1. A computer implemented method for reducing risk of service interruptions for one or more virtual machines (VMs) in a computing environment, the method comprising: computing a placement scheme for placing at least one VM on one or more hosts according to a set of placement constraints defined for the VM, wherein the set of placement constraints comprises at least one availability constraint defined for the VM, wherein the availability constraint designates a N resiliency level, wherein N corresponds to number of host failures that may occur before the services provided by the VM are interrupted, migrating the VM from a first host to a second host in a computing environment, in response to determining that the first host pertains to a group of up to N hosts susceptible to failure and that the second host is a migration target; and creating one or more shadow VMs for a VM with availability constraints, wherein the shadow VMs are utilized to protect the VM against the certain number of host failures as designated by the availability constraints; wherein a first shadow VM is converted to a second shadow VM, if the host on which the first shadow VM is placed is a failing host and a host on which the second shadow VM is placed is designated as a migration target, and wherein the set of placement constraints defined for the shadow VMs comprises an anti-collocation constraint prohibiting shadow VMs created for the first VM from being collocated with each other.