DBA's Journey: April 2021

Sunday, April 4, 2021

Installation of Weblogic 12c (12.2.1.4) on Linux

Prerequisites:

a. Download JDK1.8 (jdk-8u281-linux-x64.tar.gz) from below link.

https://www.oracle.com/java/technologies/javase/javase-jdk8-downloads.html

b. Download weblogic 12.2.1.4 (fmw_12.2.1.4.0_wls_Disk1_1of1.zip) from below link.

https://www.oracle.com/in/middleware/technologies/weblogic-server-downloads.html

c. Create user webadmin who installs and configures weblogic server.

useradd webadmin

d. Create the prerequisite directory to hold oracle WebLogic software

mkdir /u01/app/web_12214

mkdir /u01/app/oraInventory

e. create /etc/oraInst.loc & add the below lines.

inventory_loc=/u01/app/oraInventory

inst_group=webadmin

f. Stage the software under /u01/app/softwares .

[webadmin@jaytch softwares]$ pwd

/u01/app/softwares

[webadmin@jaytch softwares]$ ls -ltr

total 986544

-rw-rw-r--. 1 opc opc 866494253 Apr 4 07:56 fmw_12.2.1.4.0_wls_Disk1_1of1.zip

-rw-rw-r--. 1 webadmin webadmin 143722924 Apr 4 10:27 jdk-8u281-linux-x64.tar.gz

[webadmin@jaytch softwares]$ unzip fmw_12.2.1.4.0_wls_Disk1_1of1.zip

Archive: fmw_12.2.1.4.0_wls_Disk1_1of1.zip

inflating: fmw_12.2.1.4.0_wls.jar

[webadmin@jaytch app]$ cd /u01/app

[webadmin@jaytch app]$ tar -zxvf /u01/app/softwares/jdk-8u281-linux-x64.tar.gz

Installation:

export PATH=/u01/app/jdk1.8.0_281/bin:$PATH

cd /u01/app/softwares/

java -jar fmw_12.2.1.4.0_wls.jar

After the graphical wizard opens, use the guidelines in the following table to install WebLogic Server 12c (12.2.1):

Step	Window/Page Description	Choices or Values
a.	Step 1 of 9 - Welcome	Click Next.
b.	Step 2 of 9 - Auto Updates	Select Skip Auto Updates. Click Next.
c.	Step 3 of 9 - Installation Location	Enter /u01/app/web_12214 for Oracle Home. Click Next.
d.	Step 4 of 9 - Installation Type	Select Complete with Examples. [ If it is production box, Please choose weblogic server ] Click Next.
e.	Step 5 of 9 - Prerequisite Checks	Click Next.
f.	Step 6 of 9 - Security Updates	Unselect I wish to receive security updates via My Oracle Support. Click Next.
g.	My Oracle Support Username/Email Address Not Specified	Click Yes.
h.	Step 7 of 9 - Installation Summary	Click Install.
i.	Step 8 of 9 - Installation Progress	Click Next.
j.	Step 9 of 9 - Installation Complete	Click Finish.

Environment File Setup:

Create the env file $HOME/web12c.env

ORACLE_HOME=/u01/app/web_12214; export ORACLE_HOME

MW_HOME=$ORACLE_HOME ; export MW_HOME

WLS_HOME=$MW_HOME/wlserver; export WLS_HOME

DOMAIN_HOME=/u01/app/web_12214/user_projects/domains/jay_domain; export DOMAIN_HOME

JAVA_HOME=/u01/app/jdk1.8.0_281; export JAVA_HOME

export PATH=$JAVA_HOME/bin:$ORACLE_HOME/OPatch:$PATH

Creating Weblogic Domain:

source $HOME/web12c.env

$ORACLE_HOME/oracle_common/common/bin/config.sh

Start the Services:

Create the boot.properties under $DOMAIN_HOME/WLS_DEMO/security folder .

nohup $DOMAIN_HOME/bin/startNodeManager.sh > /dev/null 2>&1 &

nohup $DOMAIN_HOME/startWebLogic.sh > /dev/null 2>&1 &

nohup $DOMAIN_HOME/bin/startManagedWebLogic.sh WLS_DEMO > /dev/null 2>&1 &

Saturday, April 3, 2021

R12.2 Forms Server Fails With "Could not reserve enough space for object heap" on OEL6

Issue :

Not able to start the forms managed server with XMX as 2G.

Cause:

It was working fine. No changes has been made.

Solution:

Unlike oacore, Forms servers are running on top of 32 bit JVM. There is a bug (or) limitation on 32 bit libraries to reserve the memory more than 1G. Please see the output 32 and 64 bit java output below.

$COMMON_TOP/util/jdk32/jre/bin/java -Xms32m -Xmx3072m -XX:MaxPermSize=256m -version

Error occurred during initialization of VM

Could not reserve enough space for object heap

Error: Could not create the Java Virtual Machine.

Error: A fatal exception has occurred. Program will exit.

$COMMON_TOP/util/jdk64/jre/bin/java -Xms32m -Xmx3072m -XX:MaxPermSize=256m -version

java version "1.7.0_85"

Java(TM) SE Runtime Environment (build 1.7.0_85-b15)

Java HotSpot(TM) 64-Bit Server VM (build 24.85-b06, mixed mode)

This is caused by the prelink command. It calculates shared library load addresses, and updates the shared libraries with them. Simplest thing to do is to undo what prelink did, and disable it.

By default prelinking is enabled on OEL6 (not receiving this error on OEL7)

Disable prelink method

To disable prelinking

a. Login as root user & execute prelink -u --all

b. Edit /etc/sysconfig/prelink and save.

set PRELINKING=no

c. Now try to execute below command. It should not return any error.