How to Setup Openshift Origin on CentOS 8

In this article we will learn How to Setup Openshift Origin on CentOS 8.

OpenShift is an open-source PaaS platform that allows you to deploy an application on the cloud. It supports many programming languages including, Python, PHP, Perl, Node.js, Ruby, and Java. You can also add support for other languages. It is specially designed for a high-availability and scalable application platform. Moreover, It provides an easy way to scale your application as per your demand with zero downtime. It provides a powerful web UI that helps you to monitor container resources, container health, and the IP address of nodes.

First, Update your CentOS 8 machine using the following command:

dnf -y update

Install and Configure Docker:

OpenShift required docker engine on the host machine for running containers. Install Docker using the following commands:

yum install -y yum-utils device-mapper-persistent-data lvm2
yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
yum install -y  docker-ce docker-ce-cli containerd.io

Now we will add user to Docker group.

usermod -aG docker $USER
newgrp docker

After that, we will configure the Docker daemon with an insecure registry parameter of 172.30.0.0/16 using the following commands:

mkdir /etc/docker /etc/containers

sudo tee /etc/containers/registries.conf<<EOF
[registries.insecure]
registries = ['172.30.0.0/16']
EOF

sudo tee /etc/docker/daemon.json<<EOF
{
   "insecure-registries": [
     "172.30.0.0/16"
   ]
}
EOF

Now we will reload systemd and restart docker to apply above configurations.

systemctl daemon-reload
systemctl restart docker

Enable Docker so that it can automatically start after boot.

systemctl enable docker

Now, enable IP forwarding on your system using the following command:

echo "net.ipv4.ip_forward = 1" | sudo tee -a /etc/sysctl.conf
sysctl -p

Now we will allow containers access to the OpenShift master API (8443/tcp) and DNS (53/udp) endpoints in firewall. Use the following commands to do so.

DOCKER_BRIDGE=`docker network inspect -f "{{range .IPAM.Config }}{{ .Subnet }}{{end}}" bridge`
firewall-cmd --permanent --new-zone dockerc
firewall-cmd --permanent --zone dockerc --add-source $DOCKER_BRIDGE
firewall-cmd --permanent --zone dockerc --add-port={80,443,8443}/tcp
firewall-cmd --permanent --zone dockerc --add-port={53,8053}/udp
sudo firewall-cmd --reload

Download the Linux oc binary:

Download the Linux oc binary using the following command:

wget https://github.com/openshift/origin/releases/download/v3.11.0/openshift-origin-client-tools-v3.11.0-0cbc58b-linux-64bit.tar.gz
tar xvf openshift-origin-client-tools*.tar.gz
cd openshift-origin-client*/
mv  oc kubectl  /usr/local/bin/

Verify installation of OpenShift client using the following command:

oc version

Start OpenShift Origin (OKD) Local Cluster:

Now bootstrap a local single server OpenShift Origin cluster by running the following command:

oc cluster up

The command above will:

• Start OKD Cluster listening on the local interface – 127.0.0.1:8443
• Start a web console listening on all interfaces at /console (127.0.0.1:8443).
• Launch Kubernetes system components.
• Provisions registry, router, initial templates, and a default project.
• The OpenShift cluster will run as an all-in-one container on a Docker host.

After successful installation you will see the following message:

Check the cluster status using the following command:

oc cluster status

To login as an administrator, use the following command:

oc login -u system:admin

You can check the nodes status using the following command:

oc get nodes

To display the status of your created resources use the following command:

oc status

To switch user to developer use the following command:

oc login

You can check whether developer user is logged in using the following command:

oc whoami

Using OKD Admin Console:

OKD includes a web console which you can use for creation and management actions. This web console is accessible on Server IP/Hostname on the port 8443 via https.

https://YourIPAddress:8443/console

User developer as username and password.

You will see the following page:

If you are redirected to https://127.0.0.1:8443/ when trying to access OpenShift web console, then perform the following steps:

First, stop the cluster:

oc cluster down

Then, Edit the configuration file using the following command:

nano ./openshift.local.clusterup/openshift-controller-manager/openshift-master.kubeconfig

Locate line “server: https://127.0.0.1:8443“, then replace with “server: https://YourIPAddress:8443”.

Now, Start the cluster using the following command:

oc cluster up

We have successfully Setup Openshift Origin on CentOS 8. You can now use it according to your need.