Month: October 2015

Install OpenStack on KVM – How To Configure KVM for OpenStack

Posted on by Grzegorz Juszczak 4 Comments

openstack
Typical OpenStack cloud setup consists of more than one node (usually one Controller node and several Compute nodes), which requires lot of physical computers / servers available to perform the installation. This complicates the situation, especially if we need to test OpenStack on many nodes. Fortunately we can use Linux KVM (Kernel-based Virtual Machine) to create OpenStack on virtual nodes and avoid problems with obtaining physical hardware.

In this tutorial we will show you how to install OpenStack on KVM on Fedora 21 based hypervisor. We will run Openstack installation on two KVM based virtual nodes (Controller and Compute).

The most important part in configuring KVM for OpenStack installation is network setup, we also need to secure some resources (VCPUs, RAM, disk space) on KVM Hypervisor to create two virtual nodes.

openstack-kvm-network-diagram
Continue reading “Install OpenStack on KVM – How To Configure KVM for OpenStack” →

How to Disable or Enable SELinux on CentOS / Fedora / RHEL

Posted on by Grzegorz Juszczak Leave a comment

SELinux (Security Enhanced Linux) is an additional method of Linux system protection. It’s a group of security contexts that determine which process can access which files, directories, ports, etc…

SELinux has three modes:
Enforcing: SELinux protects files, directories, ports against unauthorized access and logs all SELinux events and attempts.
Permissive: SELinux allows all interactions and context violations and logs them. Permissive mode is often used for troubleshooting SELinux.
Disabled: SELinux is completely disabled.

SELinux in Enforcing mode may cause problems accessing files or ports in the system, that’s why it’s good to know how to change it’s mode or even disable it.
Continue reading “How to Disable or Enable SELinux on CentOS / Fedora / RHEL” →

How to compare two files in Linux command line

Posted on by Grzegorz Juszczak Leave a comment

You can compare two text files in Linux using the following command-line tools:
– diff
– vim / vimdiff
These tools are already installed “out-of-the-box” in most Linux distributions.
Continue reading “How to compare two files in Linux command line” →