Archive for the 'Linux' Category

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Quick Tip: Installing NodeJS 8 on CentOS 7

Node JS has been gaining more popularity as the server-side runtime environment of choice these recent years. The asynchronous event-driven feature built into Node JS can be considered a killer feature that may flatter a system architect planning to build a high-performing server-side component serving HTTP webservice to the clients.

Node JS is cross-platform. The executable can run on major OSes that include Windows, GNU Linux, and Mac OS. Having a wide OS support further accelerates Node JS adoption within the server-side technology stack. Continue reading

Using SCP to Securely Upload Files and Directories to Remote Server

Secure Shell (SSH) is a common protocol used to access or login to remote servers. The protocol is widely supported across Operating Systems. If you are Windows user, you may have heard and been using Putty, which is a SSH client for Windows. Windows 10 users can use Open SSH client that can be installed via new feature installation. UNIX OSes usually come with native SSH client support, so additional software installation is not needed. Continue reading

How To Install Docker on Ubuntu 16

Docker is a popular option for “virtual appliances” nowadays. Docker website defines the “Docker” moniker as a software containerization platform that is more flexible than traditional virtual machines since it virtualizes the operating system instead of the hardware. This means that Docker can further isolate the resources by enabling multiple Docker containers running on an operating system. If the operating system itself is running on a virtual machine either via full virtualization (bare metal) or paravirtualization, we will have a good example of IT infrastructure transformation from asset-ownership model into cloud-lease model (my related paper about such transformation can be read here). Continue reading

Fedora Quick Tip: Resolving Permission Denied Issues in HTTP and FTP services with getsebool and setsebool

If you are running Fedora Linux as a server, one issue you frequently encounter is strange permission denied error message triggered when you are accessing one of the available network services run on the server. There are a lot of network services to mention, but HTTP and FTP are two good examples of such services. Assume you are trying to access FTP server on your Fedora box. You type the IP address of the server and then supply the username and password. Voila!!! You thought you would be immediately logged in. But instead of seeing the files in your home folder, you are shown an error message. The error message may vary, from something like “Login incorrect for user blah” displayed by Midnight Commander, “500 OOPS: cannot change directory: /home/blah” from Total Commander, to other error messages shown by different FTP client programs.

If you are 100% sure that you supply the correct user and password information, why couldn’t you get in? Let us assume that you have root access to the server so that you can remotely troubleshoot from the console. This post will give some guide on how you can solve this problem based on common configurations of a Fedora server.
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Quick Tip: How to Install and Configure PHP in Fedora Linux

Previously, I have discussed about how to install MySQL on Fedora Linux. In this post, I would like to elaborate PHP installation on Fedora. Even though the installation is simple by nature, I would like to provide some notes to help you troubleshoot some post-installation problems that may occur.

As usual, I will provide the screenshots of the installation along with the commands invoked on the terminal. For the environment, some important settings are written below:
OS : Fedora 13 64-bit
Web server : Apache HTTP Server
PHP version : PHP 5.3.2
Constraints : yum is installed, commands invoked in root shell, Apache is already installed and running

Note: Apache is installed by default in Fedora. You only need to configure and verify that the server is running. How to configure Apache is explained in the online documentation. If you want the server to be public, i.e. accessible from other computers in the network, you should not firewall the HTTP port, which is usually port 80. Also, if you enable selinux, you also need to properly set the flag of some security parameters related to http. I will explain about selinux and http in another post.

Now, let’s move to the installation. Basic installation steps are as follows:
1. Install PHP via yum
root# yum install php


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