First of all you need is a Kubernetes cluster available on your computer. In this tutorial we're going to use Minikube on Ubuntu. You can find how to install it in this link https://kubernetes.io/docs/tasks/tools/install-minikube/
Once you have Minikube installed on you computer start it and check its status:
> minikube startThe output is similar to this:
minikube v1.11.0 en Ubuntu 18.04
Using the docker driver based on existing profile
Starting control plane node minikube in cluster minikube
Restarting existing docker container for "minikube" ...
Setting up Kubernetes v1.18.3 en Docker 19.03.2...
kubeadm.pod-network-cidr=10.244.0.0/16
Verifying Kubernetes components...
Enabled addons: dashboard, default-storageclass,Then you can check minikube status:
> minikube statusThe scalability/elasticity of the application , as mentioned in previous sections, is based on HPA, and metrics-server monitoring needs to be deployed in the cluster to provide metrics via the resource metrics API, because HPA uses this API to collect metrics.
To install it on Minikube:
> minikube addons enable metrics-serverAnd you have an output like this:
> metrics-server was successfully enabledInside k8s folder type next command:
> kubectl apply -f ./backend_k8s.yaml You will show an output like this:
namespace/mscarceller created
configmap/eftgca-backvertx-configmap created
secret/webchat-secrets created
service/mongodb created
statefulset.apps/mongodb created
ingress.extensions/webchat-ingress created
service/webchatservice created
service/webchat created
horizontalpodautoscaler.autoscaling/webchat-consumer created
deployment.apps/webchatbackend created
persistentvolume/eftgca-backvertx-pv-volume created
persistentvolumeclaim/eftgca-backvertx-pv-claim created
In order to check the status of all the components deployed inside the cluster you can use the next command:
> watch -n 1 kubectl get pods,services,deployments,ingress --namespace=mscarceller
And you'll see something like this:
NAME READY STATUS RESTARTS AGE
pod/mongodb-0 1/1 Running 0 75s
pod/webchatbackend-5579777b5c-lxz8f 1/1 Running 0 60s
pod/webchatbackend-5579777b5c-p8ndk 1/1 Running 0 75s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/mongodb ClusterIP None <none> <none> 75s
service/webchat LoadBalancer 10.97.123.130 <pending> 8080:31737/TCP 75s
service/webchatservice ClusterIP None <none> 5701/TCP 75s
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/webchatbackend 2/2 2 2 75s
NAME CLASS HOSTS ADDRESS PORTS AGE
ingress.extensions/webchat-ingress <none> webchat-mscarceller.cloud.okteto.net 172.17.0.2 80 75sTo check if the metric server is measuring correctly our resources you can obtain its details:
> kubectl describe hpa webchat-consumer --namespace=mscarceller
The output:
Name: webchat-consumer
Namespace: mscarceller
Labels: <none>
Annotations: CreationTimestamp: Fri, 09 Oct 2020 18:35:18 +0200
Reference: Deployment/webchatbackend
Metrics: ( current / target )
resource cpu on pods (as a percentage of request): 5% (10m) / 75%
Min replicas: 2
Max replicas: 10
Deployment pods: 2 current / 2 desired
Conditions:
Type Status Reason Message
---- ------ ------ -------
AbleToScale True ReadyForNewScale recommended size matches current size
ScalingActive True ValidMetricFound the HPA was able to successfully calculate a replica count from cpu resource utilization (percentage of request)
ScalingLimited True TooFewReplicas the desired replica count is less than the minimum replica count
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal SuccessfulRescale 19m horizontal-pod-autoscaler New size: 2; reason: Current number of replicas below Spec.MinReplicas
To access the Kubernetes Dashboard, run this commands in a shell after starting Minikube to install the addon and get the address:
Install the dashboard Addon:
> minikube dashboard
Get the address:
> minikube dashboard
Verifying dashboard health ...
🚀 Launching proxy ...
🤔 Verifying proxy health ...
🎉 Opening http://127.0.0.1:46399/api/v1/namespaces/kubernetes-dashboard/services/http:kubernetes-dashboard:/proxy/ in your default browser...it will launch the browser:
NOTE: to get the access token you can use this command:
> kubectl -n kube-system describe secret $(kubectl -n kube-system get secret | awk '/^deployment-controller-token-/{print $1}') | awk '$1=="token:"{print $2}'
When you type a domain name in your browser to go to a website, your computer translates the domain name your typed into an IP address and connect to the server that hosts the website. We have deploy an Ingress Service, so to access the application in our browser we need to configure the local host file to redirect the traffic to our minikube cluster.
The definition of our ingress service is:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: webchat-ingress
namespace: mscarceller
annotations:
kubernetes.io/ingress.class: "nginx"
spec:
rules:
- host: webchat-mscarceller.cloud.okteto.net
http:
paths:
- path: /
backend:
serviceName: webchatfrontservice
servicePort: 8081
- path: /chat
backend:
serviceName: webchat
servicePort: 8080
- path: /images
backend:
serviceName: webchat
servicePort: 8080
- path: /files
backend:
serviceName: webchat
servicePort: 8080We need to redirect webchat-mscarceller.cloud.okteto.net traffic to the ip of our ingress service exposed by minikube
NOTE: we have Ingress configuration ready to deploy a front application on port 8081
First get the ingress IP:
> watch -n 1 kubectl get ingress --namespace=mscarceller
We get something like this:
NAME CLASS HOSTS ADDRESS PORTS AGE
webchat-ingress <none> webchat-mscarceller.cloud.okteto.net 172.17.0.2 80 50m
So we need to edit our our Hosts file:
> sudo nano /etc/hosts
A similar lines below should appear in the file.
127.0.0.1 localhost
127.0.1.1 migle-portatil
# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
We have to add next line:
172.17.0.2 webchat-mscarceller.cloud.okteto.net
Save the file. Changes you make to the hosts file take effect immediately.
Now you can reach the backend and connect to websocket at webchat-mscarceller.cloud.okteto.net/chat
Okteto Cloud gives access to Kubernetes namespaces to enable developers to code, build, and run Kubernetes applications entirely in the cloud.
First of all is to configure your cli tool for developing your applications in Okteto Cloud. Follow the steps in this link:
Then you can deploy it in the same way as you do on you local Kubernetes
> kubectl apply -f ./backend_k8s.yaml
Once you have your cli tool configured to use with Okteto you can use the same commands viewed previously.
You can also visit Okteto cloud dashboard and see something like this:
First of all you need is to deploy a back-end instance of the chat application, on your local Kubernetes or on Okteto cloud. Then run next command inside k8s folder:
> kubectl apply -f ./frontend_k8s.yaml
And you'll see something like this:
service/webchatfrontservice created
deployment.apps/webchatfront createdNow you can open the application in your browser at https://webchat-mscarceller.cloud.okteto.net/
NOTE: Remember to edit the Local Hosts File if you deploy on local Kubernetes