Rehost mainframe applications by using NTT DATA UniKix

ExpressRoute
Load Balancer
Site Recovery
SQL Database
Storage

UniKix is a mainframe-rehosting software suite from NTT DATA. This suite provides a way to run migrated legacy assets on Azure. Example assets include IBM CICS transactions, IBM IMS applications, batch workloads, and JCL workloads. This article outlines a solution for rehosting mainframe applications on Azure. Besides UniKix, the solution's core components include Azure ExpressRoute, Azure Site Recovery, and Azure storage and database services.

Mainframe architecture

The following diagram shows a legacy mainframe system before it's rehosted to the cloud:

Architecture diagram that shows a mainframe system. Components include middleware, monitoring systems, applications, and data.

Workflow

  • On-premises users interact with the mainframe by using TCP/IP (A):

    • Admin users interact through a TN3270 terminal emulator.
    • Web interface users interact via a web browser over TLS 1.3 port 443.
  • Mainframes use communication protocols such as LU 6.2, TN3270, FTP, Sockets, and UTS to receive input (B).

  • Batch and online applications process the input (C).

  • Mainframe applications are in COBOL, PL/I, Assembler, 4GL, and Fortran. These languages and compatible ones run in an enabled environment (D).

  • Mainframes use hierarchical, network, and relational databases (E).

  • Services perform tasks for the applications. Services that typically run include program execution, I/O operations, error detection, and protection. (F).

  • Middleware and utility services manage tasks like tape storage, queueing, output, and web support (G).

  • Operating systems provide an interface between the engine and the software that it runs (H).

  • Partitions run separate workloads or segregate work types within the environment (I).

Azure architecture

Architecture diagram that shows a mainframe system rehosted on Azure by using N T T DATA UniKix.

Download a Visio file of this architecture.

Workflow

  1. ExpressRoute connects an on-premises corporate network to NTT DATA's UniKix mainframe rehosting software suite. Traffic from users and external interfaces that aren't on the Azure platform flows through this ExpressRoute connection to the Azure instances.

  2. Azure Load Balancer distributes online transactions across two or more Azure virtual machines (VMs). Port 4444 is used to connect with x3270. For a single-host alternative, see Alternatives.

  3. The application server runs the following NTT DATA products:

    • TPE. This environment runs:

      • Rehosted online IBM CICS transactions.
      • IBM IMS/TM applications.
      • Transformed IDMS DC programs.
      • Related resources.

      These workloads run on industry-standard servers and operating systems such as Red Hat Linux.

    • BPE. This environment provides a complete job entry subsystem (JES) environment for the administration, execution, and management of batch workloads.

    • UniKix Secure, which was previously known as Transaction Security Facility (TSF). This external security manager provides role-based access control that's based on security for online TPE-based transactions.

    • NTT DATA COBOL. This technology produces optimized, portable object code that you can deploy in Azure. NTT DATA COBOL supports ANSI-85 standard and legacy COBOL dialects.

    • NTT DATA VDSO. This mechanism provides a way to store VSAM key-sequenced dataset (KSDS) data in a SQL database rather than local disk files. NTT DATA VDSO supports many database technologies such as SQL Server, DB2, Oracle, and MySQL.

  4. Azure managed disks provide storage for shared files.

  5. UniKix Secure uses Azure Active Directory (Azure AD) to provide authentication. This security manager replaces security systems like Resource Access Control Facility (RACF), Access Control Facility 2 (ACF2), and Top Secret.

  6. The solution stores database tables and, optionally, VSAM files, in Azure SQL Database. This data is replicated to another Azure region for disaster recovery purposes.

  7. Site Recovery replicates the Azure production application VMs. This replication helps ensure business continuity by keeping business apps and workloads running during outages.

  8. The second Azure region mirrors the configuration of the primary Azure region for disaster recovery.

Components

  • ExpressRoute extends on-premises networks into Azure over a private, dedicated fiber connection from a connectivity provider. ExpressRoute establishes connections to Microsoft cloud services like Azure and Microsoft 365.

  • Load Balancer distributes incoming traffic to compute resource clusters. You can define rules and other criteria to distribute the traffic.

  • Azure Virtual Machines offers many sizes and types of on-demand, scalable computing resources. With Azure VMs, you get the flexibility of virtualization without having to buy and maintain physical hardware.

  • Azure Storage offers scalable, secure cloud storage for all your data, applications, and workloads:

    • Azure Disk Storage is high-performance, durable block storage for business-critical applications. Azure managed disks are block-level storage volumes that are managed by Azure on Azure VMs. The available types of disks are Ultra Disk Storage, Premium SSD, Standard SSD, and Standard HDD. This solution uses either Premium SSD or Ultra Disk Storage.
    • Azure Files offers fully managed file shares in the cloud that are accessible via the industry standard Server Message Block (SMB) protocol. Cloud and on-premises Windows, Linux, and macOS deployments can mount Azure Files file shares concurrently.
    • Azure Blob Storage provides scalable and secure object storage. It can manage large amounts of unstructured data, such as archives and data lakes. Blob Storage is a good fit for high-performance computing, machine learning, and cloud-native workloads.
  • Azure databases offer a choice of fully managed relational and NoSQL databases to fit modern application needs. Automated infrastructure management provides scalability, availability, and security.

  • SQL Database is a fully managed platform as a service (PaaS) database engine. SQL Database runs on the latest stable version of SQL Server and a patched operating system. Automated functionality includes upgrading, patching, backups, and monitoring. Because SQL Database offers built-in PaaS capabilities, you can focus on domain-specific, business-critical database administration and optimization.

  • Site Recovery mirrors Azure VMs to a secondary Azure region. If the primary datacenter fails, the secondary region provides quick failover and disaster recovery.

Alternatives

  • Sometimes scaling isn't possible, due to licensing constraints or your application's design. In those cases, you can mirror the mainframe setup with a single host.
  • For disaster recovery, the solution replicates the SQL Server data to another region. As another option, you can use the Always On availability groups feature of SQL Server as a disaster recovery solution.
  • In some scenarios, some of the solution's components and workflows are optional or interchangeable.

Scenario details

UniKix is a mainframe-rehosting software suite from NTT DATA. This suite provides a way to run migrated legacy assets on Azure. Example assets include IBM CICS transactions, IBM IMS applications, batch workloads, and JCL workloads.

The NTT DATA software offers many useful features:

  • A means for converting Integrated Database Management System (IDMS), Natural, and other application environments so that they operate within UniKix
  • A robust, logically threaded NTT DATA engine that provides a rich online transaction processing environment (TPE)
  • A complete, native batch processing environment (BPE)
  • A powerful COBOL compiler
  • A streamlined runtime environment
  • A graphical source-level debugger
  • A portable indexed file system

By using UniKix to rehost mainframe applications, you can take advantage of these features. You can also:

  • Avoid licensing fees for mainframe software.
  • Reduce infrastructure maintenance and operating costs.
  • Minimize risk and disruption by retaining existing user interfaces and business logic.
  • Modernize your IT environment.
  • Capitalize on Azure solutions for scalability, high availability, and disaster recovery.
  • Implement a modern DevOps workflow with NTT DATA tools and select Azure tools.

This article outlines a solution for rehosting mainframe applications on Azure. Besides UniKix, the solution's core components include Azure ExpressRoute, Azure Site Recovery, and Azure storage and database services.

Potential use cases

Industries that use mainframes can benefit from UniKix rehosting solutions. The following sectors that process large volumes of transactions on a daily basis are possibilities:

  • Banking and finance
  • Insurance
  • Healthcare
  • The military and government
  • E-commerce and retail

Considerations

The following considerations, based on the Azure Well-Architected Framework, apply to this solution:

Reliability

The solution uses Site Recovery to mirror Azure VMs to a secondary Azure region. If the primary datacenter fails, the secondary region provides quick failover and disaster recovery.

Security

This solution uses an Azure network security group to manage traffic between Azure resources. For more information, see Network security groups.

Cost optimization

  • Azure provides cost optimization by running on VMs. You can turn off the VMs when not in use, and script a schedule for known usage patterns. For more information about cost optimization for VM instances, see the Azure Well-Architected Framework.

  • For managed disks, the VMs in this solution use either Premium SSD or Ultra Disk Storage. For more information about disk options and pricing, see Managed disks pricing.

  • To estimate the cost of implementing this solution, use the Pricing calculator.

Contributors

This article is maintained by Microsoft. It was originally written by the following contributors.

Principal author:

Other contributors:

Next steps