Add backup module for proxmox

[IamLunchbox]

SUMMARY

This module adds a task to create backup tasks in a proxmox virtual environment cluster.

ISSUE TYPE

• New Module/Plugin Pull Request

COMPONENT NAME

proxmox_backup

ADDITIONAL INFORMATION

Currently, not all api options are covered, since they are either difficult to implement or only available for the root-user of the instance used.

For example, the api offers an exclude-mode next to the include, pool and all-mode. But this would would require other dependent settings to be set at as well. It could be added though, but I thought this will probably not be used, when include-mode and node-restrictions are available.

As to root-limited options (e.g. tmpdir api-parameter): I opted reproducing the options available in the GUI of a proxmox cluster, the options which I not implemented are not visible there either. And since I suspect most organizations would rather use a dedicated user or api-key to perform backups instead of the master-root user, I opted for simplicity and left these options out entirely. Users, which rely soley on the GUI to schedule and perform backups won't even know, that these options exist.

Compared to other proxmox modules, this module adds several checks regarding available permissions, but I value backups as mission critical and wanted to ensure a reasonable user experience by failing gracefully, if basic conditions are not met.
But on the other hand, this adds some complexity to the module, so if this is overburdening for an ansible module, i can delete them as well.

Lastly, I have seen PR #8360, but I have two issues with it:

1. It does not implement what is states to do. It uses the cluster/backup-api endpoint, which is only used to schedule backups, not start them. Since it does not do what i need (actually starting backups, not just planning them), I opted for an implementation using the correct api endpoint (nodes/{node}/vzdump).
2. The aforementioned endpoint needs high privileges to begin with: (Check: ["perm","/",["Sys.Modify"]]). Any user who would want to perform backups using feat/add proxmox backup module  #8360 would essentially need root-privileges, while proxmox has a quite detailed permission system, which allows user to have a dedicated VM.Backup permission. This fine grained control is quite interesting for CI/CD setups, where an api-key with low level permissions can be used, to create a backup before for example a patch is deployed.

If #8360 is merged at some point, I suggest it to be renamed to proxmox_backup_schedule, since that is what it does. I know that the proxmox api documentation is kind of misleading regarding the relationship of those two endpoints. If need be, I can post images of the GUI usage and the corresponding api-calls to the proxmox backend.

[ansibullbot]

@IamLunchbox this PR contains the following merge commits:

• 2da18d8

Please rebase your branch to remove these commits.

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[ansibullbot]

cc @Ajpantuso @Thulium-Drake @UnderGreen @joshainglis @karmab @krauthosting
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[felixfontein]

Thanks for your contribution! I've added some first comments on the documentation.

[IamLunchbox]

Thanks for your contribution! I've added some first comments on the documentation.

Thank you for the review! I implemented your suggestions and added an additional option, which was recently released.

Does action_group_added need to be 10.0.1 as well?

[felixfontein]

version_added for attributes is only needed if they are added in later versions. So you can remove it.

Also note that you did not add the module to the action group. Only the modules listed for the proxmox action group in meta/runtime.yml are actually part of it.

[IamLunchbox]

Ok, thanks. I will implement those two fixes today.

[felixfontein]

If nobody objects, I'll merge this PR for the next release.