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Configure Oracle Enterprise Manager 12c on CentOS 6

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This article is the first part of Oracle Enterprise Manager 12c Cloud Control or OEM12c installation. Here, we will configure an Oracle Database 11g server that will serve as the Oracle Management Repository for Oracle Enterprise Manager Cloud Control 12c on CentOS 6. 

What is Oracle Enterprise Manager 12c?

But first, we would like to briefly define a few terms, that you may encounter in this article frequently. The architecture of the Oracle Enterprise Manager 12c has three distinct components:

  1. the collection agent (Oracle Management Agent or OMA)
  2. the aggregation agent (Oracle Management Server or OMS)
  3. the repository agent (Oracle Management Repository or OMR)

The Oracle Management Agent / OMA runs on the target host and collects information on the hardware, operating system, and applications, which are running on that target host.

The Oracle Management Server / OMS runs on a central server and collects the data generated by multiple Oracle Management Agents / OMAs. The OMS also provides a web interface for monitoring & management of services.

The Oracle Management Repository / OMR is an Oracle Database 11g R2. The OMS pulls the information from multiple OMAs and aggregates the data into the OMR.

Configure Oracle Enterprise Manager 12c on CentOS 6
Configure Oracle Enterprise Manager 12c on CentOS 6

System Specification:

We have provisioned a KVM virtual machine with following specifications:

CPU:3.4 Ghz (2 Cores)
Memory:2 GB
Storage:50 GB
Operating System:Centos 6.5 x86_64

We are using the CentOS 6 operating system for Oracle Management Repository 12c. However, you can use any certified distribution of Linux operating system. For installation of CentOS 6, you may follow the installation steps available in our previous article Installation of CentOS 6.3 Server.

We are using the following network settings, you may adjust it according to your environment.

Hostname:omr12c.mydomain.com
IP Address:170.172.0.121/16
Gateway:170.172.0.1
DNS Server:170.172.0.3

Installing Oracle Database 11g R2 on CentOS 6:

We are not using a Private DNS server for our network, therefore, we will configure local DNS resolver as follows.

cat >> /etc/hosts << EOF
170.172.0.121 omr12c.mydomain.com omr12c
170.172.0.123 oms12c.mydomain.com oms12c
EOF

Set the reqiured Linux Kernel’s parameters by executing the following commands.

cat >> /etc/sysctl.conf << EOF
fs.file-max = 6815744
kernel.sem = 250 32000 100 128
kernel.shmmni = 4096
kernel.shmall = 1073741824
kernel.shmmax = 4398046511104
net.core.rmem_default = 262144
net.core.rmem_max = 4194304
net.core.wmem_default = 262144
net.core.wmem_max = 1048576
fs.aio-max-nr = 1048576
net.ipv4.ip_local_port_range = 9000 65500
EOF
sysctl –p

Execute following command to set limits for oracle user.

cat >> /etc/security/limits.conf << EOF
oracle soft nofile 1024
oracle hard nofile 65536
oracle soft nproc 16384
oracle hard nproc 16384
oracle soft stack 10240
oracle hard stack 32768
EOF

There are some packages required by Oracle Database 11g R2. You can use yum command to install online from Internet, or setup a local yum repository.

Our Linux server is not connected to Internet, neither we have configured any local yum repository, therefore, we are using rpm to install packages from the CentOS 6 installation DVD / ISO.

rpm -Uvh binutils-2.20.51.0.2-5.36.el6.x86_64.rpm
rpm -Uvh compat-libcap1-1.10-1.x86_64.rpm
rpm -Uvh compat-libstdc++-33-3.2.3-69.el6.x86_64.rpm
rpm -Uvh gcc-4.4.7-4.el6.x86_64.rpm
rpm -Uvh gcc-c++-4.4.7-4.el6.x86_64.rpm
rpm -Uvh glibc-2.12-1.132.el6.x86_64.rpm
rpm -Uvh glibc-devel-2.12-1.132.el6.x86_64.rpm
rpm -Uvh ksh-20120801-10.el6.x86_64.rpm
rpm -Uvh libgcc-4.4.7-4.el6.x86_64.rpm
rpm -Uvh libstdc++-4.4.7-4.el6.x86_64.rpm
rpm -Uvh libstdc++-devel-4.4.7-4.el6.x86_64.rpm
rpm -Uvh libaio-0.3.107-10.el6.x86_64.rpm
rpm -Uvh libaio-devel-0.3.107-10.el6.x86_64.rpm
rpm -Uvh libXext-1.3.1-2.el6.x86_64.rpm
rpm -Uvh libXtst-1.2.1-2.el6.x86_64.rpm
rpm -Uvh libX11-1.5.0-4.el6.x86_64.rpm
rpm -Uvh libXau-1.0.6-4.el6.x86_64.rpm
rpm -Uvh libxcb-1.8.1-1.el6.x86_64.rpm
rpm -Uvh libXi-1.6.1-3.el6.x86_64.rpm
rpm -Uvh make-3.81-20.el6.x86_64.rpm
rpm -Uvh sysstat-9.0.4-22.el6.x86_64.rpm
rpm -Uvh unixODBC-2.2.14-12.el6_3.x86_64.rpm
rpm -Uvh unixODBC-devel-2.2.14-12.el6_3.x86_64.rpm
rpm -Uvh elfutils-devel-0.152-1.el6.x86_64.rpm

Following users and groups are required by Oracle Database 11g R2. You can create these users and groups by using following commands.

groupadd -g 601 oinstall
groupadd -g 602 dba
groupadd -g 603 oper
useradd -u 601 -g oinstall -G dba,oper oracle
echo "oracle" | passwd oracle –-stdin

I am creating another user for myself to perform DBA tasks.

useradd -u 603 -g oinstall -G dba,oper ahmer
echo “123” | passwd ahmer –-stdin

To change SELinux mode to permissive, please execute the following commands.

sed -i 's/^SELINUX=.*/SELINUX=permissive/g' /etc/sysconfig/selinux
setenforce permissive

Allow Oracle Listener Port 1521/tcp in Linux Firewall.

iptables -I INPUT 5 -p tcp --dport 1521 -m state --state NEW,ESTABLISHED -j ACCEPT
service iptables save

Execute the following command to add PAM configuration.

cat >> /etc/pam.d/login << EOF 
session required pam_limits.so
EOF

Create the ORACLE_BASE directory and change owner to oracle user.

mkdir -p /u01/app/oracle
chown -R oracle:oinstall /u01/app
chmod -R 775 /u01/app

Although, CentOS 6 will automatically synchronize time with its NTP Servers, if connected to Internet. But, as we mentioned earlier that our machine is not connected to the Internet. Therefore, we must use our Internal NTP servers for time synchronization. Execute the following commands.

sed -i 's/^server*/#server/g' /etc/ntp.conf
cat >> /etc/ntp.conf << EOF
server 170.172.0.3
server 170.172.0.2
EOF
chkconfig ntpd on
service ntpd start

Set environment parameters as required by Oracle Database 11g R2.

su - oracle
cat >> ~/.bash_profile << EOF
ORACLE_BASE=/u01/app/oracle
ORACLE_SID=omr12c
export ORACLE_BASE ORACLE_SID
unset ORACLE_HOME
unset TNS_ADMIN
EOF

Execute the ~/.bash_profile to apply the changes to environment.

. ~/.bash_profile

Run Installer from the Oracle Database 11g R2 Setup directory. Install the Oracle RDBMS with default options and create a database with name omr12c.

./runInstaller

After installation update the ~/.bash_profile.

cat >> ~/.bash_profile << EOF
if [ $USER = "oracle" ]; then
 if [ $SHELL = "/bin/ksh" ]; then
    ulimit -p 16384
    ulimit -n 65536
 else
    ulimit -u 16384 -n 65536
 fi
fi
ORACLE_HOSTNAME=omr12c.mydomain.com
ORACLE_HOME=$ORACLE_BASE/product/11.2.0/dbhome_1
export ORACLE_HOSTNAME ORACLE_HOME
TNS_ADMIN=$ORACLE_HOME/network/admin
LD_LIBRARY_PATH=$ORACLE_HOME/dbhome_1/lib
PATH=$PATH:$ORACLE_HOME/bin
export TNS_ADMIN LD_LIBRARY_PATH PATH
EOF

Setup auto-start of Oracle Database & Listener:

By default, Oracle Installer do not configure autostart of Database and Listener during system startup. Therefore, we have to create a service script for this purpose.

su - root
cat >> /etc/init.d/dbora << EOF
#!/bin/sh
# chkconfig: 345 99 10
# description: Oracle auto start-stop script.
#
# Change the value of ORACLE_HOME to specify the correct Oracle home
# directory for your installation.
ORACLE_HOME=/u01/app/oracle/product/11.2.0/db_1
#
# Change the value of ORACLE to the login name of the
# oracle owner at your site.
# 
ORACLE_USER=oracle
PATH=${PATH}:$ORACLE_HOME/bin
export ORACLE_HOME ORACLE_USER PATH
#
case $1 in
'start')
     runuser -l $ORACLE_USER -c '$ORACLE_HOME/bin/dbstart $ORACLE_HOME &' 
     touch /var/lock/subsys/dbora
     ;;
'stop')
     runuser -l $ORACLE_USER -c '$ORACLE_HOME/bin/dbshut $ORACLE_HOME' 
     rm -f /var/lock/subsys/dbora
     ;;
*)
     echo "usage: $0 {start|stop}"
     exit
     ;;
esac
#
exit
EOF
chmod 750 /etc/init.d/dbora
chkconfig dbora on
sed -i 's/:Y/:N/g' /etc/oratab
reboot

We have successfully installed Oracle Database 11g R2 on CentOS 6.

Configure Oracle Management Repository 12c:

Connect to omr12c database and adjust following system parameters.

sqlplus / AS SYSDBA

Execute following commands at sqlplus prompt.

ALTER SYSTEM SET processes=300 SCOPE=SPFILE;
ALTER SYSTEM SET session_cached_cursors=200 SCOPE=SPFILE;
ALTER SYSTEM SET sga_target=1200M SCOPE=SPFILE;
ALTER SYSTEM SET shared_pool_size=600M SCOPE=SPFILE;
ALTER SYSTEM SET pga_aggregate_target=300M SCOPE=SPFILE;
ALTER SYSTEM SET job_queue_processes=20 SCOPE=SPFILE;
SHUTDOWN IMMEDIATE
STARTUP

If you select the option to configure EM during database creation, then you have to remove it now.

shutdown immediate;
startup restrict;
EXEC sysman.emd_maintenance.remove_em_dbms_jobs;
EXEC sysman.setEMUserContext('',5);
REVOKE dba FROM sysman;
DECLARE
   CURSOR c1 IS
       SELECT owner, synonym_name name
       FROM dba_synonyms
       WHERE table_owner = 'SYSMAN' ;
   BEGIN
       FOR r1 IN c1 LOOP
         IF r1.owner = 'PUBLIC' THEN
           EXECUTE IMMEDIATE 'DROP PUBLIC SYNONYM '||r1.name;
         ELSE
           EXECUTE IMMEDIATE 'DROP SYNONYM '||r1.owner||'.'||r1.name;
        END IF;
      END LOOP;
   END;
   /
DROP USER mgmt_view CASCADE;
DROP ROLE mgmt_user;
DROP USER sysman CASCADE;
ALTER SYSTEM DISABLE RESTRICTED SESSION;
exit

emca -deconfig dbcontrol db -repos drop

Oracle recommends Redo logfile size for Oracle Management Repository / OMR  to be 300GB.

ALTER DATABASE ADD LOGFILE ('/u01/app/oracle/oradata/omr12c/redo04a.log','/u01/app/oracle/oradata/omr12c/redo04b.log') size 300M;
ALTER DATABASE ADD LOGFILE ('/u01/app/oracle/oradata/omr12c/redo05a.log','/u01/app/oracle/oradata/omr12c/redo05b.log') size 300M;
ALTER DATABASE ADD LOGFILE ('/u01/app/oracle/oradata/omr12c/redo06a.log','/u01/app/oracle/oradata/omr12c/redo06b.log') size 300M;
ALTER DATABASE DROP LOGFILE GROUP 1;
ALTER DATABASE DROP LOGFILE GROUP 2;
ALTER DATABASE DROP LOGFILE GROUP 3;
ALTER SYSTEM SWITCH LOGFILE;
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Conclusion – Oracle Enterprise Manager 12c:

We have successfully configured Oracle Enterprise Manager 12c Repository on CentOS 6 server. Continue reading our next article Configure Oracle Management Server / OMS on CentOS 6.

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