1. A computer implemented method for determining resources allocation for fulfilling service level agreements (SLA) to a service consumer, the method comprising: identifying resources in a distributed computing environment over a network, wherein each of the resources is capable of performing at least a part of an assigned task; computing an optimal resources configuration of the identified resources using each of a set of pre-determined parameters including, at least a target completion time interval in which to complete the assigned task, provisioning parameters based on a plurality of properties of the resources in the distributed computing environment, configuration parameters based on quantification and computations related to the network for a plurality of sample transactions between the distributed computing environment and a plurality of pre-defined quanta of assigned tasks from a service consumer, and service parameters, wherein the service parameters include at least one of a number of records to be processed and an amount of data to be processed, and wherein the SLA is a layer between the distributed computing environment and the service consumer; selecting a time interval from at least one of a manually defined time interval and a pre-determined time interval; and determining, at the selected time interval, if there is at least one change in at least one of the service parameters, the provisioning parameters and the configuration parameters; and if the at least one change occurs: identifying a changed parameter corresponding to the at least one change, wherein the changed parameter corresponds with one of the service parameters, the provisioning parameters and the configuration parameters; and acquiring a preset threshold range for the changed parameter; if the at least one change is greater than the preset threshold range of the changed parameter: modifying the optimal resources configuration in response to the at least one change; modifying at least one of a computed optimal completion time interval required for completion of the assigned task and a computed optimal cost, wherein the modification is performed using a modified optimal resources configuration; and performing the assigned task execution utilizing the modified optimal resources configuration.