Enhancement Proposal: Add Proxmox Backup Server Data Mover

[andremohr]

Describe the feature you'd like to have.
We would like to add support for Proxmox Backup Server (PBS) as a VolSync data mover.
The implementation could leverage the proxmox-backup-client in a similar way that other existing data movers (e.g., Restic, Rclone) are integrated.

What is the value to the end user? (why is it a priority?)

• Having native PBS support in VolSync would enable users to reuse their existing PBS infrastructure for Kubernetes volume backups.
• PBS provides an additional method for backups with deduplication, compression and encryption.

How will we know we have a good solution? (acceptance criteria)

• Users can configure VolSync with PBS as a target in a similar manner as existing data movers.
• Data can be pushed to and restored from a PBS repository using VolSync.
• Authentication, secrets management, and configuration follow established VolSync conventions.
• Documentation and examples are available for end users to set it up.

Additional context
Per CONTRIBUTING.md, we are opening this issue to discuss the idea before investing significant development time.
Would the maintainers be open to accepting such a contribution, and are there specific design considerations we should be aware of before starting?

[tesshuflower]

@andremohr Thanks very much for opening this proposal. Unfortunately I think we're not considering adding more backup movers at this time to the core product - we're looking at kopia right now, but it's probably too soon to add others.

That being said, we are starting to talk about possibly enabling something to allow external movers in a more generalized way - unsure yet how this would work, but it's possible at some point this could allow for you to include your own mover image/job without needing as much work on the volsync side.

[andremohr]

@tesshuflower Thanks for the quick response and for clarifying the current roadmap. I understand the hesitation around adding more backup movers directly into the core project. The idea of supporting external movers in a generalized way sounds very promising. That would provide the flexibility we’re looking for without increasing maintenance burden on the core team.

In the meantime, we’ll probably experiment with a PBS mover as a PoC outside the repo to validate the approach. Would you be open to us sharing early feedback from that work, in case it helps inform the external mover design?

[tesshuflower]

Sounds good, will let you know if we make any progress towards external movers!