Vtrio Sysadmins » Misc

Authentication in mongodb

Thu, 08 May 2014 11:50:28 +0000

Mysql databases allow username and password. Similarly if you require to keep authentication for your mongodb database as well, please do the following. Suppose, I have a database named abc, and I need to create a user named abc with password abc123.

First, create an admin user.

root@abc:~# mongo
MongoDB shell version: 2.4.10
connecting to: test
> use admin
> db.addUser(“admin”, “admin”)

> use abc (Switch to the database abc)

> db.addUser(“abc”, “abc123″)

Quit the mongoshell and stop mongo

root@abc:~# /etc/init.d/mongodb stop

root@abc:~# vi /etc/mongodb.conf and make the following change

auth = true

root@abc:~#/etc/init.d/mongodb start

Now we need to test if authentication works. Which means, if not authenticated, you should not be able to saw the details of the database.

root@abc:~# mongo
MongoDB shell version: 2.4.10
connecting to: test

> use abc

> show collections

“$err” : “not authorized for query on abc.system.namespaces”,
“code” : 16550

Now it shows the error that you are not authorized to view the collections. Now, authenticate with the details you created earlier and try.

> db.auth(“abc”, “abc123″)
>show collections
testcollection
system.indexes

This is how you create a user for mongodb database.

Accessing Gmail with Roundcube

Thu, 08 May 2014 11:27:07 +0000

Requirement : I want to access my gmail under my own domain with the help of webmail.

Say my domain name is abc.com , I want to access it as http://abc.com/mail

Suppose I am on a cpanel server. Download and install Roundcube as follows.

root@me [/home/abc/public_html]# wget http://downloads.sourceforge.net/project/roundcubemail/roundcubemail/1.0.0/roundcubemail-1.0.0.tar.gz

root@me [/home/abc/public_html]# tar -xzvf roundcubemail-1.0.0.tar.gz

root@me [/home/abc/public_html]# mv roundcubemail-1.0.0 mail

root@me [/home/abc/public_html]# chown -R abc:abc mail

root@me [/home/abc/public_html]# cd mail

Now login to your cpanel and create a database for roundcube installation, create a database user and assign privileges. This can all be done from cpanel.

Once done, go to the installer link as http://abc.com/mail/installer, follow the on screen instructions, make sure to give the database details correct and do not overwrite or create any conflict with the existing roundcube installation that comes with cpanel.

Once the installation is done, there are two files which requires attention.

root@me [/home/abc/public_html/mail]# cd /home/abc/public_html/mail/config

Make sure the config.inc.php and defaults.inc.php are populated with the correct database details.

root@me [/home/abc/public_html/mail/config]# vi defaults.inc.php and edit the following fields

// IMAP Settings
$rcmail_config[‘default_host’] = ‘ssl://imap.gmail.com';
$rcmail_config[‘defaul_port’] = 993;
$rcmail_config[‘imap_auth_type’] = null;
$rcmail_config[‘username_domain’] = ‘yourdomainname'; // Give the domain name that use googleapps. If you are using gmail account, give gmail.com
$rcmail_config[‘mail_domain’] = ‘yourdomainname'; // Give the domain name that use googleapps. If you are using gmail account, give gmail.com
// SMTP Settings
$rcmail_config[‘smtp_server’] = ‘ssl://smtp.gmail.com';
$rcmail_config[‘smtp_port’] = 465;
$rcmail_config[‘smtp_user’] = ‘%u';
$rcmail_config[‘smtp_pass’] = ‘%p';
//MBOX Settings
$rcmail_config[‘drafts_mbox’] = ‘[Gmail]/Drafts';
$rcmail_config[‘junk_mbox’] = ‘[Gmail]/Spam';
$rcmail_config[‘sent_mbox’] = ”;
$rcmail_config[‘trash_mbox’] = ”;

Save and quit the file. Remove the installer folder.

root@me [/home/abc/public_html/mail/config]# rm -rf /home/abc/public_html/mail/installer

Now access your gmail through your roundcube installation.

http://abc.com/mail

Username : test if my gmail account is test@gmail.com

Password : test123 if my gmail pass is test123

Migrating emails from mailenable to exim

Thu, 08 May 2014 11:24:58 +0000

If you want to copy emails from a windows mailenable server to linux server with exim, you can do it as follows.

I am copying the email account test@abc.com to new server. Its password is test123c on both servers.

root@abc [~]# cd /usr/local/src/

root@abc [/usr/local/src]# wget http://home.arcor.de/armin.diehl/imapcopy/imapcopy.tar.gz

root@abc [/usr/local/src]# tar -xvf imapcopy.tar.gz

root@abc [/usr/local/src]# cd imapcopy

root@abc [/usr/local/src/imapcopy]# ls
./ ../ imapcopy* ImapCopy.cfg

root@abc [/usr/local/src/imapcopy]# cp -pv ImapCopy.cfg ImapCopy.cfg.original

`ImapCopy.cfg’ -> `ImapCopy.cfg.original’

root@abc [/usr/local/src/imapcopy]# vi ImapCopy.cfg
You need to edit the following values to make the migration smoother.

##############
# Sourceserver
##############
SourceServer 1.2.3.4 (Source Server IP Address)
SourcePort 143
###################
# Destinationserver
###################
DestServer localhost
DestPort 143

#############################
# List of users and passwords
#############################

# SourceUser SourcePassword DestinationUser DestinationPassword
Copy “test@abc.com” “test123c” “test@abc.com” “test123c”

[/stextbox]

Make sure you are able to connect to port 143 of source server from destination server

[stextbox id=”info”]

root@abc [/usr/local/src/imapcopy]# telnet 1.2.3.4 143
Trying 1.2.3.4…
Connected to abc.greproot.com (1.2.3.4).
Escape character is ‘^]’.
* OK IMAP4rev1 server ready at 05/07/14 05:46:17
^]
telnet> q
Connection closed.
[/stextbox]

Now test the configuration

[stextbox id=”info”]

root@abc [/usr/local/src/imapcopy]# ./imapcopy -t
IMAPCopy 1.04 – 2009/07/18 [compiled with FreePascal]
written 2001-2009 by Armin Diehl
Running on Linux

Login on sourceserver as test@abc.com OK
Login on destinationserver as test@abc.com OK
Getting folderlist on sourceserver OK, found 1 folder

1 User processed, 0 Messages copied, 0 Error(s)
0 Folder(s) created, 0 Folder create errors, 0 Folder not copied
[/stextbox]

The configuration looks fine without any errors. Now we can start copying the email account contents.

[stextbox id=”info”]

root@abc [/usr/local/src/imapcopy]#./imapcopy
IMAPCopy 1.04 – 2009/07/18 [compiled with FreePascal]
written 2001-2009 by Armin Diehl
Running on Linux

Login on sourceserver as test@abc.com OK
Login on destinationserver as test@abc.com OK
Getting folderlist on sourceserver OK, found 1 folder
Getting List of messages in “INBOX” OK, 7 Messages found
Processing Folder INBOX
7 Messages copied, 0 Errors

1 User processed, 7 Messages copied, 0 Error(s)
0 Folder(s) created, 0 Folder create errors, 0 Folder not copied
[/stextbox]

Now the mails have been copied. Try accessing webmail of the account test@abc.com and see if mails are displayed fine.

Xen Virtualization in Centos 6

Thu, 03 Apr 2014 04:06:16 +0000

Xen virtualization steps are given below.

1. Make sure that SELinux is disabled or permissive.

vi /etc/sysconfig/selinux

and set “SELINUX=disabled”. Then reboot server.

2. Creating A Network Bridge.

We need to set up a network bridge on our server so that our virtual machines can be accessed from other hosts as if they were physical systems in the network.

To do this, we install the package bridge-utils

=========

yum install bridge-utils

=========

… and configure a bridge. Create the file /etc/sysconfig/network-scripts/ifcfg-br0 (please use the IPADDR, PREFIX, GATEWAY, DNS1 and DNS2 values from the/etc/sysconfig/network-scripts/ifcfg-eth0 file); make sure you use TYPE=Bridge, not TYPE=Ethernet:

vi /etc/sysconfig/network-scripts/ifcfg-br0

DEVICE="br0"
NM_CONTROLLED="yes"
ONBOOT=yes
TYPE=Bridge
BOOTPROTO=none
IPADDR=192.168.0.100
PREFIX=24
GATEWAY=192.168.0.1
DNS1=8.8.8.8
DNS2=8.8.4.4
DEFROUTE=yes
IPV4_FAILURE_FATAL=yes
IPV6INIT=no
NAME="System br0"

Modify /etc/sysconfig/network-scripts/ifcfg-eth0 as follows (comment out BOOTPROTO, IPADDR, PREFIX, GATEWAY, DNS1, and DNS2 and add BRIDGE=br0):

vi /etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE="eth0"
NM_CONTROLLED="yes"
ONBOOT=yes
HWADDR=00:1E:90:F3:F0:02
TYPE=Ethernet
#BOOTPROTO=none
#IPADDR=192.168.0.100
#PREFIX=24
#GATEWAY=192.168.0.1
#DNS1=8.8.8.8
#DNS2=8.8.4.4
DEFROUTE=yes
IPV4_FAILURE_FATAL=yes
IPV6INIT=no
NAME="System eth0"
UUID=5fb06bd0-0bb0-7ffb-45f1-d6edd65f3e03
BRIDGE=br0

Restart the network:
/etc/init.d/network restart

and run "ifconfig", it should network bridge.

[root@server1 ~]# ifconfig
br0       Link encap:Ethernet  HWaddr 00:1E:90:F3:F0:02
          inet addr:192.168.0.100  Bcast:192.168.0.255  Mask:255.255.255.0
          inet6 addr: fe80::21e:90ff:fef3:f002/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:17 errors:0 dropped:0 overruns:0 frame:0
          TX packets:29 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:1196 (1.1 KiB)  TX bytes:2794 (2.7 KiB)

eth0      Link encap:Ethernet  HWaddr 00:1E:90:F3:F0:02
          inet6 addr: fe80::21e:90ff:fef3:f002/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:4554 errors:0 dropped:0 overruns:0 frame:0
          TX packets:3020 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:6249612 (5.9 MiB)  TX bytes:254928 (248.9 KiB)
          Interrupt:25 Base address:0x6000

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:3 errors:0 dropped:0 overruns:0 frame:0
          TX packets:3 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:1304 (1.2 KiB)  TX bytes:1304 (1.2 KiB)

3. Installing XEN:
First check if your CPU supports hardware virtualization - if this is the case, the command
egrep '(vmx|svm)' --color=always /proc/cpuinfo

should display something, e.g. like this:

[root@server1 ~]# egrep ‘(vmx|svm)’ –color=always /proc/cpuinfo
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall
nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow pni cx16 lahf_lm cmp_legacy svm extapic cr8_legacy misalignsse
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall
nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow pni cx16 lahf_lm cmp_legacy svm extapic cr8_legacy misalignsse
[root@server1 ~]#

If nothing is displayed, then your processor doesn’t support hardware virtualization. This means you can use only paravirtualization with Xen, but not hardware virtualization.

As CentOS 6 is based on RedHat 6, and RedHat has dropped support for Xen in version 6, we need to get Xen from a third-party repository. We can enable the repo as follows:

yum install wget

yum install http://au1.mirror.crc.id.au/repo/kernel-xen-release-6-3.noarch.rpm

yum install kernel-xen xen

This installs Xen and a Xen kernel on our CentOS system.

Before we can boot the system with the Xen kernel, please check your GRUB bootloader configuration. We open /boot/grub/menu.lst:

vi /boot/grub/menu.lst

The first listed kernel should be the Xen kernel that you’ve just installed:

[...]
title CentOS (2.6.32.54-1.el6xen.x86_64)
        root (hd0,0)
        kernel /vmlinuz-2.6.32.54-1.el6xen.x86_64 ro root=/dev/mapper/VolGroup00-LogVol00 rd_NO_LUKS LANG=en_US.UTF-8 rd_NO_MD quiet SYSFONT=latarcyrheb-sun16 rhgb crashkernel=auto  KEYBOARDTYPE=pc KEYTABLE=de rd_LVM_LV=VolGroup00/LogVol01 rd_LVM_LV=VolGroup00/LogVol00 rd_NO_DM
        initrd /initramfs-2.6.32.54-1.el6xen.x86_64.img
[...]

We need to modify that section so that the Xen hypervisor gets loaded first. In the kernel /vmlinuz... line, replace the first word kernel with module. Do the same in the next line - replace the first word initrd with module in the initrd /initramfs... line. Then add the line kernel /xen.gz dom0_mem=1024M cpufreq=xen dom0_max_vcpus=1 dom0_vcpus_pin after the root line and before the first module line (if you have more than one CPU core, you can specify another number than 1 fordom0_max_vcpus). The final kernel section should look like this:

[...]
title CentOS (2.6.32.54-1.el6xen.x86_64)
        root (hd0,0)
        kernel /xen.gz dom0_mem=1024M cpufreq=xen dom0_max_vcpus=1 dom0_vcpus_pin
        module /vmlinuz-2.6.32.54-1.el6xen.x86_64 ro root=/dev/mapper/VolGroup00-LogVol00 rd_NO_LUKS LANG=en_US.UTF-8 rd_NO_MD quiet SYSFONT=latarcyrheb-sun16 rhgb crashkernel=auto  KEYBOARDTYPE=pc KEYTABLE=de rd_LVM_LV=VolGroup00/LogVol01 rd_LVM_LV=VolGroup00/LogVol00 rd_NO_DM
        module /initramfs-2.6.32.54-1.el6xen.x86_64.img
[...]

Change the value of default to 0 (so that the first kernel (the Xen kernel) will be booted by default):

[...]
default=0
[...]

The complete /boot/grub/menu.lst should look something like this:

# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE:  You have a /boot partition.  This means that
#          all kernel and initrd paths are relative to /boot/, eg.
#          root (hd0,0)
#          kernel /vmlinuz-version ro root=/dev/mapper/VolGroup00-LogVol00
#          initrd /initrd-[generic-]version.img
#boot=/dev/sde
default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title CentOS (2.6.32.54-1.el6xen.x86_64)
        root (hd0,0)
        kernel /xen.gz dom0_mem=1024M cpufreq=xen dom0_max_vcpus=1 dom0_vcpus_pin
        module /vmlinuz-2.6.32.54-1.el6xen.x86_64 ro root=/dev/mapper/VolGroup00-LogVol00 rd_NO_LUKS LANG=en_US.UTF-8 rd_NO_MD quiet SYSFONT=latarcyrheb-sun16 rhgb crashkernel=auto  KEYBOARDTYPE=pc KEYTABLE=de rd_LVM_LV=VolGroup00/LogVol01 rd_LVM_LV=VolGroup00/LogVol00 rd_NO_DM
        module /initramfs-2.6.32.54-1.el6xen.x86_64.img
title CentOS (2.6.32-220.el6.x86_64)
        root (hd0,0)
        kernel /vmlinuz-2.6.32-220.el6.x86_64 ro root=/dev/mapper/VolGroup00-LogVol00 rd_NO_LUKS LANG=en_US.UTF-8 rd_NO_MD quiet SYSFONT=latarcyrheb-sun16 rhgb crashkernel=auto  KEYBOARDTYPE=pc KEYTABLE=de rd_LVM_LV=VolGroup00/LogVol01 rd_LVM_LV=VolGroup00/LogVol00 rd_NO_DM
        initrd /initramfs-2.6.32-220.el6.x86_64.img

Before we reboot, we install the libvirt and python-virtinst (which contains the virt-install tool which we will use later on to install Xen VMs) packages:

yum install libvirt python-virtinst

Because the libvirt package from CentOS 6/RedHat 6 has no support for Xen, we must rebuild it with Xen support. To do this, we install a few prerequisites now:

yum groupinstall 'Development Tools'

yum install python-devel xen-devel libxml2-devel xhtml1-dtds readline-devel ncurses-devel libtasn1-devel gnutls-devel augeas libudev-devel libpciaccess-devel yajl-devel sanlock-devel libpcap-devel libnl-devel avahi-devel libselinux-devel cyrus-sasl-devel parted-devel device-mapper-devel numactl-devel libcap-ng-devel netcf-devel libcurl-devel audit-libs-devel systemtap-sdt-devel

Now reboot machine to load new kernel

The system should now automatically boot the new Xen kernel. After the system has booted, we can check that by running

uname -r

[root@server1 ~]# uname -r
2.6.32.54-1.el6xen.x86_64
[root@server1 ~]#

So it’s really using the new Xen kernel!

a. xm list

b. to check if Xen has started. It should list Domain-0 (dom0):

[root@server1 ~]# xm list
Name ID Mem VCPUs State Time(s)
Domain-0 0 1024 1 r—– 18.9
[root@server1 ~]#

Instead of using the xm command, I will from now on use the virsh command to manage Xen VMs. This is the preferred way as we are using libvirt.

virsh list

should show this:

[root@server1 ~]# virsh list
Id Name State
———————————-
0 Domain-0 running

[root@server1 ~]#

4. Paravirtualization:

CentOS has a nice tool called virt-install with which we can create virtual machines for Xen. To start it, we simply run

virt-install –prompt –network bridge=br0 –virt-type=xen

The tools asks a few questions before it creates a virtual machine. I want to call my first virtual machine vm01, with 1024MB RAM and a disk size of 10GB. I want to store it in the file /var/lib/libvirt/images/vm01.img:

Would you like a fully virtualized guest (yes or no)? This will allow you to run unmodified operating systems.
<– no
What is the name of your virtual machine?
<– vm01
How much RAM should be allocated (in megabytes)?
<– 1024
What would you like to use as the disk (file path)?
<– /var/lib/libvirt/images/vm01.img
How large would you like the disk (/vm/vm01.img) to be (in gigabytes)?
<– 10
What is the install URL?
<– http://ftp.tu-chemnitz.de/pub/linux/centos/6.2/os/x86_64

Regards,

Jeen

Multiple php versions on Centos

Wed, 05 Feb 2014 06:28:22 +0000

Hi , you may come across situations to have multiple php versions installed on a server. Here I will explain a simple method to accomplish this. Lets take php versions 5.2 and 5.4 and I am going to install it in different locations than default installation directory.

Note for 2 versions of php one version should be compiled as fcgi.

1. Install php 5.2:

a. Download php tar file from “http://php.net/downloads.php”

Here I am going to compile this php as fastcgi and using custom installation directory /opt/php52. Configure command is given below.

==========

# ./configure –prefix=/opt/php52 –with-config-file-path=/opt/php52 –with-curl –enable-cli –enable-fastcgi –enable-discard-path –enable-force-cgi-redirect –with-mysql –with-mysqli –enable-bcmath –enable-ftp –enable-magic-quotes –with-pear –enable-sockets –with-zlib –with-gd –with-jpeg-dir=/usr/lib –with-libdir=lib64 –with-bz2 –enable-calendar –with-curl –enable-dbase –enable-exif –with-gettext –with-gmp –enable-mbstring –with-mcrypt –with-mhash –with-ncurses=shared –with-openssl –enable-pcntl –with-pdo-mysql –with-pspell –with-readline –enable-shmop –with-snmp=shared –enable-sysvsem –enable-sysvshm –enable-sysvmsg –enable-wddx –with-kerberos –with-imap-ssl –enable-zip –with-xsl –with-tidy –enable-soap

# make && make install

============

If you got error while executing ‘make’ command like “Compile: /usr/bin/ld: cannot find -lltdl, collect2: ld returned 1 exit status” please install libtool using following command.

yum install libtool-ltdl-devel

Copy php.ini-recommended from the install directory to /opt/php52/

2. Install php 5.4

This one also going to install in separate location say /opt/php54

===========

#./configure –prefix=/opt/php54 –with-config-file-path=/opt/php54 –with-curl –enable-cli –enable-discard-path –with-mysql –with-mysqli –enable-bcmath –enable-ftp –enable-magic-quotes –with-pear –enable-sockets –with-zlib –with-gd –with-jpeg-dir=/usr/lib –with-libdir=lib64 –with-bz2 –enable-calendar –with-curl –enable-dbase –enable-exif –with-gettext –with-gmp –enable-mbstring –with-mcrypt –with-mhash –with-ncurses=shared –with-openssl –enable-pcntl –with-pdo-mysql –with-pspell –with-readline –enable-shmop –with-snmp=shared –enable-sysvsem –enable-sysvshm –enable-sysvmsg –enable-wddx –with-kerberos –with-imap-ssl –enable-zip –with-xsl –with-tidy –enable-soap

# make && make install

===========

Copy php.ini-production from install directory to /opt/php54.

Now in apache configuration file include following line or uncomment it.

Include conf/extra/httpd-fastcgi.conf

Now create this file “/usr/local/apache/conf/extra/httpd-fastcgi.conf” and add below contents to it.

==========

LoadModule fastcgi_module modules/mod_fastcgi.so
FastCgiIpcDir /opt/tmp/fcgi
AddHandler fastcgi-script .fcgi
FastCgiConfig -autoUpdate -singleThreshold 200 -killInterval 600 -idle-timeout 150
AddType application/x-httpd-php .php
ScriptAlias /fastcgi/ /usr/local/apache/cgi-bin/

Options ExecCGI
SetHandler fastcgi-script
Order allow,deny
Allow from all

==========

Make sure that “mod_fastcgi.so” exists in the modules directory. Now create a directory “/opt/tmp/fcgi” and give 777 permission.

Navigate to directory “/usr/local/apache/cgi-bin/”.

a. Create a file for php 5.2 say “php52.fcgi” with 755 or executable permission and add following contents to it. Make sure you have added correct path for php-cgi binary.

==========

#!/bin/sh
PHP_FCGI_CHILDREN=8
export PHP_FCGI_CHILDREN
PHP_FCGI_MAX_REQUESTS=5000
export PHP_FCGI_MAX_REQUESTS
exec /opt/php52/bin/php-cgi

==========

Similarly create a file for php 5.4 say php54.cgi with following contents.

==========

#!/bin/sh
PHP_FCGI_CHILDREN=8
export PHP_FCGI_CHILDREN
PHP_FCGI_MAX_REQUESTS=5000
export PHP_FCGI_MAX_REQUESTS
exec /opt/php54/bin/php-cgi

==========

Finally go to virtual host section of each domain and specify which php to use for the domain. Imagine I have to use php 5.2 for a domain called abc.com. Go to virtual host of domain abc.com and add following line to it.

==========

Action application/x-httpd-php /fastcgi/php52.fcgi

==========

For domains using php version 5.4 add following line.

==========

Action application/x-httpd-php /fastcgi/php54.fcgi

==========

Finally restart apache service. Thats it. Put a php info page and check php versions displaying.

Thanks,

Jeen

PHP Script to download multiple files concurrently

Mon, 13 Jan 2014 08:46:25 +0000

This script will show you an example of how to download multiple files concurrently
using the curl_multi commands in PHP 5.While php itself doesn’t support multi threading and concurrency,
libcurl does and php allows us to download multiple files at the same time from php.

Script Author – JeenaJoy

//using the curl_multi commands in PHP 5.While php itself doesnt support multi threading and concurrency,
//libcurl does and php allows us to download multiple files at the same time from php.// Files to download
$urls = array(‘http://abc.com/docs/cdbwpohq0ayey.pdf’,
‘http://abc.com/docs/8wyxlxfufftas.pdf’,
‘http://abc.com/docs/9q29bbglnc2gk.pdf’,);

$save_to=’/tmp/'; // Path to save files in

$mh = curl_multi_init();
// Add curl multi handles
foreach ($urls as $i => $url) {

// Path to save files in
$g=$save_to.basename($url);

$conn[$i]=curl_init($url);
$fp[$i]=fopen ($g, “wb”);

curl_setopt ($conn[$i], CURLOPT_HEADER ,0);///it should come first
curl_setopt ($conn[$i], CURLOPT_FILE, $fp[$i]);
curl_multi_add_handle ($mh,$conn[$i]);

}
// Download the files
do {
$n=curl_multi_exec($mh,$active);
}
while ($active);
foreach ($urls as $i => $url)
{
curl_multi_remove_handle($mh,$conn[$i]);

curl_close($conn[$i]);
fclose ($fp[$i]);

}
curl_multi_close($mh);

Adding SSL to a site in nginx

Thu, 09 Jan 2014 11:03:30 +0000

1) First create a folder where SSL certs are to be placed

#mkdir /etc/ssl/certs

#cd /etc/ssl/certs

Create key

# openssl genrsa -out abc.com.key 2048

# chmod 600 abc.com.key

Generate CSR

# openssl req -new -key abc.com.key -out abc.com.csr

If all that you need is a self signed certificated, do as follows.

# openssl x509 -req -days 365 -in abc.com.csr -signkey abc.com.key -out abc.com.crt

Otherwise get the cert signed and place it in /etc/ssl/certs/abc.com.crt

Now, open up your nginx config file for this domain.

# vi /etc/nginx/sites-available/abc.com

If you are planning to use both http and https, you need two separate server modules in your config. Hence, copy the config for 80 and put it to the bottom of the page and make modifications. What you need to add to the https server module is given below. Paste it before server_name line.

server {

listen 1.2.1.3:443 ssl;

ssl    on;
ssl_certificate    /etc/ssl/certs/abc.com.crt;
ssl_certificate_key    /etc/ssl/certs/abc.com.key;
server_name abc.com www.abc.com

….

…

}

Now restart nginx.

#/etc/rc.d/init.d/nginx restart

Now try accessing site with https.

Password protecting a site in nginx

Thu, 09 Jan 2014 10:45:46 +0000

This post will explain how to password protect a site in nginx. It is very simple and it uses the normal htpasswd protection

Suppose I need to password protect the site abc.com whose document root is /var/www/abc/public_html

Simple follow the steps given below

[root@abc ~]# cd /var/www/abc/public_html

[root@abc ~]# htpasswd -c .htpasswd admin where admin is the username chosen. It will prompt for password, give a strong password.

Now, your login details are stored to the file /var/www/abc/public_html/.htpasswd and we need to call this file from abc.com’s conf.

Simply add the following two lines before the locations

[root@abc ~]# cd /etc/nginx/sites-available/

[root@abc ~]# vi abc.com

auth_basic “Restricted”;
auth_basic_user_file /var/www/abc/public_html/.htpasswd;

So your final conf will now look as follows.

server {
server_name www.abc.com abc.com;
access_log /var/www/abc/logs/access.log;
error_log /var/www/abc/logs/error.log;
root /var/www/abc/public_html/;

auth_basic “Restricted”;
auth_basic_user_file /var/www/abc/public_html/.htpasswd;

location / {

index index.html index.htm index.php;

}

location ~ \.php$ {
if (!-e $request_filename) { rewrite / /index.php last; }
include /etc/nginx/fastcgi_params;
fastcgi_pass 127.0.0.1:9000;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME /var/www/abc/public_html$fastcgi_script_name;
fastcgi_param MAGE_RUN_CODE base;
fastcgi_param MAGE_RUN_TYPE website;

}
}

All done, save the configuration file and exit. Now restart nginx and see if it starts without errors.

[root@abc ~]# /etc/rc.d/init.d/nginx restart
Stopping nginx: [ OK ]
Starting nginx: [ OK ]

Now clear your browser cache and try accessing the site. Bingo!! isnt’t it protected?

MongoDB backup/restore

Tue, 31 Dec 2013 06:42:46 +0000

Want to know how the backup of mongo database can be taken. Read below…

Four tools are described here.

1) mongoexport

mongoexport can be used to take the backup of a mongo database. It takes the backup to a CSV, TSV or JSON files. The syntax is as follows.

mongoexport -d db_name -c test -o db_name.csvwhere -d is the database name
-c is the collection name
-o is the file name to which the backup is to be taken

2) mongoimport

mongoimport can be used to import a backup to a database. You can import from the backup file as follows.

mongoimport -d db_restore -c test –file db_name.csvwhere -d is the name of the database to which the file is to be restored
-c is the collection name
–file is the backup file

3) mongodump

For those who need a complete backup of the database, you can use mongodump command to do so. Unlike mongoexport, the backup will be done into a folder and not file.

mongodump -d db_test -o /backuptestwhere -d is the database name
-o is the folder to which data is to be backed up

Once completed, the backup will be present in /backuptest/db_test/

4) mongorestore

To restore an entire database, you can use the mongorestore command. Let’s restore the backup that we took in the previous step.

mongorestore -d db_test_restore /backuptest/db_test/where -d is the existing or new database to which the data is to be restored
and the folder /backuptest/db_test/ is where the backup of db_test exists.

Try it and see, it works

WARNING: You are running on a NUMA machine We suggest launching mongod like this to avoid performance problems: ** numactl –interleave=all mongod [other options]

Tue, 31 Dec 2013 06:40:52 +0000

Mongo was working fine in my Ubuntu machine, but whenever I access mongo shell, it will display the following warning.

root@abc:~# mongo
MongoDB shell version: 2.4.5
connecting to: test
Server has startup warnings:
Tue Aug 13 03:47:13.764 [initandlisten]
Tue Aug 13 03:47:13.764 [initandlisten] ** WARNING: You are running on a NUMA machine.
Tue Aug 13 03:47:13.764 [initandlisten] ** We suggest launching mongod like this to avoid performance problems:
Tue Aug 13 03:47:13.764 [initandlisten] ** numactl –interleave=all mongod [other options]
Tue Aug 13 03:47:13.764 [initandlisten]

First I checked, whether my hardware is NUMA(Non-Uniform Access Memory) enabled. I got the following output which said the answer is yes, it is NUMA enabled.

root@abcl# dmesg | grep -i numa
[ 0.000000] NUMA: Node 1 [mem 0x00000000-0xcfffffff] + [mem 0x100000000-0x82fffffff] -> [mem 0x00000000-0x82fffffff]

I can simply start mongo as said in the warning message, but what I was looking forward was a permanent fix which will let me start/stop mongo using the startup script.

Unfortunately, numactl command was not present in the server, so I installed the package as follows.

apt-get install numactl

After that, I did the following.

Added the following line to /etc/sysctl.conf

vm.zone_reclaim_mode = 0

Now, made the following change to the file /etc/init/mongodb.conf

Commented out line 18 which is as follows.

# if [ “x$ENABLE_MONGODB” = “xyes” ]; then exec start-stop-daemon –start –quiet –chuid mongodb –exec /usr/bin/mongod — –config /etc/mongodb.conf; fi

Now added the following line.

if [ “x$ENABLE_MONGODB” = “xyes” ]; then exec start-stop-daemon –start –quiet –chuid mongodb –exec /usr/bin/numactl — –interleave=all /usr/bin/mongod –config /etc/mongodb.conf; fi

Save and quit the file.

After doing this you need to restart mongodb and check whether mongo shell is accessible without the warning.

root@abc# /etc/init.d/mongodb start
Rather than invoking init scripts through /etc/init.d, use the service(8)
utility, e.g. service mongodb start

Since the script you are attempting to invoke has been converted to an
Upstart job, you may also use the start(8) utility, e.g. start mongodb
mongodb start/running, process 21750

Check if mongo is running

root@abc# ps aux | grep mongo
mongodb 21750 1.0 0.0 348116 37516 ? Ssl 04:13 0:00 /usr/bin/mongod –config /etc/mongodb.conf
root 21762 0.0 0.0 9384 920 pts/0 S+ 04:13 0:00 grep –color=auto mongo

Try accessing the mongo shell

root@abc# mongo
MongoDB shell version: 2.4.5
connecting to: test
>
bye

Success!!!! In case of error, you can check the log file at /var/log/mongodb/mongodb.log