Linux has many services, daemons, systems, subsystems and applications running. You use system logging to gather data about your running system from the moment it boots. From time to time you have to check the health of processes, monitor the activity.

In this article we will process upgrade from CentOS 6 to CentOS 7. Operation system CentOS 7 was released right after the main Red Hat Enterprise Linux 7 release. OS includes the same long-waiting feature sets as base RHEL. One of the key features is Systemd and Docker functionality. But the most interesting feature is a possibility to perform upgrades from version 6 to version 7 automatically without the need of the installation images. This upgrade still requires a reboot but this enables upgrading procedures very convenient for servers operated remotely.

Composer is a dependency management tool for PHP similar to npm for Node.js and bundle for ruby. It is not a package manager in the same sense as Yum or Apt are. Yes, it deals with “packages” or libraries, but it manages them on a per-project basis, installing them in a directory (e.g. vendor) inside your project. By default it does not install anything globally. It does however support a “global” project for convenience via the global command. It permits you to declare the subordinate libraries your task needs and it will install them in your project for you.

The most convient way is to login via SSH to your server and check it in console.
For Centos 7+ (RHEL) we will need to use the following command:

There are several ways on how to check what version of CentOS is running on your VPS/Dedicated server. The simplest way to check for the CentOS version number is to execute the cat /etc/centos-release command in console via SSH. Checking a CentOS version very important for all server operations so commands are different from one to another CentOS system.

At this moment cPanel does not support ionCube Loader 5 on WHM/cPanel servers, which will cause issues for client running files made with ionCube v9. cPanel currently installs ionCube PHP Loader v4.7.5, when you install PHP using cPanel EasyApache utility.

TUN/TAP are commonly used in computer networking. Basically they are used to provide packet reception and transmission for user space programs. TUN stands for network TUNnel is a network layer device (it operates with layer 3 packets like IP packets) and TAP stands for network TAP and it is a link layer device and both of them are the virtual-network kernel devices. The TUN simulates a network layer device and it operates with layer 3 packets like IP packets.