🚀 Migration and Modernization of HR Management Application and Oracle Database to a MultiCloud Architecture (En version)

with Microsoft Azure App Service (Serverless Docker-Based Managed Service) and Oracle Autonomous Database (Serverless Database).

🎯 General Context

In this project, I took on the role of Cloud Architect in a realistic workload migration scenario.

The goal was to modernize an HR management application, initially running on an on-premises VM connected to a local Oracle Database, to a MultiCloud model leveraging:

• Oracle Cloud Infrastructure (OCI) for the data layer, running on serverless Exadata (Autonomous Database).
• Microsoft Azure App Service for the application layer, running in serverless managed containers.

🏗️ Solution Architecture

This process followed key architectural premises: ✔ Oracle Database on a self-managed infrastructure (ATP on Exadata). ✔ Application containerized (VM → Docker). ✔ Deployment on a serverless container service. ✔ Infrastructure provisioned as code (IaC).

🗄️ Part 01 — Provisioning and Configuration of Oracle Autonomous Database

Creating the ATP in OCI

• Service: Autonomous Transaction Processing (ATP)
• Workload: Transaction Processing
• Infrastructure: Shared Infrastructure
• Database Version: 19c
• Logical Name: dbhr
• Admin User: ADMIN

Creating the application user

CREATE USER APP_HR IDENTIFIED BY Welcome123456;
GRANT CONNECT, RESOURCE TO APP_HR;
ALTER USER APP_HR QUOTA UNLIMITED ON DATA;

This user was created to handle all interactions between the application and the database.

Creating a test table

CREATE TABLE employees (
  id INTEGER PRIMARY KEY,
  name VARCHAR2(80),
  surname VARCHAR2(100),
  email VARCHAR2(200),
  phone VARCHAR2(20)
);

Wallet download

The Wallet was downloaded from the OCI console. This file contains certificates and connection credentials, essential for secure communication between the application and the database.

🐳 Part 02 — Application Modernization, Implementation, and Testing

Build VM creation

• OS: Oracle Linux 8
• Name: docker-vm
• SSH Key: ssh-key-docker-vm.key

Docker installation

sudo dnf update -y
sudo dnf config-manager --add-repo=https://download.docker.com/linux/centos/docker-ce.repo
sudo dnf install docker-ce docker-ce-cli containerd.io -y
sudo systemctl start docker
sudo systemctl enable docker
sudo usermod -aG docker opc

Preparing the application directory

wget https://objectstorage.us-ashburn-1.oraclecloud.com/.../oci-final-project-registration-employees-app.zip
unzip oci-final-project-registration-employees-app.zip
mkdir wallet
scp -i ssh-key-docker-vm.key Wallet_dbhr.zip opc@your-vm-public-ip:/home/opc/oci-final-project-registration-employees-app/wallet/
cd wallet && unzip Wallet_dbhr.zip

Creating the Dockerfile

FROM oraclelinux:7-slim
WORKDIR /app
ARG release=19
ARG update=10  

RUN yum install -y oracle-epel-release-el7 oracle-release-el7 && \
    yum-config-manager --enable ol7_oracle_instantclient && \
    yum -y install oracle-instantclient${release}.${update}-basic \
                   oracle-instantclient${release}.${update}-devel \
                   oracle-instantclient${release}.${update}-sqlplus && \
    yum install -y gcc gcc-c++ make && \
    rm -rf /var/cache/yum

RUN yum install -y oracle-softwarecollection-release-el7 && \
    yum-config-manager --enable software_collections && \
    yum-config-manager --enable ol7_latest ol7_optional_latest && \
    yum install -y scl-utils rh-python36 && \
    yum install -y python-pip

ENV PATH=$PATH:/usr/lib/oracle/${release}.${update}/client64/bin
ENV TNS_ADMIN=/usr/lib/oracle/${release}.${update}/client64/lib/network/admin

ADD ./wallet /usr/lib/oracle/${release}.${update}/client64/lib/network/admin/
COPY ./requirements.txt /app/requirements.txt
COPY ./app.py ./config.py ./forms.py ./models.py ./Procfile ./README /app/
COPY ./static /app/static
COPY ./templates /app/templates

RUN /opt/rh/rh-python36/root/usr/bin/python3.6 -m pip install --upgrade pip
RUN /opt/rh/rh-python36/root/usr/bin/python3.6 -m pip install -r /app/requirements.txt

EXPOSE 8000
CMD ["/opt/rh/rh-python36/root/usr/bin/gunicorn","app:app","--config=config.py"]

Building and pushing the image to Docker Hub

docker build -t "oci-final-project-registration-employees-app:latest" .
docker tag oci-final-project-registration-employees-app:latest your-dockerhub-id/oci-final-project-registration-employees-app:latest
docker login
docker push your-dockerhub-id/oci-final-project-registration-employees-app:latest

DOCKER HUB

☁️ Part 03 — Deployment on Azure App Service

docker-compose.yml file

version: "3.9"
services:
  app:
    image: "your-dockerhub-id/oci-final-project-registration-employees-app"
    environment:
      - DB_CONNECT_STRING=dbhr_high
      - DB_USER=app_hr
      - DB_PASSWORD=Welcome123456

Creating Azure App Service

• Resource Group: oci-final-project
• Instance Name: oci-final-project-fhp
• Publish: Container
• OS: Linux
• Plan: Free F1
• Configuration: Docker Compose (public image from Docker Hub)

Log Stream

Deployment Center Logs

After deployment, the application was available through the default Azure domain.

📂 Part 04 — Importing the On-Premises Dump

Export and upload to OCI Object Storage

The database dump was stored in a private bucket (bucket-dbhr-fhp) in OCI Object Storage.

uploading the dump file

Creating PAR — Pre Authenticated Request

Connecting to Autonomous DB via Wallet

export TNS_ADMIN=/tmp/tns-wallet
sqlplus admin/Welcome123456@dbhr_high

Importing with Oracle Data Pump

impdp admin/Welcome123456@dbhr_high \
  credential=not_used \
  TABLE_EXISTS_ACTION=REPLACE \
  directory=data_pump_dir \
  dumpfile=https://objectstorage.us-ashburn-1.oraclecloud.com/.../exp_app_hr01.dmp \
  logfile=import.log

Validation

• Testing record insertion.

• Testing record deletion.

• Verifying active database sessions:

SELECT * FROM v$session;

📊 Results

• Application successfully migrated to Azure App Service with serverless containers.
• Database restored and fully operational in Oracle Autonomous Database (Exadata Serverless/OCI).
• Data successfully imported from the on-premises environment.
• Temporary resources deleted, following FinOps best practices.

📝 Conclusion

The implementation validated the feasibility of adopting a MultiCloud strategy for enterprise systems:

• OCI ensures resilience and security for the data layer.
• Azure provides agility and scalability for the application layer in a serverless model.

This project reinforces my expertise in Cloud Architecture, DevOps, IaC, and complex workload migrations, delivering high-value solutions for companies and industries undergoing digital transformation.