Service Mesh and Serverless Chatbots with Linkerd, K8s and OpenFaaS - Lab

Kubernetes Cluster Creation

1. Create a Digital Ocean k8s cluster
2. Instalar Kubectl

curl -LO https://storage.googleapis.com/kubernetes-release/release/`curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt`/bin/linux/amd64/kubectl
chmod +x ./kubectl
sudo mv ./kubectl /usr/local/bin/kubectl

Installing OpenFaaS

Helm Installation and configuration

Download and install helm

curl -fsSL -o get_helm.sh https://raw.githubusercontent.com/helm/helm/master/scripts/get-helm-3
chmod 700 get_helm.sh
./get_helm.sh

Adding some useful charts to helm

helm repo add stable https://kubernetes-charts.storage.googleapis.com/

Adding OpenFaaS Helm Chart

helm repo add openfaas https://openfaas.github.io/faas-netes/

Some useful OpenFaaS documentation:

• Source: https://docs.openfaas.com/deployment/kubernetes/ Chart
• Readme: https://github.com/openfaas/faas-netes/blob/master/chart/openfaas/README.md
• Helm readme: https://github.com/openfaas/faas-netes/blob/master/HELM.md
• Detail: https://github.com/openfaas/faas-netes/blob/master/chart/openfaas/README.md

Creating openfaas and openfaas-fn namespaces used by the default installation:

kubectl apply -f https://raw.githubusercontent.com/openfaas/faas-netes/master/namespaces.yml

Installing nginx-ingress to give public access to openfaas

helm install nginx-ingress --namespace openfaas stable/nginx-ingress

Creating default user and password login

kubectl -n openfaas create secret generic basic-auth --from-literal=basic-auth-password=kubeconeu123 --from-literal=basic-auth-user=admin

Create values.yaml file

async: "false"
basic_auth: "false"
faasIdler: 
  dryRun: "false"
  inactivityDuration: "1m"
gateway: 
  readTimeout: "900s"
  replicas: "2"
  upstreamTimeout: "800s"
  writeTimeout: "900s"
queueWorker: 
  replicas: "2"    
functionNamespace: "openfaas"

Suggested installation

helm install openfaas --namespace openfaas openfaas/openfaas -f values.yaml

test just dry-run(optional)

helm install openfaas --namespace openfaas openfaas/openfaas -f values.yaml --dry-run    

Check deployment

kubectl -n openfaas get deployments -l "release=openfaas, app=openfaas"

Create ingress rule with nginx-ingress to expose OpenFaaS

kubectl create -f public-openfaas.yaml
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  annotations:
    kubernetes.io/ingress.class: nginx
  name: public-openfaas
  namespace: openfaas
spec:
  rules:
    - host: openfaas.curzona.net
      http:
        paths:
          - backend:
              serviceName: gateway
              servicePort: 8080
            path: /
  # Optional section if you are using TLS
  tls:
      - hosts:
          - openfaas.curzona.net
        secretName: openfaas-cert

Installing faas cli

curl -sSL https://cli.openfaas.com | sudo sh

login to OpenFaaS via CLI

faas-cli login --username admin --password kubeconeu123 --gateway openfaas.curzona.net 

OpenFaaS Logout

faas-cli logout --gateway openfaas.curzona.net

Note: use the option --tls-no-verify for self signed certifies

Linkerd installation

Steps

curl -sL https://run.linkerd.io/install | sh

Add the following line to ~/.profile

export PATH=$PATH:$HOME/.linkerd2/bin

Run .profile to load the updated PATH

. ~/.profile

Check the version of linkerd cli

linkerd version

Pre-check before linkerd installation, look if there is not another installation

linkerd check --pre

Install Linkerd

linkerd install | kubectl apply -f -

Check the installation

linkerd check

Check everything is deployed

kubectl -n linkerd get deploy

Accesing to the Linkerd Dashboard

linkerd dashboard

Securing the Linkerd dashboard

apt-get install -y apache2-utils

Create auth credentials with htpasswd

htpasswd -c auth admin    [Enter password for admin, stored in the auth file]

kubectl -n linkerd create secret generic basic-auth --from-file auth 

Create public-linkerd.yaml

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  annotations:
    kubernetes.io/ingress.class: nginx
    nginx.ingress.kubernetes.io/auth-type: basic
    nginx.ingress.kubernetes.io/auth-secret: basic-auth
    nginx.ingress.kubernetes.io/upstream-vhost: $service_name.$namespace.svc.cluster.local:8084
    nginx.ingress.kubernetes.io/configuration-snippet: |
      proxy_set_header Origin "";
      proxy_hide_header l5d-remote-ip;
      proxy_hide_header l5d-server-id;
  name: public-linkerd
  namespace: linkerd
spec:
  rules:
    - host: linkerd.curzona.net
      http:
        paths:
          - backend:
              serviceName: linkerd-web
              servicePort: 8084
            path: /

Create a ingress with password protection with the next command:

kubectl -n linkerd create -f public-linkerd.yaml

Tutorial Bot

• https://github.com/slackapi/python-slackclient/blob/master/tutorial/03-responding-to-slack-events.md
• https://readthedocs.org/projects/python-slackclient/downloads/pdf/latest/

Essentials packages for Slack chatbots in python

apt-get install python3-dev
apt-get install python3-pip

Creating a serverless Slack chatbot with python with OpenFaaS

apt-get install docker.io

mkdir faas

cd faas

faas template pull https://github.com/openfaas-incubator/python-flask-template

faas new --lang python3-flask chatbot #then add your code

The final result is located in the chatbot directory of this repository.

Create a Slack bot with Slack API

1. Create a Slack app(https://api.slack.com/apps/new) (if you don't already have one).
2. Add a Bot User and configure your bot user with some basic info (display name, default username and its online presence).
3. Once you've completed these fields, click Add Bot User.
4. Next, give your bot access to the Events API.
5. Finally, add your bot to your workspace.

Inject OpenFaaS pods with linkerd

kubectl -n openfaas get deploy gateway -o yaml | linkerd inject --skip-outbound-ports=4222 - | kubectl apply -f -
kubectl -n openfaas get deploy/basic-auth-plugin -o yaml | linkerd inject - | kubectl apply -f -
kubectl -n openfaas get deploy/faas-idler -o yaml | linkerd inject - | kubectl apply -f -
kubectl -n openfaas get deploy/queue-worker -o yaml | linkerd inject  --skip-outbound-ports=4222 - | kubectl apply -f -

kubectl annotate namespace openfaas linkerd.io/inject=enabled

Inject ingress controller

kubectl -n openfaas get deploy/nginx-ingress-controller -o yaml | linkerd inject - | kubectl apply -f -

Add the following in the annotations block

kubectl -n openfaas edit deployment nginx-ingress-controller
nginx.ingress.kubernetes.io/configuration-snippet: |
  proxy_set_header l5d-dst-override gateway.openfaas.svc.cluster.local:8080;
  proxy_hide_header l5d-remote-ip;
  proxy_hide_header l5d-server-id;

Deploy 3 services echo chatbot-root is a dummy service

faas-cli deploy --gateway=http://openfaas.curzona.net --image hub.cloudsociety.dev/openfaas/chatbot:latest --name chatbot-green
faas-cli deploy --gateway=http://openfaas.curzona.net --image hub.cloudsociety.dev/openfaas/chatbot:latest --name chatbot-blue
faas-cli deploy --gateway=http://openfaas.curzona.net --image hub.cloudsociety.dev/openfaas/chatbot:latest --name chatbot-root

Test the access to the services

curl http://openfaas.curzona.net/function/chatbot-green.openfaas/slack/events
curl http://openfaas.curzona.net/function/chatbot-blue.openfaas/slack/events
curl http://openfaas.curzona.net/function/chatbot.openfaas/slack/events

Inject the green and blue chatbots

kubectl get -n openfaas deployment chatbot-root -o yaml \
  | linkerd inject - \
  | kubectl apply -f -

kubectl get -n openfaas deployment chatbot-green -o yaml \
  | linkerd inject - \
  | kubectl apply -f -

kubectl get -n openfaas deployment chatbot-blue -o yaml \
  | linkerd inject - \
  | kubectl apply -f -

Apply the traffic splitting rule

kubectl apply -f -
apiVersion: split.smi-spec.io/v1alpha1
kind: TrafficSplit
metadata:
  name: function-split
  namespace: openfaas
spec:
  # The root service that clients use to connect to the destination application.
  service: chatbot-root
  # Services inside the namespace with their own selectors, endpoints and configuration.
  backends:
  - service: chatbot-blue
    weight: 500m
  - service: chatbot-green
    weight: 500m

Sending traffic with a loop

for i in {0..10}; do  curl http://openfaas.curzona.net/function/echo.openfaas; done    

Removing the traffic splitting

kubectl delete -f -
apiVersion: split.smi-spec.io/v1alpha1
kind: TrafficSplit
metadata:
  name: function-split
  namespace: openfaas
spec:
  # The root service that clients use to connect to the destination application.
  service: echo
  # Services inside the namespace with their own selectors, endpoints and configuration.
  backends:
  - service: echo-blue
    weight: 100m
  - service: echo-green
    weight: 900m

Resourses

[install linkerd2 with observability in OpenFaaS] (https://github.com/openfaas-incubator/openfaas-linkerd2)