drenv: Add an interesting demo

demo environment deploys a web page accessible
from a web browser or curl command. This is an
attempt to create an interesting demonstration of
drenv tool with an interactive use case.

Example run:
$ drenv start envs/demo.yaml
2023-06-14 17:40:35,327 INFO    [demo] Starting environment
2023-06-14 17:40:36,008 INFO    [demo1] Starting minikube cluster
2023-06-14 17:40:37,069 INFO    [demo2] Starting minikube cluster
2023-06-14 17:45:00,790 INFO    [demo1] Cluster started in 264.78 seconds
2023-06-14 17:45:00,790 INFO    [demo1/0] Running addons/demo/start
2023-06-14 17:45:30,166 INFO    [demo2] Cluster started in 293.10 seconds
2023-06-14 17:45:30,167 INFO    [demo2/0] Running addons/demo/start
2023-06-14 17:46:09,158 INFO    [demo1/0] addons/demo/start completed in 68.37 seconds
2023-06-14 17:46:09,158 INFO    [demo1/0] Running addons/demo/test
2023-06-14 17:46:09,857 INFO    [demo1/0] addons/demo/test completed in 0.70 seconds
2023-06-14 17:46:45,639 INFO    [demo2/0] addons/demo/start completed in 75.47 seconds
2023-06-14 17:46:45,640 INFO    [demo2/0] Running addons/demo/test
2023-06-14 17:46:45,989 INFO    [demo2/0] addons/demo/test completed in 0.35 seconds
2023-06-14 17:46:45,989 INFO    [demo] Environment started in 370.66 seconds

Example interaction with the webpage for the context demo1:
- obtain the url of the deployed web page
  $minikube ip --profile demo1
  http://192.168.122.133

- use curl to access the web page in html format
  $curl http://192.168.122.133/ | grep '<h1>'
  <h1>Welcome to nginx!</h1>

  OR

  pass the obtained url on your favorite browser to see the
  welcome web page of nginx server.

Updates: RamenDR#643
Signed-off-by: Shwetha K Acharya <sacharya@redhat.com>

test/README.md

@@ -545,6 +545,7 @@ simpler and faster to work with a minimal environment.
 
 - `test.yaml` - for testing `drenv`
 - `example.yaml` - example for experimenting with the `drenv` tool
+- `demo.yaml` - interactive demo for exploring the `drenv` tool
 - `external.yaml` - example for using external clusters
 - `minio.yaml` - for testing `minio` deployment
 - `ocm.yaml` - for testing `ocm` deployment

test/addons/demo/deployment.yaml

@@ -0,0 +1,25 @@
+# SPDX-FileCopyrightText: The RamenDR authors
+# SPDX-License-Identifier: Apache-2.0
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: demo-deployment
+  labels:
+    app: demo
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: demo
+  template:
+    metadata:
+      labels:
+        app: demo
+    spec:
+      containers:
+      - name: demo
+        image: docker.io/library/nginx:stable
+        ports:
+        - containerPort: 80
+          name: demo-port

test/addons/demo/ingress.yaml

@@ -0,0 +1,18 @@
+# SPDX-FileCopyrightText: The RamenDR authors
+# SPDX-License-Identifier: Apache-2.0
+---
+apiVersion: networking.k8s.io/v1
+kind: Ingress
+metadata:
+  name: demo-ingress
+spec:
+  rules:
+  - http:
+      paths:
+      - path: /
+        pathType: Prefix
+        backend:
+          service:
+            name: demo-service
+            port:
+              number: 80

test/addons/demo/service.yaml

@@ -0,0 +1,16 @@
+# SPDX-FileCopyrightText: The RamenDR authors
+# SPDX-License-Identifier: Apache-2.0
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: demo-service
+  labels:
+    app: demo
+spec:
+  type: NodePort
+  ports:
+  - port: 80
+    name: demo-port
+  selector:
+    app: demo

test/addons/demo/start

@@ -0,0 +1,42 @@
+#!/usr/bin/env python3
+
+# SPDX-FileCopyrightText: The RamenDR authors
+# SPDX-License-Identifier: Apache-2.0
+
+import os
+import sys
+
+from drenv import kubectl
+
+if len(sys.argv) != 2:
+    print(f"Usage: {sys.argv[0]} cluster")
+    sys.exit(1)
+
+os.chdir(os.path.dirname(__file__))
+cluster = sys.argv[1]
+
+print("Deploying demo")
+kubectl.apply("--filename", "deployment.yaml", context=cluster)
+
+print("Creating the service")
+kubectl.apply("--filename", "service.yaml", context=cluster)
+
+print("Waiting until deployment is rolled out")
+kubectl.rollout(
+    "status",
+    "deployment",
+    "--timeout=120s",
+    context=cluster,
+)
+
+print("Waiting until ingress controller deployment is rolled out")
+kubectl.rollout(
+    "status",
+    "ingress",
+    "--namespace=ingress-nginx",
+    "--timeout=120s",
+    context=cluster,
+)
+
+print("Configuring ingress")
+kubectl.apply("--filename", "ingress.yaml", context=cluster)

test/addons/demo/test

@@ -0,0 +1,26 @@
+#!/usr/bin/env python3
+
+# SPDX-FileCopyrightText: The RamenDR authors
+# SPDX-License-Identifier: Apache-2.0
+
+import os
+import sys
+import subprocess
+
+print(sys.argv)
+if len(sys.argv) != 2:
+    print(f"Usage: {sys.argv[0]} cluster")
+    sys.exit(1)
+
+os.chdir(os.path.dirname(__file__))
+cluster = sys.argv[1]
+
+print("Testing demo deployment")
+
+cmd = ["minikube", "ip", "--profile", cluster]
+node_addr = subprocess.check_output(cmd).decode().rstrip()
+
+cmd = ["curl", f"http://{node_addr}/"]
+out = subprocess.check_output(cmd).decode().rstrip()
+
+assert "Welcome to nginx!" in out

test/envs/demo.yaml

@@ -0,0 +1,21 @@
+# SPDX-FileCopyrightText: The RamenDR authors
+# SPDX-License-Identifier: Apache-2.0
+
+# Demo environment.
+---
+name: demo
+templates:
+  - name: "demo-cluster"
+    driver: kvm2
+    container_runtime: containerd
+    network: default
+    addons:
+      - ingress
+    workers:
+      - addons:
+          - name: demo
+profiles:
+  - name: demo1
+    template: demo-cluster
+  - name: demo2
+    template: demo-cluster