Tag Archives: CentOS

Oracle 11g XE: Setting Environment Variables on CentOS/RHEL

There are many posts on how to set the required environment variables, namely ORACLE_HOME, after the installation of Oracle 11g Express Edition (XE). They usually tell you to change some init scripts for bash (e.g. ~/.bashrc or ~/.bash_profile). While this is a possible approach, it is more complicated than necessary and certainly not elegant.

CentOS/RHEL has a nice mechanism to add environment variables on a global basis and separately for different programs. Just check out this directory:
/etc/profile.dEach file in there sets the environment variables for just a single program, so things are kept nicely separated. The files are just normal shell scripts with regard to syntax and do not need to be executable.

And since Oracle 11g XE has already created a file with exactly the right content as part of the installation, it is just enough to create a symlink from /etc/profile.d to this file.
ln -s /u01/app/oracle/product/11.2.0/xe/bin/oracle_env.sh /etc/profile.d/Just login to another shell session and check the environment variables with set. You should see, among other variables, the following values
NLS_LANG=AMERICAN_AMERICA.WE8ISO8859P1
ORACLE_HOME=/u01/app/oracle/product/11.2.0/xe
ORACLE_SID=XE
PATH=[..]:/u01/app/oracle/product/11.2.0/xe/bin:[..]
Hope that helps!

CentOS 5.4 64 bit does not work with ESXi 4.1

I have recently tried to install the 64 bit version of CentOS 5.4 on ESXi 4.1, but without much success. It stalls immediately after start (also in text mode) and all I got was a non-flashing underscore or dash. Several people reported similar problems. The general recommendation is to enable virtualisation support (VT) in the ESXi host’s mainboard BIOS. However, I had already installed other 64 bit OSes and therefore doubted this would help. Instead I simply tried CentOS 5.5 x86-64 and this immediately solved the issue.

USVN with CentOS 5

If you are looking for a Subversion web interface, chances are you come across USVN (User-friendly SVN). I first used it in August 2009 during a complex proof-of-concept (PoC). The current version at the time was 0.7.2 and it was of great help. Nevertheless there were a few things missing, esp. LDAP support. So I was really happy to recently learn that the project is being continued (it is an end-of-studies project) and in fact one of the first new features is support for LDAP.

One of the challenges I came across during the installation was the systems check that reported “Subversion has not been detected”. This simply means that the Subversion client binary (svn) was not found on the search path (PATH). The reason for this in my case was the fact that I had done a custom installation of Subversion and not relied on the one that comes with CentOS. For details on this please check this post where I also present a way to custom-define environment variables for the Apache web server. Here is the respective snippet with the search path added (my changes are in bold)start() {
echo -n $"Starting $prog: "
check13 || exit 1
LANG=$HTTPD_LANG LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/opt/CollabNet_Subversion/lib PATH=$PATH:/opt/CollabNet_Subversion/bin daemon --pidfile=${pidfile} $httpd $OPTIONS
RETVAL=$?
echo
[ $RETVAL = 0 ] && touch ${lockfile}
return $RETVAL
}
With this amendment the system check passed just fine. It should be noted, however, that at least for v1.0.1 this check is not complete. E.g. it misses on PHP support for the database. So you most likely also want to install php-pdo and php-mysql:yum install php-pdo php-mysql SQLite did not work at a first try whereas MySQL did, so I went for the latter.

Use CollabNet Subversion with Regular Apache

CollabNet are providing up-to-date binary packages of Subversion for many platforms. In my case this is CentOS 5, which by itself only has a rather dated version of Subversion. So I downloaded and installed the client, server and extras packages from CollabNet. The server package comes with a bundled Apache and a pretty nice installation script. However, I wanted to use my regular Apache for hosting the Subversion repositories, which means that I had to include the Apache modules from the CollabNet installation. So here are the respective lines from /etc/httpd/conf/httpd.confLoadModule dav_svn_module /opt/CollabNet_Subversion/modules/mod_dav_svn.so
LoadModule authz_svn_module /opt/CollabNet_Subversion/modules/mod_authz_svn.so
Those modules require access to additional libraries from /opt/CollabNet_Subversion/lib, so Apache needs to be told to include this directory into the search path (LD_LIBRARY_PATH). The bold part in the below snippet from /etc/init.d/httpd shows what needs to be added:start() {
echo -n $"Starting $prog: "
check13 || exit 1
LANG=$HTTPD_LANG LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/opt/CollabNet_Subversion/lib daemon --pidfile=${pidfile} $httpd $OPTIONS
RETVAL=$?
echo
[ $RETVAL = 0 ] && touch ${lockfile}
return $RETVAL
}
Simply sourcing in LD_LIBRARY_PATH does not work, because the daemon function calls a separate Bash instance. The only way to feed environment variables into Apache, was by prepending them as shown above. This is also the approach to take for extending the PATH variable (which I needed to do for including /opt/CollabNet_Subversion/bin).

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