Docker

How to install Kubernetes cluster on Linux CentOS 8 VPS, VDS, Server

On the global internet, there are many good guides out there describing how to install Kubernetes on CentOS 8. Nevertheless, some steps might be unnecessary and some might be missing. This guide is based on our notes from real-world deployments and has worked great. All this is possible to install and configure on our VPS, VDS, and Servers. Prerequisites for both Master and Worker nodes In this guide, we will be using minimal resources with just two cloud servers for simplicity. After the initial setup, you can add more workers when necessary. For this guide to work, you would need to Deploy two CentOS 8 Linux servers. One for the master and the other for the worker node. Kubernetes has minimum requirements for the server and both master and worker nodes need to have at least 2 GB RAM and 2 CPUs, the € 4.99/mo each plan covers these requirements and with double the memory.…

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How to Install Kubernetes on Master and Worker nodes

In our previous guide, you could read on How to install Kubernetes cluster on Linux CentOS 8 VPS, VDS, Server that is located HERE. But in this guide, we will show you how you can install Master and Worker nodes. With all the necessary parts installed, we can get Kubernetes installed as well. Add the Kubernetes repository to your package manager by creating the following file. cat < /etc/yum.repos.d/kubernetes.repo [kubernetes] name=Kubernetes baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-\$basearch 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 exclude=kubelet kubeadm kubectl EOF Then update the repo info. dnf upgrade -y Install all the necessary components for Kubernetes. dnf install -y kubelet kubeadm kubectl --disableexcludes=kubernetes Start the Kubernetes services systemctl start kubelet Enable the Kubernetes services on the startup. systemctl enable kubelet Once running on both nodes, begin configuring Kubernetes on the Master by following the instructions in the next section. By clicking here you will find a user guide on How to configuring Kubernetes on the Master…

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How to configuring Kubernetes on the Master node only

Here you could find a guide, on How to Install Kubernetes on Master and Worker nodes Configure kubeadm. kubeadm config images pull Open the necessary ports used by Kubernetes. firewall-cmd --zone=public --permanent --add-port={6443,2379,2380,10250,10251,10252}/tcp Allow docker access from another node, replace the worker-IP-address with yours. firewall-cmd --zone=public --permanent --add-rich-rule 'rule family=ipv4 source address=worker-IP-address/32 accept' Allow access to the host’s localhost from the docker container. firewall-cmd --zone=public --permanent --add-rich-rule 'rule family=ipv4 source address=172.17.0.0/16 accept' Make the changes permanent. firewall-cmd --reload Install CNI (container network interface) plugin for Kubernetes. For this setup, we’ll be using Calico Issue the following command: kubeadm init --pod-network-cidr 192.168.0.0/16 You should see something like the example below. Make note of the discovery token, it’s needed to join worker nodes to the cluster. Note that the join token below is just an example. kubeadm join 94.237.41.193:6443 --token 4xrp9o.v345aic7zc1bj8ba \ --discovery-token-ca-cert-hash sha256:b2e459930f030787654489ba7ccbc701c29b3b60e0aa4998706fe0052de8794c Make the following directory and configuration files. mkdir -p $HOME/.kube cp -i /etc/kubernetes/admin.conf…

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How to configuring Kubernetes on the Worker node only

So we now continue our Kubernetes settings if you have missed here you can find a guide on How to configuring Kubernetes on the Master node only Each Kubernetes installation needs to have one or more worker nodes that run the containerized applications. We’ll only configure one worker in this example but repeat these steps to join more nodes to your cluster. Open ports used by Kubernetes. firewall-cmd --zone=public --permanent --add-port={10250,30000-32767}/tcp Make the changes permanent. firewall-cmd --reload Join the cluster with the previously noted token. Note that the join token below is just an example. kubectl get nodes The output should be: NAME STATUS ROLES AGE VERSION master Ready master 10m v1.18.0 worker Ready 28s v1.18.0 On success, you should see two nodes with ready status. If not, wait a moment and repeat the command. Congratulations, you should now have a working Kubernetes installation running on two nodes. In case anything goes wrong, you can…

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How to install Kubernetes on Linux CentOS 8 / RHEL VPS, VDS, Server

Now that the New Linux CentOS 8 is taking the lead and many companies need to upgrade from CentOS 6 or CentOS 7. Then the best choice at the moment at beginning of 2021 is CentOS 8 since it has a long support time and security updates support. Based on all the before mentioned the Kubernetes have accordingly changed the installation of Kubernetes. let's have a look at how to install it. Just a reminder, that Kubernetes can also be installed on our hosted VPS/VDS servers The things that you would need to prepare before Kubernetes installation are. 1. A running instance of CentOS 8 2. Docker CE installed and running 3. A user with Sudo privileges 4. Access to the root user   Now how to install Kubernetes Remember, you must have Docker CE installed, before starting this process. Once you have the Docker engine up and running, how to add Kubernetes to the server.…

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How to install Docker on Centos 8

If you would need a Development server and Production to be the same, then Docker Compose is a good option for defining and running multi-container Docker applications on the same server with the same configurations. With Docker Compose, you can link multiple containers and deploy an application from a single command. Docker Compose uses a YAML file to define a complex stack in a file. Then, with a single command, you create and start all the services from your configuration. Before you start you would need to update your Centos 8 operating system: dnf update -y Add Docker-CE repository to your system: dnf config-manager --add-repo=https://download.docker.com/linux/centos/docker-ce.repo Install the latest version of docker: dnf install docker-ce --nobest Let's add a docker to startup: systemctl enable docker Let's start docker: systemctl start docker Verify the docker version: docker --version The output should be: Docker version 20.10.1, build 831ebea Now, let's install Docker Compose: Download Docker Compose: curl -L…

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How to setup Docker Swarm on Centos 7

Docker offers 3 types of cluster systems Kubernetes (Developed by Google) and Docker Swarm (Developed by Docker). Yes, there is a difference between both cluster systems, of course, there is the third one developed by Redhat what is purchasable ( Openshift ) witch also is very powerful and resourceful. But this time I’m creating a tutorial on Docker Swarm. I have played with both Kubernetes and Swarm and I prefer Swarm over Kubernetes. Of course, others might have a different opinion on this matter and everyone works with the soft that is comfortable for himself. I guess that I like Swarm more since it's much closer to Docker. Kubernetes is also awesome but they have removed many Docker commands replacing them with KUBECTL and so on and one. I’m sure that maybe in the future when I will have some more time I will create a tutorial or tutorials about Kubernetes and Openshift also. But…

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Docker Tips: Clean Up Your Local Machine

In this tutorial, we’ll go back to basics. We will look at how Docker uses the disk space of the host machine and how to reclaim it when it is not being used anymore. Overall Consumption Docker is great, there’s no doubt about that. A couple of years ago, it provided a new way to build, ship and run any workloads by democratizing the usage of containers and hugely simplifying management of their lifecycle. It also brought the developer the ability to run any applications without polluting the local machine. But, when we run containers, pull images, deploy complex application stacks, and build our own images the footprint on our host filesystem might increase in a significant way. If we have not cleaned up our local machine for a while we might be surprised by the result of this command: docker system df This command shows Docker’s disk usage in several categories: Images: The size…

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How to Manage Docker Containers using Portainer on Centos 7

You can manage your Docker containers using the terminal (Actually nothing hard, only hardest part if you want specific containers with specific configuration) since I will be deploying several sites with the same based configuration and the same Image then I would prefer a web interface system for managing Docker containers. The one that I know at the moment and it's an open-source is called Portainer. About portainer: Portainer can be installed as a docker container and standalone without a docker container. In this tutorial, we will install Portainer as a Docker container. It’s really simple to install and run on any system because we just need to ensure the system support, Docker. Before installing Portainer, download the Portainer image from the DockerHub using the docker pull command below. docker pull portainer/portainer Now run Portainer using the simple docker command below. docker run -d --name portainer-manager -p 9000:9000 -v /var/run/docker.sock:/var/run/docker.sock portainer/portainer Portainer is now running…

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How to install Docker on Centos 7

As we all know, that times change a new technology is coming in. If in the past there was a bare-metal server that was updated to VPS services, then now VPS are updated or replaced with Docker. Since Docker, it is easy to maintain and the applications are limitless. So in this tutorial, we will show you how you can install Docker and Docker Compose. Now keep in mind that you can also install this on our Amber IT VPS servers since we don't limit any possibility and allow you to use the VPS for Docker hosting. Install Docker yum install -y yum-utils device-mapper-persistent-data lvm2 1.1 Configure the docker-ce repo: sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo 1.2. Install docker-ce: yum -y install docker-ce 1.3. Add your user to the docker group with the following command: sudo usermod -aG docker $(whoami) 1.4. Set Docker to start automatically at boot time: systemctl enable docker.service 1.5. Finally, start the Docker…

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Centos 7 install Docker, Nginx, Reverse proxy, Let’s encrypt certificate manager and Docker web-based management Portainer

There is no secret, that these day's many applications are running on Docker since Docker is flexible and also easy to scale. We know, that there are many options, that come with Docker, for example, Docker Kubernetes and Docker Swarm, and many companies are starting to develop systems, system architecture, and even apps on Docker-based environments. But some companies use Docker for testing apps before deploying them to a production server. Also, large Linux distributors like Centos are creating a specific Docker-based system, which is a license based one and is getting where large popularity in terms of large industries. But today we will create a manual on how to install Docker, create our first 3 containers. 1. Docker web-based management system known as portainer; 2. Docker Nginx reverse proxy, that forwards incoming traffic to port 80 and 443 to correct container in our tutorial we will be creating a Docker-based environment for some web-based…

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