acs/proxy

自定义代理镜像，通过FROM dockercloud/haproxy的方式继承自镜像dockercloud/haproxy，动态感知容器的状态，做到后端容器负载均衡代理和服务发现。特点是将HAProxy负载均衡软件的所有配置都参数化了，方便用户自定义自己的需求和配置。该镜像的主要用于aliyun容器服务的默认路由服务不能满足用户的场景，方便用户对HAProxy进行自定义配置。

动态负载均衡代理和服务发现的原理

• 镜像acs/proxy通过容器自身环境变量确定负载均衡的全局(GLOBAL)和默认(DEFAULT)的配置
• 镜像acs/proxy侦听集群中的事件，例如容器状态的变化，发生变化后重新获取集群中相关容器的信息，确定最新的负载均衡配置
• 镜像acs/proxy根据最新的负载均衡配置去重新加载（reload）该配置，使得该配置生效。

如何确定负载均衡的后端容器

• 根据acs/proxy的环境变量ADDITIONAL_SERVICES来确定范围
  • ADDITIONAL_SERVICES: “*” # 范围为整个集群
  • ADDITIONAL_SERVICES: “project_name1:service_name1,project_name2:service_name2” # 范围为当前应用和指定应用的指定服务
  • ADDITIONAL_SERVICES 不设置或者为空 # 范围为当前应用的容器
• 根据每个容器的标签来确定是否加入acs/proxy的后端。
  • aliyun.proxy.VIRTUAL_HOST: “www.toolchainx.com” # 加入后端，且域名为www.toolchainx.com
  • aliyun.proxy.required: “true” # 加入后端，且作为默认的后端

如何在前端绑定SLB

• 使用自定义SLB标签，例如：aliyun.lb.port_80: ‘tcp://proxy:80’

示例模板

lb:
  image: registry.aliyuncs.com/acs/proxy:0.5
  ports:
   - '80:80'
  restart: always
  labels:
    aliyun.addon: "proxy"
    aliyun.global: "true"
    aliyun.lb.port_80: tcp://proxy:80
  environment:
    ADDITIONAL_SERVICES: "*"
web:
  image: registry.aliyuncs.com/acs-sample/wordpress:4.5
  ports:
    - '80'
  environment:
    WORDPRESS_AUTH_KEY: changeme
    WORDPRESS_SECURE_AUTH_KEY: changeme
    WORDPRESS_LOGGED_IN_KEY: changeme
    WORDPRESS_NONCE_KEY: changeme
    WORDPRESS_AUTH_SALT: changeme
    WORDPRESS_SECURE_AUTH_SALT: changeme
    WORDPRESS_LOGGED_IN_SALT: changeme
    WORDPRESS_NONCE_SALT: changeme
    WORDPRESS_NONCE_AA: changeme
  restart: always
  links:
    - 'db:mysql'
  labels:
    aliyun.logs: /var/log
    aliyun.probe.url: http://container/license.txt
    aliyun.probe.initial_delay_seconds: '10'
    aliyun.proxy.VIRTUAL_HOST: www.toolchainx.com
    aliyun.scale: '3'
db:
  image: registry.aliyuncs.com/acs-sample/mysql:5.7
  environment:
    MYSQL_ROOT_PASSWORD: password
  restart: always
  labels:
    aliyun.logs: /var/log/mysql

配置说明

通过acs/proxy镜像的环境变量设置全局（GLOBAL）和默认（DEFAULT）的配置

Settings in this part is immutable, you have to redeploy HAProxy service to make the changes take effects

被代理的后端服务通过相应服务镜像的标签（LABEL）进行某一后端服务的配置

即通过将标签（LABEL）写到后端服务的镜像上面来配置
Settings here can overwrite the settings in HAProxy, which are only applied to the linked services. If run in Docker Cloud, when the service redeploys, joins or leaves HAProxy service, HAProxy service will automatically update itself to apply the changes

Check the HAProxy configuration manual for more information on the above.

Virtual host and virtual path

Both virtual host and virtual path can be specified in environment variable VIRTUAL_HOST, which is a set of comma separated urls with the format of [scheme://]domain[:port][/path].

examples of matching

Note:

1. The sequence of the acl rules generated based on VIRTUAL_HOST are random. In HAProxy, when an acl rule with a wide scope(e.g. *.domain.com) is put before a rule with narrow scope(e.g. web.domain.com), the narrow rule will never be reached. As a result, if the virtual hosts you set have overlapping scopes, you need to use VIRTUAL_HOST_WEIGHT to manually set the order of acl rules, namely, giving the narrow virtual host a higher weight than the wide one.
2. Every service that has the same VIRTUAL_HOST environment variable setting will be considered and merged into one single service. It may be useful for some testing scenario.

SSL termination

acs/proxy supports ssl termination on multiple certificates. For each application that you want ssl terminates, simply set SSL_CERT and VIRTUAL_HOST. HAProxy, then, reads the certificate from the link environment and sets the ssl termination up.

Attention: there was a bug that if an environment variable value contains “=”, which is common in the SSL_CERT, docker skips that environment variable. As a result, multiple ssl termination only works on docker 1.7.0 or higher.

SSL termination is enabled when:

1. at least one SSL certificate is set, and
2. either VIRTUAL_HOST is not set, or it is set with “https” as the scheme.

To set SSL certificate, you can either:

1. set DEFAULT_SSL_CERT in acs/proxy, or
2. set aliyun.proxy.SSL_CERT and/or DEFAULT_SSL_CERT in the application services linked to HAProxy

The difference between aliyun.proxy.SSL_CERT and DEFAULT_SSL_CERT is that, the multiple certificates specified by SSL_CERT are stored in as cert1.pem, cert2.pem, …, whereas the one specified by DEFAULT_SSL_CERT is always stored as cert0.pem. In that case, HAProxy will use cert0.pem as the default certificate when there is no SNI match. However, when multiple DEFAULT_SSL_CERTIFICATE is provided, only one of the certificates can be stored as cert0.pem, others are discarded.

PEM Files

The certificate specified in acs/proxy or in the linked application services is a pem file, containing a private key followed by a public certificate(private key must be put before the public certificate and any extra Authority certificates, order matters). You can run the following script to generate a self-signed certificate:

openssl req -x509 -newkey rsa:2048 -keyout key.pem -out ca.pem -days 1080 -nodes -subj '/CN=*/O=My Company Name LTD./C=US'
cp key.pem cert.pem
cat ca.pem >> cert.pem

Once you have the pem file, you can run this command to convert the file correctly to one line:

awk 1 ORS='\\n' cert.pem

Copy the output and set it as the value of aliyun.proxy.SSL_CERT or DEFAULT_SSL_CERT.

Affinity and session stickiness

There are three method to setup affinity and sticky session:

1. set aliyun.proxy.BALANCE=source in your application service. When setting source method of balance, HAProxy will hash the client IP address and make sure that the same IP always goes to the same server.
2. set aliyun.proxy.APPSESSION=<value>. use application session to determine which server a client should connect to. Possible value of <value> could be JSESSIONID len 52 timeout 3h
3. set aliyun.proxy.COOKIE=<value>. use application cookie to determine which server a client should connect to. Possible value of <value> could be SRV insert indirect nocache

Check HAProxy:appsession and HAProxy:cookie for more information.

TCP load balancing

By default, acs/proxy runs in http mode. If you want a linked service to run in a tcp mode, you can specify the environment variable TCP_PORTS, which is a comma separated ports(e.g. 9000, 9001).

For example, if you run:

docker --name app-1 --expose 9000 --expose 9001 -e TCP_PORTS="9000, 9001" your_app
docker --name app-2 --expose 9000 --expose 9001 -e TCP_PORTS="9000, 9001" your_app
docker run --link app-1:app-1 --link app-2:app-2 -p 9000:9000, 9001:9001 acs/proxy

Then, haproxy balances the load between app-1 and app-2 in both port 9000 and 9001 respectively.

Moreover, If you have more exposed ports than TCP_PORTS, the rest of the ports will be balancing using http mode.

For example, if you run:

docker --name app-1 --expose 80 --expose 22 -e TCP_PORTS=22 your_app
docker --name app-2 --expose 80 --expose 22 -e TCP_PORTS=22 your_app
docker run --link app-1:app-2 --link app-2:app-2 -p 80:80 -p 22:22 acs/proxy

Then, haproxy balances in http mode at port 80 and balances in tcp on port at port 22.

In this way, you can do the load balancing both in tcp and in http at the same time.

In TCP_PORTS, if you set port that ends with ‘/ssl’, for example 2222/ssl, HAProxy will set ssl termination on port 2222.

Note:

1. You are able to set VIRTUAL_HOST and TCP_PORTS at the same them, giving more control on http mode.
2. Be careful that, the load balancing on tcp port is applied to all the services. If you link two(or more) different services using the same TCP_PORTS, acs/proxy considers them coming from the same service.

WebSocket support

There are two ways to enable the support of websocket:

1. As websocket starts using HTTP protocol, you can use virtual host to specify the scheme using ws or wss. For example, `-e VIRTUAL_HOST=”ws://ws.domain.com, wss://wss.domain.com”
2. Websocket itself is a TCP connection, you can also try the TCP load balancing mentioned in the previous section.

Use case scenarios

My webapp container exposes port 8080(or any other port), and I want the proxy to listen in port 80

Use the following:

docker run -d --expose 80 --name webapp dockercloud/hello-world
docker run -d --link webapp:webapp -p 80:80 acs/proxy

My webapp container exposes port 80 and database ports 8083/8086, and I want the proxy to listen in port 80 without my database ports added to haproxy

docker run -d -e EXCLUDE_PORTS=8803,8806 --expose 80 --expose 8033 --expose 8086 --name webapp dockercloud/hello-world
docker run -d --link webapp:webapp -p 80:80 acs/proxy

My webapp container exposes port 8080(or any other port), and I want the proxy to listen in port 8080

Use the following:

docker run -d --expose 8080 --name webapp your_app
docker run -d --link webapp:webapp -p 8080:80 acs/proxy

I want the proxy to terminate SSL connections and forward plain HTTP requests to my webapp to port 8080(or any port)

Use the following:

docker run -d -e SSL_CERT="YOUR_CERT_TEXT" --name webapp dockercloud/hello-world
docker run -d --link webapp:webapp -p 443:443 -p 80:80 acs/proxy

or

docker run -d --link webapp:webapp -p 443:443 -p 80:80 -e DEFAULT_SSL_CERT="YOUR_CERT_TEXT" acs/proxy

The certificate in YOUR_CERT_TEXT is a combination of private key followed by public certificate. Remember to put \n between each line of the certificate. A way to do this, assuming that your certificate is stored in ~/cert.pem, is running the following:

docker run -d --link webapp:webapp -p 443:443 -p 80:80 -e DEFAULT_SSL_CERT="$(awk 1 ORS='\\n' ~/cert.pem)" acs/proxy

I want the proxy to terminate SSL connections and redirect HTTP requests to HTTPS

Use the following:

docker run -d -e FORCE_SSL=yes -e SSL_CERT="YOUR_CERT_TEXT" --name webapp dockercloud/hello-world
docker run -d --link webapp:webapp -p 443:443 acs/proxy

I want to load my SSL certificate from volume instead of passing it through environment variable

You can use CERT_FOLDER envvar to specify which folder the certificates are mounted in the container, using the following:

docker run -d --name webapp dockercloud/hello-world
docker run -d --link webapp:webapp -e CERT_FOLDER="/certs/" -v $(pwd)/cert1.pem:/certs/cert1.pem -p 443:443 acs/proxy

I want to set up virtual host routing by domain

Virtual hosts can be configured by the proxy reading linked container environment variables (VIRTUAL_HOST). Here is an example:

docker run -d -e VIRTUAL_HOST="www.webapp1.com, www.webapp1.org" --name webapp1 dockercloud/hello-world
docker run -d -e VIRTUAL_HOST=www.webapp2.com --name webapp2 your/webapp2
docker run -d --link webapp1:webapp1 --link webapp2:webapp2 -p 80:80 acs/proxy

In the example above, when you access http://www.webapp1.com or http://www.webapp1.org, it will show the service running in container webapp1, and http://www.webapp2.com will go to container webapp2.

If you use the following:

docker run -d -e VIRTUAL_HOST=www.webapp1.com --name webapp1 dockercloud/hello-world
docker run -d -e VIRTUAL_HOST=www.webapp2.com --name webapp2-1 dockercloud/hello-world
docker run -d -e VIRTUAL_HOST=www.webapp2.com --name webapp2-2 dockercloud/hello-world
docker run -d --link webapp1:webapp1 --link webapp2-1:webapp2-1 --link webapp2-2:webapp2-2 -p 80:80 acs/proxy

When you access http://www.webapp1.com, it will show the service running in container webapp1, and http://www.webapp2.com will go to both containers webapp2-1 and webapp2-2 using round robin (or whatever is configured in BALANCE).

I want all my *.node.io domains point to my service

docker run -d -e VIRTUAL_HOST="*.node.io" --name webapp dockercloud/hello-world
docker run -d --link webapp:webapp -p 80:80 acs/proxy

I want web.domain.com go to one service and *.domain.com go to another service

docker run -d -e VIRTUAL_HOST="web.domain.com" -e VIRTUAL_HOST_WEIGHT=1 --name webapp dockercloud/hello-world
docker run -d -e VIRTUAL_HOST="*.domain.com" -e VIRTUAL_HOST_WEIGHT=0 --name app dockercloud/hello-world
docker run -d --link webapp:webapp --link app:app -p 80:80 acs/proxy

I want all the requests to path /path point to my service

docker run -d -e VIRTUAL_HOST="*/path, */path/*" --name webapp dockercloud/hello-world
docker run -d --link webapp:webapp -p 80:80 acs/proxy

I want all the static html request point to my service

docker run -d -e VIRTUAL_HOST="*/*.htm, */*.html" --name webapp dockercloud/hello-world
docker run -d --link webapp:webapp -p 80:80 acs/proxy

I want to see stats of HAProxy

docker run -d --link webapp:webapp -e STATS_AUTH="auth:auth" -e STATS_PORT=1936 -p 80:80 -p 1936:1936 acs/proxy

I want to send all my logs to papertrailapp

Replace <subdomain> and <port> with your the values matching your papertrailapp account:

docker run -d --name web1 dockercloud/hello-world
docker run -d --name web2 dockercloud/hello-world
docker run -it --env RSYSLOG_DESTINATION='<subdomain>.papertrailapp.com:<port>' -p 80:80 --link web1:web1 --link web2:web2 acs/proxy

Topologies using virtual hosts

阿里云容器服务代理拓扑图

                                                           |---- container_a1
                                    |----- service_a ----- |---- container_a2
                                    |   (virtual host a)   |---- container_a3
internet --- SLB ----- acs/proxy--- |
                                    |                      |---- container_b1
                                    |----- service_b ----- |---- container_b2
                                        (virtual host b)   |---- container_b3

Manually reload haproxy

In most cases, acs/proxy will configure itself automatically when the linked services change, you don’t need to reload it manually. But for some reason, if you have to do so, here is how:

• docker exec <haproxy_id> /reload.sh, if you are on the node where acs/proxy deploys