Openshift introduction

 

Openshift is a platform as service.

Open shift origin - It is based on Docker container and the Kubernetes cluster manager with added developer and operational centric tools that enable rapid application development, deployment and lifecycle management. It is classified as 4 different types as bellow's.

* Openshift origin - Open source application platform

* Openshift online - Public version of Openshift origin by Redhat.

* Openshift dedicate - Managed a dedicate private cloud

* Openshift enterprise

Containerization: 

* Docker utilize a LXCI container

* LXC container often consider as something in the middle of chroot and full fledged virtual machine.

* LXCFS is a simple userspace file system designed to work around some current limitation of the linux kernel.

 Orchestration Technologies

* Docker Swarm , Kubernetes and MESOS

Openshift Architecture:

* Openshift container registery 

* Openshift console web - Users & Project

Openshift setup

* All in one deployment

* Single master and multiple nodes

* We can installed through 2 methods.

* Package manager (RPM) & Containerized

=> Rest API 

*getting a authroization token

>oc whoami -t

Openshift project:

* project is created a top of the K8S as namespace.

* Openshift comes with default 3 types of users.

* regular user, system user and service account

Regular user - Developer

System User - system.admin and system.master

Service account - It is need for each project

Master configuration file - /etc/openshift/master/master-config.yaml

>oc get users [list the users]

Openshift build and deployment:

Source code management 

Create Build -> Download source -> Build image -> Push to Registry -> Deploy 

Openshift is introduce an image stream- It will manage an images across the hosts.

Image stream is not point out the target names instead of point out for the target id which is unique.

*Web hook is a advance technology for https request.

* Replicas used to set as 1 by default and strategy get as Rolling.

* Blue/green deployment method and Advance strategy method

CLI:

>oc rollout latest dc/simpleweb-docker

>oc rollout history dc/simpleweb-docker

>oc rollout describe dc simpleweb-docker

>oc rollout undo dc/simpleweb-docker

Openshift network:

Openshift software define network [SDN] will ensure the communication between the pods.

*Open Vswitch

* Vlan tagging, Trunking, LACP and Port mirroring

*Openshift has a DNS server and maintain an IP address with hosts.

*ovs-multitenant will assign a unique IP address of each pods.

Route-Load balance:

* source is a default routing in Openshift.

* roundrobin 

* least connection

Add template in Openshift:

github -> openshift => Origin -> examples -> db-templates

Import json object from Openshift console

copy the template and create via import option

Project:

Front end page:

github -> mmumshad -> example-voting-app -> vote

select advance option incase if you delcare with sub branch under master branch.