How to setup Kubernetes Cluster in Ubuntu using Kubeadm | Install Kubernetes Cluster in Ubuntu | Setup Master Node and worker Node in Ubuntu EC2

Kubernetes  is an open source container platform that eliminates many of the manual processes involved in deploying and scaling containerized applications. We will learn how to setup Kubernetes Cluster in Ubuntu 18.0.4. You can setup Kubernetes Cluster in many ways. One of the ways is to use Kubeadm.

Kubeadm is a tool built to provide kubeadm init and kubeadm join as best-practice “fast paths” for creating Kubernetes clusters.

Watch the steps in YouTube video:

Prerequisites:

1. Ubuntu instance with 4 GB RAM - Master Node - (with ports open to all traffic)

2. Ubuntu instance with at least 2 GB RAM - Worker Node - (with ports open to all traffic)

Kubernetes Setup using Kubeadm

###Start - Execute the below commands in both Master/worker nodes##########

Login to both instances execute the below commands:
sudo apt-get update -y  && sudo apt-get install apt-transport-https -y

Change to root user

sudo su -
sudo curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add -

cat <<EOF >/etc/apt/sources.list.d/kubernetes.list
deb https://apt.kubernetes.io/ kubernetes-xenial main
EOF

sudo apt-get update

#Disable swap memory for better performance
swapoff -a
sudo sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab

Enable IP tables
#We need to enable IT tables for pod to pod communication.

modprobe br_netfilter
sysctl -p
sudo sysctl net.bridge.bridge-nf-call-iptables=1

Install Docker on both Master and Worker nodes
apt-get install docker.io -y

Add ubuntu user to Docker group

usermod -aG docker ubuntu
systemctl restart docker
systemctl enable docker.service

Type exit to come out of root user.
Install Kubernetes Modules
sudo apt-get install -y kubelet kubeadm kubectl kubernetes-cni

sudo systemctl daemon-reload
sudo systemctl start kubelet
sudo systemctl enable kubelet.service

sudo systemctl status docker

#End - Execute the above commands in both Master/worker nodes##########

Initialize Kubeadm on Master Node(only on Master Node)

#Execute the below command as root user to initialize Kubernetes Master node.
sudo su -
kubeadm init

Make sure you see the above message to confirm master node is up.

#Now type exit to exit from root user and execute below commands as normal user

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

Installing the Weave Net Add-On
kubectl apply -f "https://cloud.weave.works/k8s/net?k8s-version=$(kubectl version | base64 | tr -d '\n')"

It make take a few mins to execute the above command and show show the below message.

Now execute the below command to see the pods.

kubectl get pods  --all-namespaces

Now login to Worker Node

Join worker node to Master Node

The below command will join worker node to master node, execute this a normal user by putting sudo before:

sudo kubeadm join <master_node_ip>:6443 --token xrvked.s0n9771cd9x8a9oc \
    --discovery-token-ca-cert-hash sha256:288084720b5aad132787665cb73b9c530763cd1cba10e12574b4e97452137b4a

Go to Master and type the below command

kubectl get nodes

the above command should display both Master and worker nodes.

It means Kubernetes Cluster - both Master and worker nodes are setup successfully and up and running!!!

Deploy Nginx on a Kubernetes Cluster
Let us run some apps to make sure they are deployed to Kuberneter cluster. We will do this in master node. The below command will create deployment:

kubectl create deployment nginx --image=nginx

View Deployments
kubectl get deployments

Create as a service 

kubectl create service nodeport nginx --tcp=80:80

kubectl get svc

run the above command to see a summary of the service and the ports exposed.

Now go Master or worker node, enter public dns and access it with port exposed

You should see the welcome page!

ERROR: java.lang.RuntimeException: io.kubernetes.client.openapi.ApiException | Kubernetes Deployment Error

Kubernetes Deployment Error from Jenkins to EKS Cluster. When ever you deploy to Kubernetes from Jenkins, you may have the below error.

ERROR: java.lang.RuntimeException: io.kubernetes.client.openapi.ApiException: hudson.remoting.ProxyException: java.lang.RuntimeException: io.kubernetes.client.openapi.ApiException:

Fix - Set a clusterrole as cluster-admin

By default, clusterrolebinding has system:anonymous set which blocks the cluster access. Execute the following command to set a clusterrole as cluster-admin which will give you the required access.

kubectl create clusterrolebinding cluster-system-anonymous --clusterrole=cluster-admin --user=system:anonymous

How to enable webhooks for multibranch pipeline in Jenkins | Create webhooks for multibranch pipeline in Jenkins

How to kick start multibranch pipeline in Jenkins pipeline automatically every time you make a code change in your SCM?

Pre-requisites:

We need to install multibranch scan webhook trigger plug-in

Go to Jenkins, Manage Jenkins. Manage plug-ins.

search by  multibranch scan

Once plug-in is installed, let's create a hook.

Please watch the above steps in YouTube channel:

Steps:

Go to Jenkins, click on your existing multibranch pipeline job. Click on configure.

After installing the plug-ins, click on scan multibranch pipeline trigger section. click on scan by webhook. and enter token info.

Copy Jenkins url for configuring webhooks. click on ?

Now create a webhook in GitHub

Go to your git repo, click on settings, Webhooks.enter jenkins url

JENKINS_URL/multibranch-webhook-trigger/invoke?token=myToken123

Click on update webhook. make sure it has configured correctly.

Now if you make a code change, it should trigger multi branch pipeline job.

How to create another branch from Main branch using command line

 Go to your EC2 instance or where ever your code exists in local repository. login to your instance and go to your repo.

cd reponame

Now let's create a new branch called develop from main branch.

git checkout -b develop

Now you can see how many branches are created locally.

git branch

git push --set-upstream origin develop

That is how you create a new branch from command line and push that branch into Remote repo.

How to create Multibranch pipeline in Jenkins | Multibranch pipeline tutorial

Let us learn how to create multi branch pipeline using Jenkins.

What is Multi-branch pipeline?

 - Automatically create new pipelines for every Git branch in source version control.

- Enables different pipeline implementation for every branch. for e.g let us say you want to have CICD pipeline for master branch and only CI pipeline for develop branch.

- an automatically discover new branches in the source control (GitHub or any SCM) and automatically create a pipeline for that branch.

Watch the steps in YouTube:

Pre-requisites:

• Jenkins up and running
• source code configured in GitHub or any SCM

Create Jenkinsfile first

Please follow the link above to understand how to create Declarative pipeline - Jenkinsfile.

How to create multibranch pipeline?

 Go to Jenkins. Create a new Item. give a name like myMultiBranchPipelineJob

Click ok

Click branch source,  Add source, Add git.

Give your repo URL which has Jenkinsfile already.

Give your Git repo url, credentials. select credentials from the drop down.

Click apply and Save.

Now the pipeline job will automatically scan and creates pipeline per branch.

How to upload Docker images to Azure Container Registry | Hosting Docker images in Azure Container Registry

Azure Container Registry is a managed, private docker registry service. You can create and maintain Azure container registries to store and manage your private Docker container images.

It is alternative to Docker Hub. Azure Container Registry allows you to build, store, and manage container images and artifacts in a private registry for all types of container deployments.

Let us see how to upload a docker images from your VM into ACR.

Watch the steps below in YouTube channel:

Pre-requisites:

Make sure you have docker installed on your VM.
 

Step 1 - Create Azure Container Registry (ACR)

Go to https://portal.azure.com/
Create a Resource, Give container registry as a name

Click on Create

  

Enter values as mentioned below:

Give registry name, resource group and choose Enable admin user and SKU as Basic 

 Click on Review and then create, now your container registry is been created.

Step 2 - Download sample Python App

Go to your machine where you have docker images stored. perform below command to download sample pythonapp which is already dockerized.

 

git clone https://bitbucket.org/ananthkannan/mydockerrepo/src/master/pythonApp/ 

cd  pythonApp/pythonApp

Step 3 - Create docker image

docker build . -t mypythonapp

type below command:

sudo docker images

this should show docker images you have created locally.

Now go to ACR, click on docker registry you created. Click on access keys under Settings.

Copy value under login server 

Login to Azure Container Registry through command line.

sudo docker login mydockerazureregistry.azurecr.io

Username: mydockerazureregistry

Enter password by copying value below password

Step 4 - Tag and Push your docker image to ACR

Now tag the docker image per as below:

sudo docker tag mypythonapp mydockerazureregistry.azurecr.io/mypythonapp

sudo docker push mydockerazureregistry.azurecr.io/mypythonapp

That's it..Docker image is pushed into ACR. 

You can see the Docker image uploaded under Services--> repositories