案例场景
下面,我们创建一个经典的 Web 项目:一个 Haproxy,挂载三个 Web 容器。
创建一个 compose-haproxy-web 目录,作为项目工作目录,并在其中分别创建两个子目录: haproxy 和 web 。
web 子目录
这里用 Python 程序来提供一个简单的 HTTP 服务,打印出访问者的 IP 和 实际的本地 IP。
index.py
编写一个 index.py 作为服务器文件,代码为
root@node5 web]# vi index.py
#!/usr/bin/python
#authors: yeasy.github.com
#date: 2013-07-05
import sys
import BaseHTTPServer
from SimpleHTTPServer import SimpleHTTPRequestHandler
import socket
import fcntl
import struct
import pickle
from datetime import datetime
from collections import OrderedDict
class HandlerClass(SimpleHTTPRequestHandler):
def get_ip_address(self,ifname):
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
return socket.inet_ntoa(fcntl.ioctl(
s.fileno(),
0x8915, # SIOCGIFADDR
struct.pack('256s', ifname[:15])
)[20:24])
def log_message(self, format, *args):
if len(args) < 3 or "200" not in args[1]:
return
try:
request = pickle.load(open("pickle_data.txt","r"))
except:
request=OrderedDict()
time_now = datetime.now()
ts = time_now.strftime('%Y-%m-%d %H:%M:%S')
server = self.get_ip_address('eth0')
host=self.address_string()
addr_pair = (host,server)
if addr_pair not in request:
request[addr_pair]=[1,ts]
else:
num = request[addr_pair][0]+1
del request[addr_pair]
request[addr_pair]=[num,ts]
file=open("index.html", "w")
file.write("<!DOCTYPE html> <html> <body><center><h1><font color=\"blue\" face=\"Georgia, Arial\" size=8><em>HA</em></font> Webpage Visit Results</h1></center>")
for pair in request:
if pair[0] == host:
guest = "LOCAL: "+pair[0]
else:
guest = pair[0]
if (time_now-datetime.strptime(request[pair][1],'%Y-%m-%d %H:%M:%S')).seconds < 3:
file.write("<p style=\"font-size:150%\" >#"+ str(request[pair][1]) +":<font color=\"red\">"+str(request[pair][0])+ "</font> requests " + "from <<font color=\"blue\">"+guest+"</font>> to WebServer <<font color=\"blue\">"+pair[1]+"</font>></p>")
else:
file.write("<p style=\"font-size:150%\" >#"+ str(request[pair][1]) +":<font color=\"maroon\">"+str(request[pair][0])+ "</font> requests " + "from <<font color=\"navy\">"+guest+"</font>> to WebServer <<font color=\"navy\">"+pair[1]+"</font>></p>")
file.write("</body> </html>")
file.close()
pickle.dump(request,open("pickle_data.txt","w"))
if __name__ == '__main__':
try:
ServerClass = BaseHTTPServer.HTTPServer
Protocol = "HTTP/1.0"
addr = len(sys.argv) < 2 and "0.0.0.0" or sys.argv[1]
port = len(sys.argv) < 3 and 80 or int(sys.argv[2])
HandlerClass.protocol_version = Protocol
httpd = ServerClass((addr, port), HandlerClass)
sa = httpd.socket.getsockname()
print "Serving HTTP on", sa[0], "port", sa[1], "..."
httpd.serve_forever()
except:
exit()
index.html
生成一个临时的 index.html 文件,其内容会被 index.py 更新。
[root@node5 web]# touch index.html
编写 Dockerfile 文件,内容为
[root@node5 web]# vi Dockerfile
FROM python:2.7
WORKDIR /code
ADD . /code
EXPOSE 80
CMD python index.py
haproxy 目录
编写 haproxy.cfg 文件,内容为
[root@node5 haproxy]# vi haproxy.cfg
global
log 127.0.0.1 local0
log 127.0.0.1 local1 notice
defaults
log global
mode http
option httplog
option dontlognull
timeout connect 5000ms
timeout client 50000ms
timeout server 50000ms
listen stats
bind 0.0.0.0:70
stats enable
stats uri /
frontend balancer
bind 0.0.0.0:80
mode http
default_backend web_backends
backend web_backends
mode http
option forwardfor
balance roundrobin
server weba weba:80 check
server webb webb:80 check
server webc webc:80 check
option httpchk GET /
http-check expect status 200
docker-compose.yml
编写 docker-compose.yml 文件,这个是 Compose 使用的主模板文件。内容十分简单,指定
3 个 web 容器,以及 1 个 haproxy 容器。
[root@node5 compose-haproxy-web]# vi docker-compose.yml
version: "3"
services:
weba:
build: ./web
expose:
- 80
webb:
build: ./web
expose:
- 80
webc:
build: ./web
expose:
- 80
haproxy:
image: haproxy:latest
volumes:
- ./haproxy:/haproxy-override
- ./haproxy/haproxy.cfg:/usr/local/etc/haproxy/haproxy.cfg:ro
ports:
- "80:80"
- "70:70"
expose:
- "80"
- "70"
运行 compose 项目
现在 compose-haproxy-web 目录结构如下:
[root@node5 compose-haproxy-web]# tree
.
├── docker-compose.yml
├── haproxy
│ └── haproxy.cfg
└── web
├── Dockerfile
├── index.html
└── index.py
在该目录下执行 docker-compose up 命令,会整合输出所有容器的输出。
[root@node5 compose-haproxy-web]# docker-compose up
Recreating composehaproxyweb_webb_1...
Recreating composehaproxyweb_webc_1...
Recreating composehaproxyweb_weba_1...
Recreating composehaproxyweb_haproxy_1...
Attaching to composehaproxyweb_webb_1, composehaproxyweb_webc_1,composehaproxyweb_web
a_1, composehaproxyweb_haproxy_1
此时访问本地的80端口,会经过haproxy自动转发到后端的某个web容器上,刷新页面,可以观察到访问的容器地址的变化。
访问本地 70 端口,可以查看到 haproxy 的统计信息。