Add Tenant Update Zones api

[cesnietor]

Since the Tenant's zones is an array, a PUT operation was done where
all zone elements on the Tenant are replaced by the defined ones on the request.

Api to update zones is done on:
PUT /namespaces/{namespace}/tenants/{tenant}/zones

Payload can be E.g.:

{
    "zones": [
        {
            "name": "zone-0",
            "servers": 2,
            "volumes_per_server": 2,
            "volume_configuration": {
                "storage_class_name": "standard",
                "size": 1073741824
            },
            "resources": {
                "requests": {
                    "memory": 3221225472
                }
            },
            "tolerations": [
                                {
                    "effect": "NoExecute",
                    "key": "node.kubernetes.io/not-ready",
                    "operator": "Exists",
                    "tolerationSeconds": {
                        "seconds": 300
                    }
                },
                {
                    "effect": "NoExecute",
                    "key": "node.kubernetes.io/unreachable",
                    "operator": "Exists",
                    "tolerationSeconds": {
                        "seconds": 300
                    }
                },
            ],
            "affinity": {
                "podAntiAffinity": {
                    "requiredDuringSchedulingIgnoredDuringExecution": [
                        {
                            "topologyKey": "kubernetes.io/hostname",
                            "labelSelector": {
                                    "matchExpressions": [
                                        {
                                            "key": "v1.min.io/tenant",
                                            "operator": "In",
                                            "values": ["minio-tenant-1"]
                                        },
                                        {
                                            "key": "v1.min.io/zone",
                                            "operator": "In",
                                            "values": ["zone-0"]
                                        }
                                    ]
                            }
                        }
                    ]
                }   
            }
        }
    ]
}

Response will be in the format of models.Tenant (the one gotten on /namespaces/{namespace}/tenants/{tenant})

[Alevsk]

not a blocker but its a good practice to have an empty line at the end of the file because of file processing https://stackoverflow.com/questions/729692/why-should-text-files-end-with-a-newline

[cesnietor]

done

[dvaldivia]

This implies that if the put operation is missing a zone it would be deleted from the array right? Wouldn't it be better to only update the zones named in the request array?

[cesnietor]

no, there can be multiple zones with the same name

[dvaldivia]

parseTenantZoneRequest would allow to change fields that shouldn't be changed after zone creation, such as PVC storage Class or size, number of servers, etc, we should be careful not to change them since that could break havok on the tenant, can we just grab the fields that are safe to change? like memory, node selector, affinity and tolerations?

[cesnietor]

since it is possible to have two zones with the same name, it would be difficult to modify the correct one, also it would make it messy in the sense that we would need to loop to find which to edit.