Cloud Computing

Tutorials, tips, news, reviews, and guides for users of cloud computing ( rss feed ) .

Recently I created a simple shell script called backup.sh in /root/scripts directory to just backup MySQL database and dumped it to /nfs/mysql/ directory. I put a file (more like used the ln command to create a soft link ) in /etc/cron.hourly/ and it doesn’t run. There was no error in systemd log or cron log. Why is my cron job was not working, and here is how I troubleshoot it.
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I recently read that TCP BBR has significantly increased throughput and reduced latency for connections on Google’s internal backbone networks and google.com and YouTube Web servers throughput by 4 percent on average globally – and by more than 14 percent in some countries. The TCP BBR patch needs to be applied to the Linux kernel. The first public release of BBR was here, in September 2016. The patch is available to any one to download and install. Another option is using Google Cloud Platform (GCP). GCP by default turned on to use a cutting-edge new congestion control algorithm named TCP BBR. This page explains how to boost your Linux server’s Internet speed with TCP BBR configurations.
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Recently I come across a nice little nifty tool called parallel ssh (PSSH) to run a single command on multiple Linux / UNIX / BSD servers. You can easily increase your productive with this SSH IT automation tool.

More about pssh

pssh is a command line tool for executing ssh in parallel on some hosts. It specialties includes:

  1. Sending input to all of the processes
  2. Inputting a password to ssh
  3. Saving output to files
  4. IT/sysadmin task automation such as patching servers or looking for error logs
  5. Timing out and more

Let us see how to install and use pssh on Linux and Unix-like system.


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It is always a good idea to keep backups of all of your data in multiple places. Every Linux or Unix sysadmin needs to master the art of backups if they want to keep their data forever.

Most seasoned sysadmins recommend and follow the 3-2-1 rule:

  1. At least three copies of data
  2. In two different formats
  3. With one of those copies off-site

What is a Tarsnap service?

A Tarsnap service is a secure online backup system for Linux, OSX, *BSD or UNIX-like system. They encrypt and store data in Amazon S3. The services also use rsync-like algorithms, and only backup data that has been changed since the last dump. The backups are protected by a security key only known to a backup operator or sysadmin.

Tarsnap Mastery book

To use Tarsnap perfectly and feel secure about your backups, I recommend the “Tarsnap Mastery” book by Michael W. Lucas. It is no secret that I’m a big fan of his book series and this book didn’t disappoint.
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Cloud storage is nothing but an enterprise-level cloud data storage model to store the digital data in logical pools, across the multiple servers. You can use a hosting company such as Amazon, Google, Rackspace, Dropbox and others for keeping your data available and accessible 24×7. You can access data stored on cloud storage via API or desktop/mobile apps or web based systems.

In this post, I’m going to list amazingly awesome open source cloud storage engines that you can use to access and sync your data privately for security and privacy reasons.
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Vagrant is a multi-platform command line tool for creating lightweight, reproducible and portable virtual environments. Vagrant acts as a glue layer between different virtualization solutions (Software, hardware PaaS and IaaS) and different configuration management utilities (Puppet, Chef, etc’). Vagrant was started back at 2010 by Mitchell Hashimoto as a side project and later became one of the first products of HashiCorp – the company Mitchell founded.

While officially described as a tool for setting up development environments, Vagrant can be used for a lot of other purposes by non developers as well:

  • Creating demo labs
  • Testing configuration management tools
  • Speeding up the work with non multi-platform tools such as Docker

In this tutorial I’ll show how can we take Vagrant as use it to create small virtual test lab which we will be able to pass to our colleagues.
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You can send visitors to different servers based on country of their IP address using Amazon Route 53 cloud based dns server. For example, if you have a server in Amsterdam, a server in America, and a server in Singapore, then you can easily route traffic for visitors in Europe to the Amsterdam server, people in Asia go to the Singapore server and those in the rest of the world be served by the American server. This will results into the various kinds of benefits such as:

  1. Better performance as you are sending web site visitors to their nearest web server.
  2. Reduced load on origin.
  3. Geomarketing/online advertising.
  4. Restricting content to those geolocated in specific countries (I am not a big fan of DRM).
  5. In some cases you can get potentially lower costs and more.

In this post, I will explain how to configure and test GeoDNS using AWS Route 53 service.
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A typical WordPress blog contains a mix of static stuff such as images, javascript, style sheets and dynamic content such as posts, pages and comments posted by users. You can speed up your blog by serving static content via content delivery network such as Akamai, Edgecast and so on. The big boys of CDN business also offered the solution to accelerate dynamic content to improve the performance and reliability of the blog. However, solutions offered by big and traditional CDNs are expensive. Amazon cloudfront recently started to serving dynamic content at lowered price. In this blog post, I will explain:

  1. How to serve your entire blog using cloudfront.
  2. DNS settings.
  3. WordPress settings.
  4. Documenting limitations of cloudfront.
  5. Documenting performance improvements.

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