Introduction:

Kubernetes used to manage the docker containers across multiple cloud & virtualization platform. Kubernetes was designed by the Google. And k3s is used to reduce the higher load of k8sdeployment. So, here we’ll cover the installation of Kubernetes on Ubuntu 20.04 using k3s.

Setup Requirements:

We’ll need one Master node & the 2 worker nodes in order to perform our installation.

Master Node:

It handles the cluster, API calls and other process.

Workers Node:

Used to control the workloads, where pods deployed & applications run.

So, here we’ll be using one Master node & two worker nodes in order to complete our installation guide.

Step 1: Update Your System

As usual we do, update your system to have the latest updates installed.

sudo apt update && sudo apt upgrade -y

Once the update finished, reboot your system.

sudo systemctl reboot

Step 2: Mapping the Hosts On Ubuntu 20.04

Now, map the master and worker nodes on each host. To do this edit the file /etc/hosts/. And update according to hosts IP’s.

sudo nano /etc/hosts
172.16.10.3 master
172.16.10.4 worker01
172.16.10.10 worker02

Step 3: Install Docker On Ubuntu 20.04

Fire the below commands in your terminal to install docker on Ubuntu 20.04 as needed to use the Kubernetes. So, make sure docker is installed and running properly.

sudo apt update
sudo apt install apt-transport-https ca-certificates curl software-properties-common -y
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu focal stable"
sudo apt update
sudo apt install docker-ce -y

Note: Make sure to perform this action(docker installation) on all hosts.

And then start & enable docker services.

sudo systemctl start docker
sudo systemctl enable docker

Verify the status of docker by typing

sabi@ubuntu:~$ sudo systemctl status docker
● docker.service - Docker Application Container Engine
Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled)
Active: active (running) since Mon 2020-11-30 08:30:39 CET; 19s ago
TriggeredBy: ● docker.socket
Docs: https://docs.docker.com
Main PID: 9275 (dockerd)
Tasks: 8
Memory: 35.6M
CGroup: /system.slice/docker.service
└─9275 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock
Nov 30 08:30:39 ubuntu dockerd[9275]: time="2020-10-30T08:30:39.460569874+01:00" level=warning msg="Your kernel does not support cgroup rt runtime"
Nov 30 08:30:39 ubuntu dockerd[9275]: time="2020-10-30T08:30:39.460672730+01:00" level=warning msg="Your kernel does not support cgroup blkio weight"
Nov 30 08:30:39 ubuntu dockerd[9275]: time="2020-10-30T08:30:39.460820506+01:00" level=warning msg="Your kernel does not support cgroup blkio weight_device"
Nov 30 08:30:39 ubuntu dockerd[9275]: time="2020-10-30T08:30:39.461286028+01:00" level=info msg="Loading containers: start."
Nov 30 08:30:39 ubuntu dockerd[9275]: time="2020-10-30T08:30:39.620849970+01:00" level=info msg="Default bridge (docker0) is assigned with an IP address 172.17.0>
Nov 30 08:30:39 ubuntu dockerd[9275]: time="2020-10-30T08:30:39.717281156+01:00" level=info msg="Loading containers: done."
Nov 30 08:30:39 ubuntu dockerd[9275]: time="2020-10-30T08:30:39.754253372+01:00" level=info msg="Docker daemon" commit=4484c46d9d graphdriver(s)=overlay2 version>
Nov 30 08:30:39 ubuntu dockerd[9275]: time="2020-10-30T08:30:39.755461813+01:00" level=info msg="Daemon has completed initialization"
Nov 30 08:30:39 ubuntu systemd[1]: Started Docker Application Container Engine.

In order to avoid using sudo whenever you type docker commands, simply add your user to docker group. This can be done by typing.

sudo usermod -aG docker ${USER}
newgrp docker

Step 4: Setup the Master K3s Node

First of all we’ll setup the master node. On this node we’ll install the k3s sevice. To install k3s hit the given command in your terminal.

curl -sfL https://get.k3s.io | sh -s - --docker

You’ll see the similar output:

[INFO] Finding release for channel stable
[INFO] Using v1.18.9+k3s1 as release
[INFO] Downloading hash https://github.com/rancher/k3s/releases/download/v1.18.9+k3s1/sha256sum-amd64.txt
[INFO] Downloading binary https://github.com/rancher/k3s/releases/download/v1.18.9+k3s1/k3s
[INFO] Verifying binary download
[INFO] Installing k3s to /usr/local/bin/k3s
[INFO] Creating /usr/local/bin/kubectl symlink to k3s
[INFO] Creating /usr/local/bin/crictl symlink to k3s
[INFO] Skipping /usr/local/bin/ctr symlink to k3s, command exists in PATH at /usr/bin/ctr
[INFO] Creating killall script /usr/local/bin/k3s-killall.sh
[INFO] Creating uninstall script /usr/local/bin/k3s-uninstall.sh
[INFO] env: Creating environment file /etc/systemd/system/k3s.service.env
[INFO] systemd: Creating service file /etc/systemd/system/k3s.service
[INFO] systemd: Enabling k3s unit
Created symlink /etc/systemd/system/multi-user.target.wants/k3s.service → /etc/systemd/system/k3s.service.
[INFO] systemd: Starting k3s

Make sure the installation is successfull.

sudo systemctl status k3s
● k3s.service - Lightweight Kubernetes
Loaded: loaded (/etc/systemd/system/k3s.service; enabled; vendor preset: enabled)
Active: active (running) since Mon 2020-11-30 08:32:46 CET; 53s ago
Docs: https://k3s.io
Process: 11151 ExecStartPre=/sbin/modprobe br_netfilter (code=exited, status=0/SUCCESS)
Process: 11152 ExecStartPre=/sbin/modprobe overlay (code=exited, status=0/SUCCESS)
Main PID: 11153 (k3s-server)
Tasks: 0
Memory: 420.9M
CGroup: /system.slice/k3s.service
└─11153 /usr/local/bin/k3s server --docker
Nov 30 08:33:32 ubuntu k3s[11153]: I1030 08:33:32.532935 11153 reconciler.go:196] operationExecutor.UnmountVolume started for volume "helm-traefik-token-dmfz6">
Nov 30 08:33:32 ubuntu k3s[11153]: I1030 08:33:32.533481 11153 reconciler.go:196] operationExecutor.UnmountVolume started for volume "values" (UniqueName: "kub>
Nov 30 08:33:32 ubuntu k3s[11153]: W1030 08:33:32.533849 11153 empty_dir.go:453] Warning: Failed to clear quota on /var/lib/kubelet/pods/d1fae0b1-f3ac-481a-b6a>
Nov 30 08:33:32 ubuntu k3s[11153]: I1030 08:33:32.538649 11153 operation_generator.go:782] UnmountVolume.TearDown succeeded for volume "kubernetes.io/configmap>
Nov 30 08:33:32 ubuntu k3s[11153]: I1030 08:33:32.555370 11153 operation_generator.go:782] UnmountVolume.TearDown succeeded for volume "kubernetes.io/secret/d1>
Nov 30 08:33:32 ubuntu k3s[11153]: I1030 08:33:32.653113 11153 reconciler.go:319] Volume detached for volume "helm-traefik-token-dmfz6" (UniqueName: "kubernete>
Nov 30 08:33:32 ubuntu k3s[11153]: I1030 08:33:32.653137 11153 reconciler.go:319] Volume detached for volume "values" (UniqueName: "kubernetes.io/configmap/d1f>
Nov 30 08:33:33 ubuntu k3s[11153]: W1030 08:33:33.978774 11153 pod_container_deletor.go:77] Container "23d34e0acde3f4ab7e41d99e9cff16e7ba8cd76122158dfc18b64ae0>
Nov 30 08:33:33 ubuntu k3s[11153]: W1030 08:33:33.997821 11153 pod_container_deletor.go:77] Container "a52fe91aa3e7b137ebe4dd993e358c382f96b5df342cb1c098acadb6>
Nov 30 08:33:35 ubuntu k3s[11153]: W1030 08:33:35.022454 11153 pod_container_deletor.go:77] Container "2b9f302427059276bc2e1d012db5cbcaeb72ed373cb52218edb6eb4b

Make sure that Master node is running properly.

sudo kubectl get nodes -o wide

Output:

sabi@ubuntu20:~$ sudo kubectl get nodes -o wide
NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME
master Ready master 3m2s v1.18.9+k3s1 172.16.10.3 Ubuntu 20.04.1 LTS 5.4.0-52-generic docker://19.3.8

Step 5: Allow Firewall Access

Allow the firewall access to the 443 and 6443 ports in order to start the communication b/w the master & worker nodes.

sudo ufw allow 6443/tcp
sudo ufw allow 443/tcp

Now, run the below command in your terminal to get a tocken from the master node that will be later used on worker node to join the master node.

sudo cat /var/lib/rancher/k3s/server/node-token

Output:

K1078f2861628c95aa328595484e77f831adc3b58041e9ba9a8b2373926c8b034a3::server:417a7c6f46330b601954d0aaaa1d0f5b

Step 6: Install K3s Service On Worker Nodes

Now, install the k3s service on worker nodes & connect them to the master node.

curl -sfL http://get.k3s.io | K3S_URL=https://<master_IP>:6443 K3S_TOKEN=<join_token> sh -s - --docker

master_IP: IP of Master Node
join_token: Token generated on Master Node in above step.

curl -sfL http://get.k3s.io | K3S_URL=https://172.16.10.3:6443 K3S_TOKEN=K1078f2861628c95aa328595484e77f831adc3b58041e9ba9a8b2373926c8b034a3::server:417a7c6f46330b601954d0aaaa1d0f5b sh -s - --docker

Make sure that k3s-agent is running properly on worker nodes by typing.

sudo systemctl status k3s-agent

Fire the given command to verify that worker nodes are added to cluster.

sudo kubectl get nodes

You’ll see the similar output upon success.

sabi@ubuntu20:~$ kubectl get nodes -o wide
NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME
master Ready master 14m v1.18.9+k3s1 172.16.10.3 Ubuntu 20.04.1 LTS 5.4.0-52-generic docker://19.3.8
worker02 Ready 90s v1.18.9+k3s1 172.16.10.10 Ubuntu 20.04.1 LTS 5.4.0-52-generic docker://19.3.8
worker01 Ready 41s v1.18.9+k3s1 172.16.10.4 Ubuntu 18.04.5 LTS 4.15.0-122-generic docker://19.3.6

Install Helm CLI Tool On k3s

Visit the link to download the latest version of Helm.

And extract the downloaded file with the help of tar.

tar -xvcf <downloaded-file>

Then move the binary file to /usr/local/bin/helm

mv linux-amd64/helm /usr/local/bin/helm

Verify the version

heml version

Finally add helm repo in order to allow installation with helm.

helm repo add stable https://charts.helm.sh/stable
helm repo update

Deploy Application On K3s

Here we’ll add Nginx as test purposes.

Run the below command to install nginx using helm

helm install nginx-ingress stable/nginx-ingress --namespace kube-system \
--set defaultBackend.enabled=false

Verify the added application by typing

kubectl get pods -n kube-system -l app=nginx-ingress -o wide

sabi@ubuntu20:~$ kubectl get pods -n kube-system -l app=nginx-ingress -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx-ingress-controller-56547fb57-vsjdm 1/1 Running 0 28s 10.42.2.6 worker01

So, it shows that we’ve successfully deployed nginx on k3s.

Removing K3s

In order to remove k3s on the worker nodes, hit

sudo /usr/local/bin/k3s-agent-uninstall.sh
sudo rm -rf /var/lib/rancher

To remove k3s on master node, type

sudo /usr/local/bin/k3s-uninstall.sh
sudo rm -rf /var/lib/rancher

So, this is how you can install kubernetes on Ubuntu 20.04 using k3s.

The post How To Install Kubernetes Cluster On Ubuntu 20.04 Using K3s appeared first on Linux Windows and android Tutorials.

Kubernetes is a revolution in the world of containers. Since Google donated the project to the Cloud Native Computing Foundation, the number of contributors to the source code has increased overwhelmingly. In addition to all this, the big companies behind the world’s major Linux distributions constantly support Kubernetes. So Canonical, Red Hat, Suse, and others must be very pleased with this release.

Kubernetes 1.14 is available: The features

There are many novelties that make this launch something important however, it is good to highlight three:

• Add support for Windows nodes. This allows you to add them as working nodes and program containers for them.
• Kubectl is now much more powerful than before. It now supports complements allowing developers to take full advantage of this tool. On the other hand, the kubectl documentation has been completely rewritten.
• Persistent local volumes. With this, local storage is favored, which in many cases works better with remote storage, saving costs and improving performance. For example, local storage on an SSD is much faster than on a local disk.

In total, there are many improvements that come with this version. For example, Kubernetes 1.14 includes at least 30 new features. Of which 7 are completely new and 10 transformed to stable and 12 with beta support. So in effect, we are talking about a completely important version and the best that has been published.

Evidently, these are the main novelties, there are many more that can be consulted through the official announcement. On the other hand, the code of this new version is now available in Github so you can download it there.

Conclusion

As you can see, Kubernetes is an important technology in the Linux cloud. This version must be called the most important yet because it adds compatibility with Windows nodes and adds the functionality of Kubectl. In addition large Linux companies are under the development of this tool.

Please share this post with your friends.

The post Kubernetes 1.14 is available appeared first on Linux Windows and android Tutorials.

In short, Kubernetes is an open-source system for automating deployment, scaling, and management of containerized applications. The most important factor that sets Kubernetes apart from other cloud computing solutions is that it was built to work with Docker. That’s why it’s the most used tool to deploy Dockers applications.

Now, I will show you how to install it on CentOS 7.

0. Prerequisites

The installation is not as complicated as it seems, however, you should have a little knowledge about Terminal and commands. Also required is a computer that will serve as a server and another that will serve as a node. The central idea is to add them in a cluster.

Both computers run CentOS 7 and it’s on a local network. Let’s start.

1. Install Kubernetes on the server

As I said before the idea is to make a cluster, for it, first we must configure the server where you will run Kubernetes. First, you have to disable SELinux and apply various rules in the Firewall for everything to work well. Note: all commands must be run as root user.

:~# hostnamectl set-hostname osradar
:~# exec bash
:~# setenforce 0
:~# sed -i --follow-symlinks 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/sysconfig/selinux

Next, set the firewall rules:

:~# firewall-cmd --permanent --add-port=6443/tcp
:~# firewall-cmd --permanent --add-port=2379-2380/tcp
:~# firewall-cmd --permanent --add-port=10250/tcp
:~# firewall-cmd --permanent --add-port=10251/tcp
:~# firewall-cmd --permanent --add-port=10252/tcp
:~# firewall-cmd --permanent --add-port=10255/tcp
:~# firewall-cmd --reload
:~# modprobe br_netfilter
:~# echo '1' > /proc/sys/net/bridge/bridge-nf-call-iptables

In case you don’t have a DNS server configured. Edit the file /etc/hosts and add the information of your node and server.

:~# nano /etc/hosts

And add the following:

192.168.1.8 osradar
192.168.1.9 node1

Of course, replace the configuration with yours depending on the IP addresses and hostname chosen.

2. Install Kubernetes

In order to install Kubernetes on CentOS 7, you must add its repository. With this, the installation will be quick and easy. Run

:~# nano /etc/yum.repos.d/kubernetes.repo

And put the following:

[kubernetes]
name=Kubernetes
baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg
https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg

Then, you can install it. Also, you have to install docker:

:~# yum install kubeadm docker

Then, start and enable both docker and kubectl services:

:~# systemctl enable docker
:~# systemctl start docker
:~# systemctl enable kubelet
:~# systemctl start kubelet

3. Initialize Kubernetes in CentOS 7

Now you can start Kubernetes with the next command:

.~# kubeadm init

If you see something like this, everything is OK.

As you can see from the image, you must now execute these commands:

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

The next step is to check the status of the clusters and pods

:~# kubectl get nodes
:~# kubectl get pods --all-namespaces

To ensure that there is communication between the nodes of the cluster, you have to run the following:

:~# export kubever=$(kubectl version | base64 | tr -d '\n')
:~# kubectl apply -f "https://cloud.weave.works/k8s/net?k8s-version=$kubever"

Now, re-run the command to show all the pods.

:~# kubectl get pods --all-namespaces

Everything is going OK.

4.- Working on the node or nodes

In this step, you must work on the number of nodes you want to configure. In this case, it will be only one, but remember that they can be more.

At each node, run the following. First, change the hostname and set the firewall rules:

:~# setenforce 0
:~# sed -i --follow-symlinks 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/sysconfig/selinux
:~# firewall-cmd --permanent --add-port=10250/tcp
:~# firewall-cmd --permanent --add-port=10255/tcp
:~# firewall-cmd --permanent --add-port=30000-32767/tcp
:~# firewall-cmd --permanent --add-port=6783/tcp
:~# firewall-cmd  --reload

Next, install Kubernetes.

:~# cat <<EOF > /etc/yum.repos.d/kubernetes.repo

And add the following:

> [kubernetes]
> name=Kubernetes
> baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64
> enabled=1
> gpgcheck=1
> repo_gpgcheck=1
> gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg
>         https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
> EOF

Next, install it:

:~# yum install kubeadm docker

Then, enable and start the services:

:~# systemctl enable docker
:~# systemctl start docker
:~# systemctl enable kubelet
:~# systemctl start kubelet

Finally, join to the master node.

:~# kubeadm join --token xnxlx4.k6qupcvb9g7tq2ti 192.168.1.8

Conclusion

As you can see, the process of installing Kubernetes on CentOS 7 is simple and we are talking about a very powerful tool in the Linux world.

We want to know about you, have you used Kubernetes? do you use Docker?

Please spread this article on your social networks

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