Multitenant Services
As with any shared service, tenants aren’t totally isolated
from each other. Many cloud service providers
offer different levels of services and use virtualization
to separate clients, which includes sharing virtual
machines or allocating a virtual machine to a
single user. Still, the work pattern of one user can
affect other users of the same service. For example,
excessive use or locking of resources is a common
problem that impacts service availability and can
lead to DoS attacks. End users of cloud services
work in heterogeneous environments, and the cloud
service provider has little influence on their setup.
Users can utilize the service from Internet cafes
with little protection or from desktop computers in a
well-protected environment behind a firewall. However,
one user’s environment can affect the server
and other users. Malware can spread via the server,
infect applications, and move on to other clients.
Virtual environments offer more protection between
virtual machines than within a machine, but they
still don’t provide complete isolation.