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Setting up HTTP Load Balancing with Ingress
Create a backend service
Create a simple web services, analogous to those encountered in the previous chapter but of type NodePort, that are listening on a HTTP server on port 80. When you create a Service of type NodePort, Kubernetes makes your Service available on a randomly selected high port number (in the range 30000-32767) on all the nodes in your cluster.
| Code Block |
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| language | yml |
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| title | Example deployment |
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| collapse | true |
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|
apiVersion: apps/v1
kind: Deployment
metadata:
name: coffee
spec:
replicas: 2
selector:
matchLabels:
app: coffee
template:
metadata:
labels:
app: coffee
spec:
containers:
- name: coffee
image: nginxdemos/nginx-hello:plain-text
ports:
- containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
name: coffee-svc
labels:
app: coffee
spec:
ports:
- port: 80
targetPort: 8080
protocol: TCP
name: http
selector:
app: coffee
type: NodePort # <--- Pay attention
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: tea
spec:
replicas: 3
selector:
matchLabels:
app: tea
template:
metadata:
labels:
app: tea
spec:
containers:
- name: tea
image: nginxdemos/nginx-hello:plain-text
ports:
- containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
name: tea-svc
labels:
app: tea
spec:
ports:
- port: 80
targetPort: 8080
protocol: TCP
name: http
selector:
app: tea
type: NodePort # <--- Pay attention |
We could verify the service using its CLUSTER-IP on Kubernetes master node
| Code Block |
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| language | bash |
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| title | Verify Service |
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|
$ kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
coffee-svc NodePort 10.110.66.194 <none> 80:31156/TCP 3d1h
tea-svc NodePort 10.96.32.111 <none> 80:30458/TCP 3d1h
# Verify that the service is working
$ curl 10.110.66.194
Server address: 172.16.231.221:8080
Server name: coffee-6f4b79b975-v7cv2
Date: 30/Oct/2020:16:33:20 +0000
URI: /
Request ID: 8d870888961431bf04dd2305d614004f |
Create an Ingress resource
Now we create an Ingress resource, to make your HTTP web server application publicly accessible. The following command defines an Ingress resource that forwards traffic that requests http://webserver-bar.com to the webserver
| Code Block |
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| language | yml |
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| title | Ingress resource |
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| collapse | true |
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|
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: lb
annotations:
kubernetes.io/ingress.class: "openstack"
octavia.ingress.kubernetes.io/internal: "false" # Set true, if you don't want your Ingress to be accessible from the public internet
spec:
rules:
- host: webserver-bar.com
http:
paths:
- path: /tea
pathType: Prefix
backend:
service:
name: tea-svc
port:
number: 80
- path: /coffee
pathType: Prefix
backend:
service:
name: coffee-svc
port:
number: 80 |
Verify that Ingress Resource has been created. Please note that the IP address will not be defined right away (wait for the ADDRESS field to get populated). It is possible to follow the implementation of the LoadBalancer step by step, from the creation of its components (Listener, Pool, Policy) to the assignment of the FIP, from the log of the Pod of the Ingress Controller (the whole operation can take a few minutes).