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How to Run a Fleet with Parameters


Running a Fleet with parameters allows you to override the standard environment variables of your Fleet for one-off runs. This guide will walk you through the steps to run a Fleet with custom parameters using our application.


  • Basic understanding of JSON.
  • Familiarity with the Fleet and Vessel concepts in our application.


Step 1 - Access a Fleet​

  • Navigate to the Fleets page.
  • Click on the Fleet you want to run with parameter overrides.

Step 2 - Open Parameter Overrides​

  • Click the button with the parameters symbol {...} to open the Parameter Overrides modal.

Step 3 - Review the Instructions​

  • The modal will include instructions for how to use the JSON editor.
  • Read through the instructions and make sure the example JSON structure makes sense to you.

Step 4 - Providing Parameter Overrides​

  • In the Parameter Overrides section, you will see a Vessel overrides JSON structure already created from the Vessels in your Fleet.
  • The JSON structure will include:
    • A vessel_overrides key with an array of Vessel objects.
    • Each Vessel object will include:
      • A name key with the Vessel's name.
      • An environment_variable_overrides key with key-value pairs for the variables already within that Vessel. The values will be set to null by default. You can override these values with your own or add new key-value pairs.
  • You can edit the JSON structure directly in the editor.
  • As you type, the editor will indicate any syntax errors or inconsistencies with your JSON structure.

Step 5 - Reset or Run​

  • You can reset your inputs to the original pre-generated JSON using the Reset button.
  • Once the JSON is valid, the Run Now with Parameters button will be enabled.
  • Click this button to execute the Fleet with your specified parameter overrides.

Example JSON​

"vessel_overrides": [
"name": "Vessel A",
"environment_variable_overrides": {
"ENV_VAR_1": "One",
"ENV_VAR_2": "Two",
"ENV_VAR_3": "Three",
"explicit_empty": "",
"explicit_do_not_set": null
"name": "Vessel B",
"environment_variable_overrides": {
"ENV_VAR_A": "Apple",
"ENV_VAR_B": "Blossom",
"ENV_VAR_C": "Chai"