Deploying App Engine flexible apps

Much like with the standard environment, applications can be deployed by providing application source code along with an app.yaml configuration file. Assuming the source code is written in one of the supported languages and complies with some basic conventions, the Google Cloud SDK will be able to package and deploy the application on your behalf. When deploying a service to the App Engine flexible environment, several things take place:

• Source code is pushed to a temporary Cloud Storage bucket
• Google Container Builder compiles the source code and packages the application into a new Docker image
• The Docker image is tagged with the service's version and stored in the Google Container Registry (GCR)
• A new managed Compute Engine VM is created based on the requested resources
• The Docker image is deployed to the VM

The end result of this deployment process is your application running on App Engine as a container inside a managed Compute Engine VM. Because this deployment process touches several Google Cloud services, performing the deployment requires a few additional IAM permissions than a deployment to the standard environment. Specifically, deploying to the flexible environment requires:

• Storage object creator: To push source code to a temporary Cloud Storage bucket
• Container builder editor: To use Container Builder in building the Docker image
• App Engine deployer: To deploy new versions of an App Engine service

Additionally, before any services can be deployed to the flexible environment, the App Engine Flexible Environment API must be enabled for the project.