Exclude single apps from blue / green deployment

[LukasMelzer]

Description

Hi, Working on a project with multiple apps and aiming for a zero downtime deployment, I stumbled across two questions:

• Is it possible to exclude a single app from the blue / green mechanism provided by bg-deploy? We are using an approuter to maintain the active user sessions. While deploying a new version of the other apps we would like to keep it stable and avoid a restart to keep all session alive.
• Is it possible to define a 'cool down' period for a single app? Currently the re-routing is bound to the deletion of the old version. As there could be long running, asynchronous task on the old instance it would be beneficial to keep it alive for some amount of time while the new version already handles the incoming requests.

The only workaround I identified was aborting the bd-deploy during the evaluation phase and handling the process afterwards manually. This leaves the problem, that the stable approuter does not fit the alternating naming convention (*_green <-> *_blue) and a second deployment does not work. Are there any features existing or planned to allow such behavior?

Your environment

• MultiApps CF CLI Plugin version - 2.2.1

[ikasarov]

Hello, Sorry for the delayed response. Hopefully these answers will help you:

• It isn't currently possible to exclude an app from the deploy process, but we have implemented the opposite - partial deploy which works by listing the modules and resources you want deployed. Here is an example of the partial deploy feature (https://github.com/SAP-samples/cf-mta-examples/tree/master/partial-build-deploy) but make sure that you use it with the newer version of the blue-green deploy, as I think there were some bugs fixed with that (https://github.com/SAP-samples/cf-mta-examples/tree/master/blue-green-deploy-strategy). Basically you would need to list all modules and resources except the one you want skipped, so it would look like "cf deploy my.mtar --strategy blue-green -m module1,module2 --all-resources"

• For this, you could use a module hook with a 'sleep' command (https://github.com/SAP-samples/cf-mta-examples/tree/master/hooks, https://help.sap.com/viewer/65de2977205c403bbc107264b8eccf4b/Cloud/en-US/b9245ba90aa14681a416065df8e8c593.html). I believe the one you would want is 'blue-green.application.before-unmap-routes.live'. I can try to find a specific example of this if you'd like.