Tag Archives: centos

Helpful Tips

VirtualBox Images CentOS keyboard settings problem

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I was using readymade CentOS images for VirtualBox from VirtualBoxes CentOS images. I noticed that some of the images come with weird keyboard settings, such that you can’t use the pipe (passing information from command to command), dash (for command parameters), @ (email sign), etc keys. In other words, when you try to type these keys, other keys would appears and vice versa. All of these keys are crucial to running any commands on the CentOS server.

The problem is that the VirtualBox image stores the keyboard setting that was used when it was created. Since this server image was built in Italy, and I am located in the US, there were obviously key differences.

The obvious solution is to change it to your preferred keyboard layout. There are 2 ways of doing it:

  1. Easier way: Install system-config-keyboard through yum. The caveat is this will install 75+ other bloat packages that you probably don’t need. However the command system-config-keyboard would configure your keyboard for you. 
    yum install system-config-keyboard
  2. Advanced way: Use 
    loadkeys

    command to change the keys temporarily and then make a change to 

    /etc/sysconfig/keyboard

    to make a permanent change (after restart).

    loadkeys us # or your own locale
vim /etc/sysconfig/keyboard # replace KEYTABLE value to your locale
Helpful Tips

No php53-pear for RHEL 5.6, download it the traditional way!

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I had to update to the latest vBulletin 4, but for that I needed php5.3. Luckily, RHEL has put out php53-* packages (I installed php 5.3.3-1.el5_6.1 btw). I downloaded them all but they were missing php53-pear* package. I’m not sure if this is just the case for x86_64.

So the main problem was getting PEAR packages to install. I tried to get the newer way of downloading pear packages, pyrus (pear2). However, the command php pyrus.phar install ___ resulted in messages like these:
The sqlite3 extension is required.
You must compile PHP with sqlite3 enabled, or install the necessary extension for your distribution.
(Not sure which extension of php53 would resolve this)

The sqlite3 extension is required.
You must compile PHP with sqlite3 enabled, or install the necessary extension for your distribution.
(This one is resolved by downloading php53-xml, thankfully available)

Anyhow, I didn’t want to go on a hunt to try to get these php53 special packages by following the instructions listed in the manual. However, the url listed in the manual http://pear.php.net/go-pear.phar makes php-fcgi put up a blank/empty page. I had a feeling it’s these .phar (weird php compressed archives) files that they’re using. Luckily in the comments, I noticed somebody said to get http://pear.php.net/go-pear. Now that my friends worked like a charm. All I had to do was download that to the server, open it up in the browser and follow the steps as it shows.

The rest comes easy. If you got questions, fire away.

Helpful Tips

Virtualenvwrapper on CentOS/RHEL with Virtualmin

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I used the IUS Community and EPEL repositories to install python 2.6 on my RHEL 5.6 Tikanga box. However I faced some errors, which I didn’t see fully documented online so I figured they would come handy to myself and whoever else tries to do similar things.

Problem 1: Error on mkvirtualenv and other commands: No module named virtualenvwrapper.hook_loader
Resolution: After looking at the source code, virtualenvwrapper can’t find our special python installation. Put the following line in your .bashrc:

VIRTUALENVWRAPPER_PYTHON=/usr/bin/python26

along with the other two lines that everybody tells you to put in:

export WORKON_HOME=$HOME/.virtualenvs
source <strong>/usr/bin/virtualenvwrapper.sh</strong>

(Note that virtualenvwrapper was installed to the above location, this is a different location than the one that everybody else (who is documenting the procedure) is installing at. I’m not sure if this is a new change in virtualenv or because of our special python26 installation. So use locate to find your location properly.)

Problem 2: Virtualenvwrapper commands do not auto-complete or can’t be found also unless .bashrc is sourced manually.
Reason: .bashrc is not executed when logging in to the box (like it should be because it is listed inside .bash_profile, which should be executed also)
Solution: This happens because virtualmin setup’s default $SHELL for each non-root user is /bin/sh. To fix this for on user, open up /etc/passwd, find the user that you are interested in, and change the /bin/sh part to /bin/bash. To fix the default for each virtualmin created user, go to virtualmin’s admin page, under System Customization > Custom Shells > Choose the /bin/bash custom shell.

Helpful Tips

Fix Pear/Mail due to CentOS/RHEL repos using old pear

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I couldn’t install the Mail PEAR package because the pear version shipped with the current CentOS/RHEL is 1.4.9, whereas the required version is 1.5.6 or above. The following is the error that you may see.

# pear install Mail
WARNING: channel "pear.php.net" has updated its protocols, use "channel-update pear.php.net" to update
Did not download optional dependencies: pear/Net_SMTP, use --alldeps to download automatically
pear/Mail requires PEAR Installer (version >= 1.5.6), installed version is 1.4.9
pear/Mail can optionally use package "pear/Net_SMTP" (version >= 1.4.1)
No valid packages found
install failed

There are three problems above:

  1. WARNING: channel “pear.php.net” has updated its protocols, use “channel-update pear.php.net” to update
  2. Did not download optional dependencies: pear/Net_SMTP, use –alldeps to download automatically
  3. Main problem: pear/Mail requires PEAR Installer (version >= 1.5.6), installed version is 1.4.9

To fix problem #1 (update channel pear.php.net):

# pear channel-update pear.php.net
Retrieving channel.xml from remote server
Update of Channel "pear.php.net" succeeded

To fix problem #2 (Net_SMTP is not installed), run:

# pear install --alldeps Mail 
pear/Mail requires PEAR Installer (version >= 1.5.6), installed version is 1.4.9
downloading Net_SMTP-1.4.4.tgz ...
Starting to download Net_SMTP-1.4.4.tgz (12,264 bytes)
.....done: 12,264 bytes
downloading Net_Socket-1.0.10.tgz ...
Starting to download Net_Socket-1.0.10.tgz (5,429 bytes)
...done: 5,429 bytes
downloading Auth_SASL-1.0.4.tgz ...
Starting to download Auth_SASL-1.0.4.tgz (5,795 bytes)
...done: 5,795 bytes
install ok: channel://pear.php.net/Auth_SASL-1.0.4
install ok: channel://pear.php.net/Net_Socket-1.0.10
install ok: channel://pear.php.net/Net_SMTP-1.4.4

To fix problem #3 (old pear version), first upgrade pear:

# pear upgrade pear
pear/PEAR dependency package "pear/Structures_Graph" downloaded version 1.0.4 is not the recommended version 1.0.3, but may be compatible, use --force to install
pear/PEAR dependency package "pear/Console_Getopt" downloaded version 1.3.0 is not the recommended version 1.2.3, but may be compatible, use --force to install
pear/Archive_Tar requires PEAR Installer (version >= 1.5.4), installed version is 1.4.9
pear/Console_Getopt requires PEAR Installer (version >= 1.9.1), installed version is 1.4.9
downloading Structures_Graph-1.0.4.tgz ...
Starting to download Structures_Graph-1.0.4.tgz (30,318 bytes)
.........done: 30,318 bytes
downloading XML_Util-1.2.1.tgz ...
Starting to download XML_Util-1.2.1.tgz (17,729 bytes)
...done: 17,729 bytes
upgrade ok: channel://pear.php.net/XML_Util-1.2.1
upgrade ok: channel://pear.php.net/Structures_Graph-1.0.4

But this still doesn’t update base pear, so run:

# pear upgrade --force pear
warning: pear/PEAR dependency package "pear/Console_Getopt" downloaded version 1.3.0 is not the recommended version 1.2.3
warning: pear/Archive_Tar requires PEAR Installer (version >= 1.5.4), installed version is 1.4.9
warning: pear/Console_Getopt requires PEAR Installer (version >= 1.9.1), installed version is 1.4.9
downloading PEAR-1.9.1.tgz ...
Starting to download PEAR-1.9.1.tgz (293,587 bytes)
.............................................................done: 293,587 bytes
downloading Archive_Tar-1.3.7.tgz ...
Starting to download Archive_Tar-1.3.7.tgz (17,610 bytes)
...done: 17,610 bytes
downloading Console_Getopt-1.3.0.tgz ...
Starting to download Console_Getopt-1.3.0.tgz (4,408 bytes)
...done: 4,408 bytes
upgrade ok: channel://pear.php.net/Console_Getopt-1.3.0
upgrade ok: channel://pear.php.net/Archive_Tar-1.3.7
upgrade ok: channel://pear.php.net/PEAR-1.9.1
PEAR: Optional feature webinstaller available (PEAR's web-based installer)
PEAR: Optional feature gtkinstaller available (PEAR's PHP-GTK-based installer)
PEAR: Optional feature gtk2installer available (PEAR's PHP-GTK2-based installer)
To install use "pear install pear/PEAR#featurename"

Now we can install pear’s Mail:

# pear install --alldeps Mail
downloading Mail-1.2.0.tgz ...
Starting to download Mail-1.2.0.tgz (23,214 bytes)
........done: 23,214 bytes
install ok: channel://pear.php.net/Mail-1.2.0

You might also need Mail_mime:

# pear install Mail_mime
downloading Mail_Mime-1.8.1.tgz ...
Starting to download Mail_Mime-1.8.1.tgz (31,530 bytes)
.........done: 31,530 bytes
install ok: channel://pear.php.net/Mail_Mime-1.8.1
Helpful Tips

Yum install rpm files manually

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I love yum on CentOS/Red Hat/Fedora. It saves so much of my time installing software on servers. Sometimes, the need comes when I cannot find the package inside the usual “safe” repositories, such as RHEL repos and RPMForge. So I search it and find it on pbone, rpmfind, or epel packages. I have always tried installing with rpm, but often end up with dependencies problems.

Example:

# rpm -Uvh icecast-2.3.2-4.el5.x86_64.rpm 
warning: icecast-2.3.2-4.el5.x86_64.rpm: Header V3 DSA signature: NOKEY, key ID 217521f6
error: Failed dependencies:
        libogg.so.0()(64bit) is needed by icecast-2.3.2-4.el5.x86_64
        libspeex.so.1()(64bit) is needed by icecast-2.3.2-4.el5.x86_64
        libtheora.so.0()(64bit) is needed by icecast-2.3.2-4.el5.x86_64
        libtheora.so.0(libtheora.so.1.0)(64bit) is needed by icecast-2.3.2-4.el5.x86_64
        libvorbis.so.0()(64bit) is needed by icecast-2.3.2-4.el5.x86_64

Then I would have to go hunt down each of those dependencies. Too much time wasted. If only you could use yum to resolve those “resolvable” dependencies (using rpmforge/rhel repositories). Well you can:

# yum localinstall icecast-2.3.2-4.el5.x86_64.rpm
    However, there are two caveats:

  1. Sometimes yum can’t find the dependencies, so you must search those out. (obvious)
  2. You probably haven’t imported the gpgcheck for the rpm package that you are trying to download.
    Example:

    warning: rpmts_HdrFromFdno: Header V3 DSA signature: NOKEY, key ID 217521f6
Public key for icecast-2.3.2-4.el5.x86_64.rpm is not installed

    So you can either import it, or you can ignore the gpg check by doing this

    # yum --nogpgcheck localinstall icecast-2.3.2-4.el5.x86_64.rpm
Helpful Tips

Installing VirtualMin – “Error: Missing Dependency: libGeoIP.so.1 is needed by package proftpd”

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On my Red Hat 5.5 box (similar to CentOS), I was trying to install Virtualmin.

I got two errors while installing.

#1.
-This system is not registered with RHN.
RHN support will be disabled.
\Error: Missing Dependency: ruby-rdoc is needed by package rubygems-0.9.2-1.el5.noarch (virtualmin)
Error: Missing Dependency: perl(XML::Parser) is needed by package perl-XML-Simple-2.14-4.fc6.noarch (virtualmin)
Error: Missing Dependency: libdistcache.so.1()(64bit) is needed by package 2:mod_ssl-2.2.3-43.3.vm.x86_64 (virtualmin)
Error: Missing Dependency: libaprutil-1.so.0()(64bit) is needed by package 1:httpd-2.2.3-43.3.vm.x86_64 (virtualmin)
Error: Missing Dependency: libnal.so.1()(64bit) is needed by package 2:mod_ssl-2.2.3-43.3.vm.x86_64 (virtualmin)
This simply meant that I had to run rhn_register to register using the Red Hat login/password that I had received. Because you cannot run yum/update without registering with RHN, unlike CentOS which can update without registering. Simple enough.

#2.
Error: Missing Dependency: libGeoIP.so.1 is needed by package proftpd
This happens because apparently Virtualmin updated to proftpd from 1.3.2 to 1.3.3 without testing properly (source: Virtualmin Forums). To fix, I installed RPMForge and ran install script again.

Helpful Tips

Install Python 2.6 on CentOS 5.x

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Steps to success:

  1. Download all the Python 2.6 rpm for your CentOS (i386 or x86_64) from geekymedia.
  2. Install tcl, tk, tix (required dependencies): yum -y install tcl tk tix
  3. Install the geekymedia rpms.

    Note that the python26-libs-2.6-geekymedia1.*.rpm and python26-2.6-geekymedia1.*.rpm must be installed together like this rpm -Uvh python26-libs-2.6-geekymedia1.*.rpm python26-2.6-geekymedia1.*.rpm. Similarly, *tools* and *tkinter* rpm must be installed together like this rpm -Uvh *tools*rpm *tkinter*rpm.

Helpful Tips

Yum update stops resolving dependencies for clamav-server

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On my CentOS/VirtualMin server configured for RPMForge, I wanted to run yum update, but I was getting the following errors while resolving dependencies for the clam* packages (you can list them by typing: rpm -qa | grep clam.

clamav-server-sysv-0.96-1.vm.el5.i386 from installed has depsolving problems
--> Missing Dependency: clamav-server = 0.96-1.vm.el5 is needed by package clamav-server-sysv-0.96-1.vm.el5.i386 (installed)
Error: Missing Dependency: clamav-server = 0.96-1.vm.el5 is needed by package clamav-server-sysv-0.96-1.vm.el5.i386 (installed)

I’ve had this problem on other servers where I had simply ignored it. But it was getting too much. So I researched and found the following solution working perfectly.

Solution

  1. Remove the clam rpms without removing the dependencies (virtualmin-base) by typing: rpm --nodeps -e clamav-0.96-1.vm.el5 and rpm --nodeps -e clamav-server-sysv-0.96-1.vm.el5.
  2. Run yum update

And voila, I get the following:

Dependencies Resolved

=====================================================================================================================================================================================================
 Package                                                  Arch                                    Version                                            Repository                                 Size
=====================================================================================================================================================================================================
Installing:
 clamav                                                   i386                                    0.96.4-1.el5.rf                                    rpmforge                                  2.2 M
     replacing  clamav-lib.i386 0.96-1.vm.el5

 clamav-db                                                i386                                    0.96.4-1.el5.rf                                    rpmforge                                   25 M
     replacing  clamav-update.i386 0.96-1.vm.el5

 clamd                                                    i386                                    0.96.4-1.el5.rf                                    rpmforge                                  233 k
     replacing  clamav-server.i386 0.96-1.vm.el5

Another solution: I have had servers that had conflicts even on the yum update, because maybe dependent packages came from conflicting repos. Specifically, clamav dependencies of rpmforge conflicted with clamav dependencies of virtualmin. To solve this, I ran: yum --disablerepo=* --enablerepo=virtualmin install clamav clamav-filesystem clamav-data clamav-lib

Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package clamav.x86_64 0:0.96.5-1.vm.el5 set to be updated
---> Package clamav-data.x86_64 0:0.96.5-1.vm.el5 set to be updated
---> Package clamav-filesystem.x86_64 0:0.96.5-1.vm.el5 set to be updated
---> Package clamav-lib.x86_64 0:0.96.5-1.vm.el5 set to be updated
--> Finished Dependency Resolution

Dependencies Resolved

===========================================================================================================================================
 Package                               Arch                       Version                             Repository                      Size
===========================================================================================================================================
Installing:
 clamav                                x86_64                     0.96.5-1.vm.el5                     virtualmin                     934 k
 clamav-data                           x86_64                     0.96.5-1.vm.el5                     virtualmin                      25 M
 clamav-filesystem                     x86_64                     0.96.5-1.vm.el5                     virtualmin                      18 k
 clamav-lib                            x86_64                     0.96.5-1.vm.el5                     virtualmin                     4.4 M

Transaction Summary
===========================================================================================================================================
Install       4 Package(s)
Upgrade       0 Package(s)

Total download size: 31 M
Is this ok [y/N]: y
Downloading Packages:
(1/4): clamav-filesystem-0.96.5-1.vm.el5.x86_64.rpm                                                                 |  18 kB     00:00     
(2/4): clamav-0.96.5-1.vm.el5.x86_64.rpm             (0%) 17% [=======                                   ]  0.0 B/s | 160 kB     --:-- ETA 
(3/4): clamav-lib-0.96.5-1.vm.el5.x86_64.rpm         (3%)  3% [=-                                        ]  0.0 B/s | 168 kB     --:-- ETA 
(4/4): clamav-data-0.96.5-1.vm.el5.x86_64.rpm       (17%)  0% [                                          ]  0.0 B/s |  40 kB     --:-- ETA 
-------------------------------------------------------------------------------------------------------------------------------------------
Total                                                                                                      914 kB/s |  31 MB     00:34     
Running rpm_check_debug
Running Transaction Test
Finished Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing     : clamav-filesystem                                                                                                   1/4 
  Installing     : clamav-data                                                                                                         2/4 
  Installing     : clamav-lib                                                                                                          3/4 
  Installing     : clamav                                                                                                              4/4 

Installed:
  clamav.x86_64 0:0.96.5-1.vm.el5            clamav-data.x86_64 0:0.96.5-1.vm.el5        clamav-filesystem.x86_64 0:0.96.5-1.vm.el5       
  clamav-lib.x86_64 0:0.96.5-1.vm.el5

Along with the above solution, you must remember to disable the conflicting repository. In this case, rpmforge. If rpmforge ever has a newer version of one of the clamav packages, and anyone runs yum update, the dependencies will again stop resolving (because rpmforge and virtualmin repositories do not have a symbiotic relationship). To disable rpmforge, edit /etc/yum.repos.d/rpmforge.repo and add/replace enabled=0 to the [rpmforge] section. Also note, that anytime you want to explicitly use rpmforge, you can do yum --disablerepo=* --enablerepo=rpmforge (or if you want to use it in conjunction with other enabled repositories, remove the –disablerepo flag).

Helpful Tips

Nginx with m4a/aac/mp4 seek support on CentOS 5

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I was working on Sikh Sangeet website which serves a lot of static audio media files. For the past couple of months, we’ve been paying overage (i.e. bandwidth charges for surpassing limits). I either had the option of paying much more (hundreds) for a better server or keep paying the overage charges (usually less than a hundred). So, I wanted to convert all the listening audio to a smaller format, such that I could provide full quality mp3s for downloading and provide smaller format audio for listening. I ended up choosing H264’s aac-HE, because it is supported in flash, android and iphone.

Previously on our dedicated Sikh Sangeet server, I ran nginx because the server was very limited with hardware, yet needed to serve the huge files that were mp3s. I had the latest nginx rpm (0.6.39-5.el5) from epel setup, but to get mp4 support, I had to install nginx from source with mp4 support.

I will reproduce the steps in the hopes that if I or anybody needs to do this in the future, they can get a quick idea:

Install nero encoders (best encoders for aac).
Convert mp3 to wav: mplayer -vc null -vo null "orig_file.mp3" -ao pcm:fast:file="/tmp/out.wav"
Convert wav to aac/m4a: neroAacEnc -br 56000 -if /tmp/out.wav -of "new_file.m4a"
Tag the m4a file with proper info: neroAacTag "new_file.m4a" -meta:title="title" -meta:artist="artist" -meta:track="track" -meta:album="album" -meta:genre="genre"

Now we have a m4a (aac) file, but this file is still not interleaved like an mp4 should be for nginx to stream parts of it. We must now convert the m4a (aac) file to mp4.

Install MP4Box (best way to convert regular audio into mp4 containers).
Convert m4a to mp4: MP4Box -add new_file.m4a:sbr final_file.mp4

Now we have our audio part ready. Now we just need to setup nginx:
Use the compile/make instructions from the original creators of the mp4 streaming module for nginx.

Notes:

  • If using the latest nginx server, the configure statement will not work. For two reasons:
    1. The nginx source requires pcre, even if you have pcre and pcre-dev(el) packages installed. For some reason nginx ./configure wasn't picking them up, so I downloaded pcre from pcre ftp. And without running make/configure or anything on it, used the following ./configure statement for nginx: ./configure --add-module=$HOME/nginx_mod_h264_streaming-2.2.7 --sbin-path=/usr/local/sbin --with-debug --with-pcre=$HOME/pcre-8.10
    2. The nginx_mod_h264_streaming-2.2.7 module has an incompatibility with the latest nginx (confirmed with 0.8.53):
      nginx_mod_h264_streaming-2.2.7/src/ngx_http_streaming_module.c:158: error: ângx_http_request_tâ has no member named âzero_in_uriâ.
      So, you must patch the ngx_http_streaming_module.c file using this patch.
  • For Red Hat/CentOS/Fedora users: If you want to use service nginx start/stop/reload/etc, download this Nginx Init Script.

Once you have nginx ready serving regular files from your document root (public_html, www, etc). Then simply put this directive inside the server context:

location ~ \.mp4$ {
root /your/document/root/full/path/here;
mp4;
}

The mp4 line will take care of the final_file.mp4?start=25 variable (i.e. start at 25 seconds) that flash players send to the server and cut off the mp4 at the right place.