Nextcloud update/start order

[pabloeisenhut]

When updating all apps or updating TrueNAS are started without a specific order.

Example:
The following apps are linked together: Nextcloud, Redis, Collabora

In this example it is important to start the Redis and Collabora app first and after both are started then start the Nextcloud app. Otherwise it can lead to problems with the Nextcloud and cause various errors.

Possible solution:
A field in each container which works like the Docker Compose function depends_on.

[stavros-k]

There is no such thing as depends_on in kubernetes, however there are initContainers, but those need custom scripts/commands for each scenario, but considering the vast amount of options and/or use cases, its not something that can be in a UI field.

That being said, for the nextcloud+redis case, you can follow #1304.

[pabloeisenhut]

There is no such thing as depends_on

https://docs.docker.com/compose/startup-order/

The solution for each use case would be a field in each app where the name of the dependent app can be entered.

For example Nextcloud+Redis+Collabora

Nextcloud App Config:
Depends on: Redis

Redis App Config:
Depends on: Collabora

Collabora App Config:
Depends on: -

With this solution, a dependency could be created to determine the order of the apps to be launched.

@stavros-k What do you think about it?

[stavros-k]

https://docs.docker.com/compose/startup-order/

Apps do not run on docker, but on kubernetes (https://kubernetes.io/)

So it's not just a "field" to populate.
Custom initContainers and scripts for each of those services must be written. Which will also open new ways for users to shoot themselves on the feet.
Those scripts will rely on the user to provide correct connection details for each of the services, the scripts must then account for all possible scenarios of deployments of those services, eg, setup with password, setup without, setup with https, http etc.