docs(self-managed): add multi-namespace deployment guide

docs/self-managed/platform-deployment/helm-kubernetes/guides/multi-namespace-deployment.md

@@ -0,0 +1,125 @@
+---
+id: multi-namespace-deployment
+title: "Multi-namespace deployment"
+description: "Deploy Camunda 8 Self-Managed across namespaces for better resources utilization and to reduce redundancy"
+---
+
+You can deploy Camunda 8 Self-Managed across namespaces, where we have a single management deployment (Identity and Web Modeler), and multiple automation deployments (Zeebe, Operate, Tasklist, Optimize).
+
+In this set up each namespace has its own Helm deployment independently, but each one uses a different values file based on if the deployment mode is `management` or `automation`.
+
+The following are three values files, one for the `managment` deployment and two for the `automation` deployment:
+
+## Management deployment
+
+This deployment includes Identity and Web Modeler only, and allows the other two deployments to authenticate against Keycloak:
+
+```yaml
+# Namespace: camunda-main
+global:
+  identity:
+    auth:
+      connectors:
+        existingSecret: <APP_MACHINE2MACHINE_SECRET>
+      operate:
+        existingSecret: <APP_MACHINE2MACHINE_SECRET>
+        redirectUrl: "https://camunda-team1.example.com/operate,https://camunda-team2.example.com/operate"
+      tasklist:
+        existingSecret: <APP_MACHINE2MACHINE_SECRET>
+        redirectUrl: "https://camunda-team1.example.com/tasklist,https://camunda-team2.example.com/tasklist"
+      optimize:
+        existingSecret: <APP_MACHINE2MACHINE_SECRET>
+        redirectUrl: "https://camunda-team1.example.com/optimize,https://camunda-team2.example.com/optimize"
+      zeebe:
+        existingSecret: <APP_MACHINE2MACHINE_SECRET>
+zeebe:
+  enabled: false
+zeebe-gateway:
+  enabled: false
+operate:
+  enabled: false
+tasklist:
+  enabled: false
+optimize:
+  enabled: false
+connectors:
+  enabled: false
+elasticsearch:
+  enabled: false
+```
+
+## Team1 deployment
+
+This deployment includes Zeebe, Operate, Tasklist, and Optimize, and authenticates against Keycloak in the management deployment:
+
+```yaml
+# Namespace: camunda-team1
+global:
+  identity:
+    auth:
+      publicIssuerUrl: "https://camunda-main.example.com/auth/realms/camunda-platform"
+      connectors:
+        existingSecret: <APP_MACHINE2MACHINE_SECRET>
+      operate:
+        existingSecret: <APP_MACHINE2MACHINE_SECRET>
+      tasklist:
+        existingSecret: <APP_MACHINE2MACHINE_SECRET>
+      optimize:
+        existingSecret: <APP_MACHINE2MACHINE_SECRET>
+      zeebe:
+        existingSecret: <APP_MACHINE2MACHINE_SECRET>
+    service:
+      url: "http://camunda-main-identity.camunda-main.svc.cluster.local:80/identity"
+    keycloak:
+      url:
+        protocol: "http"
+        host: "camunda-main-keycloak.camunda-main.svc.cluster.local"
+        port: "80"
+identity:
+  enabled: false
+webModeler:
+  enabled: false
+postgresql:
+  enabled: false
+```
+
+## Team2 deployment
+
+This deployment includes Zeebe, Operate, Tasklist, and Optimize, and authenticates against Keycloak in the management deployment:
+
+```yaml
+# Namespace: camunda-team2
+global:
+  identity:
+    auth:
+      publicIssuerUrl: "https://camunda-main.example.com/auth/realms/camunda-platform"
+      connectors:
+        existingSecret: <APP_MACHINE2MACHINE_SECRET>
+      operate:
+        existingSecret: <APP_MACHINE2MACHINE_SECRET>
+      tasklist:
+        existingSecret: <APP_MACHINE2MACHINE_SECRET>
+      optimize:
+        existingSecret: <APP_MACHINE2MACHINE_SECRET>
+      zeebe:
+        existingSecret: <APP_MACHINE2MACHINE_SECRET>
+    service:
+      url: "http://camunda-main-identity.camunda-main.svc.cluster.local:80/identity"
+    keycloak:
+      url:
+        protocol: "http"
+        host: "camunda-main-keycloak.camunda-main.svc.cluster.local"
+        port: "80"
+identity:
+  enabled: false
+webModeler:
+  enabled: false
+postgresql:
+  enabled: false
+```
+
+:::note
+The values mentioned above only highlight the values needed to set up the multi-namespace deployment, but it's still needed to add other values as usual (for TLS and Ingress set up, for example).
+
+Additionally, the machine-to-machine secrets should be the same across namespaces for each application to authenticate against Keycloak.
+:::

sidebars.js

@@ -832,6 +832,7 @@ module.exports = {
                 "self-managed/platform-deployment/helm-kubernetes/guides/aws-marketplace",
                 "self-managed/platform-deployment/helm-kubernetes/guides/install-zeebe-exporters",
                 "self-managed/platform-deployment/helm-kubernetes/guides/running-custom-connectors",
+                "self-managed/platform-deployment/helm-kubernetes/guides/multi-namespace-deployment",
               ],
             },
             "self-managed/platform-deployment/troubleshooting",