Virtualization offers a wide array of benefits from power and environmental constraints to physical space limitations and disaster recovery efforts. As leaders for Unified Vulnerability Management, we realize these benefits offer a significant value to our install base and we are in full support of virtualization for our solutions.
Although virtualization is in many ways identical to running on physical hardware from a software perspective, there are certain caveats that are unique to a connection sensitive application such as a vulnerability assessment scanner. Having an extremely diverse customer base including some of the largest deployments of vulnerability assessment, Retina has had a significant amount of in various environments and the challenges that can go along with them.
As virtualized environments and configurations vary widely, we can provide some guidance for scanning from these environments and anomalies you may encounter. Regardless of the scanning solution, best practice guides, minimum prerequisites, and user documentation should be adhered to during the installation of the products. eEye has developed a set of recommendations that will optimize the solution in a virtual environment and minimize any potential run times errors or scan anomalies:
Dedicated Network Interface Cards
Retina should have a dedicated physical NIC for its scanning jobs since UDP packets by nature can be dropped during high utilization from another application sharing the NIC. It is our experience that highly utilized virtualized systems favor established TCP connections over half-open or SYN only connections as well. This can have an undesirable effect on scan results too.
MS SQL Database
MS SQL should not be virtualized unless database considerations are taken for virtualization and best practices implemented per the virtualization vendor. MS SQL server requires a significant amount of resources to function correctly. In our experience we have seen a few cases where the management components, and especially MS SQL instances, have been given far inadequate amounts of resources. This always results in poor performance. Disk speed and utilization is also a contributor to performance. MS SQL is by nature disk intensive and performs best when delivered by a RAID array or SAN solution. Bottom line, virtualization of a machine does not change the resources required for it to function properly. Under powering SQL or management components can have a drastic impact on performance and user experience.
Dedicated Virtual Machines
Virtual machines for scanning and management components should not be shared with other applications. The Retina Network Security Scanner, Retina CS, and MS SQL are all enterprise ready solutions. Enterprise class software is optimally designed to run on enterprise class hardware. Shared resources generally lead to overburdened machines and again poor performance and user experience.
Industrial Virtualization Suites
There are many options when selecting a virtualization suite. We do not recommend one particular suite over another but do recommend choosing an industrial grade, server level, solution with commercial support and maintenance. VMWare ESX, Parallels, Xen, and MS Virtual Serverare all acceptable technologies. Using workstation or other non-industrial virtualization technology is not recommended.