This guide is only for assemblers being deployed with a virtual machine in VMware. 

Each assembler you create must be deployed via a virtual machine, and then you can add your technology as a security device in Workbench to complete the full integration. For more information about the Expel Assembler or how it works, see the About the Expel Assembler guide.

Note: The following instructions assume you are using VMWare Fusion, but you’re free to use another tool.


  • You must have completed all of the steps in Add a New Assembler for each assembler you wish to deploy.

Quick Start

Setup includes the following steps (select any step for detailed instructions):

  1. Download the Ignition File
  2. Import the CoreOS Image and Configure in VMware
  3. Verify a “Connected” Status in Workbench

Step 1: Download the Ignition File

  1. Log in to Workbench.
  2. In the side menu, navigate to Organization Settings > Assemblers.
  3. Find the assembler you created, and select Download the CoreOS Ignition File. This action will download a JSON file that you will need in the next section.
  4. Repeat steps 1-3 for any additional assemblers. Important: you must keep track of the files and output, and which came from which assembler, because each assembler has its own unique ignition file.

Step 2: Import the CoreOS Image and Configure in VMware

  1. Open VMware.
  2. Select File > New to open the Installation menu.
  3. Drag the .ova file onto the window to start the installation process. The .ova file is the file you downloaded from Fedora in the Add a New Assembler documentation.
  4. The .ova file appears in the Recent items list. Select Continue.
  5. On the Additional Settings screen, select the arrow to select Others and see the “Ignition config data” and “Ignition config data encoding” fields. Complete the fields as follows:
    • Ignition config data - paste the contents of the ignition file
    • Ignition config data encoding - leave blank
  6. Select Continue.
  7. A Save As dialogue displays, allowing you to name your virtual machine and save it in a specific location. You can save it in a shared folder at this time, if you wish. This will be the name of the machine within VMware.
  8. Select Save.
  9. Let the import complete and select Finish.

Step 3: Verify a “Connected” Status in Workbench

It can take 10 to 15 minutes for the assembler’s status to update in Workbench.

  1. Log in to Workbench.
  2. In the side menu, navigate to Organization Settings > Assemblers (or, refresh the page if you never logged out).
  3. Find your newly created assembler(s) and verify that the status has changed from “Not Yet Connected” to “Connected.” 
    • If the status has not updated yet, make sure you have waited at least 15 minutes, then refresh the page and check again.


If your assembler is still not showing as “Connected” after 15 minutes:

  • Make sure you have the proper firewall configurations to allow our outbound ports (see Add a New Assembler).
  • Make sure your chosen machine’s size meets the required minimums (2 virtual CPUs, 8 GB RAM, and 20 GB disk space).

Ignition file too large? 

Base64 encode the downloaded file via the following:

  1. Open a command line tool.
  2. cd to the directory where you downloaded the file.
  3. Run one of the following commands, making sure to use the Ignition file's name:
    • Windows Powershell:

      [convert]::ToBase64String((Get-Content -path "FILE_PATH_AND_NAME" -Encoding byte))

    • Linux:

      base64 -w0 FILENAME.json

    • Mac:

      base64 -i FILENAME.json

  4. Copy the output from the above command and use it during Step 2 for the Ignition config data field. For the Ignition config data encoding field, enter "base64"

If all firewall and machine size settings are correct and you are still unable to connect the assembler, contact your Expel Engagement Manager for help.