Category Archives: Linux/Unix

how to firewalld

“Firewalld provides a dynamically managed firewall with support for network/firewall zones that define the trust level of network connections or interfaces. It has support for IPv4, IPv6 firewall settings, ethernet bridges and IP sets. There is a separation of runtime and permanent configuration options. It also provides an interface for services or applications to add firewall rules directly.” –

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Setup Docker CE for CentOS 7


In this tutorial I will show how to Setup Docker CE for CentOS 7.
The default Docker version that comes with CentOS is very old and only supports docker-compose syntax version 2. To use a higher level of docker-compose syntax we need the latest Docker CE.
This tutorial is the short version of the official Docker CE tutorial.

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Traefik Reverse Proxy for Docker

Traefik is a reverse proxy / load balancer that’s easy, dynamic, automatic, fast, full-featured, open source, production proven, provides metrics, and integrates with every major cluster technology.


In this tutorial I will share my Traefik docker-compose.yml setup files and how to use them.
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Setup BIND DNS Server on CentOS 7

Setup BIND DNS Server on CentOS 7

This tutorial provides an example how to Setup BIND DNS Server on CentOS 7.
This example is suited for secure private networks behind a gateway.

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configure apache

Apache Active Directory Authentication


This tutorial provides an example of Apache Active Directory Authentication using the Authz LDAP module.
Apache and SSL settings are not in the scope of this tutorial.
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Basic SELinux Security Concepts


“SELinux is a security enhancement to Linux which allows users and administrators more control over access control.” (”
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VMWare Workstation start on boot CentOS

CentOS 7 VirtualBox Guest Additions Installation

CentOS 7 VirtualBox Guest Additions Installation Tutorial

In the following tutorial, I’ll demonstrate how to install Guest Additions on your VirtualBox hosted CentOS 7 Minimal machine.
Although this tutorial is intended for CentOS 7 minimal, it’s will probably also work on other CentOS releases.

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CentOS Grails installation tutorial for newbs – CentOS 6.x

centos grails

centos grails installation tutorial for newbs. for CentOS 6.x (And probably for older/later)



You have to install Groovy (which require JDK). If you don’t have Groovy (And JDK) installed follow those instructions.

  • Java SDK 1.4+ for Grails 1.0.x and 1.1.x
  • Java SDK 1.5+ for Grails 1.2 or greater (For this tutorial make sure you have JDK 1.5+ installed)


Install Grails

Option 1: Using GVM (Recommended)

If you’ve installed groovy using GVM, you can use the GVM to install grails too. use:

gvm install grails

centos grails

centos grails

Option 2: Manual Installation

We’d go by the official Grails manual:

The folder we’ll install Grails is: /usr/grails, but you can choose any other as you like.

Init Folder

cd /usr
mkdir grails
cd grails

Here we’ll put the grails files by version.

Visit the download page to get the latest version. as for now it’s 2.3.7


Install wget & unzip if you don’t yet have them install by: yum install wget unzip

add the following to your ~/.bash_profile or ~/.bash_rc (or wherever you init your user environment):

# grails
export GRAILS_HOME=/usr/grails/grails-2.3.7

That’s it

Option 3: Using GIT

If you want to be updated with latest patches (and bugs) you can clone the git repo.

Prerequisities: you should have JDK installed, your JAVA_HOME set and GIT installed (yum install git).

For the 2.0.x and the ‘master’ branch:

cd /usr
git clone
cd grails-core && ./gradlew install

and set your GRAILS_HOME in the ~/.bash_profile (or ~.bash_rc):

# grails
export GRAILS_HOME=/usr/grails-core

If you want to install older branch read here.


Testing grails

Type at command:

grails --version

You should get something like this output (depend on version)



That’s It! you have centos grails installed.