StackStorm分析之 StackStorm介绍


StackStorm介绍

StackStorm是一个强大的自动化平台,结合DevOps和ChatOps,提供可扩展、灵活和健壮的工具链用于应用、服务和工作流的自动化能力。


StackStorm核心概念

QQ截图20180515143016.png


StackStorm的工作步骤大体如下:
1. StackStorm Sensor感应并触发事件。
2. Rules Engine对事件进行规则匹配,如果匹配产生任务。
3. StackStorm Worker执行任务,一般是调用到外部系统。
4. StackStorm记录审计任务执行的细节。
5.任务执行结果返回给Rules Engine进行进一步处理。

可以看出StackStorm是个以事件驱动的系统,为此抽象出一系列概念来分解事件从产生、触发、规则匹配到执行的整个生命周期事件,具体包含核心概论如下:

Sensor感应器

Sensor是一系列的感应器用于接受或者监测事件,当事件发生的时候,Sensor将会通知Trigger提交事件到StackStorm。
Sensor是Python插件实现,只要实现StackStorm定义的接口,然后配置元数据YAML注册到StackStorm:
---
class_name: "SampleSensor"
entry_point: "sample_sensor.py"
description: "Sample sensor that emits triggers."
trigger_types:
-
  name: "event"
  description: "An example trigger."
  payload_schema:
    type: "object"
    properties:
      executed_at:
        type: "string"
        format: "date-time"
        default: "2014-07-30 05:04:24.578325"


Trigger触发器

Trigger代表事件,一般事件是由外部系统产生,比如监控告警,JIRA问题更新等等,另外也有通用的事件触发器,比如定时器或者WebHook。
在StackStorm系统中,Trigger只是String类型的对象,由Sensor注册,用户可以在Sensor插件自定义新的Trigger。

Action 动作/任务

Action是事件触发后的处理方式,一般是由外部系统执行,包括:
  • 重启服务
  • 创建云服务
  • 发生邮件
  • 启动Docker容器
  • 制作VM快照


Action可以是通用的执行方式,比如SSH,REST API调用,也能够集成Openstack、Docker/Kubernetes等系统实现。Action Runner是Action的执行环境,StackStorm的内置Action Runner:
Action Runner Description
  • local-shell-cmd This is the local runner. This runner executes a Linux command on the same host where StackStorm components are running.
  • local-shell-script This is the local runner. Actions are implemented as scripts. They are executed on the same hosts where StackStorm components are running.
  • remote-shell-cmd This is a remote runner. This runner executes a Linux command on one or more remote hosts provided by the user.
  • remote-shell-script This is a remote runner. Actions are implemented as scripts. They run on one or more remote hosts provided by the user.
  • python-script This is a Python runner. Actions are implemented as Python classes with arun method. They run locally on the same machine where StackStorm components are running.
  • http-request HTTP client which performs HTTP requests for running HTTP actions.
  • action-chain This runner supports executing simple linear work-flows.
  • mistral-v2 Those runners are built on top of the Mistral OpenStack project and support executing complex work-flows.

  • cloudslang This runner is built on top of the CloudSlang project and supports executing complex workflows.

    通过Action Runner用户可以自定义Action的实现,以下是一个python-script类型的Action用于发送SMS:
    ---
    name: "send_sms"
    runner_type: "python-script"
    description: "This sends an SMS using twilio."
    enabled: true
    entry_point: "send_sms.py"
    parameters:
    from_number:
    type: "string"
    description: "Your twilio 'from' number in E.164 format. Example +14151234567."
    required: true
    position: 0
    to_number:
    type: "string"
    description: "Recipient number in E.164 format. Example +14151234567."
    required: true
    position: 1
    secret: true
    body:
    type: "string"
    description: "Body of the message."
    required: true
    position: 2
    default: "Hello {% if system.user %} {{ system.user }} {% else %} dude {% endif %}!"


Workflow 工作流

Workflow是Action集合,Workflow能够定义Action的执行顺序和条件,组合一系列Action完成复杂的任务。Workflow可以认为是广义意义上的Action。

StackStorm支持2种类型的Workflow:
- ActionChain:通过简单的语法定义Action链

---
chain:
    -  name: "c1"
        ref: "core.local"
        parameters:
            cmd: "echo c1"
        on-success: "c2"
        on-failure: "c4"
    - name: "c2"
        ref: "core.local"
        parameters:
            cmd: "echo \"c2: parent exec is {{action_context.parent.execution_id}}.\""
        on-success: "c3"
        on-failure: "c4"
    - name: "c3"
        ref: "core.local"
        parameters:
            cmd: "echo c3"
        on-failure: "c4"
    - name: "c4"
        ref: "core.local"
        parameters:
            cmd: "echo fail c4"
default: "c1"

  • Mistral :Openstack的工作流组件,可以同Stackstorm集成,支持复杂的工作流配置。

version: '2.0'
examples.mistral-join:
    description: >
        A sample workflow that demonstrates how to join parallel branches.
    type: direct
    tasks:
        a:
            action: core.local
            input:
                cmd: "echo 'a'"
            on-success:
                - b
                - c
                - d
        b:
            action: core.local
            input:
                cmd: "echo 'b'"
            on-success:
                - e
        c:
            action: core.local
            input:
                cmd: "echo 'c'"
            on-success:
                - e
        d:
            action: core.local
            input:
                cmd: "echo 'd'"
            on-success:
                - e
        e:
            join: all
            action: core.local
            input:
                cmd: "echo 'e'"


Rule 规则

Rule是映射Trigger到Action(或者Workflow),即当事件触发后,通过Rule定义的标准(Criteria)进行匹配,当匹配成功将执行Action(或者Workflow)。

Rule的定义格式:
---
name: "rule_name"                      # required
pack: "examples"                       # optional
description: "Rule description."       # optional
enabled: true                          # required

trigger:                               # required
    type: "trigger_type_ref"

criteria:                              # optional
    trigger.payload_parameter_name1:
        type: "regex"
        pattern : "^value$"
    trigger.payload_parameter_name2:
        type: "iequals"
        pattern : "watchevent"

action:                                # required
    ref: "action_ref"
    parameters:                        # optional
        foo: "bar"
        baz: "{{trigger.payload_parameter_1}}"


Audit 审计

Audit是用来跟踪和记录Action的执行细节,用于查询定位:

{
"status": "succeeded",
"start_timestamp": "2014-10-31T02:00:46.679000Z",
"parameters": {
    "cmd": "ifconfig"
},
"callback": {},
"result": {
    ...
},
"context": {
    "user": "stanley"
},
"action": "core.local",
"id": "5452ed4e0640fd6b59e75908"
}


ChatOps

ChatOps是一种新的DevOps方法,ChatOps是诞生于GitHub的一种基于会话驱动的协作开发方法,过去团队之间的通讯和开发操作是两层皮,导致各种不透明和低效率。ChatOps将开发工具带入开发者聊天室,通过定制的插件和脚本,一个聊天机器人能够执行聊天中输入的各种命令,实现在聊天平台上的团队协作开发自动化,把团队沟通和执行统一整合到一个可视化更高的聊天环境中,“聊着天就把事情办了”。
目前流行的ChatOps聊天机器人主要有Hubot(GitHub的bot,用CoffeeScript和Node.js开发)、Lita(用Ruby开发)和Err(用Python开发)三种,都是开源软件,而且可以整合到开发团队在工作中经常会使用一些聊天工具例如HipChat、Slack、Flowdock和Campfire等。
StackStorm中集成了Hubot作为聊天机器人提供ChatOps,同时提供Action Alias 和Notifications 机制实现更好的体验。

参考:https://docs.stackstorm.com/_i ... o.gif

参考

https://docs.stackstorm.com/index.html

作者简介

吴龙辉,现任网宿科技云计算架构师,致力于云计算PaaS的研究和实践,《Kubernetes实战》作者,活跃于CloudFoundry,Docker,Kubernetes等开源社区,贡献代码和撰写技术文档。
邮箱:wlh6666@qq.com

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