[BUG] Deleting `opensearch_cluster_settings` destructively overwrites all settings with defaults

[pflaquerre-figma]

What is the bug?

When deleting an opensearch_cluster_settings resource, it destructively clobbers all settings back to defaults:

terraform-provider-opensearch/provider/resource_opensearch_cluster_settings.go

Line 372 in 59aec32

err := clearAllSettings(meta)

which goes to this request that wipes all settings:

terraform-provider-opensearch/provider/resource_opensearch_cluster_settings.go

Lines 415 to 425 in 59aec32

	body := `{
	"persistent" : {
	"cluster.*": null,
	"indices.*": null,
	"action.*": null,
	"script.*": null,
	"network.*": null,
	"search.*": null,
	"plugins.*": null
	}
	}`

This means that if someone wants to stop using opensearch_cluster_settings to manage cluster settings for any reason and delete it, they will end up wiping all of their cluster's settings. This is a) extremely surprising and b) ...not great if you were planning on continuing to use that cluster.

Is there a reason why this has to happen at all at delete time? Could that step potentially be removed?

How can one reproduce the bug?

• Create an OS cluster
• Tweak any settings manually
• Add opensearch_cluster_settings
• Remove opensearch_cluster_settings

What is the expected behavior?

Settings don't change when removing opensearch_cluster_settings.

[peterzhuamazon]

Hi @prudhvigodithi could you take a look on this?

Thanks.