基于Swarm mode 的极简Serverless实践

函数计算（FaaS）是目前最新的云服务模式，阿里云容器服务基于 swarm mode 集群上实现了一个极简的Serverless 框架，支持将任意 Unix 进程作为函数实现来对外提供服务。更多扩展知识，可参考 阿里云函数计算。``

架构原理


在 FaaS 原型系统中，包括以下几个模块，其中:

1. 任何进程都可以转化成为一个函数，并利用Docker镜像进行打包和交付。
2. 利用 Docker Swarm 集群的资源调度和routing mesh的负载均衡能力简洁地实现了函数的调度能力。其中每个函数对应一个Docker集群中的服务。
3. 基于 Prometheus 实现函数调用监控和自动伸缩。

• API Gateway 负责接受服务调用，路由请求到后端函数实现，并采集服务调用的指标发送给 Prometheus。 Prometheus 则会根据一段时间内服务调用的次数，回调API Gateway 来动态伸缩服务容器实例数量。
• 
  Function Watchdog 将HTTP请求转发为进程调用，并将请求数据通过 STDIN 传递给进程，而将进程的 STDOUT 作为 HTTP 响应的结果返回给调用者。将函数进程和Function Watchdog打包成一个容器镜像进行部署。其调用流程如下：
  

1. 
   首先您需要准备一个本地的Docker Swarm集群，如果没有，可以安装最新 Docker Engine 并执行下面命令：
   docker swarm init
2. 
   执行如下命令来部署 FaaS[backcolor=transparent] git clone https[backcolor=transparent]:[backcolor=transparent]//github.com/alexellis/faas
3. [backcolor=transparent] cd faas
4. [backcolor=transparent] [backcolor=transparent]./[backcolor=transparent]deploy_stack[backcolor=transparent].[backcolor=transparent]sh

1. [backcolor=transparent] $ docker stack services func
2. [backcolor=transparent] ID            NAME               MODE        REPLICAS  IMAGE
3. [backcolor=transparent] [backcolor=transparent]1a8b2tb19ulk[backcolor=transparent]  func_gateway       replicated  [backcolor=transparent]1[backcolor=transparent]/[backcolor=transparent]1[backcolor=transparent]       functions[backcolor=transparent]/[backcolor=transparent]gateway[backcolor=transparent]:[backcolor=transparent]0.5[backcolor=transparent].[backcolor=transparent]6
4. [backcolor=transparent] [backcolor=transparent]4jdexem6kppg[backcolor=transparent]  func_webhookstash  replicated  [backcolor=transparent]1[backcolor=transparent]/[backcolor=transparent]1[backcolor=transparent]       functions[backcolor=transparent]/[backcolor=transparent]webhookstash[backcolor=transparent]:[backcolor=transparent]latest
5. [backcolor=transparent] [backcolor=transparent]9ju4er5jur9l[backcolor=transparent]  func_wordcount     replicated  [backcolor=transparent]1[backcolor=transparent]/[backcolor=transparent]1[backcolor=transparent]       functions[backcolor=transparent]/[backcolor=transparent]alpine[backcolor=transparent]:[backcolor=transparent]health
6. [backcolor=transparent] e190suippx7i  func_markdown      replicated  [backcolor=transparent]1[backcolor=transparent]/[backcolor=transparent]1[backcolor=transparent]       alexellis2[backcolor=transparent]/[backcolor=transparent]faas[backcolor=transparent]-[backcolor=transparent]markdownrender[backcolor=transparent]:[backcolor=transparent]latest
7. [backcolor=transparent] l70j4c7kf99t  func_alertmanager  replicated  [backcolor=transparent]1[backcolor=transparent]/[backcolor=transparent]1[backcolor=transparent]       functions[backcolor=transparent]/[backcolor=transparent]alertmanager[backcolor=transparent]:[backcolor=transparent]latest
8. [backcolor=transparent] mgujgoa2u8f3  func_decodebase64  replicated  [backcolor=transparent]1[backcolor=transparent]/[backcolor=transparent]1[backcolor=transparent]       functions[backcolor=transparent]/[backcolor=transparent]alpine[backcolor=transparent]:[backcolor=transparent]health
9. [backcolor=transparent] o44asbnhqbda  func_hubstats      replicated  [backcolor=transparent]1[backcolor=transparent]/[backcolor=transparent]1[backcolor=transparent]       alexellis2[backcolor=transparent]/[backcolor=transparent]faas[backcolor=transparent]-[backcolor=transparent]dockerhubstats[backcolor=transparent]:[backcolor=transparent]latest
10. [backcolor=transparent] q8rx49ow3may  func_echoit        replicated  [backcolor=transparent]1[backcolor=transparent]/[backcolor=transparent]1[backcolor=transparent]       functions[backcolor=transparent]/[backcolor=transparent]alpine[backcolor=transparent]:[backcolor=transparent]health
11. [backcolor=transparent] t1ao5psnsj0s  func_base64        replicated  [backcolor=transparent]1[backcolor=transparent]/[backcolor=transparent]1[backcolor=transparent]       functions[backcolor=transparent]/[backcolor=transparent]alpine[backcolor=transparent]:[backcolor=transparent]health
12. [backcolor=transparent] vj5z7rpdlo48  func_prometheus    replicated  [backcolor=transparent]1[backcolor=transparent]/[backcolor=transparent]1[backcolor=transparent]       functions[backcolor=transparent]/[backcolor=transparent]prometheus[backcolor=transparent]:[backcolor=transparent]latest
13. [backcolor=transparent] xmwzd4z7l4dv  func_nodeinfo      replicated  [backcolor=transparent]1[backcolor=transparent]/[backcolor=transparent]1[backcolor=transparent]       functions[backcolor=transparent]/[backcolor=transparent]nodeinfo[backcolor=transparent]:[backcolor=transparent]latest

• 默认情况下，您最多可以创建 5 个集群（所有地域下），每个集群中最多可以添加 20 个节点。如果您需要创建更多的集群或添加更多的节点，请提交 工单申请。
• 随集群一同创建的负载均衡实例只支持按量付费的方式。
• 用户账户需有 100 元的余额并通过实名认证，否则无法创建按量付费的 ECS 实例和负载均衡。

1. 
   创建 Swarm mode 集群。 FaaS 基于Docker Swarm mode集群进行部署的，您首先需要在阿里云容器服务创建一个 Swarm mode 集群。
   
2. 
   使用编排模板创建应用，参见 使用编排模板创建应用。
   编排示例如下：[backcolor=transparent] version[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"3"
3. [backcolor=transparent] services[backcolor=transparent]:
5. [backcolor=transparent] [backcolor=transparent]# Core API services are pinned, HA is provided for functions.
6. [backcolor=transparent]     gateway[backcolor=transparent]:
7. [backcolor=transparent]         volumes[backcolor=transparent]:
8. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] [backcolor=transparent]"/var/run/docker.sock:/var/run/docker.sock"
9. [backcolor=transparent]         ports[backcolor=transparent]:
10. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] [backcolor=transparent]8080[backcolor=transparent]:[backcolor=transparent]8080
11. [backcolor=transparent]         labels[backcolor=transparent]:
12. [backcolor=transparent]             aliyun[backcolor=transparent].[backcolor=transparent]routing[backcolor=transparent].[backcolor=transparent]port_8080[backcolor=transparent]:[backcolor=transparent] faas
13. [backcolor=transparent]         image[backcolor=transparent]:[backcolor=transparent] functions[backcolor=transparent]/[backcolor=transparent]gateway[backcolor=transparent]:[backcolor=transparent]0.5[backcolor=transparent].[backcolor=transparent]6
14. [backcolor=transparent]         networks[backcolor=transparent]:
15. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] functions
16. [backcolor=transparent]         environment[backcolor=transparent]:
17. [backcolor=transparent]             dnsrr[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"true"[backcolor=transparent]  [backcolor=transparent]# Temporarily use dnsrr in place of VIP while issue persists on PWD
18. [backcolor=transparent]         deploy[backcolor=transparent]:
19. [backcolor=transparent]             placement[backcolor=transparent]:
20. [backcolor=transparent]                 constraints[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent][[backcolor=transparent]node[backcolor=transparent].[backcolor=transparent]role [backcolor=transparent]==[backcolor=transparent] manager[backcolor=transparent]]
22. [backcolor=transparent]     prometheus[backcolor=transparent]:
23. [backcolor=transparent]         image[backcolor=transparent]:[backcolor=transparent] functions[backcolor=transparent]/[backcolor=transparent]prometheus[backcolor=transparent]:[backcolor=transparent]latest  [backcolor=transparent]# autobuild from Dockerfile in repo.
24. [backcolor=transparent]         command[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"-config.file=/etc/prometheus/prometheus.yml -storage.local.path=/prometheus -storage.local.memory-chunks=10000 --alertmanager.url=http://alertmanager:9093"
25. [backcolor=transparent]         ports[backcolor=transparent]:
26. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] [backcolor=transparent]9090[backcolor=transparent]:[backcolor=transparent]9090
27. [backcolor=transparent]         depends_on[backcolor=transparent]:
28. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] gateway
29. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] alertmanager
30. [backcolor=transparent]         labels[backcolor=transparent]:
31. [backcolor=transparent]             aliyun[backcolor=transparent].[backcolor=transparent]routing[backcolor=transparent].[backcolor=transparent]port_9090[backcolor=transparent]:[backcolor=transparent] prometheus
32. [backcolor=transparent]         environment[backcolor=transparent]:
33. [backcolor=transparent]             no_proxy[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"gateway"
34. [backcolor=transparent]         networks[backcolor=transparent]:
35. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] functions
36. [backcolor=transparent]         deploy[backcolor=transparent]:
37. [backcolor=transparent]             placement[backcolor=transparent]:
38. [backcolor=transparent]                 constraints[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent][[backcolor=transparent]node[backcolor=transparent].[backcolor=transparent]role [backcolor=transparent]==[backcolor=transparent] manager[backcolor=transparent]]
40. [backcolor=transparent]     alertmanager[backcolor=transparent]:
41. [backcolor=transparent]         image[backcolor=transparent]:[backcolor=transparent] functions[backcolor=transparent]/[backcolor=transparent]alertmanager[backcolor=transparent]:[backcolor=transparent]latest    [backcolor=transparent]# autobuild from Dockerfile in repo.
42. [backcolor=transparent]         environment[backcolor=transparent]:
43. [backcolor=transparent]             no_proxy[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"gateway"
44. [backcolor=transparent]         command[backcolor=transparent]:
45. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] [backcolor=transparent]'-config.file=/alertmanager.yml'
46. [backcolor=transparent]         networks[backcolor=transparent]:
47. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] functions
48. [backcolor=transparent]         ports[backcolor=transparent]:
49. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] [backcolor=transparent]9093[backcolor=transparent]:[backcolor=transparent]9093
50. [backcolor=transparent]         deploy[backcolor=transparent]:
51. [backcolor=transparent]             placement[backcolor=transparent]:
52. [backcolor=transparent]                 constraints[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent][[backcolor=transparent]node[backcolor=transparent].[backcolor=transparent]role [backcolor=transparent]==[backcolor=transparent] manager[backcolor=transparent]]
54. [backcolor=transparent]     [backcolor=transparent]# Sample functions go here.
56. [backcolor=transparent]     [backcolor=transparent]# Service label of "function" allows functions to show up in UI on http://gateway:8080/
57. [backcolor=transparent]     webhookstash[backcolor=transparent]:
58. [backcolor=transparent]         image[backcolor=transparent]:[backcolor=transparent] functions[backcolor=transparent]/[backcolor=transparent]webhookstash[backcolor=transparent]:[backcolor=transparent]latest
59. [backcolor=transparent]         labels[backcolor=transparent]:
60. [backcolor=transparent]             [backcolor=transparent]function[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"true"
61. [backcolor=transparent]         depends_on[backcolor=transparent]:
62. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] gateway
63. [backcolor=transparent]         networks[backcolor=transparent]:
64. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] functions
65. [backcolor=transparent]         environment[backcolor=transparent]:
66. [backcolor=transparent]             no_proxy[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"gateway"
67. [backcolor=transparent]             https_proxy[backcolor=transparent]:[backcolor=transparent] $https_proxy
69. [backcolor=transparent]     [backcolor=transparent]# Pass a username as an argument to find how many images user has pushed to Docker Hub.
70. [backcolor=transparent]     hubstats[backcolor=transparent]:
71. [backcolor=transparent]         image[backcolor=transparent]:[backcolor=transparent] alexellis2[backcolor=transparent]/[backcolor=transparent]faas[backcolor=transparent]-[backcolor=transparent]dockerhubstats[backcolor=transparent]:[backcolor=transparent]latest
72. [backcolor=transparent]         labels[backcolor=transparent]:
73. [backcolor=transparent]             [backcolor=transparent]function[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"true"
74. [backcolor=transparent]         depends_on[backcolor=transparent]:
75. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] gateway
76. [backcolor=transparent]         networks[backcolor=transparent]:
77. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] functions
78. [backcolor=transparent]         environment[backcolor=transparent]:
79. [backcolor=transparent]             no_proxy[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"gateway"
80. [backcolor=transparent]             https_proxy[backcolor=transparent]:[backcolor=transparent] $https_proxy
82. [backcolor=transparent]     [backcolor=transparent]# Node.js gives OS info about the node (Host)
83. [backcolor=transparent]     nodeinfo[backcolor=transparent]:
84. [backcolor=transparent]         image[backcolor=transparent]:[backcolor=transparent] functions[backcolor=transparent]/[backcolor=transparent]nodeinfo[backcolor=transparent]:[backcolor=transparent]latest
85. [backcolor=transparent]         labels[backcolor=transparent]:
86. [backcolor=transparent]             [backcolor=transparent]function[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"true"
87. [backcolor=transparent]         depends_on[backcolor=transparent]:
88. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] gateway
89. [backcolor=transparent]         networks[backcolor=transparent]:
90. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] functions
91. [backcolor=transparent]         environment[backcolor=transparent]:
92. [backcolor=transparent]             no_proxy[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"gateway"
93. [backcolor=transparent]             https_proxy[backcolor=transparent]:[backcolor=transparent] $https_proxy
95. [backcolor=transparent]     [backcolor=transparent]# Uses `cat` to echo back response, fastest function to execute.
96. [backcolor=transparent]     echoit[backcolor=transparent]:
97. [backcolor=transparent]         image[backcolor=transparent]:[backcolor=transparent] functions[backcolor=transparent]/[backcolor=transparent]alpine[backcolor=transparent]:[backcolor=transparent]health
98. [backcolor=transparent]         labels[backcolor=transparent]:
99. [backcolor=transparent]             [backcolor=transparent]function[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"true"
100. [backcolor=transparent]         depends_on[backcolor=transparent]:
101. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] gateway
102. [backcolor=transparent]         networks[backcolor=transparent]:
103. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] functions
104. [backcolor=transparent]         environment[backcolor=transparent]:
105. [backcolor=transparent]             fprocess[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"cat"
106. [backcolor=transparent]             no_proxy[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"gateway"
107. [backcolor=transparent]             https_proxy[backcolor=transparent]:[backcolor=transparent] $https_proxy
109. [backcolor=transparent]     [backcolor=transparent]# Counts words in request with `wc` utility
110. [backcolor=transparent]     wordcount[backcolor=transparent]:
111. [backcolor=transparent]         image[backcolor=transparent]:[backcolor=transparent] functions[backcolor=transparent]/[backcolor=transparent]alpine[backcolor=transparent]:[backcolor=transparent]health
112. [backcolor=transparent]         labels[backcolor=transparent]:
113. [backcolor=transparent]             [backcolor=transparent]function[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"true"
114. [backcolor=transparent]             com[backcolor=transparent].[backcolor=transparent]faas[backcolor=transparent].[backcolor=transparent]max_replicas[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"10"
115. [backcolor=transparent]         depends_on[backcolor=transparent]:
116. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] gateway
117. [backcolor=transparent]         networks[backcolor=transparent]:
118. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] functions
119. [backcolor=transparent]         environment[backcolor=transparent]:
120. [backcolor=transparent]             fprocess[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"wc"
121. [backcolor=transparent]             no_proxy[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"gateway"
122. [backcolor=transparent]             https_proxy[backcolor=transparent]:[backcolor=transparent] $https_proxy
124. [backcolor=transparent]     [backcolor=transparent]# Calculates base64 representation of request body.
125. [backcolor=transparent]     base64[backcolor=transparent]:
126. [backcolor=transparent]         image[backcolor=transparent]:[backcolor=transparent] functions[backcolor=transparent]/[backcolor=transparent]alpine[backcolor=transparent]:[backcolor=transparent]health
127. [backcolor=transparent]         labels[backcolor=transparent]:
128. [backcolor=transparent]             [backcolor=transparent]function[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"true"
129. [backcolor=transparent]         depends_on[backcolor=transparent]:
130. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] gateway
131. [backcolor=transparent]         networks[backcolor=transparent]:
132. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] functions
133. [backcolor=transparent]         environment[backcolor=transparent]:
134. [backcolor=transparent]             fprocess[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"base64"
135. [backcolor=transparent]             no_proxy[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"gateway"
136. [backcolor=transparent]             https_proxy[backcolor=transparent]:[backcolor=transparent] $https_proxy
138. [backcolor=transparent]     [backcolor=transparent]# Decodes base64 representation of request body.
139. [backcolor=transparent]     decodebase64[backcolor=transparent]:
140. [backcolor=transparent]         image[backcolor=transparent]:[backcolor=transparent] functions[backcolor=transparent]/[backcolor=transparent]alpine[backcolor=transparent]:[backcolor=transparent]health
141. [backcolor=transparent]         labels[backcolor=transparent]:
142. [backcolor=transparent]             [backcolor=transparent]function[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"true"
143. [backcolor=transparent]         depends_on[backcolor=transparent]:
144. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] gateway
145. [backcolor=transparent]         networks[backcolor=transparent]:
146. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] functions
147. [backcolor=transparent]         environment[backcolor=transparent]:
148. [backcolor=transparent]             fprocess[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"base64 -d"
149. [backcolor=transparent]             no_proxy[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"gateway"
150. [backcolor=transparent]             https_proxy[backcolor=transparent]:[backcolor=transparent] $https_proxy
152. [backcolor=transparent]     [backcolor=transparent]# Converts body in (markdown format) -> (html)
153. [backcolor=transparent]     markdown[backcolor=transparent]:
154. [backcolor=transparent]         image[backcolor=transparent]:[backcolor=transparent] alexellis2[backcolor=transparent]/[backcolor=transparent]faas[backcolor=transparent]-[backcolor=transparent]markdownrender[backcolor=transparent]:[backcolor=transparent]latest
155. [backcolor=transparent]         labels[backcolor=transparent]:
156. [backcolor=transparent]             [backcolor=transparent]function[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"true"
157. [backcolor=transparent]         depends_on[backcolor=transparent]:
158. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] gateway
159. [backcolor=transparent]         networks[backcolor=transparent]:
160. [backcolor=transparent]             [backcolor=transparent]-[backcolor=transparent] functions
161. [backcolor=transparent]         environment[backcolor=transparent]:
162. [backcolor=transparent]             no_proxy[backcolor=transparent]:[backcolor=transparent] [backcolor=transparent]"gateway"
163. [backcolor=transparent]             https_proxy[backcolor=transparent]:[backcolor=transparent] $https_proxy
165. [backcolor=transparent] networks[backcolor=transparent]:
166. [backcolor=transparent]     functions[backcolor=transparent]:
167. [backcolor=transparent]         driver[backcolor=transparent]:[backcolor=transparent] overlay

• aliyun.routing.port_8080: faas : API Gatway 的虚拟域名
• aliyun.routing.port_9090: prometheus: prometheus 服务的虚拟域名

• 夏日清风 - 基于 Docker Swarm 的极简 Serverless 实践
• 开源 github 项目地址