feature(lxc): enable root disk resize without recreate. recreate container if mount points are added, deleted or changed in size

[lexxxel]

Contributor's Note

• I have added / updated documentation in /docs for any user-facing features or additions.
• I have added / updated acceptance tests in /fwprovider/tests for any new or updated resources / data sources.
• I have ran make example to verify that the change works as expected.

This PR is an addition to #2319. So please do merge #2319 before reviewing this PR!

Proof of Work

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Closes #1435
After some playing around with mount points, I also documented and fixed #2322

[gemini-code-assist]

Summary of Changes

Hello @lexxxel, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the proxmox_lxc_container Terraform resource by introducing the ability to resize LXC container root disks and update several root filesystem properties in-place. This change improves the flexibility and operational efficiency for managing LXC containers, as users can now modify disk size and other rootfs settings without the need for resource recreation, with reboots triggered only when essential for certain property changes.

Highlights

• LXC Root Disk Resizing: Introduced the capability to resize LXC container root disks dynamically, allowing for in-place expansion of storage without requiring container recreation.
• In-place RootFS Property Updates: Enabled in-place updates for various root filesystem properties including ACL, quota, replication, and mount options. Changes to these properties will now trigger a container reboot if necessary, rather than forcing recreation.
• API Client Enhancement: Added a new ResizeContainerDisk method to the Proxmox API client, facilitating direct communication with the Proxmox API for disk resizing operations.
• Terraform Schema Updates: Modified the ForceNew attribute for disks and rootfs.size within the Terraform proxmox_lxc_container resource schema from true to false, allowing these attributes to be updated without destroying and recreating the container.

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[gemini-code-assist]

Code Review

This pull request adds a valuable feature for resizing LXC container root disks. The overall approach is sound, but I've identified a few critical issues in the resource update logic that could lead to runtime panics or silent failures. My review comments focus on adding necessary error handling, ensuring safe access to pointer fields to prevent panics, and correcting flawed comparison logic. I've also included a suggestion to improve consistency in one of the new data structures. Addressing these points will significantly improve the robustness of the implementation.

[lexxxel]

I implemented the resize path that increases the root disk without a forced replacement. However, in case the new disk should be smaller than the current disk, I do 'just' return an error. It would make sense to trigger a forceNew, but I'm not so familiar with this code base and I don't see where I can do the check (smaller -> recreate; larger -> update). Any suggestions would be appreciated.

[lexxxel]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces a valuable feature to allow resizing the root disk of an LXC container without forcing a recreation of the resource. The implementation is largely on the right track, but I've identified a few critical issues that need to be addressed. These include an unhandled error which could lead to an inconsistent state, potential nil pointer dereferences that could cause the provider to panic, and a logic bug in change detection for the quota property. I've provided specific code suggestions to resolve these problems. Additionally, I've included a minor suggestion to improve an error message for better clarity.

[lexxxel]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces a valuable feature to allow resizing the root disk of an LXC container without forcing a recreation of the resource. The overall approach is sound, but I've identified a couple of critical issues in the update logic that could lead to panics or silent error swallowing. Additionally, I've provided a suggestion to improve the resource lifecycle by handling disk shrinking at the plan stage, as hinted by a TODO in the code.

[lexxxel]

/gemini review

[gemini-code-assist]

Code Review

This pull request enables resizing the root disk for LXC containers without forcing a recreation of the container. The changes involve removing ForceNew from the disk schema, adding a custom diff function to handle disk shrinking by forcing a new resource, and updating the container update logic to call the new resize API endpoint. The implementation is mostly correct, but I've found a few issues, including a bug that would cause unnecessary API calls, some leftover debugging code, and a potential Go version compatibility issue. My review comments provide suggestions to address these points.

[lexxxel]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces the ability to resize an LXC container's root disk without forcing a new container resource. This is achieved by removing ForceNew from the disk schema and adding update logic to handle resizing. The changes also include a custom diff function to prevent disk shrinking by forcing a new resource in that case.

My review includes two main points:

1. A high-severity bug in the update logic where disk sizes are compared by pointer instead of by value, which would lead to unnecessary API calls.
2. A medium-severity suggestion to clean up the custom diff function by removing debug code and a confusing ForceNew call.

Overall, the changes are well-structured and address the intended feature. After addressing the identified issues, the PR should be in good shape.

[lexxxel]

/gemini review

[gemini-code-assist]

Code Review

This pull request enables resizing the root disk of an LXC container without forcing a new resource, which is a great enhancement. The changes involve removing ForceNew from the disk size attribute, adding a CustomizeDiff to handle disk shrinking, and implementing the resize logic in the containerUpdate function. The approach is sound, but I've identified two critical issues. One is the use of Go 1.22-specific syntax, which could cause compilation failures on older Go versions. The other is a potential nil pointer dereference in the update logic when checking the old disk size. Please address these issues to ensure the stability and compatibility of this new feature.

[gemini-code-assist]

There is a potential nil pointer dereference here. oldSize is of type *types.DiskSize and can be nil if the size property is not returned by the Proxmox API for the container's rootfs. Dereferencing it with *oldSize on this line will cause a panic. You should add a nil check for oldSize before dereferencing it.

Suggested change

	if *oldSize > *size {
	if oldSize != nil && *oldSize > *size {

[bpg]

Okay, we'd need to rebase this, after the previous PR got merged.

[lexxxel]

Yes and I will clean it up too. Will take me untill Tuesday unfortunately.