Universal Sharing Model

4 minute read

After many years working as a fullstack architect, currently I’m digging back deeper in to the security territory. Security does not only includes a technical point of view (how-), but also the security architecture (what-) and the security governance (why-domain). The according security standards are per example ISO/IEC 27001 or the NIST Cyber Security Framework.

This blog post is about how to accomplish multitenancy and the software supply chain from a compliance perspective.



Multitenancy is the ability of systems to independently represent legal and/or organizational units, denominated below as «entity». This is accomplished by sharing capacities such as computing, communication and persistency. Setup and management of capacities both technically and organizationally concerned can take place in shared manner as well.

Software Supply Chain

The software supply chain encompasses all steps between development to production. The separation of environments requires data fixtures and synthetic data on all preproduction stages and a high degree of data management. Only if this can be ensured, then the specific degree of multitenancy can vary stage by stage.

Proposing USM, the «Universal Sharing Model»

Obviously a generic model is abstract by design. So if you don’t bother about, step over directly to the conclusions below.

A generic model does not depend on vendors or implementations. Nesting technologies, making more and more software defined and thus continuously sophisticating far reaching automation, maybe at some point AI based, does not require to reinvent the wheel. The rules must be stable and clear. The aim is to create a simplified but coherent view on the relevant pieces:

Universal Sharing Model

The specific degree of reuse between of «share all» and «share nothing» eg. fully dedicated is motivated by an economic point of view, while legal and regulatory compliance must be followed. Sharing of capacities such as compute, network and storage and far-reaching automation do also represent a technical and organizational challange.


There is no need to reinvent the wheel on every new technology arising. Usually contradictions are indicating a redefinition of something existent, thus representing just an implementation detail.

The specific degree of segregation is depending on data-protection requirements but must also take into account the management perspective if anyway fully shared in case of SaaS offerings.

Sharing must be considered by fully taking into account all base ingredients like compute, network, storage and the management.

Reducing the specific degree of sharing does not necessairly increase the level of protection.

Security must be economical adequate, thus globally do encryption at some level as countermeasure of non quantified risks is probably not rationale.


  1. Define generic segregation rules based on «USM» (the sharing model above)
  2. Challenge the rules with your business requirements and non-functionals (legal and regulation point of view)
  3. Continuously adjust and improve the rules

«USM» Implementation Details



  • Dedicated: Named Individuals on same company as the entity itself
  • Shared: Outsourcing mandate


Technical management from a legacy point of view (imperative maintenance). Today «orchestration» for new declarative technologies eg. cloud and container based services. Maybe there will be a new definition for AI based management, but the topic will remain the same.

  • Dedicated: Management consoles and orchestrators per entity
  • Shared: Networks like VPN, Management Conosoles, Orchestrators etc.



  • Dedicated: Physical hardware per entity
  • Shared: Accomplished by hypervisor based (type 1 and 2) virtualization like KVM, ESX, LPAR, etc. protecting and exposing ressources top operating systems on top

Operating System

Running on any dedicated or shared hardware:

  • Dedicated: Any per entity
  • Shared: Accomplished by non-separation at all, BSD Jails, Sun Zones, LXC, Containers etc. protecting and exposing kernel syscalls to userland processes on top


Running on any dedicated or shared OS:

  • Dedicated: Binary self-contained executable per entity
  • Shared: Accomplished by application runtimes like JVM, .NET CLR, Tomcat, Weblogic, Wildfly, etc. protecting and exposing logical calls to applications on top


Running on any dedicated or shared processes:

  • Dedicated: Single software service instance per entity
  • Shared: Logical multi-instance software service



  • Dedicated: Physical interface per entity
  • Shared: Virtual interface accomplished by shared hardware or shared operating system


On top of any dedicated or shared interface:

  • Dedicated: Broadcast domain delimited by dedicated network cables and devices per entity
  • Shared: Virtual broadcast domains delimited by tagging or encapsulation technologies like VLAN, VXLAN, MPLS, GRE, etc.


On top of any dedicated or shared domain:

  • Dedicated: Specific routable addressing per entity
  • Shared: Overlay addressing accomplished by extensive NAT and encapsulation methods


On top of any dedicated or shared address:

  • Dedicated: Single listener software service per entity
  • Shared: Multiple software services on the same listener



  • Dedicated: Physical device per entity
  • Shared: Virtual device accomplished by partitioning


On top of any dedicated or shared Device:

  • Dedicated: Logical volume per entity
  • Shared: Logical volume accomplished

File System

On top of any dedicated or shared volume:

  • Dedicated: Mount point per entity
  • Shared: One mount point accomplished by NFS, NIFS, SMB, etc.


On top of any dedicated or shared file system:

  • Dedicated: Clear delimited folders and files per entity
  • Shared: Non delimited data persistency fully depending on software service logic (application)


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