ArchitectureNetworking model
Published ports
Each container that listens publishes its port on 127.0.0.1 with a random host port.
The app listens on its container port, here 80.
1 / 3
The deploy log shows the published port of each instance:
==> Started instance 9c5087 (port 80, published on 127.0.0.1:63120)Who publishes a port
| Container | Published port |
|---|---|
| Web services, private services, static sites | The container port, on 127.0.0.1:<random port> |
| Background workers, cron jobs, job runs | None |
The container port
At each deploy, Ferry chooses the container port and gives it to the app in PORT. The app must listen on that port on 0.0.0.0. An app that listens on 127.0.0.1 in its container fails the health check. See The port of your app.
To know why the address is 127.0.0.1, see Why 127.0.0.1.