Troubleshooting Deployment Failure Due to Gemfile and Gemfile.lock Mismatch


A deployment failure can occur in your environment due to a mismatch between the versions of a gem specified in the Gemfile and the Gemfile.lock. This issue is often indicated by error messages during the deployment process. A common scenario is when a gem, such as Sidekiq, is updated in the Gemfile but the Gemfile.lock is not updated to reflect this change, causing a conflict during deployment.

The error message will include this excerpt:

You are trying to install in deployment mode after changing your Gemfile. Run `bundle install` elsewhere and add the updated Gemfile.lock to version control.


To resolve this issue, follow these steps:

  1. Run `bundle install` locally. This will update the Gemfile.lock to reflect the changes made in the Gemfile.
  2. Push the updated Gemfile.lock to your repository.
  3. Redeploy your application.

After these steps, the updated version of your gem should be running successfully in your environment.


Deployment failures due to a mismatch between the Gemfile and Gemfile.lock can be resolved by running `bundle install` locally to update the Gemfile.lock, pushing the changes to the repository, and then redeploying the application.


  1. What does `bundle install` do?
    It updates the Gemfile.lock to reflect any changes made in the Gemfile.
  2. What happens if I don't update the Gemfile.lock after changing the Gemfile?
    It can cause a conflict during the deployment process, leading to a deployment failure.
  3. How can I confirm that the updated version of the gem is running successfully?
    After redeploying your application, you can check the version of the gem in your environment to confirm.


Article is closed for comments.