Intermittent: stacks/volumes rarely will fail to POST

[bodom0015]

While I have not been able to reliably reproduce the behavior, I have noticed that sometimes creating a stack fails with a 404. More rarely, creating the stack is successful but creating and/or attaching its associated volumes may fail.

Obviously both cases are undesirable, but the volumes failing poses the bigger problem of leaving the user's project in a bad state: with no volumes allocated to a stack, the data will disappear when the stack is restarted. Furthermore the user is given no indication that the failure has occurred (unless they happen to be watching the Developer Console), giving them no chance to rectify the problem.

More investigation is needed as to why this issue occurs and how to prevent it.

[bodom0015]

It seems like this comes about when attempting to create a volume from the GUI with the same name as an existing volume. This was never enforced from the frontend, but could be done easily.

Steps to recreate:

• Create a stack (i.e. Clowder-01) with an attached volume (i.e. mongo-01)
• Create a duplicate of the same stack (i.e. Clowder-02) with an attached volume (i.e. mongo-02)
• Delete Clowder-01 and its associated volume mongo-01
• Now, creating a new Clowder stack will succeed (assuming the default name is changed), but creating its volume will fail (with 409: Conflict) since mongo-02 is the default name and that volume already exists.

Enforcing unique volume names from the wizard will hide this problem, but we should consider a better strategy for generating unique default names for stack and volumes.

[bodom0015]

To resolve this issue, we plan to remove unique naming as a requirement for creating stacks and volumes. This will be implemented as described in NDS-180.