Load Balancing with Nginx and Docker
这次利用Docker建立3个Containers， 分别是 Nginx，Django + uWSGI， Postgres (https://github.com/zengtian006/Load-Balancing-with-Nginx-and-Docker)
主要说有一下Nignx 里面的Dockerfile
FROM nginx:latest
//先將 nginx.conf 複製到 /etc/nginx/nginx.conf 的路徑
COPY nginx.conf /etc/nginx/nginx.conf
//將 my_nginx.conf 複製到 /etc/nginx/sites-available/ 裡面
COPY my_nginx.conf /etc/nginx/sites-available/
//將 sites-enabled 以及 my_nginx.conf 連結起來。
RUN mkdir -p /etc/nginx/sites-enabled/\
&& ln -s /etc/nginx/sites-available/my_nginx.conf /etc/nginx/sites-enabled/
CMD ["nginx", "-g", "daemon off;"]
nginx.conf
更改了两个地方
1, user root;
2,
# include /etc/nginx/conf.d/*.conf;
include /etc/nginx/sites-available/*;
另外一个重要的文件 my_nginx.conf
# the upstream component nginx needs to connect to
upstream uwsgi {
# server api:8001; # use TCP
server demo_api_1:8001 weight=4; # use TCP
server demo_api_2:8001 weight=6; # use TCP
}
# configuration of the server
server {
# the port your site will be served on
listen 80;
# index index.html;
# the domain name it will serve for
# substitute your machine's IP address or FQDN
server_name tim.com www.tim.com;
charset utf-8;
client_max_body_size 75M; # adjust to taste
# Django media
# location /media {
# alias /docker_api/static/media; # your Django project's media files - amend as required
# }
location /static {
alias /docker_api/static; # your Django project's static files - amend as required
}
location / {
uwsgi_pass uwsgi;
include /etc/nginx/uwsgi_params; # the uwsgi_params file you installed
}
}
####Nginx 主要的 Load balance 有三种
round-robin — requests to the application servers are distributed in a round-robin fashion
使用轮询的方式，也可以加上 weight 权重，让比较强的 Server 承受比较大的压力（ weight 设定高一点）。
least-connected — next request is assigned to the server with the least number of active connections
此种方式，Nginx 会将请求给负载 Loading 较轻的 Server，避免负载（A Server） Loading 已经很大了，还将请求交给 A Server 处理。
ip-hash — a hash-function is used to determine what server should be selected for the next request (based on the client’s IP address)
不管是 round-robin 还是 least-connected 的 Load balance ，每个 User 送出的请求都可能会被分到不同的
Server，并不能保证同一个 User 每次的请求都一定会连到同一台 Server， 因为这个原因，於是有了 ip-hash，
透过这个方法，会使用 ip 的方式将同一个 User 的请求都导到同一台 Server （除非这台 Server 掛了 ）
介绍完了 Nginx 主要的三种 Load balance 演算法，至於要使用哪一种，就看你自己的需求了
更多范例以及详细的说明可参考官网 http://nginx.org/en/docs/http/load_balancing.html
uwsgi.ini
[uwsgi]
# http=0.0.0.0:8000
socket=:8001
master=true
# maximum number of worker processes
processes=4
threads=2
# Django's wsgi file
module=demo.wsgi:application
# chmod-socket=664
# uid=www-data
# gid=www-data
# clear environment on exit
vacuum = true
设定完成后, 建立新的image docker-compose build
执行启动Dokcerdocker-compose up -d --scale api=2