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Get started with Balena Fin (CM3) and Node.js


In this guide, we will build a simple Node.js web server project on a Balena Fin (CM3). At its most basic, the process for deploying code to a Balena Fin (CM3) consists of two major steps:

  • Setting up your Balena Fin (CM3) with balenaOS, the host OS that manages communication with balenaCloud and runs the core device operations.
  • Pushing your Node.js project to the balena image builder, which pulls in all necessary dependencies and creates the container image for your fleet.

Once you complete these steps, your Balena Fin (CM3) will download the container image, start your application, and begin sending logs to your balena dashboard!

What you will need

  • A Balena Fin. See our supported devices list for other boards.
  • A 5.5/2.1mm Barrel Jack Power supply rated at 6 - 24 Vdc. It is also possible to power the fin via the phoenix connector next to the barrel jack, be sure to never apply power to both connectors simultaneously!
  • A micro USB cable.
  • [Optional] An ethernet cable.
  • A balena account.

Account setup

If you don't already have a balena account, make sure to sign up before continuing.

Create a fleet

A fleet is a group of devices that share the same architecture and run the same code. When you provision a device, it is added to a specific fleet, but can be migrated to another fleet at any time.

To create your first fleet, log into your balenaCloud dashboard and click the Create fleet button.

Create a fleet

Select the Balena Fin (CM3) device type, choose a fleet type, enter a name, and click Create new fleet:

Note: To create a fleet with multiple containers, you'll want to use the Starter or Microservices fleet type. The Starter fleets are full-featured and free for all users, with a limit of up to 10 total devices across all Starter fleets.

After the fleet has been created, you will be redirected to the dashboard for the newly created fleet, where you can add your first Balena Fin (CM3).

Add your first device

To connect with balenaCloud, your Balena Fin (CM3) needs a balenaOS image configured for your device type, fleet, and network. Start by clicking Add device in your fleet dashboard:

Add a device

For most fleets, you will have the option to select a device type. By default, the device type you chose when you first created the fleet will be selected. Fleets can, however, support any devices that share the same architecture, so you can choose another device type if needed.

After selecting a device type, select an OS type of balenaOS, and you will see a list of available balenaOS versions. In general, you should use the most recent version available. You can also select whether to use a Development or Production edition with the respective toggle:

Add new device

Note: When you're getting started, a Development image is the most useful, as it permits many testing and troubleshooting features. For production use, be sure to switch to a Production image. More details on the differences between Development and Production images are detailed here.

A toggle is also used to select whether your network connection will be through Ethernet Only or with the option for Wifi + Ethernet. Selecting Wifi + Ethernet allows you to enter a Wifi SSID and Wifi Passphrase:

Network configuration

Clicking Advanced presents the option to select the rate at which your device checks for updates:

Advanced options

Once you have finished your image configuration, click the Download balenaOS button. When the download completes, you should have a zipped image file with a name like, where First-Fleet is the name you gave your fleet on the dashboard. Alternatively, by clicking on the toggle section of the download button, you also have the option to download just a configuration file (config.json) rather than an entire image.

Advanced options

Provision device

Next you will need to flash the downloaded image onto your Balena Fin (CM3)'s internal eMMC. To flash the image onto the device, we suggest using balena’s Etcher. Support for the Balena Fin (CM3) is available on Etcher starting from version 1.2.1 for OSX and Windows (Windows requires the Raspberry Pi Foundation usbboot drivers to be installed).

If you want to use the tool provided by the Raspberry Pi Foundation for flashing instead, please follow their instructions here.

Once everything is set up, launch Etcher and connect your Balena Fin (CM3) via the Micro USB programming port. If you are using a Balena Fin (CM3) v1.0.x, you will also need to connect either the barrel jack or the phoenix connector for power.

The Balena Fin (CM3) eMMC should be detected on your computer by Etcher, after a couple of seconds, which will initialize and list the board as a Compute Module based device. Select the downloaded image and press the "Flash!" button.

After flashing is complete, power off your Balena Fin (CM3) and unplug the programming micro-USB cable. Powering the Balena Fin (CM3) on will now allow the device to boot the balena OS image from the eMMC.

Note: You can flash several Balena Fin (CM3)s with the same OS image file and subsequent devices will boot and provision into your fleet. You can also disable the auto-ejecting or validation steps from the Etcher settings panel.

Install the balena CLI

Now that we have a device or two connected to a balena fleet, it's time to deploy some code. We will use the balena CLI for this. Follow the instructions below to install it on your computer (development workstation). Choose the tab for your operating system.

  1. Download the CLI installer.
  2. Double click the downloaded file to run the installer and follow the installer's instructions.
  3. To run balena CLI commands, open the Terminal app (Terminal User Guide).

  1. Download the CLI installer.
  2. Double click the downloaded file to run the installer and follow the installer's instructions.
  3. To run balena CLI commands, open a command prompt: Click on the Windows Start Menu, type PowerShell, and then click on Windows PowerShell.

  1. Download the standalone CLI.
  2. Extract the contents of the zip file to any folder you choose, for example /home/james. The extracted contents will include a balena-cli folder.
  3. Add that folder (e.g. /home/james/balena-cli) to the PATH environment variable. Check this StackOverflow post for instructions. Close and re-open the terminal window so that the changes to PATH can take effect.

For more detailed information, visit the detailed Linux installation instructions.

After the balena CLI is installed, login to your balena account with the balena login command on the terminal:

$ balena login
 _            _
| |__   __ _ | |  ____  _ __    __ _
| '_ \ / _` || | / __ \| '_ \  / _` |
| |_) | (_) || ||  ___/| | | || (_) |
|_.__/ \__,_||_| \____/|_| |_| \__,_|

Logging in to
? How would you like to login? (Use arrow keys)
❯ Web authorization (recommended)
  Authentication token
  I don't have a balena account!

You will be asked to choose an authentication method. Choosing Web authorization will bring up a web browser window that allows you to login to your balenaCloud account. When asked to authorize the CLI, click the Authorize button and head back to the terminal.

Web authorization

Note: Other authentication methods include using your username and password credentials or obtaining an authentication token from the dashboard. Authentication tokens come in two types, API tokens, and JSON Web Token (JWT) session tokens. While API tokens do not expire, JWT session tokens do after 7 days.

Add release

After logging in, test out the balena CLI by running the balena fleets command, which should return information about the fleet you created in the previous step. Take note of the FLEET NAME as you'll need this in the next step to push your code to all devices in that fleet.

$ balena fleets
98264 First-Fleet  Balena Fin (CM3)   0              0

Note: See all the commands available with balena CLI by running balena help

A nice first project to get started is balena-node-hello-world, an Express.js web server that serves a static page on port :80. Download a zipped file of the project, (JavaScript) or (TypeScript), unzip it and open a terminal in the root of the project directory.

Note: You may also use git to deploy code to a device. If you wish to deploy via git, see the instructions here.

Now to deploy this code to all device(s) in the fleet, use the balena push First-Fleet command replacing First-Fleet with the name of your fleet. Ensure you are in the root of the project directory before issuing this command or specify the --source option to provide an alternate location of the project directory.

$ balena push First-Fleet

This command will package up and push the code from the local directory to the balena builders, where it will be compiled, built and deployed to every device in the fleet.

You'll know your code has been successfully compiled and built when our friendly unicorn mascot appears in your terminal:

[main]     Successfully built d5f1de77fad3
[Info]     Uploading images
[Success]  Successfully uploaded images
[Success]  Release successfully created!
[Info]     Release: f4e3925bf7d32226365225e1b7201b90 (id: 89693)
[Info]     ┌─────────┬────────────┬────────────┐
[Info]     │ Service │ Image Size │ Build Time │
[Info]     ├─────────┼────────────┼────────────┤
[Info]     │ main    │ 205.13 MB  │ 1 second   │
[Info]     └─────────┴────────────┴────────────┘
[Info]     Build finished in 7 seconds
                _.-(6'  \
               (=___._/` \
                    )  \ |
                   /   / |
                  /    > /
                 j    < _\
             _.-' :      ``.
             \ r=._\        `.
            <`\\_  \         .`-.
             \ r-7  `-. ._  ' .  `\
              \`,      `-.`7  7)   )
               \/         \|  \'  / `-._
                          ||    .'
                           \\  (
                            >\  >
                        ,.-' >.'

Your release will then be downloaded and started by all the devices you have connected in your fleet. The first push is slower to deploy, but all subsequent pushes are much faster due to Docker layer sharing. You can see the progress of the device code updates on the device dashboard:

Service download progress

You should now have a node.js web server running on your device and see some logs on your dashboard.

To give your device a public URL, access the device page, and choose the Public Device URL toggle. You may also activate this for many devices in your fleet at the same time via the Actions menu on the device list within a fleet.

Enable public URLs

Follow the URL to view a page with additional balena learning resources and next steps. Alternatively, you can point your browser to your device's IP address.

Next steps

  • Head to balenaHub, for more ready-to-deploy fleets, or have a go at building and sharing your own cool projects using balenaBlocks.
  • Try out local mode, which allows you to build and sync code to your device locally for rapid development.
  • Take a modular approach to application development with multiple containers.
  • Manage your device fleet with the use of configuration.
  • Pass named values, parameters and data to your application using variables.
  • Visit our blog to find step-by-step tutorials for some classic balena projects.
  • If you find yourself stuck or confused, help is just a click away.

Enjoy balenafying all the things!