elasticsearch5使用snapshot接口备份索引

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。