Archive for June 21st, 2011

Runing sudo command simultaneously on multiple servers with SSHSUDO

Tuesday, June 21st, 2011

ssh multiple server command execute
I just was recommended by a friend a nifty tool, which is absoutely nifty for system administrators.

The tool is called sshsudo and the project is hosted on http://code.google.com/p/sshsudo/.

Let’s say you’re responsible for 10 servers with the same operating system let’s say; CentOS 4 and you want to install tcpdump and vnstat on all of them without logging one by one to each of the nodes.

This task is really simple with using sshsudo.
A typical use of sshsudo is:


[root@centos root]# sshsudo -u root \
comp1,comp2,comp3,comp4,comp5,comp6,comp7,comp8,comp9,comp10 yum install tcpdump vnstat

Consequently a password prompt will appear on the screen;
Please enter your password:

If all the servers are configured to have the same administrator root password then just typing one the root password will be enough and the command will get issued on all the servers.

The program can also be used to run a custom admin script by automatically populating the script (upload the script), to all the servers and issuing it next on.

One typical use to run a custom bash shell script on ten servers would be:


[root@centos root]# sshsudo -r -u root \
comp1,comp2,comp3,comp4,comp5,comp6,comp7,comp8,comp9,comp10 /pathtoscript/script.sh

I’m glad I found this handy tool 😉

How to fix php “Fatal error: Class ‘SimpleXMLElement’ not found” and “Fatal error: Class ‘JLoader’ not found” on FreeBSD

Tuesday, June 21st, 2011

One of the contact forms running on a FreeBSD server configured to work on top of Apache+MySQL suddenly stopped working.

The errors that appeared on the webpage during a page request to the form url was:

Fatal error: Class 'SimpleXMLElement' not found in /var/www/joomla/plugins/system/plugin_googlemap2_helper.php on line 2176 Fatal error: Class 'JLoader' not found in /var/www/joomla/plugins/libraries/loader.php on line 161

As you see in the output the website which was causing the issues was running a Joomla version 1.5.23 Stable configured with RSForm!ver 1.5.x (as a contact form solution) and Google Maps version 2.13b plugins.

The Google Map from Google Maps plugin and the RSform were configured to appear on one physical configured article in Joomla and seemed to work just until now. However yesterday suddenly the error messages:
Fatal error: Class ‘SimpleXMLElement’ not found
Fatal error: Class ‘JLoader’ not found

came out of nothing, it’s really strange as I don’t remember doing any changes to either Joomla or the PHP installation on this server.
There is one more guy who has access to the Joomla installation which I suspect might have changed something in the Joomla, but this scenario is not very likely.

Anyways as the problem was there I had to fix it up. Obviously as the error message Fatal error: Class ‘SimpleXMLElement’ not found reported the server php simplexml was missing!

Just to assure myself the php simplexml extension is not present on the server I used the classical method of setting up a php file with phpinfo(); in it to check all the installed php extensions on the server.

Finally to solve the issue I had to install the module from ports php5-simplexml , e.g.:

freebsd# cd /usr/ports/textproc/php5-simplexml
freebsd# make install clean

Afterwards to make the new settings take place I did restart of my Apache server:

freebsd# /usr/local/etc/rc.d/apache2 restart
Syntax OK
Stopping apache2.
Waiting for PIDS: 63883.
Performing sanity check on apache2 configuration:
Syntax OK
Starting apache2.

Now my Joomla contact form is back to normal 😉

If someone has any idea why this error occured without any php or server modifications, and how comes that all worked fine beforehand even though I did not have the simplexml module instlaled on the server o_O, I would be enormously greatful.