Kubernetes is an open-source system for automating the management of containerized applications. Istio is an open platform to connect, manage, and secure microservices.
Service mesh is a configurable infrastructure layer for microservices application that makes communication between services reliable, fast, and secure. A service mesh typically consists of a data plane and a control plane. The data plane is composed of a set of intelligent proxies that mediate communication between microservices. The control plane manages and configures the proxies.
Istio is a service mesh for Kubernetes. It is composed of a data plane and a control plane. The data plane is composed of a set of intelligent proxies that mediate communication between microservices. The control plane manages and configures the proxies.
Kubernetes with Istio can be used to implement a service mesh for your applications. In this article, we will show you how to install and configure Istio on a Kubernetes cluster, and how to deploy a sample microservices application.
Istio can be installed on a Kubernetes cluster using the Helm package manager. Helm is a tool for managing Kubernetes applications.
To install Istio, you need to first install Helm and add the Istio Helm repository.
Download the Helm binary from the Helm website.
Extract the helm binary and add it to your PATH.
tar xzf helm-v2.16.5-linux-amd64.tar.gz
sudo mv linux-amd64/helm /usr/local/bin/
Initialize Helm and install Tiller, the server-side component of Helm.
helm init
Add the Istio Helm repository.
helm repo add istio.io https://storage.googleapis.com/istio-release/releases/1.5.2/charts/
Update the Helm repository.
helm repo update
We will deploy a sample microservices application consisting of four services:
The frontend and backend services will be deployed in separate pods. The database service will be deployed in a separate pod. The load balancer service will be deployed in a separate pod.
The frontend service will make requests to the backend service. The backend service will make requests to the database service. The load balancer service will route traffic to the frontend and backend services.
We will deploy the application using the Istio Helm chart.
Install the Istio Helm chart with the following command:
helm install --name istio-system -f /path/to/custom-values.yaml istio.io/istio
The Istio Helm chart is installed in the istio-system namespace.
Create a pod for the frontend service.
apiVersion: v1
kind: Pod
metadata:
name: frontend
labels:
app: frontend
spec:
containers:
- name: frontend
image: node:12-alpine
ports:
- containerPort: 3000
Deploy the pod.
kubectl apply -f /path/to/frontend-pod.yaml
Create a pod for the backend service.
apiVersion: v1
kind: Pod
metadata:
name: backend
labels:
app: backend
spec:
containers:
- name: backend
image: golang:1.14-alpine
ports:
- containerPort: 3000
Deploy the pod.
kubectl apply -f /path/to/backend-pod.yaml
Create a pod for the database service.
apiVersion: v1
kind: Pod
metadata:
name: database
labels:
app: database
spec:
containers:
- name: database
image: mysql:5.7
ports:
- containerPort: 3306
Deploy the pod.
kubectl apply -f /path/to/database-pod.yaml
Create a pod for the load balancer service.
apiVersion: v1
kind: Pod
metadata:
name: load-balancer
labels:
app: load-balancer
spec:
containers:
- name: load-balancer
image: nginx:1.17.9-alpine
ports:
- containerPort: 80
Deploy the pod.
kubectl apply -f /path/to/load-balancer-pod.yaml
To test the application, we will send a request to the load balancer service. The load balancer service will route the request to the frontend service. The frontend service will make a request to the backend service. The backend service will make a request to the database service.
First, we need to get the IP address of the load balancer service.
kubectl get svc
The output should look like this:
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
frontend ClusterIP 10.108.1.194 <none> 3000/TCP 1m
backend ClusterIP 10.96.247.199 <none> 3000/TCP 1m
database ClusterIP 10.111.142.247 <none> 3306/TCP 1m
load-balancer LoadBalancer 10.102.129.251 <pending> 80:32000/TCP 1m
The load balancer service has a ClusterIP of 10.102.129.251 and a PORT of 80:32000.
We can now send a request to the load balancer service.
curl -v http://10.102.129.251:80
The output should look like this:
* Trying 10.102.129.251:80...
* TCP_NODELAY set
* Connected to 10.102.129.251 (10.102.129.251) port 80 (#0)
> GET / HTTP/1.1
> Host: 10.102.129.251:80
> User-Agent: curl/7.64.1
> Accept: */*
>
< HTTP/1.1 200 OK
< Content-Type: text/html
< Content-Length: 28
<
<html>
<body>
Hello, World!
</body>
</html>
* Connection #0 to host 10.102.129.251 left intact
The request was routed to the frontend service and the response was returned.
In this article, we have shown you how to install and configure Istio on a Kubernetes cluster, and how to deploy a sample microservices application. Istio can be used to implement a service mesh for your applications.