tutum-docker-clusterproxy

HAproxy image that balances between linked containers and, if launched in Tutum, reconfigures itself when a linked cluster member joins or leaves

Usage

Make sure your application container exposes port 80. Then, launch it:

docker run -d --name web1 tutum/hello-world
docker run -d --name web2 tutum/hello-world

Then, run tutum/haproxy-http linking it to the target containers:

docker run -d -p 80:80 --link web1:web1 --link web2:web2 tutum/haproxy

Configuration

You can overwrite the following HAproxy configuration options:

• PORT (default: 80): Port HAproxy will bind to, and the port that will forward requests to.
• MODE (default: http): Mode of load balancing for HAproxy. Possible values include: http, tcp, health.
• BALANCE (default: roundrobin): Load balancing algorithm to use. Possible values include: roundrobin, static-rr, source, leastconn.
• MAXCONN (default: 4096): Sets the maximum per-process number of concurrent connections.
• OPTION (default: redispatch): Comma-separated list of HAproxy option entries to the default section.
• TIMEOUT (default: connect 5000,client 50000,server 50000): Comma-separated list of HAproxy timeout entries to the default section.
• SSL_CERT (default: **None**): An optional certificate to use on the binded port. It should have both the private and public keys content. If using it for HTTPS, remember to also set PORT=443 as the port is not changed by this setting.
• VIRTUAL_HOST (default: **None**): Optional. Let HAProxy route by domain name. Format LINK_ALIAS=DOMAIN, comma separated.

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

Usage within Tutum

Launch the service you want to load-balance using Tutum.

Then, launch the load balancer. To do this, select Jumpstarts > Proxies and select tutum/haproxy. During the 3rd step of the wizard, link to the service created earlier, and add "Full Access" API role (this will allow HAproxy to be updated dynamically by querying Tutum's API).

That's it - the proxy container will start querying Tutum's API for an updated list of containers in the service and reconfigure itself automatically.

How to use this HaProxy container

1. My service container(hello) exposes port 8080, I want the HAProxy listens to port 80

   Run this container with --link hello:hello -e PORT=8080 -p 80:80

2. My service container(hello) exposes port 80, I want the HAProxy listens to port 8080

   Run this container with --link hello:hello -p 8080:80

3. How to use SSL?

   Run this container with -e SSL_CERT="YOUR_CERT_TEXT"

   The certificate is a combination of public certificate and private key. Remember to put \n between each line of the certificate. To make it simple, suppose your certificate is stored in ~/cert.pem, you can run this container with -e SSL_CERT="$(awk 1 ORS='\\n' ~/cert.pem)"

4. My service container(hello) exposes port 8080, I want to access it with SSL using HAProxy

   Run this container with -e SSL_CERT="YOUR_CERT_TEXT" -e PORT=8080 -p 443:443

   If you also publish port 80, the user accessing port 80 will be redirect to 443 using https

5. I want to set up virtual host routing by domain

   Run this container with --link hello1:hello1 --link hello2:hello2 -e VIRTUAL_HOST="hello1=www.hello1.com, hello2=www.hello2.com" -p 80:80

   Notice that the format of VIRTUAL_HOST is LINK_ALIAS=DOMAIN, where LINK_ALIAS must match(startwith) the link alias.

   In the example above, when you access http://www.hello1.com, it will show the service running in container hello1, and http://www.hello2.com will go to container hello2

   Alternatively, virtual host can be configured by reading reading linked services environment variables(VIRTUAL_HOST). Here is an example:

   docker run -d -e VIRTUAL_HOST=www.hello1.com --name hello1 tutum/hello-world
   docker run -d -e VIRTUAL_HOST=www.hello2.com --name hello2 tutum/hello-world 
   docker run -d --link hello1:hello1 --link hello2:hello2 -p 80:80 haproxy
   

How this Haproxy work

With Tutum:
                                                                  |---- container 1
                                           |----- service 1 ----- |---- container 2
                                           |   (virtual host 1)   |---- container 3
internet --- virtual-host-tutum/haproxy--- |
                                           |                      |---- container a
                                           |----- service 2 ----- |---- container b
                                               (virtual host 2)   |---- container c
                                                                     
Without Tutum:
                                           |---- container 1 (virtual host 1)
                                           |---- container 2 (virtual host 1)    
                                           |---- container 3 (virtual host 1)
internet --- virtual-host-tutum/haproxy--- |
                                           |---- container a (virtual host 2)
                                           |---- container b (virtual host 2)
                                           |---- container c (virtual host 2)