Kubernetes External Access

Neependra Khare, CloudYuga @neependra

Load Balancing Basics

LB

Server2Server1 Server N

Load Balancing Basics

• Layer 7 LB - HTTP

• Layer 4 LB - TCP/UDP

Load Balancing in K8s• Internal

• Kube-proxy

• External • Cloud LoadBalancer • NodePort • External IP • Ingress • Service LBs

Kube-proxy

kube-proxy kube-proxy kube-proxy

PodA PodA

Request to access

service for PodA

Worker Worker Worker

External - Cloud LB

kube-proxy kube-proxy kube-proxy

Cloud LB

PodA PodB

PodA

PodB

Worker Worker Worker

External - NodePort

• ` kube-proxy kube-proxy kube-proxy

PodA PodB

PodA

PodB

NodePort-2 NodePort-2NodePort-2NodePort1 NodePort1 NodePort1

Worker Worker Worker

External - Cloud LB

kube-proxy kube-proxy kube-proxy

Cloud LB

PodA PodB

PodA

PodB

NodePort-2 NodePort-2NodePort-2NodePort1 NodePort1 NodePort1

WorkerWorkerWorker

external IPexternal IP

External - External IP

kube-proxy kube-proxy kube-proxy

PodA PodB

PodA

PodB

808080 808080

External IP

Worker Worker Worker

External - Ingress

Ingress Resources

LBIngress Controllerwatches updates

External - Ingress (GKE)apiVersion: extensions/v1beta1 kind: Ingress metadata: name: test spec: rules: - host: foo.bar.com http: paths: - path: /foo backend: serviceName: s1 servicePort: 80 - path: /bar backend: serviceName: s2 servicePort: 80

LB1 LB2

PodA PodA

PodB

PodB

PodB

PodC PodC

/foo

/bar

/xyz

foo.bar.com bar.xyz.com

Worker Worker

NodePort1 NodePort-2 NodePort-3

External - Ingress (GKE)apiVersion: extensions/v1beta1 kind: Ingress metadata: name: test spec: rules: - host: foo.bar.com http: paths: - backend: serviceName: s1 servicePort: 80 - host: bar.foo.com http: paths: - backend: serviceName: s2 servicePort: 80

LB1 LB2

PodA PodA

PodB

PodB

PodB

PodC PodC

foo.bar.com

bar.foo.com

abc.xyz.com

Worker Worker

NodePort1 NodePort-2 NodePort-3

External - Ingress (Nginx)apiVersion: extensions/v1beta1 kind: Ingress metadata: name: test spec: rules: - host: foo.bar.com http: paths: - path: /foo backend: serviceName: s1 servicePort: 80 - path: /bar backend: serviceName: s2 servicePort: 80

LB1 LB2

PodA PodA

PodB

PodB

PodB

PodC PodC

/foo

/bar

/xyz

foo.bar.com bar.xyz.com

Worker Worker

Service LB

LBHAProxy

apiVersion: v1 kind: ReplicationController metadata: name: service-loadbalancer labels: app: service-loadbalancer version: v1 spec: replicas: 1 selector: app: service-loadbalancer version: v1 template: metadata: labels: app: service-loadbalancer version: v1 spec: nodeSelector: role: loadbalancer containers: - image: gcr.io/google_containers/servicelb:0.4 imagePullPolicy: Always livenessProbe: httpGet: path: /healthz port: 8081 scheme: HTTP initialDelaySeconds: 30 timeoutSeconds: 5 name: haproxy ports: # All http services - containerPort: 80 hostPort: 80 protocol: TCP # mysql - containerPort: 3306 hostPort: 3306 protocol: TCP # haproxy stats - containerPort: 1936

https://github.com/kubernetes/contrib/blob/master/service-loadbalancer/rc.yaml

PodB

PodA

PodB

Worker Worker

Q & A

Thanks

@neependra, CloudYuga.guru