2. Writing Dockerfiles to install JDK and WebLogic to create docker images

We have a couple of options to create the docker images. In the last post, we got the docker installed Linux environment available. Now in this post, we will develop the Dockerfile such that it can create an image that can have Java JRE installed and WebLogic 12c installed.

Lets jump on the task where we will prepare, create the Dockerfile and build the image and run the container to check all done successful.

Prepare software installation

Remember that official images always the preferable choice. When you search for docker images from the public repository that is hub.docker.com. We might get a huge list some of them are Automated some of them are not. The only one will be committed as an Official Image. Here selecting an image is also a strategy, logic inside. So carefully proceed further.

We need to install Java Development Kit JDK latest version and WebLogic in silent mode installation.

Step 1: Copy installers to data folder this is my convention I've used
Here few Dockerfile commands

1. FROM - used to specify the base image
2. MAINTAINER [depricated]- tell about the author
3. RUN - executable commands separated by &&
4. USER - like su command in Linux is used for switch user
5. ENV - environment variables definitions predefined
6. ADD - share directories or files
7. WORKDIR - login is like cd in Linux you perform some of the commands there and then you can use one more time and perform
8. COPY - copy the files from the host machine to container it is like scp
9. CMD - Execute command where you can give multiple commands in double quotes
10. ENTRYPOINT - when the container started immediately this instruction will be executed

Now we are good to go for creating the customized Docker Image using Dockerfile as follows:

# WLS DOCKERFILES PROJECT
# --------------------------
# Pull base image
# ---------------
FROM dnraikes/oraclelinux-7:latest

# Maintainer
# ----------
MAINTAINER Pavan Devarakonda 

RUN mkdir -p /u01 /data && \
    chmod a+xr /u01 && \
    useradd -b /u01 -d /u01/oracle -m -s /bin/bash oracle && \
    chown oracle:oracle -R /u01 && \
    chown oracle:oracle -R /data

USER oracle

ENV PATH=/bin:$PATH

ADD ./data /data
ADD ./silent /u01/silent
ADD  wls_installer.sh /u01/wls_installer.sh

WORKDIR /u01
RUN /u01/wls_installer.sh

I'm just doing this experiment how much size this container would make that really matters.

Step 2: Copy silent folder containing wls_install.rsp, oraInst.loc with appropriate group and inventory location. Ref : Single hit installation of WebLogic 12c on Vagrant box

JDK, WebLogic Installation

Revisiting the last blog post few changes made which will help you to prepare the docker image while it creates the image it will install JDK and WebLogic into the intermediate containers.

#!/bin/bash
# This script will be installing JDK installing WebLogic in silent mode
#
#- Info
#-    Author   : Pavan Devarakonda
#-    Date     : 30-March-2017
##############################################3

JDK_INSTALLER=jdk-8u121-linux-x64.tar.gz
JDK_INSTALLER_PATH=/data
INSTAL_LOC=/u01/oracle

echo "installing JDK ${JDK_INSTALLER}"
cd $INSTAL_LOC
tar -zxvf $JDK_INSTALLER_PATH/$JDK_INSTALLER

ls -l
echo confirm JDK installation
cd $INSTAL_LOC/jdk*

JAVA_HOME=`pwd`
echo "export JAVA_HOME=$JAVA_HOME">>$HOME/.bashrc
echo "export PATH=$JAVA_HOME/bin:$PATH">>$HOME/.bashrc

. $HOME/.bashrc

echo "Check for java version"
java -version

echo Installing WebLogic now...
WLS_INSTALLER=fmw_12.2.1.0.0_wls.jar
WLS_INSTALLER_PATH=/data

SILENT_DIR=/u01/silent

java -jar $WLS_INSTALLER_PATH/$WLS_INSTALLER -silent -invPtrLoc $SILENT_DIR/oraInst.loc -responseFile $SILENT_DIR/wls_install.rsp

echo "WebLogic $WLS_INSTALLER installed successfully...."
echo .
echo setting MW_HOME ...
MW_HOME=`grep ORACLE_HOME $SILENT_DIR/wls_install.rsp |cut -d'=' -f2`
echo "export MW_HOME=$MW_HOME">>$HOME/.bashrc
echo "export WL_HOME=$MW_HOME/wlserver">>$HOME/.bashrc
echo "alias wlst=$MW_HOME/oracle_common/common/bin/wlst.sh">>$HOME/.bashrc
. $HOME/.bashrc

Step 3: Run the docker build as follows:

#!/bin/bash
#

# ################## #
# BUILDING THE IMAGE #
# ################## #
echo "Building image '$IMAGE_NAME' ..."

IMAGE_NAME="wlsimg"
NOCACHE=true

BUILD_START=$(date '+%s')
docker build --force-rm=$NOCACHE --no-cache=$NOCACHE -t $IMAGE_NAME . || {
  echo "There was an error building the image."
  exit 1
}
BUILD_END=$(date '+%s')
BUILD_ELAPSED=`expr $BUILD_END - $BUILD_START`

echo ""

chmod u+x build.sh
./build.sh

After the WebLogic docker image builds completed you can see the following lines at the end:

Successful execution of docker build

The docker image list looks like this, where you can see the build image with the tag mentioned in the above :

WebLogic docker image

Further experimenting on dockerization of WebLogic - Using containers will be posted soon.

Reference:

1. GitHub link for Oracle-WebLogic docker build