.NET 10 dev container (SSH-accessible)

A Docker image with the .NET 10 SDK, git, and npm, reachable over SSH with key-only auth.

Files

• Dockerfile — builds on mcr.microsoft.com/dotnet/sdk:10.0, adds git, Node.js/npm (via NodeSource), an openssh-server, and a non-root dev user with passwordless sudo.
• entrypoint.sh — runs inside the Linux container at startup (generates SSH host keys on first boot, then execs sshd). Left as bash intentionally — it's container-internal, not something you run yourself, and bash is guaranteed present in the base image while PowerShell is not.
• generate-keys.ps1 — run on your machine. Creates a dedicated ed25519 keypair (~/.ssh/id_dotnet10dev_ed25519 by default) and copies the public half into this folder as authorized_keys, which the Dockerfile bakes into the image.
• up.ps1 — builds the image and starts the container, publishing SSH on localhost:2222.
• down.ps1 — stops and removes the container.

All host-side scripts are PowerShell Core (pwsh) — install it if you don't have it (winget install Microsoft.PowerShell / brew install powershell / etc.).

Steps

1. Generate the SSH keypair (do this wherever you'll build/run the container):

   ./generate-keys.ps1

   This never sets a password — auth is key-only.

2. Build and start the container:

   ./up.ps1

3. Connect over SSH:

ssh -i ~/.ssh/id_dotnet10dev_ed25519 -p 2222 dev@localhost

- **Host**: `localhost` (port `2222` is mapped to the container's `22`;
  change with `up.ps1 -SshPort <port>` if 2222 is taken)
- **User**: `dev` (passwordless sudo inside the container)

4. **Verify the tooling** once connected:
```bash
dotnet --version   # should report a 10.x SDK
git --version
npm --version

5. Tear down when done:

   ./down.ps1

Notes / things you may want to adjust

• PasswordAuthentication is disabled in sshd_config — key-only login, per your earlier choice.
• The Node.js major version is a build arg: docker build --build-arg NODE_MAJOR=24 ... if you'd rather track the newer LTS instead of the default (22).
• authorized_keys is gitignored — don't commit it or the private key if this folder ever becomes a git repo.
• If you're running Docker Desktop on a remote/VM host rather than locally, swap localhost for that host's address in the SSH command.