Bamboo Variable Promotion: Local Builds Succeed, Production Deployments Fail

Answer to the Core Question

Promoted build‑plan variables are not automatically propagated to deployment projects in Bamboo 8.x. The UI shows a “default to all deployments” flag, but the underlying deployment‑project configuration still requires each environment to declare the promoted variable. When an environment lacks that declaration, Bamboo silently substitutes an empty string, explaining why local builds succeed while production deployments fail.

Why the Discrepancy Occurs

• Build‑plan variables exist only in the plan’s scope until they are promoted to a deployment project.
• Promotion creates a record in the deployment project’s variables section, but the API does not automatically update all environments that reference the plan.
• UI defaults can be misleading because they only indicate that the variable is eligible for promotion; they do not modify the environment’s variable map.

Confirmed Configuration Steps

1. Verify the Promotion in the UI
   • Open the build plan, go to the Variables tab, and confirm the variable is marked Promoted.
   • Check the Deployment Projects section to see which projects are listed for promotion.
2. Inspect the Deployment Project’s Variable Map
   • Navigate to the deployment project, click Variables, and ensure the promoted variable appears under the Plan Variables section.
   • If it is missing, add it manually and set the Scope to Plan.
3. Use the REST API to Apply the Variable Explicitly
   • Retrieve the current deployment project configuration:

     curl -u user:pass \
       -H "Content-Type: application/json" \
       https://bamboo.example.com/rest/api/latest/deploy/project/PROJECT_KEY

   • In the returned JSON, locate the variables array and add an entry:

     {
       "name": "MY_VAR",
       "type": "plan",
       "value": "${bamboo.planResult.buildNumber}"
     }

   • POST the updated JSON back to the same endpoint.
4. Confirm the Variable During Deployment
   • Run a test deployment and check the agent logs for the Variable expansion step. The promoted variable should now resolve to the expected value.
5. For Child Plans or Downstream Pipelines
   • Define the variable as a Plan Variable in the parent plan, then promote it to the child. The child will inherit it only if the child’s deployment project explicitly maps the promoted variable.
   • Alternatively, convert the variable to a Global Variable in Bamboo’s Administration → Global Variables to avoid per‑environment mapping.

Key Takeaways

• UI defaults do not override missing API declarations.
• Always verify the variables section of each deployment project after a promotion.
• Global variables can simplify propagation but may mask missing promotions during local testing.

Follow‑Up Diagnostic Question

Could you confirm which deployment projects currently lack the promoted variable in their configuration? Knowing this will help pinpoint any drift between the UI and the API state.