数据备份是一个必须要考虑的问题，官网提供了 snapshot 接口来备份和恢复数据。
先来看看官方说明：
如果ES是集群，那么需要使用共享存储，支持的存储有：
a、shared file system
b、S3
c、HDFS
我使用的是第一种，NFS共享文件系统。这里要说一下权限问题，ES一般是使用 elasticsearch 用户启动的，要保证共享目录对 elasticsearch 用户有读写权限，要不然创建仓库和快照的时候会报访问拒绝500错误。
在nfs-server上导出共享目录的权限配置，这里将所有连接用户都压缩为root权限：
# 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、创建挂载目录，并给予权限
# mkidr -pv /nh/esbk/my_backup
# chmod 755 /nh/esbk/
# chown elasticsearch.elasticsearch /nh/esbk/
2、挂载共享目录
# 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，添加仓库路径，重启服务
# vim /etc/elasticsearch/elasticsearch.yml
path.repo: ["/nh/esbk"]
# /etc/init.d/elasticsearch restart
4、注册快照仓库到ES，这里是在 kibana 的 Dev Tools 上操作的，也可以使用 curl 发起请求。
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、查看仓库信息
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、创建快照
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
这里发起请求后，会立马返回 true，并在后台执行操作。
如果想等待执行完成之后再返回，可以加一个参数：
PUT /_snapshot/my_backup/snapshot_1?wait_for_completion=true
7、查看刚才创建的快照的信息
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
}
}
]
}
列出一个仓库里的所有快照
All snapshots currently stored in the repository can be listed using the following command:
GET /_snapshot/my_backup/_all
8、删除一个快照
A snapshot can be deleted from the repository using the following command:
DELETE /_snapshot/my_backup/snapshot_1
9、删除一个仓库
A repository can be deleted using the following command:
DELETE /_snapshot/my_backup
10、恢复一个快照（支持恢复部分数据以及恢复过程中修改索引信息，具体细节参考官方文档）
POST /_snapshot/my_backup/snapshot_1/_restore
11、查看快照状态信息（比如正在创建或者创建完成等）
a、列出所有当前正在运行的快照以及显示他们的详细状态信息
A list of currently running snapshots with their detailed status information can be obtained using the following command.
GET /_snapshot/_status
b、查看指定仓库的正在运行的快照以及显示他们的详细状态信息
GET /_snapshot/my_backup/_status
c、查看指定快照的详细状态信息即使不是正在运行
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、支持同时指定多个快照ID查看多个快照的信息
Multiple ids are also supported.
GET /_snapshot/my_backup/snapshot_1,snapshot_2/_status
12、如果要停止一个正在运行的snapshot任务（备份和恢复），将其删除即可。