This architecture shows an API server built with the Django Web Framework deployed as a deployment resource in an OKE cluster.

The following diagram illustrates this reference architecture.

Description of the illustration django-web-framework-oke-cluster.png

django-web-framework-oke-cluster.zip

The worker nodes of the OKE cluster are in a private subnet which makes them only accessible from inside your Virtual Cloud Network (VCN). Having the worker nodes in a private subnet allows better control of how applications inside an OKE cluster can be accessed.

An Oracle Autonomous Database instance is provisioned with a public endpoint using the OCI Service Operator for Kubernetes (OSOK), which allows an Autonomous Database to be managed from the OKE cluster. A custom resource definition (CRD) will be produced as a designation for the Autonomous Database and can be managed like any Kubernetes resource with the command-line tool, kubectl.

A service gateway is provisioned for the VCN. The service gateway provides access from the API server to the Autonomous Database without traffic traversing the internet.

A load balancer is created with an external IP address in a public subnet to access the API server to perform execute create, read, update, and delete (CRUD) operations in the Autonomous Database instance. The load balancer is managed from the OKE cluster as a service resource.

This architecture can be deployed and managed from the OKE cluster without using the OCI console or CLI and automated with a Helm chart.

The architecture has the following components:

• Tenancy

  A tenancy is a secure and isolated partition that Oracle sets up within Oracle Cloud when you sign up for Oracle Cloud Infrastructure. You can create, organize, and administer your resources in Oracle Cloud within your tenancy. A tenancy is synonymous with a company or organization. Usually, a company will have a single tenancy and reflect its organizational structure within that tenancy. A single tenancy is usually associated with a single subscription, and a single subscription usually only has one tenancy.

• Region

  An Oracle Cloud Infrastructure region is a localized geographic area that contains one or more data centers, called availability domains. Regions are independent of other regions, and vast distances can separate them (across countries or even continents).

• Compartment

  Compartments are cross-region logical partitions within an Oracle Cloud Infrastructure tenancy. Use compartments to organize your resources in Oracle Cloud, control access to the resources, and set usage quotas. To control access to the resources in a given compartment, you define policies that specify who can access the resources and what actions they can perform.

• Availability domains

  Availability domains are standalone, independent data centers within a region. The physical resources in each availability domain are isolated from the resources in the other availability domains, which provides fault tolerance. Availability domains don’t share infrastructure such as power or cooling, or the internal availability domain network. So, a failure at one availability domain is unlikely to affect the other availability domains in the region.

• Fault domains

  A fault domain is a grouping of hardware and infrastructure within an availability domain. Each availability domain has three fault domains with independent power and hardware. When you distribute resources across multiple fault domains, your applications can tolerate physical server failure, system maintenance, and power failures inside a fault domain.

• Virtual cloud network (VCN) and subnets

  A VCN is a customizable, software-defined network that you set up in an Oracle Cloud Infrastructure region. Like traditional data center networks, VCNs give you complete control over your network environment. A VCN can have multiple non-overlapping CIDR blocks that you can change after you create the VCN. You can segment a VCN into subnets, which can be scoped to a region or to an availability domain. Each subnet consists of a contiguous range of addresses that don't overlap with the other subnets in the VCN. You can change the size of a subnet after creation. A subnet can be public or private.

• Load balancer

  The Oracle Cloud Infrastructure Load Balancing service provides automated traffic distribution from a single entry point to multiple servers in the back end.

• Security list

  For each subnet, you can create security rules that specify the source, destination, and type of traffic that must be allowed in and out of the subnet.

• Network address translation (NAT) gateway

  A NAT gateway enables private resources in a VCN to access hosts on the internet, without exposing those resources to incoming internet connections.

• Service gateway

  The service gateway provides access from a VCN to other services, such as Oracle Cloud Infrastructure Object Storage. The traffic from the VCN to the Oracle service travels over the Oracle network fabric and never traverses the internet.

• Cloud Guard

  You can use Oracle Cloud Guard to monitor and maintain the security of your resources in Oracle Cloud Infrastructure. Cloud Guard uses detector recipes that you can define to examine your resources for security weaknesses and to monitor operators and users for risky activities. When any misconfiguration or insecure activity is detected, Cloud Guard recommends corrective actions and assists with taking those actions, based on responder recipes that you can define.

• Security zone

  Security zones ensure Oracle's security best practices from the start by enforcing policies such as encrypting data and preventing public access to networks for an entire compartment. A security zone is associated with a compartment of the same name and includes security zone policies or a "recipe" that applies to the compartment and its sub-compartments. You can't add or move a standard compartment to a security zone compartment.

• Object storage

  Object storage provides quick access to large amounts of structured and unstructured data of any content type, including database backups, analytic data, and rich content such as images and videos. You can safely and securely store and then retrieve data directly from the internet or from within the cloud platform. You can seamlessly scale storage without experiencing any degradation in performance or service reliability. Use standard storage for "hot" storage that you need to access quickly, immediately, and frequently. Use archive storage for "cold" storage that you retain for long periods of time and seldom or rarely access.

• FastConnect

  Oracle Cloud Infrastructure FastConnect provides an easy way to create a dedicated, private connection between your data center and Oracle Cloud Infrastructure. FastConnect provides higher-bandwidth options and a more reliable networking experience when compared with internet-based connections.

• Local peering gateway (LPG)

  An LPG enables you to peer one VCN with another VCN in the same region. Peering means the VCNs communicate using private IP addresses, without the traffic traversing the internet or routing through your on-premises network.

• Autonomous Transaction Processing

  Oracle Autonomous Transaction Processing is a self-driving, self-securing, self-repairing database service that is optimized for transaction processing workloads. You do not need to configure or manage any hardware, or install any software. Oracle Cloud Infrastructure handles creating the database, as well as backing up, patching, upgrading, and tuning the database.

• Autonomous database

  Oracle Cloud Infrastructure autonomous databases are fully managed, preconfigured database environments that you can use for transaction processing and data warehousing workloads. You do not need to configure or manage any hardware, or install any software. Oracle Cloud Infrastructure handles creating the database, as well as backing up, patching, upgrading, and tuning the database.

• Exadata DB system

  Exadata Cloud Service enables you to leverage the power of Exadata in the cloud. You can provision flexible X8M systems that allow you to add database compute servers and storage servers to your system as your needs grow. X8M systems offer RoCE (RDMA over Converged Ethernet) networking for high bandwidth and low latency, persistent memory (PMEM) modules, and intelligent Exadata software. You can provision X8M systems by using a shape that's equivalent to a quarter-rack X8 system, and then add database and storage servers at any time after provisioning.

• VCN

  When you create a VCN, determine the number of CIDR blocks required and the size of each block based on the number of resources that you plan to attach to subnets in the VCN. Use CIDR blocks that are within the standard private IP address space.

  Select CIDR blocks that don't overlap with any other network (in Oracle Cloud Infrastructure, your on-premises data center, or another cloud provider) to which you intend to set up private connections.

  After you create a VCN, you can change, add, and remove its CIDR blocks.

  When you design the subnets, consider your traffic flow and security requirements. Attach all the resources within a specific tier or role to the same subnet, which can serve as a security boundary.

• Security

  You can use Oracle Cloud Guard to monitor and maintain the security of your resources in Oracle Cloud Infrastructure. Cloud Guard uses detector recipes that you can define to examine your resources for security weaknesses and to monitor operators and users for risky activities. When any misconfiguration or insecure activity is detected, Cloud Guard recommends corrective actions and assists with taking those actions, based on responder recipes that you can define.

  For resources that require maximum security, Oracle recommends that you use security zones. A security zone is a compartment associated with an Oracle-defined recipe of security policies that are based on best practices. For example, the resources in a security zone must not be accessible from the public internet and they must be encrypted using customer-managed keys. When you create and update resources in a security zone, Oracle Cloud Infrastructure validates the operations against the policies in the security-zone recipe, and denies operations that violate any of the policies.

• Cloud Guard

  Clone and customize the default recipes provided by Oracle to create custom detector and responder recipes. These recipes enable you to specify what type of security violations generate a warning and what actions are allowed to be performed on them. For example, you might want to detect Object Storage buckets that have visibility set to public.

  Apply Cloud Guard at the tenancy level to cover the broadest scope and to reduce the administrative burden of maintaining multiple configurations.

  You can also use the Managed List feature to apply certain configurations to detectors.

• Security Zones

  For resources that require maximum security, Oracle recommends that you use security zones. A security zone is a compartment associated with an Oracle-defined recipe of security policies that are based on best practices. For example, the resources in a security zone must not be accessible from the public internet and they must be encrypted using customer-managed keys. When you create and update resources in a security zone, Oracle Cloud Infrastructure validates the operations against the policies in the security-zone recipe, and denies operations that violate any of the policies.

• Network security groups (NSGs)

  You can use NSGs to define a set of ingress and egress rules that apply to specific VNICs. We recommend using NSGs rather than security lists, because NSGs enable you to separate the VCN's subnet architecture from the security requirements of your application.

When deploying this architecture, you must consider scalability.

By deploying your Django application on Oracle Container Engine for Kubernetes (OKE), you can automatically scale the cluster using the Kubernetes Cluster Autoscaler which optimizes the usage of your OCI Compute resources and brings down your cost. When demand increases, it scales up the number of nodes to meet those demands. When demand decreases, it scales the number of nodes down and prevents excessive resources from driving up costs.

You can find a link to download and install the Kubernetes Cluster Autoscaler from Github and follow the instructions in the README document

The Helm Chart demonstrates how to automate the deployment of a web server built with the Django Web Framework and connect it to an Oracle Autonomous Transaction Processing (ATP) in a Oracle Container Engine for Kubernetes (OKE) cluster.

Learn more about the features of this architecture.

• Best practices framework for Oracle Cloud Infrastructure
• Overview of Container Engine for Kubernetes

Author: Chiping Hwang