Before your 21c database software installation, there are a number of prerequisite steps in order to get your operating system ready for the Oracle Database. This used to be a lengthy series of manual tasks, but more recently this has been simplified with the preinstall rpm file that we make available to you.

  [root@localhost sf_tmp]# yum -y install oracle-database-preinstall-21c-1.0-0.4.el8.x86_64.rpm Last metadata expiration check: 3:26:29 ago on Wed 14 Jul 2021 22:49:36 EDT. Dependencies resolved. ===============================================================================================================  Package                              Architecture Version                       Repository               Size =============================================================================================================== Installing:  oracle-database-preinstall-21c       x86_64       1.0-0.4.el8                   @commandline             31 k Installing dependencies:  compat-openssl10                     x86_64       1:1.0.2o-3.el8                ol8_appstream           1.1 M  ksh                                  x86_64       20120801-254.0.1.el8          ol8_appstream           927 k  libnsl                               x86_64       2.28-151.0.1.el8              ol8_baseos_latest       102 k  Transaction Summary =============================================================================================================== Install  4 Packages  Total size: 2.2 M Total download size: 2.1 M Installed size: 6.6 M Downloading Packages: (1/3): libnsl-2.28-151.0.1.el8.x86_64.rpm                                       28 kB/s | 102 kB     00:03     (2/3): ksh-20120801-254.0.1.el8.x86_64.rpm                                     243 kB/s | 927 kB     00:03     (3/3): compat-openssl10-1.0.2o-3.el8.x86_64.rpm                                303 kB/s | 1.1 MB     00:03     --------------------------------------------------------------------------------------------------------------- Total                                                                          571 kB/s | 2.1 MB     00:03      Running transaction check Transaction check succeeded. Running transaction test Transaction test succeeded. Running transaction   Preparing        :                                                                                       1/1    Installing       : ksh-20120801-254.0.1.el8.x86_64                                                       1/4    Running scriptlet: ksh-20120801-254.0.1.el8.x86_64                                                       1/4    Installing       : compat-openssl10-1:1.0.2o-3.el8.x86_64                                                2/4    Running scriptlet: compat-openssl10-1:1.0.2o-3.el8.x86_64                                                2/4  /sbin/ldconfig: /etc/ld.so.conf.d/kernel-5.4.17-2102.201.3.el8uek.x86_64.conf:6: hwcap directive ignored    Installing       : libnsl-2.28-151.0.1.el8.x86_64                                                        3/4    Installing       : oracle-database-preinstall-21c-1.0-0.4.el8.x86_64                                     4/4    Running scriptlet: oracle-database-preinstall-21c-1.0-0.4.el8.x86_64                                     4/4  /sbin/ldconfig: /etc/ld.so.conf.d/kernel-5.4.17-2102.201.3.el8uek.x86_64.conf:6: hwcap directive ignored    Verifying        : libnsl-2.28-151.0.1.el8.x86_64                                                        1/4    Verifying        : compat-openssl10-1:1.0.2o-3.el8.x86_64                                                2/4    Verifying        : ksh-20120801-254.0.1.el8.x86_64                                                       3/4    Verifying        : oracle-database-preinstall-21c-1.0-0.4.el8.x86_64                                     4/4   Installed:   compat-openssl10-1:1.0.2o-3.el8.x86_64           ksh-20120801-254.0.1.el8.x86_64                               libnsl-2.28-151.0.1.el8.x86_64                   oracle-database-preinstall-21c-1.0-0.4.el8.x86_64            Complete! [root@localhost sf_tmp]#  

One of the tasks this rpm takes care of is creating a set of OS groups to handle various system administration roles that you might want to delegate with OS level utilities, such as backups, dataguard maintenance, RAC tasks etc. You can see these groups in /etc/group

 [root@localhost sf_tmp]# cat /etc/group root:x:0: bin:x:1: daemon:x:2: sys:x:3: ... ... oinstall:x:54321: dba:x:54322: oper:x:54323: backupdba:x:54324: dgdba:x:54325: kmdba:x:54326: racdba:x:54330: [root@localhost sf_tmp]#  

and the installer will prompt for which groups you would like top use at installation time.

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One common thing I am seeing catch people out is that you might need to run a fresh terminal session in order to make sure that these groups can be seen by the installer. I've seen some confusion of late, where admins are running the preinstall rpm, but using an existing "oracle" terminal session to launch the installer. If you do that, the installer screen might not see those groups and thus you will only have the "oracle" option available in the drop down during installation

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Simply exit the installer, grab a fresh terminal session and you'll be good to do.

Enjoy your 21c database!