Separation Anxiety: A Tutorial for Isolating Your System with Linux Namespaces

With the advent of tools like Docker, Linux Containers, and others, it has become super easy to isolate Linux processes into their own little system environments. This makes it possible to run a whole range of applications on a single real Linux machine and ensure no two of them can interfere with each other, without having to resort to using virtual machines. These tools have been a huge boon to PaaS providers. But what exactly happens under the hood?

These tools rely on a number of features and components of the Linux kernel. Some of these features were introduced fairly recently, while others still require you to patch the kernel itself. But one of the key components, using Linux namespaces, has been a feature of Linux since version 2.6.24 was released in 2008.

Anyone familiar with chroot already has a basic idea of what Linux namespaces can do and how to use namespace generally. Just as chroot allows processes to see any arbitrary directory as the root of the system (independent of the rest of the processes), Linux namespaces allow other aspects of the operating system to be independently modified as well. This includes the process tree, networking interfaces, mount points, inter-process communication resources and more. Continue reading

Step by Step to Change website hosting without downtime

Switching to a new host can be a complicated process. Follow our steps to ensure that your move is smooth and painless

  1. The first step is to join your new host. Make sure to NOT cancel with your old hosting provider, and do not tell them you will be canceling. Keep this a secret from your old host, or they could prematurely terminate your site and cause downtime.
  2. At this point, you should have hosting accounts with two hosting providers (the old and the new one). You will now migrate your entire site from the old host to the new one. This can be done by connecting to the old host’s FTP and downloading all your files, and then by connecting to the new host’s FTP and uploading all your files (maintain the same file and folder structure).
  3. You must also backup any databases on the old host (contact the old host for instructions) and upload the backup files to the new host via FTP. You must then restore your databases from those backup files; this can be done via SSH or cPanel’s phpMyAdmin. Emails do not normally transfer, but you can archive your emails from the old host. You can accomplish this by making a POP3 connection to each email address; this way all the old emails are downloaded to your local computer. The new host will not have those old emails, but the new host will be able to get new emails.
  4. After you have all your files on both hosting accounts, it is time to change your domain name’s DNS. Your new host will provide you with the correct name servers (DNS). You may need to contact the new host to find out what DNS settings you will use for your domain name.DNS name servers usually looks like this (replace “yourhostname.com” with your host’s actual domain name):
    yourhostname.com
    ns2.yourhostname.com

Continue reading