Deploy with a Dockerfile
Docker builds start from your connected GitHub repo, not from an image you push. At build time the builder clones the repo and looks for a Dockerfile at Dockerfile path, relative to Build path — ./Dockerfile at the repo root by default. No Dockerfile at that path, no Docker build.
Detection can read EXPOSE and pre-fill Port (default 8080 if nothing is found). You still confirm both fields in the dashboard.
Step by step
Commit a Dockerfile to the repo
Put a Dockerfile at the repo root (or a subdirectory). This is the file the builder looks for when it clones your repo. An EXPOSE line lets detection pre-fill Port.
Choose Docker as the build method
Settings → Build → Build method → Docker. The builder looks for ./Dockerfile relative to Build path — set Dockerfile path if yours lives elsewhere, and Build path if the Docker context is a subdirectory.
Set Port
Port is the container port. Match EXPOSE or the port your process listens on. This is not read from a PORT env var unless you add that variable yourself.
Deploy from GitHub
Commit the app and enable Autodeploy if you want push-to-build. On every build the repo is cloned, the image is built from your Dockerfile, stored in the platform registry, and rolled out. There is no extra Ingress form.