watcher

https://wiki.openstack.org/wiki/Watcher

Watcher为OS提供资源优化。主要是通过虚拟机迁移来提高整个数据中心的运营效率，降低TCO。

功能特点：

通过虚拟机迁移来提高整个数据中心的运营效率和各种优化
advise mode (manual) or active mode (automatic),两种执行模式
通过plugin来扩展

架构图：

https://wiki.openstack.org/wiki/WatcherArchitecture

其中：

Complex Event Processing (CEP) 对event分析和做出相应的反应，数据会写到Time Series database，

如果该event会影响到优化的结果，输入到Decision Engine。

Time Series database存储数据中心/集群的各种state, metrics, events, ...，以便Decision Engine随时查询。
Watcher Actions Applier执行CEP的action，需要与Watcher DB连接来获取ation的描述，并把action的状态写入DB
REST API 提供Watcher中资源的操作，包括：Audit Templates Audits ActionPlans Actions，下面有说明例子。
Watcher Database保存以上Watcher中资源。
Watcher Decision Engine复杂根据优化目标来指定具体的优化措施。

影响最优操作的因素有：

optimization goals
deadline
aggressiveness level

Watcher Logger 把从Watcher Message/Notification Bus 来的event转送到CEP

如何使用

https://factory.b-com.com/www/watcher/doc/watcher/deploy/user-guide.html

1, 创建 audit template来定义优化目标

$ watcher audit-template-create my_first_audit SERVERS_CONSOLIDATION

2, 创建audit来请求优化

$ watcher audit-create -a <your_audit_template_uuid>

3 等待audit产生action计划，list action:

$ watcher action-plan-list --audit <the_audit_uuid>

4 每个action plan的具体action：

watcher action-list --action-plan <the_action_plan_uuid>

5, 执行action plan:

$ watcher action-plan-start <the_action_plan_uuid>

6, 查看action执行情况：

$ watcher action-list

RESTAPI资源

https://factory.b-com.com/www/watcher/doc/watcher/webapi/v1.html

Audit Templates

{
    "created_at": "2015-11-04T10:06:04.328837",
    "deleted_at": null,
    "description": "Description of my audit template",
    "extra": {
        "automatic": true
    },
    "goal": "SERVERS_CONSOLIDATION",
    "host_aggregate": 5,
    "links": ..."name": "My Audit Template",
    "updated_at": "2015-11-04T10:06:04.328840",
    "uuid": "27e3153e-d5bf-4b7e-b517-fb518e17f34c"
}

Audits

{
    "audit_template_name": null,
    "audit_template_uuid": "7ae81bb3-dec3-4289-8d6c-da80bd8001ae",
    "created_at": "2015-11-04T10:06:04.465252",
    "deadline": null,
    "deleted_at": null,
    "links": ..."state": "PENDING",
    "type": "ONESHOT",
    "updated_at": "2015-11-04T10:06:04.465255",
    "uuid": "27e3153e-d5bf-4b7e-b517-fb518e17f34c"
}

ActionPlans

{
    "audit_uuid": "abcee106-14d3-4515-b744-5a26885cf6f6",
    "created_at": "2015-11-04T10:06:04.599433",
    "deleted_at": null,
    "first_action_uuid": "57eaf9ab-5aaa-4f7e-bdf7-9a140ac7a720",
    "links": ..."state": "ONGOING",
    "updated_at": "2015-11-04T10:06:04.599439",
    "uuid": "9ef4d84c-41e8-4418-9220-ce55be0436af"
}

Actions

{
    "actions": [
        {
            "action_plan_uuid": "7ae81bb3-dec3-4289-8d6c-da80bd8001ae",
            "links": ..."next_uuid": "7ae81bb3-dec3-4289-8d6c-da80bd8001ae",
            "state": "PENDING",
            "uuid": "27e3153e-d5bf-4b7e-b517-fb518e17f34c"
        }
    ]
}