Posted in Cloud, Openstack

Tips to pass OpenStack Foundation (COA) Certified OpenStack Administrator exam.

I was busy studying OpenStack Foundation’s COA exam so couldn’t publish blog post for a while.

Luckily I have passed the COA exam and hard work pays off. As I have passed this so thought of sharing my experience with the exam.

This post is basically contains some tips/info about OpenStack Foundation (COA) Certified OpenStack Administrator exam.

Certified OpenStack Administrator (COA) is the first professional certification offered by the OpenStack Foundation. It’s designed to help companies identify top talent in the industry, and help job seekers demonstrate their skills.

The Certified OpenStack Administrator is a professional typically with at least six months of OpenStack experience, and has the skills required to provide day-to-day operation and management of an OpenStack cloud.

The current exam is based on the OpenStack Liberty version and covers the core compute, storage and networking services. To learn more about the knowledge requirements and domains covered in the exam, go to

Continue reading “Tips to pass OpenStack Foundation (COA) Certified OpenStack Administrator exam.”

Posted in Cloud, Openstack

Openstack Mitaka Installation using Devstack on Ubuntu 16.04

We can install Openstack using many tool Devstack and Packstack are two of them. In my last post I have shared Openstack Installation using Packstack on CentOS 7. In this post I am going through step by step Openstack installation using Devstack on Ubuntu 16.04.ive

I am using VirtualBox VM with following configuration.

OS – Ubuntu 16.04

RAM – 7168MB

Disk – 40GB

vCPU – 2

Network – One bridged ethernet adapter with static IP.

1. Install Ubuntu minimal server on VM and perform apt-get update and upgrade and reboot the machine.

2. Configure Bridged ethernet adapter with static IP and give relevant hostname to machine.

stack@Mitakastack:~/devstack$ cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto enp0s3
iface enp0s3 inet static

stack@Mitakastack:~/devstack$ cat /etc/hostname

Continue reading “Openstack Mitaka Installation using Devstack on Ubuntu 16.04”

Posted in Cloud, Openstack

Openstack Mitaka Installation using packstack on CentOS 7

Mitaka is 13th release of Openstack. Following are some of the notable features in Mitaka.


  • Real-time Kernel-based Virtual Machine (KVM) compute nodes and custom CPU thread policies
  • Live migration improvements


  • Rolling upgrades in Cinder
  • Disaster recovery share-replication application programming interface (API) support


  • Tenant resources cleanup
  • Improved security groups performance

I have configured allinone Openstack Mitaka setup on one Virtual VM using VirtaulBox.

My Virtual VM configuration are as follows.

OS – CentOS 7.2

RAM – 7168MB

Storage – 40GB

Network – One bridged adpater with static IP

vCPU – 2

Install CentOS 7.2 on VM and update to latest level and reboot the system.

Continue reading “Openstack Mitaka Installation using packstack on CentOS 7”

Posted in Cloud, Linux, Openstack

Basic Cinder (volume) service functionality in Openstack – Part2

We saw volume creation with related issues and probable solutions.

Now we will see volume attach to VM. Create partition on it. Remove it and detach volume from VM.

Attach created volume to testvm. Following is command-line requirement for cinder volume-attach.


Volume ID will get it from cinder-list use auto to autoassign the new device.


You can check volume status is changed to in-use now and also changed attached with VM ID.


Continue reading “Basic Cinder (volume) service functionality in Openstack – Part2”

Posted in Cloud, Linux, Openstack

Basic Cinder (volume) service functionality in Openstack – Part1

In this post I am going to show you basic functionality of openstack cinder (volume) service functionality by creating volume on internal storage. Attaching that volume to VM. Create partition on that volume in client machine and test partition remove and detaching volume from VM.

Lets take one running state vm for cinder testing as we can do this operation on the fly. I have one VM name testvm.


Check the disk and partitions on the VM. I can access the testvm using private IP and public IP. Lets access it using private IP using unique network namespace.

First check private-net network ID and test the ping to private IP of VM using network namespace. For more details about basic networking in openstack check my last blog posts.



Continue reading “Basic Cinder (volume) service functionality in Openstack – Part1”

Posted in Linux, Openstack

Failed to start OpenStack Identity Service (code-named Keystone).

When you installed Openstack using packstack you might have faced openstack-keystone service issue. When try it to restart it fails with code-name keystone error.


I have done some research on it and found the solution.

The issue is with Openstack Keystone Service which we have configured using httpd deamon in answers.cfg file ( configuration file used to install Openstack using packstack)


Now openstack-keystone service will not start as http service is already in started mode and we haven’t created any relation between openstack-keystone and http service.

So to start openstack-keystone service we have to create symbolic link and point openstack-keystone service to http service.

Continue reading “Failed to start OpenStack Identity Service (code-named Keystone).”

Posted in Cloud, network, Openstack

Basic networking in Openstack Part 1

Once you install Openstack in single node or multinode setup next thing is to setup network. To understand networking in Openstack is little tedious job. This post is to describe basic Openstack networking concept by creating internal/external networking and testing the same.

First delete all default network like public and private which were created by default after Openstack installation using

#neutron net-delete <net-name>

Let us create new internal network first.


Create subnet for network private-net with subnet address


Continue reading “Basic networking in Openstack Part 1”

Posted in Linux, Uncategorized

Graphical/Desktop UI for Centos 7/RHEL 7

Many times we need graphical UI to open/run some applications. So following are simple and quick steps to create graphical UI on Centos7/RHEL7.

First check you have yum repository configured to access local or internet repository

#yum repolist


Graphical UI filesets will install in group so that all required/dependent filesets will install automatically. Check all available groups in yum repository using group list

Continue reading “Graphical/Desktop UI for Centos 7/RHEL 7”