tutum/haproxy repository overview

⁠tutum/haproxy

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

⁠Tag

tutum/haproxy:latest    github branch master
tutum/haproxy:0.1       github tag 0.1

⁠Note: tag latest is updated with new futures, like virtual host, multiple ssl, multiple frontend. tag 0.1 is the current stable version, with less features. Usage

Launch your application container that exposes port 80:

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

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

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

The tutum/haproxy container will listen in port 80 and forward requests to both web1 and web2 backends using a roundrobin algorithm.

⁠Service vs container

*container: the building block of docker. *service: the building block of tutum and tutum/haproxy

What is a service? Service is a set of containers that have the same functionality. Usually, containers are created with the same parameters can be considered as a service. Service is a perfect concept for the load balancing management. When you scale up/down a service(changing the number of containers in the service), haproxy will balance the load accordingly.

To set containers in one service, you can:

1. Run tutum/haproxy with Tutum: When you set a link in Tutum, it sets a link between services, everything is done transparently.
2. Run tutum/haproxy outside tutum: When you link containers to tutum/haproxy, the link alias matters. Any link alias sharing the same prefix and followed by "-/_" with an integer is considered from the same service. For example: web-1 and web-2 belong to service web, app_1 and app_2 are from service app, but app1 and web2 are from different services.

⁠Configuration

###Global and default settings of HAProxy###

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

###Settings in linked application services###

Settings here can overwrite the settings in HAProxy, which are only applied to the linked services. If run in Tutum, 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: The sequence of the acl rules generated based on VIRTUAL_HOST are randomly. In HAProxy, when an acl rule with a wide scope(e.g. *.example.com) is put before a rule with narrow scope(e.g. web.example.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.

⁠SSL termination

tutum/haproxy 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, or in Tutum.

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 tutum/haprox, or
2. set SSL_CERT and/or DEFAULT_SSL_CERT in the application services linked to HAProxy

The difference between SSL_CERT and DEFAULT_SSL_CERT is that, the multiple certificates specified by SSL_CERT are stores 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_CERTICATE is provided, only one of the certificates can be stored as cert0.pem, others are discarded.

The certificate specified in tutum/haproxy 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, 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:

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

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

⁠Affinity and session stickiness

There are tree method to setup affinity and sticky session:

1. set 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 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 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, tutum/haproxy 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 tutum/haproxy

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 tutum/haproxy

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, tutum/haproxy 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.example.com, wss://wss.example.com"
2. Websocket itself is a TCP connection, you can also try the TCP load balancing mentioned in the previous section.

⁠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 "Environment variables" step of the wizard, link to the service created earlier (the name of the link is not important), and add "Full Access" API role (this will allow HAProxy to be updated dynamically by querying Tutum's API). If you are using tutumcli, or stackfile, please set role to global

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, including:

• start/stop/terminate containers in the linked application services
• start/stop/terminate/scale up/scale down/redeploy the linked application services
• add new links to HAProxy
• remove old links from HAProxy

⁠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 --link webapp:webapp -p 80:80 tutum/haproxy

⁠My webapp container exposes port 8080 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 --link webapp:webapp -e EXCLUDE_PORTS 8803,8806 -p 80:80 tutum/haproxy

⁠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 --link webapp:webapp -p 8080:80 tutum/haproxy

⁠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 tutum/hello-world
docker run -d --link webapp:webapp -p 443:443 -p 80:80 tutum/haproxy

or

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

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)" tutum/haproxy

⁠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 tutum/hello-world
docker run -d --link webapp:webapp -p 443:443 tutum/haproxy

⁠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 tutum/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 tutum/haproxy

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

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 tutum/hello-world
docker run -d --link webapp:webapp -p 80:80 tutum/haproxy

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

docker run -d -e VIRTUAL_HOST="web.example.com" -e VIRTUAL_HOST_WEIGHT=1 --name webapp tutum/hello-world
docker run -d -e VIRTUAL_HOST="*.example.com" -e VIRTUAL_HOST_WEIGHT=0 --name app tutum/hello-world
docker run -d --link webapp:webapp --link app:app -p 80:80 tutum/haproxy

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

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

⁠I want all the static html request point to my service

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

⁠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 tutum/haproxy

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

⁠Topologies using virtual hosts

Within Tutum:

                                                     |---- container_a1
                              |----- service_a ----- |---- container_a2
                              |   (virtual host a)   |---- container_a3
internet --- tutum/haproxy--- |
                              |                      |---- container_b1
                              |----- service_b ----- |---- container_b2
                                  (virtual host b)   |---- container_b3

Outside Tutum (any Docker server):

                              |---- container_a1 (virtual host a) ---|
                              |---- container_a2 (virtual host a) ---|---logic service_a
                              |---- container_a3 (virtual host a) ---|
internet --- tutum/haproxy--- |
                              |---- container_b1 (virtual host b) ---|
                              |---- container_b2 (virtual host b) ---|---logic service_b
                              |---- container_b3 (virtual host b) ---|