Update documentation on how to use shared vpc network using toolkit

examples/README.md

@@ -1694,6 +1694,29 @@ the controller and login nodes. Also since this blueprint doesn't use external
 IPs for compute nodes, one must needs to [set up cloud nat][cloudnat] and
 [set up iap][iap].
 
+Now, one need to update the blueprint to include shared vpc details. One should
+replace the host-project to the project in which shared vpc is created. In the
+network configuration, update the details for shared vpc.
+
+```yaml
+vars:
+  project_id:  <service-project>
+  host_project_id: <host-project>
+  deployment_name: hpc-small-shared-vpc
+  region: us-central1
+  zone: us-central1-c
+
+deployment_groups:
+- group: primary
+  modules:
+  - id: network1
+    source: modules/network/pre-existing-vpc
+    settings:
+      project_id: $(vars.host_project_id)
+      network_name: <shared-network>
+      subnetwork_name: <shared-subnetwork>
+```
+
 [hpc-slurm-sharedvpc.yaml]: ../community/examples/hpc-slurm-sharedvpc.yaml
 [fs-shared-vpc]: https://cloud.google.com/filestore/docs/shared-vpc
 
@@ -1751,7 +1774,7 @@ deployment_groups:
   # GitHub module over HTTPS, prefixed with github.com
   - source: github.com/org/repo//path/to/module
 
-  # Local absolute source, prefixed with / 
+  # Local absolute source, prefixed with /
   - source: /path/to/module
 
   # Local relative (to current working directory) source, prefixed with ./ or ../

modules/network/pre-existing-vpc/README.md

@@ -35,6 +35,16 @@ VM will be created.
 > **_NOTE:_** The `project_id` and `region` settings would be inferred from the
 > deployment variables of the same name, but they are included here for clarity.
 
+### Use shared-vpc
+
+If a network is created in different project, this module can be used to reference
+the network and use in different project by setting up [cloud nat][cloudnat] and
+[IAP][iap] forwarding. For more details, refer [shared-vpc][shared-vpc-doc]
+
+[cloudnat]: https://cloud.google.com/nat/docs/overview
+[iap]: https://cloud.google.com/iap/docs/using-tcp-forwarding
+[shared-vpc-doc]: ../../../examples/README.md#hpc-slurm-sharedvpcyaml-community-badge-experimental-badge
+
 ## License
 
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