Kubernetes (on-premises) Metallb LoadBalancer and sticky sessions - kubernetes

Question

I installed one Kubernetes Master and two kubernetes worker on-premises.
After I installed Metallb as LoadBalancer using commands below:
$ kubectl edit configmap -n kube-system kube-proxy
apiVersion: kubeproxy.config.k8s.io/v1alpha1
kind: KubeProxy
Configuration mode:
"ipvs" ipvs:
strictARP: true
kubectl apply -f https://raw.githubusercontent.com/metallb/metallb/v0.9.6/manifests/namespace.yaml
kubectl apply -f https://raw.githubusercontent.com/metallb/metallb/v0.9.6/manifests/metallb.yaml
kubectl create secret generic -n metallb-system memberlist --from-literal=secretkey="$(openssl rand -base64 128)"
vim config-map.yaml
apiVersion: v1
kind: ConfigMap
metadata:
namespace: metallb-system
name: config
data:
config: |
address-pools:
- name: default
protocol: layer2
addresses:
- 10.100.170.200-10.100.170.220
kubectl apply -f config-map.yaml
kubectl describe configmap config -n metallb-system
I created my yaml file as below:
myapp-tst-deploy.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: myapp-tst-deployment
labels:
app: myapp-tst
spec:
replicas: 2
selector:
matchLabels:
app: myapp-tst
template:
metadata:
labels:
app: myapp-tst
spec:
containers:
- name: myapp-tst
image: myapp-tomcat
securityContext:
privileged: true
capabilities:
add:
- SYS_ADMIN
myapp-tst-service.yaml
apiVersion: v1
kind: Service
metadata:
name: myapp-tst-service
labels:
app: myapp-tst
spec:
externalTrafficPolicy: Cluster
type: LoadBalancer
ports:
- name: myapp-tst-port
nodePort: 30080
port: 80
protocol: TCP
targetPort: 8080
selector:
app: myapp-tst
sessionAffinity: None
myapp-tst-ingress.yaml
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: myapp-tst-ingress
annotations:
kubernetes.io/ingress.class: "nginx"
nginx.ingress.kubernetes.io/affinity: "cookie"
nginx.ingress.kubernetes.io/affinity-mode: "persistent"
nginx.ingress.kubernetes.io/session-cookie-name: "INGRESSCOOKIE"
nginx.ingress.kubernetes.io/session-cookie-expires: "172800"
nginx.ingress.kubernetes.io/session-cookie-max-age: "172800"
spec:
rules:
- http:
paths:
- path: /
backend:
serviceName: myapp-tst-service
servicePort: myapp-tst-port
I run kubectl -f apply for all three files, and these is my result:
kubectl get all -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
pod/myapp-tst-deployment-54474cd74-p8cxk 1/1 Running 0 4m53s 10.36.0.1 bcc-tst-docker02 <none> <none>
pod/myapp-tst-deployment-54474cd74-pwlr8 1/1 Running 0 4m53s 10.44.0.2 bca-tst-docker01 <none> <none>
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
service/myapp-tst-service LoadBalancer 10.110.184.237 10.100.170.15 80:30080/TCP 4m48s app=myapp-tst,tier=backend
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 6d22h <none>
NAME READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR
deployment.apps/myapp-tst-deployment 2/2 2 2 4m53s myapp-tst mferraramiki/myapp-test app=myapp-tst
NAME DESIRED CURRENT READY AGE CONTAINERS IMAGES SELECTOR
replicaset.apps/myapp-tst-deployment-54474cd74 2 2 2 4m53s myapp-tst myapp/myapp-test app=myapp-tst,pod-template-hash=54474cd74
But when I try to connect using LB external IP (10.100.170.15) the system redirect the browser request
(on the same browser) on a pod, if I refresh or open a new tab (on the same url) the system reply redirect the request to another pod.
I need when a user digit url in the browser, he must be connect to a specific pod during all session, and not switch to other pods.
How can solve this problem if is it possible?
In my VM I resolved this issue using stickysession, how can enable it on LB or in Kubernetes components?

Answer 1

In the myapp-tst-service.yaml file the "sessionAffinity" is set to "None".
You should try to set it to "ClientIP".
From page https://kubernetes.io/docs/concepts/services-networking/service/ :
"If you want to make sure that connections from a particular client are passed to the same Pod each time, you can select the session affinity based on the client's IP addresses by setting service.spec.sessionAffinity to "ClientIP" (the default is "None"). You can also set the maximum session sticky time by setting service.spec.sessionAffinityConfig.clientIP.timeoutSeconds appropriately. (the default value is 10800, which works out to be 3 hours)."