#Linux

What is an Overcommit in cloud ? Overcommitting Memory Overcommitting CPU Why its important in a Public Cloud Where are the Overcommit values in Openstack Well, I have a very special requirement Solution Create the aggregate Add your computes to this Aggregate Setting up Overcommit values to this particular Aggregate How the Guest VM know, i should go to this Aggregate Inject Flavor metadata Check the flavor now Add few filters in nova Disable the current allocation from nova Restart nova Workflow Further Reading What is an Overcommit in cloud ? [Read More]

What is Python Virtualenvironment Installation Install pip Install needed Python modules Set a Directory for your Environments Add it on your bashprofile Testing the virtualenvironment Activate and Deactivate the environment Remove the Virtualenvironment Futher Reading What is Python Virtualenvironment Python applications will often use packages and modules that don’t come as part of the standard library. Applications will sometimes need a specific version of a library, because the application may require that a particular bug has been fixed or the application may be written using an obsolete version of the library’s interface. [Read More]

Courtesy Preface Assumptions Solution Import Route Target Security Group Futher Reading Courtesy Bytes around me :-) Preface Sharing Private network is a common use case in Cloud Environment. Normally RBAC will help you to achieve. Since Newton release, this feature is Available. But the question is which SDN you are using in your Environment. If you are using Opencontrail 3.2 as SDN, you cannot go with RBAC. Assumptions Openstack Release Ocata Opencontrail 3. [Read More]

Courtesy Preface Use Case Implementation New Routing Table Add Policy Rules Flush the routing cache Testing Rules Further Reading Courtesy Tutorial credit goes to [Omar Hamad ] (https://www.linkedin.com/in/omermahgoub/) the real Architect I have seen in last few years. Working with him for the past 3 Years, and learned a Lot. We are going to miss u :( Preface When configuring a Linux host with multiple interface, each with its own default gateway, ensuring route symmetric is a bet challenging for any given pair of endpoint. [Read More]

Preface Some cloud providers, limited the Bandwidth based on Flavors. Which is part of their Business rules. So, Guest virtual machines wont be able to reach the limit which fixed in the Flavor using metadata. This tutorial will help you to change the Network BW without restarting the Guest virtual machine. List the Current virsh domiflist instance-0000be23 Interface Type Source Model MAC ------------------------------------------------------- tap973d62dc-4f bridge qbr973d62dc-4f virtio fa:16:3e:fb:24:e0 virsh domiftune instance-0000be23 tap973d62dc-4f inbound. [Read More]

Preface Installation Create a Test Scenario Export the Test Results to HTML More Scenarios Preface Rally is a framework used to Validate multinode Openstack Deployment. Rally automates and unifies multi-node OpenStack deployment, cloud verification, benchmarking & profiling. Rally does it in a pluggable way, making it possible to check whether OpenStack is going to work well on, say, a 1k-servers installation under high load. Thus it can be used as a basic tool for an OpenStack CI/CD system that would continuously improve its SLA, performance and stability. [Read More]

Preface History Using ! Using part of Command Preface One of the fancy feature of Bash is the command history. History will store all the command run by the User, which will be in /home/$USER/.bash_history. This will help the user to edit / reclass previously applied commands. To get a command previous run in command you can use UP arrow or DOWN arrow keys. History 288 cd layouts/ 289 ls 290 cd . [Read More]

Page loading speed is very important now a days. If you are a web administrator, or a server administrator who is particularly responsible for organizing the things together, then you have to make it a point that users don’t get disappointed while accessing your site – so there is really need for speed curl -s -w 'Testing Website Response Time for :%{url_effective}\n\nLookup Time:\t\t%{time_namelookup}\nConnect Time:\t\t%{time_connect}\nPre-transfer Time:\t%{time_pretransfer}\nStart-transfer Time:\t%{time_starttransfer}\n\nTotal Time:\t\t%{time_total}\n' -o /dev/null http://www.google.com Output for Google. [Read More]

Preface Features Installation Output Preface Glances is a cross-platform command-line curses-based system monitoring tool based on Python Programming language. Glances is using the psutil library to grab informations from the Operating Systm. Glance will monitr CPU, Load Average, Memory, Network Interfaces, Disk I/O, Processes and File System spaces utilization. Glances is released under GPL, and works on FreeBSD and Linux systems. Many options available in Glances. Glance will allow the System administrator to set thresholds (Careful, Warning and Critical) in configuration file and informations will be shown in colors which indicates the bottleneck in the system. [Read More]

• How to find the Swap usage of Virtual Machines from a Swapped KVM host

find /proc -maxdepth 2 -path "/proc/[0-9]*/status" -readable -exec awk -v FS=":" '{process[$1]=$2;sub(/^[ \t]+/,"",process[$1]);} END {if(process["VmSwap"] && process["VmSwap"] != "0 kB") printf "%10s %-30s %20s\n",process["Pid"],process["Name"],process["VmSwap"]}' '{}' \;|grep qemu

• Output

     3529 qemu-system-x86                            15112 kB
      6362 qemu-system-x86                           151732 kB
     16441 qemu-system-x86                            32040 kB
     25338 qemu-system-x86                           267232 kB
     29052 qemu-system-x86                            66408 kB
     34747 qemu-system-x86                             7252 kB
     34876 qemu-system-x86                            26576 kB
     44797 qemu-system-x86                            11164 kB
     44838 qemu-system-x86                            77052 kB
     45507 qemu-system-x86                            13928 kB
     53475 qemu-system-x86                             8144 kB
     55232 qemu-system-x86                            22288 kB