- pay less for products so that money can be spent on projects to replace and upgrade
- pay less so that ROI can be achieved 3 years
- design so that the services can be easily replaced, migrated or transferred.
- increase skills to implement rapid replacement
- have an operational system that abstracts the device functions from their actual purpose.
Virtual Appliances are products that meet the need for short, fast lifecycles. They don’t need dedicated hardware, cabling or power. They are easier to replace and upgrade.
For some companies, subscription licensing means you can walk away from the product at anytime (provided the costs of monthly purchase orders and licensing compliance are controlled).
The real challenge lies in design skills to replace one product with another product. For this, some sort of the orchestration system is needed. Strong operational discipline is needed to prevent the use of vendor-specific features that would prevent rapid replacement with other products.
Virtual appliances are much easier to migrate and custover. Because they operate as VMs, its simple to power on and off so cutover and failback is simpler. If you have an SDN overlay network, then modification of network paths is almost risk-free and can be switched between appliances with limited impact.
Reducing project risk is key to enabling rapid replacement and keeping project costs to acceptable levels.