docs: add warning for user when using replace sync option (argoproj#1…

…1566)

* docs: adding warning to 'replace' sync option

Signed-off-by: ashutosh16 <11219262+ashutosh16@users.noreply.github.com>

* Update sync-options.md

Signed-off-by: asingh <11219262+ashutosh16@users.noreply.github.com>

Signed-off-by: ashutosh16 <11219262+ashutosh16@users.noreply.github.com>
Signed-off-by: asingh <11219262+ashutosh16@users.noreply.github.com>
Signed-off-by: emirot <emirot.nolan@gmail.com>

docs/user-guide/sync-options.md

@@ -38,8 +38,8 @@ metadata:
     argocd.argoproj.io/sync-options: Validate=false
 ```
 
-If you want to exclude a whole class of objects globally, consider setting `resource.customizations` in [system level configuration](../user-guide/diffing.md#system-level-configuration). 
-    
+If you want to exclude a whole class of objects globally, consider setting `resource.customizations` in [system level configuration](../user-guide/diffing.md#system-level-configuration).
+
 ## Skip Dry Run for new custom resources types
 
 When syncing a custom resource which is not yet known to the cluster, there are generally two options:
@@ -60,9 +60,9 @@ The dry run will still be executed if the CRD is already present in the cluster.
 
 ## Selective Sync
 
-Currently when syncing using auto sync Argo CD applies every object in the application. 
+Currently when syncing using auto sync Argo CD applies every object in the application.
 For applications containing thousands of objects this takes quite a long time and puts undue pressure on the api server.
-Turning on selective sync option which will sync only out-of-sync resources. 
+Turning on selective sync option which will sync only out-of-sync resources.
 
 You can add this option by following ways
 
@@ -77,7 +77,7 @@ spec:
   syncPolicy:
     syncOptions:
     - ApplyOutOfSyncOnly=true
-``` 
+```
 
 2) Set sync option via argocd cli
 
@@ -104,8 +104,8 @@ spec:
 
 ## Prune Last
 
-This feature is to allow the ability for resource pruning to happen as a final, implicit wave of a sync operation, 
-after the other resources have been deployed and become healthy, and after all other waves completed successfully. 
+This feature is to allow the ability for resource pruning to happen as a final, implicit wave of a sync operation,
+after the other resources have been deployed and become healthy, and after all other waves completed successfully.
 
 ```yaml
 apiVersion: argoproj.io/v1alpha1
@@ -142,6 +142,10 @@ spec:
 
 If the `Replace=true` sync option is set the Argo CD will use `kubectl replace` or `kubectl create` command to apply changes.
 
+!!! warning
+      During the sync process, the resources will be synchronized using the 'kubectl replace/create' command.
+      This sync option has the potential to be destructive and might lead to resources having to be recreated, which could cause an outage for your application.
+
 This can also be configured at individual resource level.
 ```yaml
 metadata:
@@ -299,8 +303,8 @@ sync option, otherwise nothing will happen. If the namespace doesn't already exi
 already have labels and/or annotations set on it, you're good to go. Using `managedNamespaceMetadata` will also set the
 resource tracking label (or annotation) on the namespace, so you can easily track which namespaces are managed by ArgoCD.
 
-In the case you do not have any custom annotations or labels but would nonetheless want to have resource tracking set on 
-your namespace, that can be done by setting `managedNamespaceMetadata` with an empty `labels` and/or `annotations` map, 
+In the case you do not have any custom annotations or labels but would nonetheless want to have resource tracking set on
+your namespace, that can be done by setting `managedNamespaceMetadata` with an empty `labels` and/or `annotations` map,
 like the example below:
 
 ```yaml
@@ -311,7 +315,7 @@ metadata:
 spec:
   syncPolicy:
     managedNamespaceMetadata:
-      labels: # The labels to set on the application namespace 
+      labels: # The labels to set on the application namespace
       annotations: # The annotations to set on the application namespace
     syncOptions:
     - CreateNamespace=true
@@ -374,7 +378,7 @@ spec:
   syncPolicy:
     managedNamespaceMetadata:
       annotations:
-        abc: 123 
+        abc: 123
     syncOptions:
       - CreateNamespace=true
 ```
@@ -398,4 +402,3 @@ The resulting namespace will have its annotations set to
     foo: bar
     something: completely-different
 ```
-