Kubernetes Development with MicroK8s
Using Ubuntu's MicroK8s Kubernetes environment to test a Nginx container with a NodePort and also Ingress so we can access from another machine.
install
$ sudo snap install microk8s --classic
microk8s v1.18.2 from Canonical✓ installed
$ sudo usermod -a -G microk8s rrosso
$ microk8s.kubectl get all --all-namespaces
NAMESPACE NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
default service/kubernetes ClusterIP 10.152.183.1 443/TCP 2m29s
$ microk8s.kubectl get nodes
NAME STATUS ROLES AGE VERSION
server1 Ready 3m v1.18.2-41+b5cdb79a4060a3
$ microk8s.enable dns dashboard
...
$ watch microk8s.kubectl get all --all-namespaces NOTE: alias the command
$ sudo snap alias microk8s.kubectl kubectl
Added:
- microk8s.kubectl as kubectlnginx first attempt
$ kubectl create deployment nginx --image=nginx
deployment.apps/nginx created
$ kubectl get deployments
NAME READY UP-TO-DATE AVAILABLE AGE
nginx 1/1 1 1 9s
$ kubectl get pods
NAME READY STATUS RESTARTS AGE
nginx-f89759699-jnlng 1/1 Running 0 15s
$ kubectl get all --all-namespaces
NAMESPACE NAME READY STATUS RESTARTS AGE
default pod/nginx-f89759699-jnlng 1/1 Running 0 31s
...
NAMESPACE NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
default service/kubernetes ClusterIP 10.152.183.1 443/TCP 94m
...
NAMESPACE NAME READY UP-TO-DATE AVAILABLE AGE
default deployment.apps/nginx 1/1 1 1 31s
kube-system deployment.apps/coredns 1/1 1 1 90m
...
NAMESPACE NAME DESIRED CURRENT READY AGE
default replicaset.apps/nginx-f89759699 1 1 1 31s
kube-system replicaset.apps/coredns-588fd544bf 1 1 1 90m
...
$ kubectl get all --all-namespaces
NAMESPACE NAME READY STATUS RESTARTS AGE
default pod/nginx-f89759699-jnlng 1/1 Running 0 2m38s
...
NAMESPACE NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
...
NAMESPACE NAME READY UP-TO-DATE AVAILABLE AGE
default deployment.apps/nginx 1/1 1 1 2m38s
NAMESPACE NAME DESIRED CURRENT READY AGE
default replicaset.apps/nginx-f89759699 1 1 1 2m38s
...
$ wget 10.152.183.151
--2020-05-25 14:26:14-- http://10.152.183.151/
Connecting to 10.152.183.151:80... connected.
HTTP request sent, awaiting response... 404 Not Found
2020-05-25 14:26:14 ERROR 404: Not Found.
$ kubectl get deployments
NAME READY UP-TO-DATE AVAILABLE AGE
nginx 1/1 1 1 3m40s
$ kubectl get pods
NAME READY STATUS RESTARTS AGE
nginx-f89759699-jnlng 1/1 Running 0 3m46s
$ microk8s.kubectl expose deployment nginx --port 80 --target-port 80 --type ClusterIP --selector=run=nginx --name nginx
service/nginx exposed
$ microk8s.kubectl get all
NAME READY STATUS RESTARTS AGE
pod/nginx-f89759699-jnlng 1/1 Running 0 9m29s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.152.183.1 443/TCP 103m
service/nginx ClusterIP 10.152.183.55 80/TCP 3m55s
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/nginx 1/1 1 1 9m29s
NAME DESIRED CURRENT READY AGE
replicaset.apps/nginx-f89759699 1 1 1 9m29s
$ wget 10.152.183.55
--2020-05-25 14:33:02-- http://10.152.183.55/
Connecting to 10.152.183.55:80... failed: Connection refused. NOTE: Kubernetes does not provide a loadbalancer. It is assumed that loadbalancers are an external component. MicroK8s is not shipping any loadbalancer but even if it did there would not have been any nodes to balance load over. There is only one node so if you want to expose a service you should use the NodePort service type.
There is no external LB shipping with MicroK8s, therefore there is no way to appoint an (LB provided) external IP to a service. What you can do is to expose a service to a host's port using NodePort.
nginx attempt 2
$ kubectl delete services nginx-service
service "nginx-service" deleted
$ kubectl delete deployment nginx
deployment.apps "nginx" deleted
$ kubectl create deployment nginx --image=nginx
deployment.apps/nginx created
$ kubectl expose deployment nginx --type NodePort --port=80 --name nginx-service
service/nginx-service exposed
$ kubectl get all
NAME READY STATUS RESTARTS AGE
pod/nginx-f89759699-jr4gz 1/1 Running 0 23s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.152.183.1 443/TCP 19h
service/nginx-service NodePort 10.152.183.229 80:30856/TCP 10s
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/nginx 1/1 1 1 23s
NAME DESIRED CURRENT READY AGE
replicaset.apps/nginx-f89759699 1 1 1 23s
$ wget 10.152.183.229
Connecting to 10.152.183.229:80... connected.
HTTP request sent, awaiting response... 200 OK
2020-05-26 08:05:22 (150 MB/s) - ‘index.html’ saved [612/612] ingress
$ cat ingress-nginx.yaml
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
name: http-ingress
spec:
rules:
- http:
paths:
- path: /
backend:
serviceName: nginx-service
servicePort: 80
$ kubectl apply -f ingress-nginx.yaml
ingress.networking.k8s.io/http-ingress createdNOTE: https://192.168.1.112/ pulls up Nginx homepage
after reboot:
- grafana console works
https://192.168.1.112:16443/api/v1/namespaces/kube-system/services/monitoring-grafana/proxy/?orgId=1 - ingress for nginx container works
https://192.168.1.112/ - kubernetes dashboard does not work. need to run a proxy
microk8s.kubectl proxy --accept-hosts=.* --address=0.0.0.0 &http://192.168.1.112:8001/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:/proxy
next
- persistent storage test
