1. A method, comprising: determining that use of a first system resource of a plurality of system resources a first host system satisfies a migration condition, wherein the first host system executes a plurality of virtual machines in a cloud computing environment; computing a numeric score for each of the plurality of virtual machines executing on the first host system, wherein the numeric scores are of a range of scores and are computed based on an amount of the respective system resource the respective virtual machine uses, wherein the numeric scores are computed by applying a first weight to the first system resource of the plurality of system resources, a second weight to a second system resource of the plurality of system resources, and a respective weight to each of the remaining plurality of system resources; identifying a subset of the plurality of virtual machines for migration based on a first migration policy, of a plurality of migration policies, wherein the plurality of migration policies specify a respective set of rules for identifying virtual machines for migration, wherein a first rule of the set of rules specifies a first count of virtual machines to migrate upon determining use of the first system resource exceeds a first user defined threshold, wherein a number of virtual machines in the subset is based on the first count of virtual machines specified in the first rule, wherein the first count of virtual machines is different than a second count of virtual machines specified in a first rule of a second migration policy of the plurality of migration policies, wherein the subset comprises at least a first virtual machine and a second virtual machine of the plurality of virtual machines based on the first count, wherein a second rule of the first migration policy specifies to migrate virtual machines having the lowest use of the second system resource, wherein the first and second virtual machines are further identified based on the computed scores and the second rule of the first migration policy, wherein a first rule of a third migration policy of the plurality of migration policies specifies to migrate a third count of virtual machines to migrate upon determining use of the first system resource exceeds a second threshold, wherein a first rule of a fourth migration policy of the plurality of migration policies specifies to migrate a fourth count of virtual machines to migrate upon determining use of the first system resource exceeds a third threshold, wherein the each of the plurality of migration policies specifies to migrate a different count of virtual machines; determining, based on the numeric scores, that the subset of virtual machines have the lowest use of the plurality of system resources; outputting each of the plurality of migration policies; receiving a selection of the first migration policy; storing an indication to migrate virtual machines in the cloud computing environment based on the first migration policy; and migrating: (i) the first virtual machine to a second host system in the cloud computing environment, and (ii) the second virtual machine and each remaining virtual machine in the subset from the first host system, to reduce the use of the first and second system resources on the first host system.