我们对Linkerd——本地运行完整案例，进行进一步的扩展，支持负载均衡。

新建两个微服务

两个微服务在同一个目录下，相当于一个服务启动了两个实例。目录结构如下：
+microservice
-response.json
-response1.json

• response.json

{"name":"James","nation":"china","msg":"Hello World."}

启动服务：

$ python -m http.server 9999

• response1.json

{"name":"Charlse","nation":"china","msg":"Hello beijing."}

启动服务：

$ python -m http.server 9099

新建两个客户端服务

每个客户端负责调用一个微服务。

• request.py

import requests
import threading,time

class SendRequest(threading.Thread):
  def __init__(self,interval,count):
    threading.Thread.__init__(self)
    self.interval = interval
    self.count = count
  def run(self):
    try:
      url = "http://localhost:4140/response.json"
      headers={"Host":"web"}
      result = requests.get(url,headers=headers)
      print(time.strftime('%Y-%m-%d %X',time.localtime())+" - "+str(self.count)+" - "+result.text)
      self.count = self.count+1 
    except Exception as e:
      print(e)
    finally:
      SendRequest(self.interval,self.count).start()

if __name__ == '__main__':
  count = 1
  SendRequest(0.1,count).start()

• request1.py

import requests
import threading,time

class SendRequest(threading.Thread):
  def __init__(self,interval,count):
    threading.Thread.__init__(self)
    self.interval = interval
    self.count = count
  def run(self):
    try:
      url = "http://localhost:4140/response1.json"
      headers={"Host":"web"}
      result = requests.get(url,headers=headers)
      print(time.strftime('%Y-%m-%d %X',time.localtime())+" - "+str(self.count)+" - "+result.text)
      self.count = self.count+1 
    except Exception as e:
      print(e)
    finally:
      SendRequest(self.interval,self.count).start()

if __name__ == '__main__':
  count = 1
  SendRequest(0.1,count).start()

启动客户端

$ python request.py
$ python request1.py

最后看linkerd负载均衡配置

• 首先配置disco/web

127.0.0.1 9999
127.0.0.1 9099

• 再配置config/linkerd.yaml

routers:
- protocol: http
  dtab: |
    /wadd => /#/io.l5d.fs;
    /svc => /wadd/web
  httpAccessLog: logs/access.log
  label: web
  servers:
  - port: 4140
    ip: 0.0.0.0
  client:
    failureAccrual:
      kind: io.l5d.successRate
      successRate: 0.99
      requests: 1000
    loadBalancer:
      kind: p2c
      maxEffort: 5

这里loadBalancer算法采用的是p2c（其实默认是p2c，不用特别配置），你也可以配置成别的，参考官方文档。

启动linkerd

admin UI

火狐截图_2017-12-26T11-26-06.439Z.png

微服务后台日志

我启动了三个request1.py客户端，所以看起来后台response1.json多一些

127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -
127.0.0.1 - - [26/Dec/2017 19:27:33] "GET /response1.json HTTP/1.1" 200 -