Multi-cluster Cloud-Native grpc (microservices) application demo

This tutorial demonstrates how to deploy the Online Boutique microservices demo application across multiple Kubernetes clusters that are located in different public and private cloud providers. This project contains a 10-tier microservices application developed by Google to demonstrate the use of technologies like Kubernetes.

In this tutorial, you will create a Virtual Application Network that enables communications across the public and private clusters. You will then deploy a subset of the application's grpc based microservices to each cluster. You will then access the Online Boutique web interface to browse items, add them to the cart and purchase them.

Top complete this tutorial, do the following:

Prerequisites
Step 1: Set up the demo
Step 2: Deploy the Virtual Application Network
Step 3: Deploy the application microservices
Step 4: Expose the microservices to the Virtual Application Network
Step 5: Access the Online Boutique Application
Cleaning up
Next steps

Prerequisites

The oc command-line tool (installation guide)
The skupper command-line tool, the latest version (installation guide)

The basis for this demonstration is to depict the deployment of member microservices for an application across both private and public clusters and for the ability of these microsservices to communicate across a Virtual Application Network. As an example, the cluster deployment might be comprised of:

A private cloud cluster running on your local machine or any cloud provider
Two public cloud clusters running in public cloud providers

While the detailed steps are not included here, this demonstration can alternatively be performed with three separate namespaces on a single cluster.

Step 1: Set up the demo

On your local machine, make a directory for this tutorial and clone the example repo:

mkdir boutique-demo
cd boutique-demo
git clone https://github.com/cmcornejo/skupper-example-grpc.git

Prepare the target clusters.
1. On your local machine, log in to each cluster in a separate terminal session.
2. In each cluster, create a namespace to use for the demo.
3. In each cluster, set the kubectl config context to use the demo namespace (see kubectl cheat sheet for more information)
```
oc config set-context --current --namespace <namespace>
```
1. (Optional) I use https://kcli.readthedocs.io/en/latest/[kcli] as a way to handle virtual machines to create separate environments locally.

Step 2: Deploy the Virtual Application Network

On each cluster, using the skupper tool, define the Virtual Application Network (VAN) and the connectivity for the peer clusters.

In the terminal for the east cluster, deploy the east application router. Create a connection token for connections from the west cluster:
```
skupper init --site-name east --enable-console=false
skupper token create east-token.yaml
```
In the terminal for the east-2 cluster, deploy the east-2 application router, create a connection token for connections from the west cluster:
```
skupper init --site-name east-02
skupper token create east-02-token.yaml
```

In the terminal for the west cluster, deploy the west application router and define its connections to the east and east-2 clusters.

# we are only deploying the console in this cluster
skupper init --site-name west --enable-console --enable-flow-collector --console-auth=openshift
skupper link create east-token.yaml
skupper link create east-2-token.yaml

In each of the cluster terminals, verify connectivity has been established
```
skupper link status
```

NOTE:

There are ONLY two links between sites:

east->west
east-2->west

There isn’t link between east and east-2

Step 3: Deploy the application microservices

After creating the Virtual Application Network, deploy the grpc based microservices for the Online Boutique application. There are three deployment .yaml files labelled a, b, and c. These files (arbitrarily) define a subset of the application microservices to deploy to a cluster.

Deployment	Microservices	Site
deployment-ms-a.yaml	frontend, productcatalog, recommendation	west
deployment-ms-b.yaml	ad, cart, checkout, currency, redis-cart	east
deployment-ms-c.yaml	email, payment, shipping	east-2

In the terminal for the west cluster, deploy the following:
```
oc apply -f skupper-example-grpc/deployment-ms-a.yaml
```
In the terminal for the east cluster, deploy the following:
```
oc apply -f skupper-example-grpc/deployment-ms-b.yaml
```
In the terminal for the east-2 cluster, deploy the following:
```
oc apply -f skupper-example-grpc/deployment-ms-c.yaml
```

Step 4: Expose the microservices to the Virtual Application Network

There are three script files labelled -a, -b, and -c. These files expose the services created above to join the Virtual Application Network. Note that the frontend service is not assigned to the Virtual Application Network as it is setup for external web access.

File	Deployments	Site
expose-deployments-a.sh	productcatalog, recommendation	west
expose-deployments-b.sh	ad, cart, checkout, currency, redis-cart	east
expose-deployments-c.sh	email, payment, shipping	east-2

In the terminal for the west cluster, execute the following annotation script:
```
skupper-example-grpc/expose-deployments-a.sh
```
In the terminal for the east cluster, execute the following annotation script:
```
skupper-example-grpc/expose-deployments-b.sh
```
In the terminal for the east-2 cluster, execute the following annotation script:
```
skupper-example-grpc/expose-deployments-c.sh
```

Step 5: Access The Boutique Shop Application

The web frontend for the Online Boutique application can be accessed via the frontend-external service. In the terminal for the west cluster, start a firefox browser and access the shop UI.

/usr/bin/firefox --new-window  "http://$(oc get route frontend-external -o=jsonpath='{.spec.host}')/"

Open a browser and use the url provided above to access the Online Boutique.

Step 6: Run the load generator

The Online Boutique application has a load generator that creates realistic usage patterns on the website.

In the terminal for the west cluster, deploy the load generator:

oc apply -f skupper-example-grpc/deployment-loadgenerator.yaml

In the terminal for the west cluster, observe the output from the load generator:
```
oc logs -f deploy/loadgenerator
```

In the terminal for the west cluster, stop the load generator:

oc delete -f skupper-example-grpc/deployment-loadgenerator.yaml

Step 7: Review Skupper Console

In the terminal for the west cluster, retrieve the skupper console url:

skupper status
Skupper is enabled for namespace "west" in interior mode. It is connected to 2 other sites. It has 10 exposed services.
The site console url is:  https://skupper-west.apps.<ocp-basedomain>

Check Site tab:

Check Network tab:

Check Services tab:

Check Deployments tab:

Cleaning Up

Restore your cluster environment by returning the resources created in the demonstration. On each cluster, delete the demo resources and the skupper network:

In the terminal for the west cluster, delete the resources:

skupper-example-grpc/unexpose-deployments-a.sh
oc delete -f skupper-example-grpc/deployment-ms-a.yaml
skupper delete

In the terminal for the east cluster, delete the resources:

skupper-example-grpc/unexpose-deployments-b.sh
oc delete -f skupper-example-grpc/deployment-ms-b.yaml
skupper delete

In the terminal for the east-2 cluster, delete the resources:

skupper-example-grpc/unexpose-deployments-c.sh
oc delete -f skupper-example-grpc/deployment-ms-c.yaml
skupper delete

cmcornejocrespo/skupper-example-grpc