[Dex migration] Add note: users must clear cookies (#1886)

Author: mohamed-rafraf

content/kubermatic/main/installation/upgrading/upgrade-from-2.26-to-2.27/_index.en.md

@@ -78,6 +78,10 @@ Administrators are advised to begin migrating to the new chart as soon as possib
 
 #### Migration Procedure
 
+{{% notice warning %}}
+After migrating to Dex, users may encounter login issues due to invalid tokens. To resolve, clear browser cookies for the application domain and log in again.
+{{% /notice %}}
+
 Most importantly, with this change the Kubernetes namespace where Dex is installed is also changed. Previously we installed Dex into the `oauth` namespace, but the new chart is meant to be installed into the `dex` namespace. This is the default the KKP installer will choose; if you install KKP manually you could place Dex into any namespace.
 
 Because the namespace changes, both old and new Dex can temporarily live side-by-side in your cluster. This allows administrators to verify their configuration changes before migration over to the new Dex instances.
@@ -199,11 +203,11 @@ You should see a response similar to:
 
 ```json
 {
-  "issuer": "https://kkp.securinets.tn/dex2",
-  "authorization_endpoint": "https://kkp.securinets.tn/dex2/auth",
-  "token_endpoint": "https://kkp.securinets.tn/dex2/token",
-  "jwks_uri": "https://kkp.securinets.tn/dex2/keys",
-  "userinfo_endpoint": "https://kkp.securinets.tn/dex2/userinfo",
+  "issuer": "https://kkp.example.com/dex2",
+  "authorization_endpoint": "https://kkp.example.com/dex2/auth",
+  "token_endpoint": "https://kkp.example.com/dex2/token",
+  "jwks_uri": "https://kkp.example.com/dex2/keys",
+  "userinfo_endpoint": "https://kkp.example.com/dex2/userinfo",
   ...
 }
 ```

content/kubermatic/main/installation/upgrading/upgrade-from-2.27-to-2.28/_index.en.md

@@ -144,6 +144,10 @@ Administrators are advised to begin migrating to the new chart as soon as possib
 
 #### Migration Procedure
 
+{{% notice warning %}}
+After migrating to Dex, users may encounter login issues due to invalid tokens. To resolve, clear browser cookies for the application domain and log in again.
+{{% /notice %}}
+
 With 2.28, the KKP installer will install the new `dex` Helm chart into the `dex` namespace, instead of the old `oauth` namespace. This ensures that the old `oauth` chart remains intact and is not removed by KKP, which could result in downtimes.
 
 This is the default namespace that the KKP installer will choose. If you install KKP manually you could place Dex into any namespace.
@@ -267,11 +271,11 @@ You should see a response similar to:
 
 ```json
 {
-  "issuer": "https://kkp.securinets.tn/dex2",
-  "authorization_endpoint": "https://kkp.securinets.tn/dex2/auth",
-  "token_endpoint": "https://kkp.securinets.tn/dex2/token",
-  "jwks_uri": "https://kkp.securinets.tn/dex2/keys",
-  "userinfo_endpoint": "https://kkp.securinets.tn/dex2/userinfo",
+  "issuer": "https://kkp.example.com/dex2",
+  "authorization_endpoint": "https://kkp.example.com/dex2/auth",
+  "token_endpoint": "https://kkp.example.com/dex2/token",
+  "jwks_uri": "https://kkp.example.com/dex2/keys",
+  "userinfo_endpoint": "https://kkp.example.com/dex2/userinfo",
   ...
 }
 ```

content/kubermatic/v2.27/installation/upgrading/upgrade-from-2.26-to-2.27/_index.en.md

@@ -78,6 +78,10 @@ Administrators are advised to begin migrating to the new chart as soon as possib
 
 #### Migration Procedure
 
+{{% notice warning %}}
+After migrating to Dex, users may encounter login issues due to invalid tokens. To resolve, clear browser cookies for the application domain and log in again.
+{{% /notice %}}
+
 Most importantly, with this change the Kubernetes namespace where Dex is installed is also changed. Previously we installed Dex into the `oauth` namespace, but the new chart is meant to be installed into the `dex` namespace. This is the default the KKP installer will choose; if you install KKP manually you could place Dex into any namespace.
 
 Because the namespace changes, both old and new Dex can temporarily live side-by-side in your cluster. This allows administrators to verify their configuration changes before migration over to the new Dex instances.
@@ -199,11 +203,11 @@ You should see a response similar to:
 
 ```json
 {
-  "issuer": "https://kkp.securinets.tn/dex2",
-  "authorization_endpoint": "https://kkp.securinets.tn/dex2/auth",
-  "token_endpoint": "https://kkp.securinets.tn/dex2/token",
-  "jwks_uri": "https://kkp.securinets.tn/dex2/keys",
-  "userinfo_endpoint": "https://kkp.securinets.tn/dex2/userinfo",
+  "issuer": "https://kkp.example.com/dex2",
+  "authorization_endpoint": "https://kkp.example.com/dex2/auth",
+  "token_endpoint": "https://kkp.example.com/dex2/token",
+  "jwks_uri": "https://kkp.example.com/dex2/keys",
+  "userinfo_endpoint": "https://kkp.example.com/dex2/userinfo",
   ...
 }
 ```