New as of 0.5.0, Enhanced in 0.6.0
proxy:ports <app> # List proxy port mappings for an app
proxy:ports-add <app> <scheme>:<host-port>:<container-port> [<scheme>:<host-port>:<container-port>...] # Add proxy port mappings to an app
proxy:ports-clear <app> # Clear all proxy port mappings for an app
proxy:ports-remove <app> <host-port> [<host-port>|<scheme>:<host-port>:<container-port>...] # Remove specific proxy port mappings from an app
proxy:ports-set <app> <scheme>:<host-port>:<container-port> [<scheme>:<host-port>:<container-port>...] # Set proxy port mappings for an app
In Dokku 0.5.0, port proxying was decoupled from the nginx-vhosts
plugin into the proxy plugin. Dokku 0.6.0 introduced the ability to map host ports to specific container ports. In the future this will allow other proxy software - such as HAProxy or Caddy - to be used in place of nginx.
Warning: Mapping alternative ports may conflict with the active firewall installed on your server or hosting provider. Such software includes - but is not limited to - AWS Security Groups, iptables, and UFW. Please consult the documentation for those softwares as applicable.
Users should also avoid setting the
PORT
environment variable. Dokku will use port mappings to set this value. Overriding this manually may cause issues in application routing.
New as of 0.6.0
You can now configure host -> container
port mappings with the proxy:ports-*
commands. This mapping is currently supported by the built-in nginx-vhosts plugin.
By default, buildpack apps and dockerfile apps without explicitly exposed ports (i.e. using the EXPOSE
directive) will be configured with a listener on port 80
(and additionally a listener on 443 if ssl is enabled) that will proxy to the application container on port 5000
. Dockerfile apps with explicitly exposed ports will be configured with a listener on each exposed port and will proxy to that same port of the deployed application container.
Note: This default behavior will not be automatically changed on subsequent pushes and must be manipulated with the
proxy:ports-*
commands detailed below.
To inspect the port mapping for a given application, use the proxy:ports
command:
dokku proxy:ports node-js-app
-----> Port mappings for node-js-app
-----> scheme host port container port
http 80 5000
The above application is listening on the host's port 80
, which we can test via curl:
curl http://node-js-app.dokku.me
Hello World!
There are cases where we may wish for the service to be listening on more than one port, such as port 8080. Normally, this would not be possible:
curl http://node-js-app.dokku.me:8080
curl: (7) Failed to connect to node-js-app.dokku.me port 8080: Connection refused
However, we can use the proxy:ports-add
command to add a second external port mapping - 8080
- to our application's port 5000
.
dokku proxy:ports-add node-js-app http:8080:5000
-----> Setting config vars
DOKKU_PROXY_PORT_MAP: http:80:5000 http:8080:5000
-----> Configuring node-js-app.dokku.me...(using built-in template)
-----> Creating http nginx.conf
Reloading nginx
We can now test that port 80 still responds properly:
curl http://node-js-app.dokku.me
Hello World!
And our new listening port of 8080
also works:
curl http://node-js-app.dokku.me:8080
Hello World!
Port mappings can also be force set using the proxy:ports-set
command.
dokku proxy:ports-set node-js-app http:8080:5000
-----> Setting config vars
DOKKU_PROXY_PORT_MAP: http:80:5000 http:8080:5000
-----> Configuring node-js-app.dokku.me...(using built-in template)
-----> Creating http nginx.conf
Reloading nginx
A port mapping can be removed using the proxy:ports-remove
command if it no longer necessary:
dokku proxy:ports-remove node-js-app http:80:5000
Ports may also be removed by specifying only the host-port
value. This effectively acts as a wildcard and removes all mappings for that particular host port.
dokku proxy:ports-remove node-js-app http:80
Warning: If you set a proxy port map but do not have a global domain set, Dokku will reset that map upon first deployment.
For buildpack deployments, your application must respect the PORT
environment variable. We will typically set this to port 5000
, but this is not guaranteed. If you do not respect the PORT
environment variable, your containers may start but your services will not be accessible outside of that container.
Changed as of 0.5.0
Dokku's default proxy implementation - nginx - supports HTTP and GRPC request proxying. At this time, we do not support proxying plain TCP or UDP ports. UDP ports can be exposed by disabling the nginx proxy with dokku proxy:disable myapp
. If you would like to investigate alternative proxy methods, please refer to our proxy management documentation.
Dokku will extract all tcp ports exposed using the EXPOSE
directive (one port per line) and setup nginx to proxy the same port numbers to listen publicly. If you would like to change the exposed port, you should do so within your Dockerfile
.
For example, if the Dokku installation is configured with the domain dokku.me
and an application named node-js-app
is deployed with following Dockerfile:
FROM ubuntu:18.04
EXPOSE 1234
RUN python -m SimpleHTTPServer 1234
The application would be exposed to the user at node-js-app.dokku.me:1234
. If this is not desired, the following application configuration may be applied:
# add a port mapping to port 80
dokku proxy:ports-add node-js-app http:80:1234
# remove the incorrect port mapping
dokku proxy:ports-remove node-js-app http:1234:1234
Any application that does not use an EXPOSE
directive will result in Dokku defaulting to port 5000
. This behavior mimics the behavior of a Buildpack deploy. If your application does not support the PORT
environment variable, then you will either need to:
PORT
environment variable.EXPOSE
directive in your Dockerfile.EXPOSE
usage modesWhen switching between EXPOSE
usage modes, it is important to reset your port management. The following two commands can be used to reset your state and redeploy your application.
# assuming your application is called `node-js-app`
dokku config:unset --no-restart node-js-app DOKKU_DOCKERFILE_PORTS PORT
dokku proxy:ports-clear node-js-app
When deploying an image, we will use docker inspect
to extract the ExposedPorts
configuration and if defined, use that to populate port mapping. If this behavior is not desired, you can override that configuration variable with the following commands.
# assuming your application is called `node-js-app`
dokku config:set node-js-app DOKKU_DOCKERFILE_PORTS="1234/tcp 80/tcp"
dokku proxy:ports-clear node-js-app
All other port-related behavior is the same as when deploying via Dockerfile.