参考官方文档：
https://www.elastic.co/guide/en/elasticsearch/reference/5.6/rolling-upgrades.html
1，Disable shard allocation （关闭自动分片，避免节点停止时，数据大量复制到其他节点）
curl -X PUT "localhost:9201/_cluster/settings" -H 'Content-Type: application/json' -d'
{
"transient": {
"cluster.routing.allocation.enable": "none"
}
}
'
2，Stop non-essential indexing and perform a synced flush (手动执行同步刷新操作，使节点重启后可以从本地快速恢复数据（仅对冷索引有效），大量减少节点间的数据拷贝）
curl -X POST "localhost:9201/_flush/synced"
3，Stop and upgrade a single node（更新一个节点的服务以及插件）
参考playbook:
---
- name: u"stop service"
shell: "/etc/init.d/elasticsearch stop"
- name: u"stop master service"
shell: "/etc/init.d/elasticsearch-master stop"
- name: u"部署安装包"
copy: src="elasticsearch-5.6.9.deb" dest="/tmp/elasticsearch-5.6.9.deb" owner=root group=root mode=0440
- name: u"移除默认安装目录下的jvm config，否则dpkg安装时会卡住"
shell: "mv /etc/elasticsearch/jvm.options /etc/elasticsearch/jvm.options.bak "
- name: u"初始化包"
shell: "dpkg -i /tmp/elasticsearch-5.6.9.deb"
- name: u"delete old plugins"
shell: "rm -rf /usr/share/elasticsearch/plugins/*"
- name: u"安装扩展ik"
copy: src="ik" dest="/usr/share/elasticsearch/plugins/" owner=root group=root mode=0644
- name: u"安装扩展pinyin"
copy: src="pinyin" dest="/usr/share/elasticsearch/plugins/" owner=root group=root mode=0644
- name: ES java config
template:
src=jvm.options.j2
dest=/etc/elasticsearch/jvm.options
owner=root group=root mode=644
- name: u"start service"
shell: "/etc/init.d/elasticsearch start"
- name: u"start master service"
shell: "/etc/init.d/elasticsearch-master start"
4，Wait for the node to join the cluster：
curl -X GET "localhost:9201/_cat/nodes"
5，Reenable shard allocation
curl -X PUT "localhost:9201/_cluster/settings" -H 'Content-Type: application/json' -d'
{
"transient": {
"cluster.routing.allocation.enable": "all"
}
}
'
6，Wait for the node to recover
curl -X GET "localhost:9201/_cat/health"（GREEN）
7，Repeat （重复1-6操作下一个节点）
When the cluster is stable and the node has recovered, repeat the above steps for all remaining nodes.
----------------------------------------------------------------
可选：
如需更新插件：x-pack
参考官方文档：
https://www.elastic.co/guide/en/elasticsearch/reference/5.6/installing-xpack-es.html
1、停止服务并移除老版本插件
2、安装当前版本插件：
2.1、在线更新：bin/elasticsearch-plugin install x-pack
2.2、离线更新：
2.2.1、downloadhttps://artifacts.elastic.co/downloads/packs/x-pack/x-pack-5.6.9.zip
2.2.3、bin/elasticsearch-plugin install file:///path/to/file/x-pack-5.6.9.zip
3、在/etc/elasticsearch/elasticsearch.yml 里添加一行配置：xpack_security_enabled: "false"
去掉password验证功能
4、启动es服务并等待节点加入集群（此时可以先操作第4步）
5、申请免费试用1年的license，填写信息后会收到license下载邮件，进入邮件指定地址下载对应版本的license
6、为es的运行用户elasticsearch设置登录密码
passwd elasticsearch
7、激活x-pack：
curl -XPUT -u elasticsearch 'http://127.0.0.1:9201/_xpack/license?acknowledge=true' -H "Content-Type: application/json" -d @arteezy-xie-61d89843-332f-41b7-9b75-72ef99fa0513-v5.json
curl -XPUT -u elasticsearch 'http://127.0.0.1:9202/_xpack/license?acknowledge=true' -H "Content-Type: application/json" -d @arteezy-xie-61d89843-332f-41b7-9b75-72ef99fa0513-v5.json
（输入上一步为elasticsearch设置的登录密码）
PS：仅做监控和报警的话，强烈建议投入prometheus的怀抱，官方grafana的监控demo接入即用，数据丰富多样，多集群维护同样方便。当然，你需要先安装一个prometheus...
