Problems you may encounter when attempting to install phpMyAdmin on your Centos server, and how to solve them

 

Important
This is an edited version of a post that originally appeared on a blog called The Michigan Telephone Blog, which was written by a friend before he decided to stop blogging. It is reposted with his permission. Comments dated before the year 2013 were originally posted to his blog.

This article was originally published in August, 2011 and may contain outdated information.

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I just spent an interesting couple of hours trying to install phpMyAdmin on an Asterisk server running CentOS 5.5. As I encountered each problem and solved it, I had to wade through a lot of pages that weren’t applicable to my installation, etc. Since many readers of this blog run similar configurations I thought I’d just list the hiccups I encountered, and what I had to do to solve them. Note that some distributions come with phpMyAdmin already installed, so make sure you don’t already have it before you try to install it!

NOTE: Think carefully about whether you really want to follow the instructions below, particularly if it requires adding a repository. If you do that, make sure you only install the software you actually need from that repository, then disable it (set enabled=0). If you don’t do that, you could easily get into a situation where some of your curent software (such as PHP) simply will not upgrade no matter what you do. And if you are running a PBX “install and go” distribution, they may specifically warn you not to add repositories, or it will break your installation, so don’t do it!

If you do anything suggested below, you do it at your own risk!

• yum install phpmyadmin doesn’t work — try using the dag repository — there are several pages on the Web that tell how to do this. Use Google to search for “how to enable the dag repository” (without the quotes) if you need help. The basic idea is you need to create a file called /etc/yum.repos.d/dag.repo (with the proper permissions, ownership, etc.) and put something like this inside:

[dag] name=Dag RPM Repository for Red Hat Enterprise Linux
baseurl=http://apt.sw.be/redhat/el$releasever/en/$basearch/dag
gpgcheck=1
enabled=1

BUT you also need to install a GPG key, and getting THAT can be a bit of a problem. Some instructions will tell you to do this:

rpm –import http://dag.wieers.com/rpm/packages/RPM-GPG-KEY.dag.txt

That link no longer works, and you have to do this instead:

rpm –import http://apt.sw.be/RPM-GPG-KEY.dag.txt

But for some people even THAT doesn’t work, in which case it’s suggested you use wget to obtain the file, then import it:

wget http://apt.sw.be/RPM-GPG-KEY.dag.txt
rpm –import RPM-GPG-KEY.dag.txt

I’m being a bit non-specific because the instructions could change, and I’d prefer you find a current reference on how to enable this repository. Also, some may prefer to install RPMforge, which is a collaboration of Dag and other packagers. Regardless of the effort involved, I do suggest you install phpMyAdmin using yum, because it will install everything in the correct locations for CentOS, and you don’t have to compile it or anything like that.

Note that when you do install phpMyAdmin using yum, it may also install required dependencies such as libmcrypt and php-mcrypt (another advantage to using yum).

• You don’t have permission to access /phpmyadmin/ on this server.

Go to /etc/httpd/conf.d/phpmyadmin.conf
Under the line:
Allow from 127.0.0.1
You could add a line to allow access from your local network, for example:
Allow from 192.168.0.0/255.255.255.0
(But use values appropriate to your network).

If you are accessing the box remotely, then add a line allowing access from your IP address. Be VERY careful, because you don’t want to let the entire world into your databases!

• Existing configuration file (./config.inc.php) is not readable.

If you’re doing this on a system running FreePBX, scroll down to where I discuss changing the ownership of all phpMyAdmin-related files and directories to be the same as the MySQL user. Otherwise, the easiest solution (though not necessarily the most secure) is to change the permissions of the file /usr/share/phpmyadmin/config.inc.php from the default of 640 to 644 (add user read permission). If no one can get to your system from outside your local network, this probably isn’t an issue, but if anyone has a better idea on this, feel free to leave a comment.

• “Error
The configuration file now needs a secret passphrase (blowfish_secret).”

Open /usr/share/phpmyadmin/config.inc.php and find this section:

* This is needed for cookie based authentication to encrypt password in
* cookie
*/
$cfg[‘blowfish_secret’] = ‘oh my this is such a wonderful passphrase‘; /* YOU MUST FILL IN THIS FOR COOKIE AUTH! */

Insert any phrase you like (within reason) between the second pair of single quotes in the last line shown above (but don’t use ‘oh my this is such a wonderful passphrase‘, I just inserted that as an example.  Be creative!).  Don’t worry, this isn’t something you’ll actually have to type in every time you want to use phpMyAdmin.

• #1045 – Access denied for user ‘root’@’localhost’ (using password: YES)

You don’t login as root, you use your MySQL username and password. In FreePBX-based systems these can be found in /etc/amportal.conf, in the AMPDBUSER and AMPDBPASS settings. BUT… if you enter a wrong user name before logging in correctly, it may have already set a cookie with that username and password and then you won’t be able to get in even if you DO use the correct username and password. The solution is to clear all browser cookies for the address of your server, then try again — and make sure you get it right this time! 😉

I will note here that you can avoid some of these cookie-related issues, probably including those mentioned above, by going into /usr/share/phpmyadmin/config.inc.php and finding this section:

/* Authentication type */
$cfg[‘Servers’][$i][‘auth_type’] = ‘cookie’;

If your system is behind a hardware firewall or is otherwise VERY secure, you could change the auth_type from ‘cookie’ to something else, such as ‘http’. This will save you a lot of frustration during the login process, but at the possible expense of making your database less secure.  For those concerned about security, a document on the phpMyAdmin wiki advises you to “See the page on Security or the multi–user sub–section of the FAQ for additional information, especially FAQ 4.4.”  I personally found their security documentation rather useless, because they make a lot of suggestions but provide no specific examples of how to implement those suggestions.  Anyway, I personally feel that as long as a system is behind a good firewall that doesn’t permit anyone on the “outside” to access phpMyAdmin, ‘http’ is a good compromise between a security model that might drive you crazy (‘cookie’) and one of the other models that’s fairly insecure, such as ‘config’ (which some consider insecure because it stores your server username and password in plain text).  However, if your system is otherwise VERY secure and you just don’t want to have to enter a password to use phpMyAdmin, then it is possible to change the ‘auth_type’ to ‘config’ and (in the same config file), look for these lines:

/*
 * End of servers configuration
 */

And just above those lines, insert these lines:

$cfg[‘Servers’][$i][‘user’] = ‘mysqluser’;
$cfg[‘Servers’][$i][‘password’] = ‘mysqlpassword’;

Change mysqluser and mysqlpassword to the correct vales for your system (on a FreePBX-based system, these are the values in /etc/amportal.conf mentioned above).  I do not recommend using ‘config’ because it is less secure (be sure to read the page on Security mentioned above), but it’s up to you to decide how secure you want your system to be.

(I’m fully aware that any objections to storing the user and password values in plain text in the phpMyAdmin config.inc.php fall a bit flat when you realize the same values are stored in plain text in amportal.conf, but I also feel as though the fewer places those values are exposed, the better.  Why give potential attackers one more place to find this information?)

• phpMyAdmin – Error
Cannot start session without errors, please check errors given in your PHP and/or webserver log file and configure your PHP installation properly.

Check your /var/log/httpd/error_log – in my case, the first error message of each set contained a phrase like “open(/var/lib/php/session/sess_somerandomstring, O_RDWR) failed: Permission denied (13)” and I figured that the problem was another permissions issue.

On some sites I have found a suggestion that you change the ownership of all phpMyAdmin-related files and directories to be the same as the MySQL user (in the case of an Asterisk/FreePBX system, that would be asterisk:asterisk). On a FreePBX-based system, you could try this (check to make sure these are the correct paths before doing this):

chown asterisk:asterisk /usr/share/phpmyadmin -R
chown asterisk:asterisk /var/lib/php/session -R

If that doesn’t resolve the issue (or you’re doing this on a system that’s not running FreePBX), perhaps the easiest solution (though not necessarily the most secure) is to change the permissions of the offending file. If you have the same issue I had, try changing the permissions of the directory /var/lib/php/session from the default of 770 to 777 (add full user permissions).

Strangely, this one didn’t show up until after I’d successfully run phpMyAdmin a few times. Go figure. Also, after fixing this, I had to delete cookies again (as mentioned in the previous item) before I could log in, but that was when I still had the ‘auth_type’ set to ‘cookie’ (another reason I decided to change that to ‘http’).

Found and solved any other “gotchas” while installing phpMyAdmin under CentOS? Think I could have solved a problem in a better way? Feel free to share your solutions in the comments.

EDIT: There is one other thing that can happen after you install or update PHP on your system (as might happen if you let a FreePBX-based distribution do an upgrade).  You may start seeing PHP warning messages such as:

PHP Warning:  PHP Startup: mcrypt: Unable to initialize module
Module compiled with module API=20050922, debug=0, thread-safety=0
PHP    compiled with module API=20060613, debug=0, thread-safety=0
These options need to match
 in Unknown on line 0

If that happens try updating the dependencies that came with phpMyAdmin, for example:

yum update libmcrypt
yum update php-mcrypt

It was the second of those two that vanquished the PHP warning messages for me.

And why did I NEED to install phpMyAdmin, you ask?  Well, because someone (ahem) made a slight configuration error and caused an endless loop, that within the space of about ten seconds or so, generated over a THOUSAND bogus records in the ‘asteriskcdr’ (Call Detail) database.  The only easy way to I knew of at the time to clean them out was phpMyAdmin (since I don’t “speak” MySQL), but I don’t recommend you attempt something like that unless you know what you’re doing, because one wrong move and you could delete your entire FreePBX database (trust me, that would be a VERY bad thing!). In retrospect I probably could have used Webmin, since it also has the ability to access the MySQL database, but I didn’t think of that at the time.

2 thoughts on “Problems you may encounter when attempting to install phpMyAdmin on your Centos server, and how to solve them

  1. NOTICE: All comments above this one were imported from the original Michigan Telephone Blog and may or may not be relevant to the edited article above.

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