Update readme with gcp provider

Author: praveenkumar

README.md

@@ -28,14 +28,25 @@ To facilite the usage of `crc-cloud`, a [container image](https://quay.io/reposi
 
 ### Authetication  
 
-All operations require to set the authentication mechanism in place. As so any `aws` authentication mechanism is supported by `crc-cloud`:
+All operations require to set the authentication mechanism in place.
+
+As so any `aws` authentication mechanism is supported by `crc-cloud`:
 
 - long term credentials `AWS_ACCESS_KEY_ID` and `AWS_SECRET_ACCESS_KEY` as environment variables  
 - short lived credentials (in addition to `AWS_ACCESS_KEY_ID` and `AWS_SECRET_ACCESS_KEY` would require `AWS_SESSION_TOKEN`)
 - credentials on config file (default file ~/.aws/config), in case of multiple profiles it will also accepts `AWS_PROFILE`
 
+As so any `gcp` authentication mechanism is supported by `crc-cloud`:
+
+- Credentials `GOOGLE_APPLICATION_CREDENTIALS` as environment variable
+- Project ID `GCLOUD_PROJECT` as environment variable
+- Region `GCLOUD_REGION` as environment variable
+- Zone `GCLOUD_ZONE` as environment variable
+
 ### Restrictions
 
+**Note**: `import` operation is not supported on `gcp` provider.
+
 The `import` operation downloads and transform the bundle offered by crc into an image supported by `AWS`, as so there are some disk demanding operation. So there is a requirement of at least 70G free on disk to run this operation.  
 
 The AWS instance type of choice is *c6a.2xlarge* with 8vcpu and 16 GB of RAM. This will be customizable in the future, for the moment this fixed type imposes some [restrictions](https://aws.amazon.com/about-aws/whats-new/2022/12/amazon-ec2-m6a-c6a-instances-additional-regions/) on available regions to run crc cloud, those regions are:
@@ -98,7 +109,7 @@ podman run -d --rm \
 
 `create` operation is responsible for create all required resources on the cloud provider to spin the Openshift Single Node Cluster.  
 
-Usage:
+Usage: In case of `aws` provider
 
 ```bash
 create crc cloud instance on AWS
@@ -121,6 +132,29 @@ Global Flags:
       --pullsecret-filepath string   path for pullsecret file
 ```
 
+Usage: In case of `gcp` provider
+
+```bash
+create crc cloud instance on GCP
+
+Usage:
+  crc-cloud create gcp [flags]
+
+Flags:
+      --gcp-disk-size string       Disk size in GB for the machine running the cluster. Default is 100.
+      --gcp-image-id string        GCP image identifier
+      --gcp-instance-type string   Instance type for the machine running the cluster. Default is n1-standard-8.
+  -h, --help                       help for gcp
+
+Global Flags:
+      --backed-url string            backed for stack state. Can be a local path with format file:///path/subpath or s3 s3://existing-bucket
+      --key-filepath string          path to init key obtained when importing the image
+      --output string                path to export assets
+      --project-name string          project name to identify the instance of the stack
+      --pullsecret-filepath string   path for pullsecret file
+      --tags stringToString          tags to add on each resource (--tags name1=value1,name2=value2) (default [])
+```
+
 Outputs:
 
 - `kubeconfig` file with the kube config to connect withint the cluster  
@@ -129,7 +163,7 @@ Outputs:
 - `id_rsa` key to connect the remote host
 - `password` password generated for `kubeadmin` and `developer` default cluster users
 
-Sample
+Sample for `aws` provider:
 
 ```bash
 podman run -d --rm \
@@ -149,6 +183,27 @@ podman run -d --rm \
         --key-filepath "/workspace/id_ecdsa"
 ```
 
+Sample for `gcp` provider:
+
+```bash
+podman run -d --rm \
+    -v ${PWD}:/workspace:z \
+    -e GOOGLE_APPLICATION_CREDENTIALS=${gcp_credentials} \
+    -e GCLOUD_PROJECT=${gcp_project_id} \
+    -e GCLOUD_REGION=${gcp_region} \
+    -e GCLOUD_ZONE=${gcp_zone} \
+    quay.io/crcont/crc-cloud:v0.0.2 create gcp \
+        --project-name "crc-ocp412" \
+        --backed-url "file:///workspace" \
+        --output "/workspace" \
+        --tags account=qe-pt,profile=builder \
+        --gcp-image-id "gcp-xxxx" \
+        --gcp-instance-type "n1-standard-8" \
+        --gcp-disk-size "100" \
+        --pullsecret-filepath "/workspace/pullsecret" \
+        --key-filepath "/workspace/id_ecdsa"
+```
+
 #### Destroy
 
 `destroy` operation will remove any resource created at the cloud provider, it uses the files holding the state of the infrastructure which has been store at location defined by parameter `backed-url` on `create` operation.  
@@ -168,7 +223,7 @@ Flags:
       --provider string       target cloud provider
 ```
 
-Sample
+Sample for `aws` provider:
 
 ```bash
 podman run -d --rm \
@@ -181,3 +236,18 @@ podman run -d --rm \
         --backed-url "file:///workspace" \
         --provider "aws" 
 ```
+
+Sample for `gcp` provider:
+
+```bash
+podman run -d --rm \
+    -v ${PWD}:/workspace:z \
+    -e GOOGLE_APPLICATION_CREDENTIALS=${gcp_credentials} \
+    -e GCLOUD_PROJECT=${gcp_project_id} \
+    -e GCLOUD_REGION=${gcp_region} \
+    -e GCLOUD_ZONE=${gcp_zone} \
+    quay.io/crcont/crc-cloud:v0.0.2 destroy \
+        --project-name "crc-ocp412" \
+        --backed-url "file:///workspace" \
+        --provider "gcp"
+```