Thanks to Ginny Henningsen for simplifying the installation process.
Introducing the 
oracle-validated
 RPM for Oracle Linux
Before installing Oracle Database 10g or 11g on a system, you need to preconfigure the operating environment since the database requires certain software packages, package versions, and tweaks to kernel parameters. (Be sure to review the appropriate Oracle Database installation guide to familiarize yourself with hardware, software, and operating system requirements.) On Oracle Linux, I discovered that there is a remarkably easy way to address these installation prerequisites: First install an RPM package called 
oracle-validated. This RPM performs a number of preconfiguration steps, including:
Causing the download and installation of various software packages and specific versions needed for database installation, with package dependencies resolved via 
yum or up2date capabilities
Creating the user 
oracle and the groups oinstall and dba, which are used during database installation
Modifying kernel parameters in 
/etc/sysctl.conf to change settings for shared memory, semaphores, the maximum number of file descriptors, and so on Setting hard and soft shell resource limits in /etc/security/limits.conf, such as the locked-in memory address space, the number of open files, the number of processes, and core file size Setting numa=off in the kernel for x86_64 machines
Note that 
oracle-validated parses the existing /etc/sysctl.conf and /etc/security/limits.conf files and updates values only as needed for database installation. Any precustomized settings not related to database installation are left as is.
The 
oracle-validated RPM package is accessible through the Oracle Unbreakable Linux Network (ULN, which requires a support contract), from the Oracle Linux distribution media, or from the Oracle public yum repository. Thus, whether or not your system is registered with ULN to access Oracle patches and support, you can use oracle-validated to simplify database installation on Oracle Linux. Keep in mind, however, that the Oracle public yum
 repository is not updated with security updates and bug fixes, so the best way to maintain up-to-date and secure systems is with a ULN subscription.

Installing the oracle-validated RPM
The remainder of this article steps through the procedure that I used for installing 
oracle-validated on Oracle Linux via the Oracle publicyum repository. I started with a system running Oracle Linux Release 5 Update 7 for x86_64, a 64-bit version of Oracle Linux that I downloaded from the Oracle software delivery cloud (requires registration or login). First, I set up a yum configuration file that pointed to the correct repository, and then I installed the oracle-validated RPM from that repository.
Here are the steps for preconfiguring a system for Oracle Database installation using 
oracle-validated:
As an authorized user (for example, 
root), retrieve the file that configures repository locations:

# cd /etc/yum.repos.d

# wget http://public-yum.oracle.com/public-yum-el5.repo

  1. Using a text editor, modify the file, changing the field enabled=0 to enabled=1 to reflect repositories that correspond to the machine’s operating system release.

    Here is an excerpt of public-yum-el5.repo with the changed line in boldface.

    .

    .

    .

    [ol5_u7_base]

    name=Oracle Linux $releasever – U7 – $basearch – base

    baseurl=http://public-yum.oracle.com/repo/OracleLinux/OL5/7/base/$basearch/

    gpgkey=http://public-yum.oracle.com/RPM-GPG-KEY-oracle-el5

    gpgcheck=1

    enabled=1

     

    [el5_addons]

    name=Enterprise Linux $releasever – $basearch – addons

    baseurl=http://public-yum.oracle.com/repo/EnterpriseLinux/EL5/addons/$basearch/

    gpgkey=http://public-yum.oracle.com/RPM-GPG-KEY-oracle-el5

    gpgcheck=1

    enabled=0

    .

    .

    .

    Because the target system is running Oracle Linux Release 5 Update 7 for x86_64, there is one repository to enable, [ol5_u7_base]. For some distributions that include the Oracle Unbreakable Enterprise Kernel (specifically Oracle Linux 5.5 and 5.6), the repository[el5_addons] is also needed to resolve a dependency for kernel-uek-headers.

  2. Next, install the oracle-validated RPM using the yum install command.

    The output in Listing 1 shows how the installation checks dependencies and then downloads and installs the required packages.

    Listing 1: Installing the oracle-validated RPM

    # yum install oracle-validated

    Loaded plugins: rhnplugin, security

    This system is not registered with ULN.

    ULN support will be disabled.

    Setting up Install Process

    Resolving Dependencies

    –> Running transaction check

    —> Package oracle-validated.x86_64 0:1.1.0-14.el5 set to be updated

    –> Processing Dependency: libXp.so.6 for package: oracle-validated

    –> Processing Dependency: gdb for package: oracle-validated

    –> Processing Dependency: /usr/lib/libodbccr.so for package: oracle-validated

    –> Processing Dependency: /usr/lib64/libc.so for package: oracle-validated

    –> Processing Dependency: gcc-c++ for package: oracle-validated

    –> Processing Dependency: gcc for package: oracle-validated

    –> Processing Dependency: /usr/lib64/libodbccr.so for package: oracle-validated

    –> Processing Dependency: unixODBC-devel for package: oracle-validated

    –> Processing Dependency: libaio-devel for package: oracle-validated

    –> Processing Dependency: elfutils-libelf-devel for package: oracle-validated

    –> Processing Dependency: sysstat for package: oracle-validated

    –> Processing Dependency: kernel-headers for package: oracle-validated

    –> Processing Dependency: /usr/lib64/libaio.so for package: oracle-validated

    –> Processing Dependency: glibc-headers for package: oracle-validated

    –> Processing Dependency: /usr/lib/libodbc.so.1 for package: oracle-validated

    –> Processing Dependency: /usr/lib/libaio.so for package: oracle-validated

    –> Processing Dependency: /usr/lib/libc.so for package: oracle-validated

    –> Processing Dependency: compat-gcc-34-c++ for package: oracle-validated

    –> Processing Dependency: compat-gcc-34 for package: oracle-validated

    –> Processing Dependency: /usr/lib/gcc/x86_64-redhat-linux/4.1.1/libstdc++.a for

    package: oracle-validated

    –> Processing Dependency: libdb-4.2.so()(64bit) for package: oracle-validated

    –> Processing Dependency: libodbc.so.1()(64bit) for package: oracle-validated

    –> Running transaction check

    —> Package compat-db.x86_64 0:4.2.52-5.1 set to be updated

    —> Package compat-gcc-34.x86_64 0:3.4.6-4.1 set to be updated

    —> Package compat-gcc-34-c++.x86_64 0:3.4.6-4.1 set to be updated

    —> Package elfutils-libelf-devel.x86_64 0:0.137-3.el5 set to be updated

    –> Processing Dependency: elfutils-libelf-devel-static-x86_64 = 0.137-3.el5 for

    package: elfutils-libelf-devel

    —> Package gcc.x86_64 0:4.1.2-51.el5 set to be updated

    —> Package gcc-c++.x86_64 0:4.1.2-51.el5 set to be updated

    —> Package gdb.x86_64 0:7.0.1-37.el5 set to be updated

    —> Package glibc-devel.i386 0:2.5-65 set to be updated

    —> Package glibc-devel.x86_64 0:2.5-65 set to be updated

    —> Package glibc-headers.x86_64 0:2.5-65 set to be updated

    —> Package kernel-headers.x86_64 0:2.6.18-274.el5 set to be updated

    —> Package libXp.i386 0:1.0.0-8.1.el5 set to be updated

    —> Package libaio-devel.i386 0:0.3.106-5 set to be updated

    —> Package libaio-devel.x86_64 0:0.3.106-5 set to be updated

    —> Package libstdc++-devel.x86_64 0:4.1.2-51.el5 set to be updated

    —> Package sysstat.x86_64 0:7.0.2-11.el5 set to be updated

    —> Package unixODBC.i386 0:2.2.11-7.1 set to be updated

    —> Package unixODBC.x86_64 0:2.2.11-7.1 set to be updated

    —> Package unixODBC-devel.i386 0:2.2.11-7.1 set to be updated

    —> Package unixODBC-devel.x86_64 0:2.2.11-7.1 set to be updated

    –> Running transaction check

    —> Package elfutils-libelf-devel-static.x86_64 0:0.137-3.el5 set to be updated

    –> Finished Dependency Resolution

     

    Dependencies Resolved

     

    ================================================================================

    Package Arch Version Repository Size

    ================================================================================

    Installing:

    oracle-validated x86_64 1.1.0-14.el5 ol5_u7_base 24 k

    Installing for dependencies:

    compat-db x86_64 4.2.52-5.1 ol5_u7_base 1.6 M

    compat-gcc-34 x86_64 3.4.6-4.1 ol5_u7_base 4.3 M

    compat-gcc-34-c++ x86_64 3.4.6-4.1 ol5_u7_base 13 M

    elfutils-libelf-devel x86_64 0.137-3.el5 ol5_u7_base 24 k

    elfutils-libelf-devel-static x86_64 0.137-3.el5 ol5_u7_base 64 k

    gcc x86_64 4.1.2-51.el5 ol5_u7_base 5.3 M

    gcc-c++ x86_64 4.1.2-51.el5 ol5_u7_base 3.8 M

    gdb x86_64 7.0.1-37.el5 ol5_u7_base 2.4 M

    glibc-devel i386 2.5-65 ol5_u7_base 2.0 M

    glibc-devel x86_64 2.5-65 ol5_u7_base 2.4 M

    glibc-headers x86_64 2.5-65 ol5_u7_base 594 k

    kernel-headers x86_64 2.6.18-274.el5 ol5_u7_base 1.3 M

    libXp i386 1.0.0-8.1.el5 ol5_u7_base 22 k

    libaio-devel i386 0.3.106-5 ol5_u7_base 12 k

    libaio-devel x86_64 0.3.106-5 ol5_u7_base 11 k

    libstdc++-devel x86_64 4.1.2-51.el5 ol5_u7_base 2.8 M

    sysstat x86_64 7.0.2-11.el5 ol5_u7_base 187 k

    unixODBC i386 2.2.11-7.1 ol5_u7_base 830 k

    unixODBC x86_64 2.2.11-7.1 ol5_u7_base 835 k

    unixODBC-devel i386 2.2.11-7.1 ol5_u7_base 743 k

    unixODBC-devel x86_64 2.2.11-7.1 ol5_u7_base 799 k

     

    Transaction Summary

    ================================================================================

    Install 22 Package(s)

    Upgrade 0 Package(s)

     

    Total size: 42 M

    Total download size: 594 k

    Is this ok [y/N]: y

    Downloading Packages:

    glibc-headers-2.5-65.x86_64.rpm | 594 kB 00:00

    warning: rpmts_HdrFromFdno: Header V3 DSA signature: NOKEY, key ID 1e5e0159

    ol5_u7_base/gpgkey | 1.4 kB 00:00

    Importing GPG key 0x1E5E0159 “Oracle OSS group (Open Source Software group)

    <build@oss.oracle.com>” from http://public-yum.oracle.com/RPM-GPG-KEY-oracle-el5

    Is this ok [y/N]: y

    Running rpm_check_debug

    Running Transaction Test

    Finished Transaction Test

    Transaction Test Succeeded

    Running Transaction

    Installing : unixODBC 1/22

    Installing : libstdc++-devel 2/22

    Installing : kernel-headers 3/22

    Installing : gdb 4/22

    Installing : compat-db 5/22

    Installing : sysstat 6/22

    Installing : glibc-headers 7/22

    Installing : glibc-devel 8/22

    Installing : compat-gcc-34 9/22

    Installing : glibc-devel 10/22

    Installing : unixODBC-devel 11/22

    Installing : libaio-devel 12/22

    Installing : libaio-devel 13/22

    Installing : unixODBC 14/22

    Installing : libXp 15/22

    Installing : gcc 16/22

    Installing : gcc-c++ 17/22

    Installing : compat-gcc-34-c++ 18/22

    Installing : unixODBC-devel 19/22

    Installing : elfutils-libelf-devel 20/22

    Installing : oracle-validated 21/22

    Installing : elfutils-libelf-devel-static 22/22

     

    Installed:

    oracle-validated.x86_64 0:1.1.0-14.el5

     

    Dependency Installed:

    compat-db.x86_64 0:4.2.52-5.1

    compat-gcc-34.x86_64 0:3.4.6-4.1

    compat-gcc-34-c++.x86_64 0:3.4.6-4.1

    elfutils-libelf-devel.x86_64 0:0.137-3.el5

    elfutils-libelf-devel-static.x86_64 0:0.137-3.el5

    gcc.x86_64 0:4.1.2-51.el5

    gcc-c++.x86_64 0:4.1.2-51.el5

    gdb.x86_64 0:7.0.1-37.el5

    glibc-devel.i386 0:2.5-65

    glibc-devel.x86_64 0:2.5-65

    glibc-headers.x86_64 0:2.5-65

    kernel-headers.x86_64 0:2.6.18-274.el5

    libXp.i386 0:1.0.0-8.1.el5

    libaio-devel.i386 0:0.3.106-5

    libaio-devel.x86_64 0:0.3.106-5

    libstdc++-devel.x86_64 0:4.1.2-51.el5

    sysstat.x86_64 0:7.0.2-11.el5

    unixODBC.i386 0:2.2.11-7.1

    unixODBC.x86_64 0:2.2.11-7.1

    unixODBC-devel.i386 0:2.2.11-7.1

    unixODBC-devel.x86_64 0:2.2.11-7.1

     

    Complete!

    The yum installation logs messages about kernel changes in the file /var/log/oracle-validated/results/orakernel.log, and it makes backups of current system settings in the directory /var/log/oracle-validated/backup.

  3. At this point, the system is ready for the installation of Oracle Database. For example, to install Oracle Database 11g Release 2, follow the directions in Chapter 4, Installing Oracle Database, of the Database Installation Guide for Linux.

    The directions instruct you to do the following:

  4. As root, create a parent directory in a file system that has sufficient space to be the target location for the downloaded files:
  5. # mkdir /home/OraDB11g
  6. # cd /home/OraDB11g

    The amount of disk space needed in the file system varies according to the specific installation type, but roughly twice the size of the zip archives, or 5 GB, is enough to house the software and data files.

  7. Into this target directory, download the installation media files from the Oracle Database Software Downloads page on Oracle Technology Network.
  8. Extract the files:
  9. # unzip linux.x64_11gR2_database_1of2.zip
  10. # unzip linux.x64_11gR2_database_2of2.zip
  11. Log in as the user oracle. Change directory to the database directory and enter the following command to run the Oracle Universal Installer:
  12. $ cd /home/OraDB11g/database
  13. $ ./runInstaller

    The Oracle Universal Installer performs a number of checks, verifying that the necessary OS packages and versions are installed. In addition, it checks kernel parameters set by the oracle-validated installation. During the kernel settings check, the Installer might flag a few settings as “failed,” and you should investigate these failures. In some cases, you still might be able to continue with the database installation. If you check kernel settings in /etc/sysctl.conf, you’ll see that oracle-validated recommends different settings for Oracle Database 10g than for Oracle Database 11g. If necessary, you can (as root) edit the file /etc/sysctl.conf to specify a setting manually, for example:

    # vi /etc/sysctl.conf

    # /sbin/sysctl -p

    The Oracle Universal Installer performs additional checks, such as verifying the glibc version, sufficient disk space, environmental variable and path settings, and sufficient physical memory and swap space. Generally, installing oracle-validated takes care of the prerequisites so that you can proceed directly with installing the database.