Linux Servers cPanel webhosting blog » VPS

Server wide permission issue after enabling suphp

Gunjan — Sun, 22 Jan 2012 09:24:01 +0000

After enabling the suphp on the server,many time 500 Internal Server Error occur due to the incorrect permission,ownership and incorrect php module defined in the .htaccess file and we can’t make the changes manually therefore we can use the following script to make the all the changes server.

linux7802@server[~]#cat /root/suphppermission.sh

#!/bin/bash

# Reset the directory permissions.
chmod 755 /opt/suphp
find /opt/suphp -type d -exec chmod 755 {} \;

# Reset permission,ownership for cPanel user
for user in `/bin/ls /var/cpanel/users`; do

chown -R ${user}:${user} /home/${user}/public_html
chmod 755 /home/${user}/public_html
find /home/${user}/public_html -type f -exec chmod 644 {} \;
find /home/${user}/public_html -type d -exec chmod 755 {} \;

# Remove php_values in the .htaccess file.
find /home/${user}/public_html -name ‘.htaccess’ -exec sed -ie ‘s/php_value/#php_value/’ {} \;
find /home/${user}/public_html -name ‘.htaccess’ -exec sed -ie ‘s/php_flag/#php_flag/’ {} \;
done

If you have any issue to copy the above content the download the script from following URL
scr

vzmigrate command for VPS migration

Gunjan — Tue, 10 Jan 2012 14:40:56 +0000

The vzmigrate command is used to migrate the one VPS from node to the new or another node.

For example, we want to migrate the VPS which is currently having id 110 on new node and its ip is 192.168.0.1

server@linux[~]# vzmigrate 192.168.0.1 110

server@linux[~]# vzmigrate -r no 192.168.0.1 110

Some time node on which,we are trying to migrate the VPS we are receiving the following error message

110 already exists on the destination node.

To resolve the above error we can assign new id to the VPS

server@linux[~]#vzmigrate -r no 192.168.0.1 110:120

The new id on the new node will be 120 for VPS

We can also do online migration of VPS from one to another node.

server@linux[~]#vzmigrate --online 192.168.0.1 110

or

server@linux[~]#vzmigrate --online 192.168.1.130 110:120

If you want to migrate all the running VPS from one node to another node then refer to following command

for CT in $(vzlist -H -o veid);

do vzmigrate --remove-area no --keep-dst $1 $CT; done

cPanel file manager giving 404 not found error

Gunjan — Sun, 08 Jan 2012 16:28:00 +0000

While browsing the file manager from the cPanel the 404 not found error message is occur.

Not Found

The server was not able to find the document (./frontend/x3/index.html) you requested.
Please check the url and try again. You might also want to report this
error to your web hosting provider.

whostmgrd/11.25

As per above error message x3 theme is causing the problem therefore simply move the x3 theme and resinstall it by running the upcp, you can rename the theme under which you are facing the problem.

linux@server[~]#cd /usr/local/cpanel/base/frontend

linux@server[~]#mv -v x3 x3-corrupt

linux@server[~]#/scripts/upcp –force

Now browse the file manager, it will work properly.

Mysql tuner to tune mysql service

Gunjan — Wed, 28 Dec 2011 05:42:46 +0000

Install the mysql tuner to tune the mysql service to avoid any memory usage due to incorrect settings in the /etc/my.cnf file.

root@linux7802 [~]# cd /usr/local/src/

root@linux7802 [/usr/local/src]# wget -O mysqltuner.pl mysqltuner.pl

root@linux7802 [/usr/local/src]# perl mysqltuner.pl

Above command will give you the statistics as well as recommendations to improve the server perfomance

Refer to the following image to example of statistics

For recommendations example refer to the following image and made the necessary changes in the /etc/my.cnf file and retest the script to check, if issue resolved or not……

Its an example for recommendations

Note : Most of the time it recommend to optimize the mysql at that time use the following command but make sure that you have talen backup for the /var/lib/mysql directory to avoid any problem.

mysqlcheck –optimize -A

Simple command to update templates for Virtuozzo

Gunjan — Thu, 01 Dec 2011 21:52:55 +0000

To secure the node its always better to update the templates for Virtuozzo, we can use the following simple command to update the templates for Virtuozzo

[root@root]# vzup2date -?

The question mark will show you the option available with the vzup2date command

Usage: vzup2date [OPTION...]
-s, –system update Virtuozzo itself
-t, –templates update OS and application templates for Virtuozzo

Help options:
-?, –help Show this help message
–usage Display brief usage message

Now run the vzup2date command with the -t option to update the templates for Virtuozzo

[root@root]# vzup2date -t

After running above command it will give you screen similar to the following screen

——————– Welcome to system update ——————
| |
| The Virtuozzo up-to-date utility will help you update your |
| Virtuozzo installation by means of latest Virtuozzo |
| packages located on the SWsoft website.After updating, you |
| will be able to find the update log in the |
| /var/log/vzup2date file. |
| |
| ——– ——– |
| | Quit | | Next | |
| ——– ——– |
| |
| |
—————————————————————-

Tab over to the next and press to get to the next page. On the next page you will be able to change the url that vzup2date is using for the update:

Make sure that that the url listed is as above.Now select the templates you want to update, and letting it download them

If you are not sure about login details then check the file /etc/sysconfig/vzup2date/vzup2date.conf for the login details because all the login credentials are taken from this file.

We can also download the standard OS and application templates from the Parallels FTP server, if above vzup2date not working properly.

ftp://downloads.swsoft.com/templates/standard

The above command will ask you login details which you can collect from the Parallels sales representative.

Once rpm downloaded on the server install it by using the following command

[root@root]#rpm -ihv new_template_name.rpm

Increase SSH timeout for clients

Gunjan — Sat, 26 Nov 2011 14:46:39 +0000

After login in to the shell many time shell remain idle and due to that SSH connection closed by the server and we have to re-login in to the shell, we can avoid this problem by increasing the SSH timeout in the servers main sshd configuration file.Web hosting clients complaint that they can’t remain active on the shell at the time we can increase the ssh timeout value. Login in to the server as root user and run the following commands.

[root@server ~]#pico /etc/ssh/sshd_config

Now search the line “ClientAliveInterval” and change it

From

#ClientAliveInterval 0

ClientAliveInterval 3600

In above code we have used 3600 seconds, so that ssh won’t disconnect within set 3600 seconds value.

Restart the SSHD service to reload the new sshd configuration values.

Test php script to check the exec php function

Gunjan — Sun, 20 Nov 2011 11:55:27 +0000

Simple php script to check if exec php function is enabled or not because many shared hosting provider by default disabled the exec php function to secure the server. You can refer the following script to check exec php function.

echo exec(‘whoami’);
?>

Now browse the URL yourdomain.com/test.php , it will show your cPanel user name if exec php function is enabled on the server and if exec php function is disabled on your domain hosted server then you will receive the following error after browsing the URL yourdomain.com/test.php

Warning: exec() has been disabled for security reasons in /home/cpanel_username/public_html/test.php on line 2

You can contact your hosting provider and ask them to enable the exec function. If you have any query let me know at nsk.gunjan@gmail.com

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Define wget download speed

Gunjan — Fri, 18 Nov 2011 14:54:24 +0000

Some time while downloading files via wget we are facing the higher bandwidth usage issue therefore its always better to use the downloading speed to download the content constantly to avoid any higher and lower bandwidth usage issue. We can use the following “limit-rate” option in the wget command while downloading the files.

Server@root[~]# wget –limit-rate=40k url/file

In above example the download speed is 40KB/Second

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Check RPM database update dates

Gunjan — Thu, 17 Nov 2011 14:21:19 +0000

Many time we are facing the problem with the RPM database and we are not sure when the last time we have updated the RPM databases, at that time we can use the following command to check the RPM database update dates

root@server [~]# rpm -qa -last

It will give you the result like

root@server [~]# rpm -qa -last
libxml2-devel-2.6.26-2.1.12.el5_7.1 Thu 03 Nov 2011 04:38:06 AM GMT
libxml2-2.6.26-2.1.12.el5_7.1 Thu 03 Nov 2011 04:38:00 AM GMT
freetype-devel-2.2.1-28.el5_7.1 Thu 27 Oct 2011 04:38:19 AM BST
freetype-2.2.1-28.el5_7.1 Thu 27 Oct 2011 04:38:16 AM BST
libX11-devel-1.0.3-11.el5_7.1 Thu 06 Oct 2011 04:37:58 AM BST
libX11-1.0.3-11.el5_7.1 Thu 06 Oct 2011 04:37:53 AM BST
file-4.17-15.el5_3.1 Wed 05 Oct 2011 04:39:01 AM BST
rpm-build-4.4.2.3-22.el5_7.2 Tue 04 Oct 2011 04:37:59 AM BST
rpm-python-4.4.2.3-22.el5_7.2 Tue 04 Oct 2011 04:37:58 AM BST

For example rpm-python-4.4.2.3-22.el5_7.2 is last updated on the date Tue 04 Oct 2011 04:37:58 AM BST”

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Monitor Mysql process

Gunjan — Thu, 10 Nov 2011 14:05:05 +0000

In the daily Linux monitoring,we are facing the high mysql cpu usage problem but not sure which database or mysql query is using excessive CPU, at that time we can use the following commands to monitor the mysql process and optimize the offending database.

server@root[~]#mysqladmin proc stat

The above command will show you the current status for mysql process and if you want to check the continuously running mysql process then run the following command.

server@root[~]#mysqladmin -i3 pr

You can also install watchmysql to monitor the mysql

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