Quick peek inside Kubernetes Containers.

Quick peek inside Kubernetes Containers

To get a fresh start inside the Container world I have tested a couple of technologies. The new and interresting container managament project that I tested is called Kubernetes. The Wiki definition follows: Kubernetes (commonly referred to as "k8s") is an open source container cluster manager originally designed by Google and donated to the Cloud Native Computing Foundation. It aims to provide a "platform for automating deployment, scaling, and operations of application containers across clusters of hosts".

On my simple home Lab I will install and quickly deploy Kubernetes on a fresh Centos 7 server with minimal desktop features. So let us get started.

First what we need is to disable firewall services.

 systemctl disable firewalld.service

 systemctl stop firewalld.service

After this what we need to install is the network daemon service:

yum -y install ntp

systemctl start ntpd

systemctl enable ntpd

To download the packages need for the Kubernetes cluster manager we need to add a new repository to the Centos defaults. We do this creating a file inside the /etc/yum.repos.d folder called virt7-docker-common-release.repo

This file should contain the following Urls and content for us to be able to download the Kubernetes packages need for the setup of the container manager:

[root@Cent01 yum.repos.d]# cat virt7-docker-common-release.repo

[virt7-docker-common-release]

name=virt7-docker-common-release

baseurl=http://cbs.centos.org/repos/virt7-docker-common-release/x86_64/os/

gpgcheck=0

Now are ready to download the basic Kubernetes managament packages and install them:

yum install docker etcd kubernetes 

As the packages are downloaded from the repository they will be automatically installed using the Yellow dog manager for Centos packages. If you need more info or want to see the verbose informatons add the --v switch after the install command.

To restart and enable the services we would need to define a FOR loop:

for SERVICE in docker etcd kube-apiserver kube-controller-manager kube-scheduler kube-proxy kubelet; do 

    systemctl restart $SERVICE

    systemctl enable $SERVICE

done

To make the managament available over the Web GUI (which I find very handy from the beginning) we would need to install the Cockpit manager.

yum install cockpit cockpit-kubernetes

systemctl enable cockpit.socket

systemctl start cockpit.socket

That was for now on installing the packages. The next step would be to start the web GUI using the port 9090. You just need to call this url: https://server_ip:9090

The base image of the Cockpit Kubernetes manager will show us the options needed to create and monitor the container Also the cluster managament is prepared and deployment of Micro services.

Under Tools we can still maintain the Bare metal Centos 7 server using the command line.

And as simpel as that we can find many Docker container images from the repositories and download them. From simple web servers to complex MySQL redundant scenarios. As simple as download-click-run image system is a performance booster.

What I also find interresant is the possibility to build the apps from Manifest files and deploy them as Micro Services. OpenShift supported from RedHat could be also used as a great tool to build the applications on Docker Container technology.

And in a matter of minutes we can have a running cluster based container image managament orchestra. The deploy of manifests will be explained in the next blog where I will research more on Openshift and app buiding.

Stay tuned and follow me and please send your comments.