Administrations | Bots!

Reverse Proxy with Caching

February 15, 2016 by Rumi

A Sample Nginx Reverse proxy configuration- an alternative to Varnish cache (kind of more simplistic)-

user www-data;
worker_processes 4;
pid /var/run/nginx.pid;

events {
 worker_connections 768;
 # multi_accept on;
}

http {
 proxy_cache_path /cache levels=1:2 keys_zone=STATIC:10m
 inactive=24h max_size=1g;
 server {
 location / {
 proxy_pass http://127.0.0.1:8080;
 proxy_set_header Host $host;
 proxy_cache STATIC;
 proxy_cache_valid 200 1d;
 proxy_cache_use_stale error timeout invalid_header updating
 http_500 http_502 http_503 http_504;
 }
 }
}

Reinstalling MySQL on CentOS/Redhat 6

February 7, 2016 by Rumi

Some time we faces issues with MySQL installation on Linux machine. If we simply remove MySQL packages and re-install doesn’t fixes the issue, in that case old settings may still exists on server which again affects new install. In that case first uninstall MySQL completely from system and erase all settings of old install. To do the same follow the below settings.

Note: Please do not use below steps if MySQL have any running databases.

Step 1: Uninstall MySQL Packages
First uninstall all the MySQL packages installed on your server

# yum remove mysql mysql-server

Step 2: Romove MySQL Directory
Now we need to remove MySQL data directory from system which by default exists at/var/lib/mysql. If you didn’t find this, It may be changed to some other place, which you can find in my.cnf file with variable datadir. Delete the /var/lib/mysql directory from system but we prefer to rename it to keep a backup of existing files.

# mv /var/lib/mysql /var/lib/mysql_old_backup

Simple failover cluster using UCARP on Ubuntu (Heartbeat Alternative)

January 24, 2016 by Rumi

In this tutorial, I’ll show you the steps to create a simple failover cluster on Ubuntu using CARP. To make the things meaningful,we’ll create the cluster for Apache service but you can use it for any other service, which relay on IP.

Scenario:

Here is my Setup:

PrimarySrv: This is the main server, where I configured the apache and which act as Master (IP: 192.168.1.202)
SecondarySrv: 2nd Apache Server where I configured the apache exactly like on PrimarySrv (IP : 192.168.1.203)
192.168.1.250 : Virtual IP address,created using Ucarp.

Server Monitoring with Munin and Monit on Ubuntu 14.04 LTS

January 6, 2016 by Rumi

Our system’s hostname is server1.example.com, and we have a website www.example.com on it with the document root/var/www/www.example.com/web.

The following steps have to be performed as root user. To become root user on your server, run this command:

sudo su

Ensure that the system is up to date before you start to install Munin, run:

apt-get update
apt-get upgrade

Apache is used to show the Munin pages, the apache fcgid module is required for the Munin graph zoom feature. I will install apache and the libapache2-mod-fcgid module with apt.

Linux Tune Network Stack (Buffers Size) To Increase Networking Performance

December 23, 2015 by Rumi

By default the Linux network stack is not configured for high speed large file transfer across WAN links. This is done to save memory resources. You can easily tune Linux network stack by increasing network buffers size for high-speed networks that connect server systems to handle more network packets.

The default maximum Linux TCP buffer sizes are way too small. TCP memory is calculated automatically based on system memory; you can find the actual values by typing the following commands:

$ cat /proc/sys/net/ipv4/tcp_mem

The default and maximum amount for the receive socket memory:

$ cat /proc/sys/net/core/rmem_default
$ cat /proc/sys/net/core/rmem_max

The default and maximum amount for the send socket memory:

Mount NFS Partition from WIndows 2008 Server

December 21, 2015 by Rumi

On server 2008, go to the Server manager, and Add/Remove Programs.

For my example, i already have file services installed on this server, if it’s not, install it as a role, and add this feature, “services for NFS”

SVN Server on Ubuntu 12.04 LTS with Web Access

December 9, 2015December 9, 2015 by Rumi

To install SVN server, run this command at the command prompt:

sudo apt-get install subversion libapache2-svn apache2

Make the directory where you want to keep the svn repositories and edit the dav_svn.conf file:

sudo mkdir /svn
sudo nano /etc/apache2/mods-enabled/dav_svn.conf

Delete all the data and make it simple like this 🙂

<Location /svn>
DAV svn
SVNParentPath /svn
AuthType Basic
AuthName "Subversion Repository"
AuthUserFile /etc/apache2/dav_svn.passwd
Require valid-user
</Location>

To create a svn user , use the following command:

How to setup vsftpd FTP with SSL on Ubuntu 12.04

December 7, 2015 by Rumi

This tutorial teaches you, how to setup vsftpd server on Linux based dedicated Web server. The tutorial also teaches you how to add the ftp users and lock the directory to individual users(In this scenario,lock the users into their individual web directory).

In Ubuntu 12.04, vsftpd with chrooted users gives the following error message:

500 OOPS: vsftpd: refusing to run with writable root inside chroot ()
To overcome this problem, we need to add the following vsftpd PPA:

sudo add-apt-repository ppa:thefrontiergroup/vsftpd

How to Update SSH & MOTD Banner on CentOS 6

December 7, 2015 by Rumi

For legal reasons, Some people need to display a warning banner on their Linux machine before login so that a person requires to acknowledge the contents of the banner before entering the password. To do this, edit a/etc/issue.net file and fill it with the desired context.

Edit the /etc/issue.net file:

sudo nano /etc/issue.net

Here is mine banner as a sample, you can add your’s here:

#########################################################
# Authorized access only! # 
# Disconnect IMMEDIATELY if you are not an authorized user!!! #
# All actions Will be monitored and recorded #
###############################################################

Secure RDP connection through Vyatta using PuTTY

December 6, 2015 by Rumi

Connecting to SSH Server as gateway instead of directly RDP to a PC is safer way and add another layer ofencryption.With this method,we can connect to any client that is behind the firewall provided that we have open the port 22 (or any other SSH port) to the SSH Server.

In First step, we’ll configure the vyatta, so that it will forward the ssh request to the internal Linux server that it will receive on it’s port 222.

(From the Configuration Mode, issue these commands)