Skupper Hello World using Ansible

A minimal HTTP application deployed across Kubernetes clusters using Skupper

This example is part of a suite of examples showing the different ways you can use Skupper to connect services across cloud providers, data centers, and edge sites.

Contents

• Overview
• Prerequisites
• Step 1: Install the Skupper Ansible collection
• Step 2: Install the Skupper command-line tool
• Step 3: Set up your clusters
• Step 4: Inspect the inventory file
• Step 5: Run the setup playbook
• Step 6: Access the frontend
• Step 7: Run the teardown playbook
• Next steps
• About this example

Overview

This example is a variant of Skupper Hello World that is deployed using the Skupper Ansible collection.

It contains two services:

• A backend service that exposes an /api/hello endpoint. It returns greetings of the form Hi, <your-name>. I am <my-name> (<pod-name>).

• A frontend service that sends greetings to the backend and fetches new greetings in response.

In this scenario, each service runs in a different Kubernetes cluster. The frontend runs in a namespace on cluster 1 called West, and the backend runs in a namespace on cluster 2 called East.

Skupper enables you to place the backend in one cluster and the frontend in another and maintain connectivity between the two services without exposing the backend to the public internet.

Prerequisites

• The kubectl command-line tool, version 1.15 or later (installation guide)

• Access to at least one Kubernetes cluster, from any provider you choose

• Ansible, version 2.14 or later (installation guide)

Step 1: Install the Skupper Ansible collection

Use the ansible-galaxy command to install the skupper.network collection.

Terminal:

ansible-galaxy collection install skupper.network

Step 2: Install the Skupper command-line tool

The Skupper Ansible collection uses the Skupper command-line tool to deploy Skupper.

On Linux or Mac, you can use the install script (inspect it here) to download and extract the command:

curl https://skupper.io/install.sh | sh

The script installs the command under your home directory. It prompts you to add the command to your path if necessary.

For Windows and other installation options, see Installing Skupper.

Step 3: Set up your clusters

This example uses two clusters. The clusters are accessed using two kubeconfig files:

<project-dir>/ansible/kubeconfigs/east
<project-dir>/ansible/kubeconfigs/west

For each kubeconfig, set the KUBECONFIG environment variable to the file path and run the login command for your cluster. This updates the kubeconfig with the required credentials.

Note: The cluster login procedure varies by provider. See the documentation for yours:

• Minikube
• Amazon Elastic Kubernetes Service (EKS)
• Azure Kubernetes Service (AKS)
• Google Kubernetes Engine (GKE)
• IBM Kubernetes Service
• OpenShift

Terminal:

cd <project-dir>
export KUBECONFIG=$PWD/ansible/kubeconfigs/west
# Enter your provider-specific login command for cluster 1
export KUBECONFIG=$PWD/ansible/kubeconfigs/east
# Enter your provider-specific login command for cluster 2

Step 4: Inspect the inventory file

Before we start running commands, let's examine the inventory file. It's here that we can define Skupper sites, links, and exposed services.

ansible/inventory.yml:

all:
  vars:
    ansible_connection: local
  hosts:
    west:
      kubeconfig: "{{ inventory_dir }}/kubeconfigs/west"
      namespace: west
    east:
      kubeconfig: "{{ inventory_dir }}/kubeconfigs/east"
      namespace: east
      links:
        - host: west
      services:
        backend:
          ports:
            - 8080
          targets:
            - type: deployment
              name: backend

Our example has two sites, West and East, enumerated under hosts.

The links attribute on host east defines a link from East to West.

The services attribute on host east exposes the backend on East so the frontend in West can access it.

The playbooks that follow use this inventory data to set up and tear down the Skupper network.

For more information about inventory files, see the Ansible inventory guide.

Step 5: Run the setup playbook

Now let's look at the setup playbook.

ansible/setup.yml:

- hosts: west
  tasks:
    - command: "kubectl apply -f {{ playbook_dir }}/kubernetes/west.yaml"

- hosts: east
  tasks:
    - command: "kubectl apply -f {{ playbook_dir }}/kubernetes/east.yaml"

- hosts: all
  collections:
    - skupper.network
  tasks:
    - import_role:
        name: skupper

The two kubectl tasks deploy our example application.

The last task is to use the skupper role from the skupper.network collection to deploy the Skupper network.

Use the ansible-playbook command to run the playbook:

Terminal:

ansible-playbook -i ansible/inventory.yml ansible/setup.yml

Sample output:

$ ansible-playbook -i ansible/inventory.yml ansible/setup.yml
[...]

PLAY RECAP *********************************************************************************************
west             : ok=34   changed=12   unreachable=0    failed=0    skipped=69   rescued=0    ignored=0
east             : ok=34   changed=13   unreachable=0    failed=0    skipped=69   rescued=0    ignored=0

Step 6: Access the frontend

In order to use and test the application, we need external access to the frontend.

Use kubectl port-forward to make the frontend available at localhost:8080.

Terminal:

export KUBECONFIG=$PWD/ansible/kubeconfigs/west
kubectl port-forward deployment/frontend 8080:8080

You can now access the web interface by navigating to http://localhost:8080 in your browser.

Step 7: Run the teardown playbook

To clean everything up, run the teardown playbook.

ansible/teardown.yml:

- hosts: all
  collections:
    - skupper.network
  tasks:
  - import_role:
      name: skupper_delete

- hosts: west
  tasks:
    - command: "kubectl delete -f {{ playbook_dir }}/kubernetes/west.yaml"

- hosts: east
  tasks:
    - command: "kubectl delete -f {{ playbook_dir }}/kubernetes/east.yaml"

The skupper_delete role from the skupper.network collection removes all the Skupper resources.

Terminal:

ansible-playbook -i ansible/inventory.yml ansible/teardown.yml

Sample output:

$ ansible-playbook -i ansible/inventory.yml ansible/teardown.yml
[...]

PLAY RECAP *********************************************************************************************
west             : ok=9    changed=2    unreachable=0    failed=0    skipped=3    rescued=0    ignored=0
east             : ok=9    changed=2    unreachable=0    failed=0    skipped=3    rescued=0    ignored=0

Next steps

Check out the other examples on the Skupper website.

About this example

This example was produced using Skewer, a library for documenting and testing Skupper examples.

Skewer provides utility functions for generating the README and running the example steps. Use the ./plano command in the project root to see what is available.

To quickly stand up the example using Minikube, try the ./plano demo command.