".kibana",
".monitoring-data-2",
".watcher-history-3-2017.06.27",
".monitoring-logstash-2-2017.07.10",
".monitoring-kibana-2-2017.07.10",
".monitoring-es-2-2017.07.08",
".monitoring-logstash-2-2017.07.12",
".monitoring-es-2-2017.07.10",
".watcher-history-3-2017.07.06",
".monitoring-kibana-2-2017.07.09",
".watcher-history-3-2017.07.12",
".watcher-history-3-2017.07.03",
".monitoring-alerts-2",
".monitoring-logstash-2-2017.07.08",
".watcher-history-3-2017.07.01",
".watcher-history-3-2017.07.11",
".watcher-history-3-2017.07.05",
".watcher-history-3-2017.06.29",
".watcher-history-3-2017.06.28",
".monitoring-kibana-2-2017.07.08",
".security",
".monitoring-logstash-2-2017.07.11",
".monitoring-es-2-2017.07.11",
".watcher-history-3-2017.06.30",
".triggered_watches",
".watcher-history-3-2017.07.08",
".monitoring-es-2-2017.07.12",
".watcher-history-3-2017.07.09",
".monitoring-es-2-2017.07.09",
".monitoring-kibana-2-2017.07.12",
".monitoring-kibana-2-2017.07.06",
".watcher-history-3-2017.07.10",
"test",
".monitoring-es-2-2017.07.07",
".monitoring-logstash-2-2017.07.09",
".watches",
".monitoring-es-2-2017.07.06",
".watcher-history-3-2017.07.02"
],
"state": "SUCCESS",
"start_time": "2017-07-12T04:19:08.246Z",
"start_time_in_millis": 1499833148246,
"end_time": "2017-07-12T04:20:04.717Z",
"end_time_in_millis": 1499833204717,
"duration_in_millis": 56471,
"failures": [],
"shards": {
"total": 59,
"failed": 0,
"successful": 59
}
}
]
}
列出一個倉庫里的所有快照
All snapshots currently stored in the repository can be listed using the following command:
GET /_snapshot/my_backup/_all
8、刪除一個快照
A snapshot can be deleted from the repository using the following command:
DELETE /_snapshot/my_backup/snapshot_1
9、刪除一個倉庫
A repository can be deleted using the following command:
DELETE /_snapshot/my_backup
10、恢復一個快照（支持恢復部分數據以及恢復過程中修改索引信息，具體細節參考官方文檔）
POST /_snapshot/my_backup/snapshot_1/_restore
11、查看快照狀態信息（比如正在創建或者創建完成等）
a、列出所有當前正在運行的快照以及顯示他們的詳細狀態信息
A list of currently running snapshots with their detailed status information can be obtained using the following command.
GET /_snapshot/_status
b、查看指定倉庫的正在運行的快照以及顯示他們的詳細狀態信息
GET /_snapshot/my_backup/_status
c、查看指定快照的詳細狀態信息即使不是正在運行
If both repository name and snapshot id are specified, this command will return detailed status information for the given snapshot even if it’s not currently running:
GET /_snapshot/my_backup/snapshot_1/_status
d、支持同時指定多個快照ID查看多個快照的信息
Multiple ids are also supported.
GET /_snapshot/my_backup/snapshot_1,snapshot_2/_status
12、如果要停止一個正在運行的snapshot任務（備份和恢復），將其刪除即可。