chore: update installation.md for ARM user (#245)

* chore: update installation.md

Signed-off-by: namkyu1999 <lak9348@konkuk.ac.kr>

* chore: delete specific image info

Signed-off-by: namkyu1999 <lak9348@konkuk.ac.kr>

* chore: fix typos and add hyperlink

Signed-off-by: namkyu1999 <lak9348@konkuk.ac.kr>

---------

Signed-off-by: namkyu1999 <lak9348@konkuk.ac.kr>

website/docs/getting-started/installation.md

@@ -73,6 +73,16 @@ helm install chaos litmuschaos/litmus --namespace=litmus --set portal.frontend.s
 
 > **Note:** If your Kubernetes cluster isn't local, you may want not to expose Litmus via `NodePort`. If so, remove `--set portal.frontend.service.type=NodePort` option. To connect to Litmus UI from your laptop, you can use `port-forward svc/chaos-litmus-frontend-service 9091:9091`. Then you can use your browser and open `127.0.0.1:9091`.
 
+- Litmus helm chart depends on `bitnami/mongodb` [helm chart](https://github.com/bitnami/charts/tree/main/bitnami/mongodb), which uses a mongodb image not supported on ARM. If you want to install Litmus on an ARM-based server, please replace the default one with your custom mongodb arm image as shown below.
+
+  ```bash
+  helm install chaos litmuschaos/litmus --namespace=litmus \
+  --set portal.frontend.service.type=NodePort \
+  --set mongodb.image.registry=<put_registry> \
+  --set mongodb.image.repository=<put_image_repository> \
+  --set mongodb.image.tag=<put_image_tag>
+  ```
+
 <span style={{color: 'green'}}><b>Expected Output</b></span>
 
 ```

website/versioned_docs/version-3.0.0/getting-started/installation.md

@@ -73,6 +73,16 @@ helm install chaos litmuschaos/litmus --namespace=litmus --set portal.frontend.s
 
 > **Note:** If your Kubernetes cluster isn't local, you may want not to expose Litmus via `NodePort`. If so, remove `--set portal.frontend.service.type=NodePort` option. To connect to Litmus UI from your laptop, you can use `port-forward svc/chaos-litmus-frontend-service 9091:9091`. Then you can use your browser and open `127.0.0.1:9091`.
 
+- Litmus helm chart depends on `bitnami/mongodb` [helm chart](https://github.com/bitnami/charts/tree/main/bitnami/mongodb), which uses a mongodb image not supported on ARM. If you want to install Litmus on an ARM-based server, please replace the default one with your custom mongodb arm image as shown below.
+
+  ```bash
+  helm install chaos litmuschaos/litmus --namespace=litmus \
+  --set portal.frontend.service.type=NodePort \
+  --set mongodb.image.registry=<put_registry> \
+  --set mongodb.image.repository=<put_image_repository> \
+  --set mongodb.image.tag=<put_image_tag>
+  ```
+
 <span style={{color: 'green'}}><b>Expected Output</b></span>
 
 ```