Converge upgrade guides to a single doc

UPGRADE.md

@@ -103,4 +103,156 @@ This scenario is automatically handled by the operator, however if the tenant is
 a yaml file) which is missing the added `securityContext` this problem may arise again, so update your stored yamls
 respectively. 
 
+v4.2.2 to v4.2.3
+---
+
+Before upgrading the `MinIO Operator` you need to make the following changes to all the existing `MinIO Tenants`.
+
+- Update your current `MinIO image` to the latest version in the tenant spec.
+- Make sure every `pool` in `tenant.spec.pools` explicitly set a `securityContext` if not configured already, if this is
+  the first time you are configuring a `securityContext` then your `MinIO` pods are running as root, and you need to use:
+
+```yaml
+      securityContext:
+        runAsUser: 0
+        runAsGroup: 0
+        runAsNonRoot: false
+        fsGroup: 0
+```
+
+### Example
+
+```yaml
+  image: "minio/minio:$(LATEST-VERSION)"
+  ...
+  pools:
+    - servers: 4
+      name: "pool-0"
+      volumesPerServer: 4
+      volumeClaimTemplate:
+        metadata:
+          name: data
+        spec:
+          accessModes:
+            - ReadWriteOnce
+          resources:
+            requests:
+              storage: 1Ti
+      securityContext:
+        runAsUser: 0
+        runAsGroup: 0
+        runAsNonRoot: false
+        fsGroup: 0
+```
+
+You can make all the changes directly via `kubectl edit tenants $(TENANT-NAME) -n $(NAMESPACE)` or edit your
+`tenant.yaml` and apply the changes: `kubectl apply -f tenant.yaml`.
+
+Failing to apply this changes will cause some issues during the upgrade such as `MinIO` pods not able to `read/write` on
+existing volumes (this happens if you don't add the right `securityContext`) or they will take too long to start.
+
+### Upgrade MinIO Operator and Upgrade tenants
+
+Once all your tenants are prepared for the upgrade it's time to upgrade Operator:
+
+```bash
+kubectl apply -k github.com/minio/operator/\?ref\=v4.2.3
+```
+
+The above command will update the MinIO `Tenant CRD`, update the MinIO Operator `image` and trigger the upgrade for each
+existing tenant.
+
+
+v3.x.x to v4.x.x
+---
+
+Before upgrading the `MinIO Operator` you need to make the following changes to all the existing `MinIO Tenants`.
+
+- Update your current `MinIO image` to the latest version in the tenant spec.
+- Make sure every `zone` in `tenant.spec.zones` explicitly set a zone `name` if not configured already.
+- Make sure every `zone` in `tenant.spec.zones` explicitly set a `securityContext` if not configured already.
+
+### Example
+
+```yaml
+  image: "minio/minio:$(LATEST-VERSION)"
+  ...
+  zones:
+    - servers: 4
+      name: "zone-0"
+      volumesPerServer: 4
+      volumeClaimTemplate:
+        metadata:
+          name: data
+        spec:
+          accessModes:
+            - ReadWriteOnce
+          resources:
+            requests:
+              storage: 1Ti
+      securityContext:
+        runAsUser: 0
+        runAsGroup: 0
+        runAsNonRoot: false
+        fsGroup: 0
+  - servers: 4
+      name: "zone-1"
+      volumesPerServer: 4
+      volumeClaimTemplate:
+        metadata:
+          name: data
+        spec:
+          accessModes:
+            - ReadWriteOnce
+          resources:
+            requests:
+              storage: 1Ti
+      securityContext:
+        runAsUser: 0
+        runAsGroup: 0
+        runAsNonRoot: false
+        fsGroup: 0
+```
+
+You can make all the changes directly via `kubectl edit tenants $(TENANT-NAME) -n $(NAMESPACE)` or edit your
+`tenant.yaml` and apply the changes: `kubectl apply -f tenant.yaml`.
+
+Failing to apply this changes will cause some issues during the upgrade such as the tenants not able to provision because
+of wrong `persistent volume claims` (this happens if you don't add the zone name) or MinIO not able to `read/write` on
+existing volumes (this happens if you don't add the right `securityContext`) or they will take too long to start.
+
+### Upgrade MinIO Operator and Upgrade tenants
+
+Once all your tenants are prepared for the upgrade it's time to upgrade Operator:
+
+```bash
+kubectl apply -k github.com/minio/operator/\?ref\=v4.4.18
+```
+
+The above command will update the MinIO `Tenant CRD`, update the MinIO Operator `image` and trigger the upgrade for each
+existing tenant.
+
+---
+
+# Upgrade MinIO Operator via Helm Charts
+
+Make sure your current version of the `tenants.minio.min.io` `CRD` includes the necessary `labels` and `annotations` for `Helm`
+to perform the upgrade:
+
+```bash
+kubectl label crd tenants.minio.min.io app.kubernetes.io/managed-by=Helm --overwrite
+kubectl annotate crd tenants.minio.min.io meta.helm.sh/release-name=minio-operator meta.helm.sh/release-namespace=minio-operator --overwrite
+```
+
+Run the `helm upgrade` command:
+
+```bash
+helm upgrade -n minio-operator [RELEASE] [CHART] [flags]
+```
+
+or
+
+```bash
+helm upgrade -n minio-operator minio-operator [RELEASE-FOLDER]
+```