1. A virtual machine migration management method, wherein the method comprises: calculating a migration duration time required for migrating a to-be-migrated virtual machine from a source computing node to a destination computing node according to an allocated memory size, a memory change rate, or a migration network bandwidth of the to-be-migrated virtual machine; separately acquiring a current available migration duration time of the source computing node and a current available migration duration time of the destination computing node; comparing the current available migration duration time of the source computing node and the current available migration duration time of the destination computing node to the migration duration time; migrating the to-be-migrated virtual machine from the source computing node to the destination computing node if both the current available migration duration time of the source computing node and the current available migration duration time of the destination computing node are greater than the migration duration time; and subtracting the migration duration time from the current available migration duration time of the source computing node, and subtracting the migration duration time from the current available migration duration time of the destination computing node, wherein the calculating, according to the allocated memory size, the memory change rate, or the migration network bandwidth of the to-be-migrated virtual machine, migration duration time required for migrating the to-be-migrated virtual machine from a source computing node to a destination computing node comprises: calculating migration duration time MTV ij =a 0 (1−q n )/(1−q) required for migrating the to-be-migrated virtual machine from a source computing node i to a destination computing node j, and the number of transfer times n=min{N 0 ,N} , wherein a o =((MV ij ×CV ij )/BWV ij ), q=MCRV ij ×((MV ij ×CV ij )/BWV ij ) <1, MV ij , is the allocated memory size of the to-be-migrated virtual machine, MCRV ij is the memory change rate of the to-be-migrated virtual machine, BWV ij is the migration network bandwidth allocated to the to-be-migrated virtual machine, N 0 is a preset maximum number of transfer times, N is a minimum integer value meeting a condition in which a 0 ×q N−1 is less than a preset memory dirty page threshold, and CV ij is a memory compression ratio of the to-be-migrated virtual machine.