Efficient container migration

A computer system for container migration, the computer system comprising:

• a communication fabric;
• a set of computer-readable storage media connected to the communication fabric, wherein the set of computer-readable storage media collectively stores program instructions;
• and
• a set of processors connected to the communication fabric, wherein the set of processors executes the program instructions to:
• perform a comparison of a first new read only layer of a second container image and a second new read only layer of a third container image to detect any data changes made by write input/output operations corresponding to a service occurring between a second timestamp when the write input/output operations were resumed to a first container on a first host node and a third timestamp when the write input/output operations of the first container were queued to operating system memory for a second time;
• determine whether a set of data changes exists in the second new read only layer of the third container image that occurred between the second timestamp and the third timestamp based on the comparison;
• send a copy of the set of data changes to a second host node in response to determining that the set of data changes does exist in the second new read only layer of the third container image that occurred between the second timestamp and the third timestamp based on the comparison;
• merge the set of data changes into a read/write layer of the second container corresponding to the service running on the second host node;
• and
• resume the write input/output operations to the second container running on the second host node at a fourth timestamp using previously queued write input/output operations corresponding to the second container and new incoming write input/output operations to the second container so that the second container is processing read input/output operations and the write input/output operations corresponding to the service.

A computer program product for container migration, the computer program product comprising a set of computer-readable storage media having program instructions collectively stored therein, the program instructions executable by a computer to cause the computer to:

• perform a comparison of a first new read only layer of a second container image and a second new read only layer of a third container image to detect any data changes made by write input/output operations corresponding to a service occurring between a second timestamp when the write input/output operations were resumed to a first container on a first host node and a third timestamp when the write input/output operations of the first container were queued to operating system memory for a second time;
• determine whether a set of data changes exists in the second new read only layer of the third container image that occurred between the second timestamp and the third timestamp based on the comparison;
• send a copy of the set of data changes to a second host node in response to determining that the set of data changes does exist in the second new read only layer of the third container image that occurred between the second timestamp and the third timestamp based on the comparison;
• merge the set of data changes into a read/write layer of the second container corresponding to the service running on the second host node;
• and
• resume the write input/output operations to the second container running on the second host node at a fourth timestamp using previously queued write input/output operations corresponding to the second container and new incoming write input/output operations to the second container so that the second container is processing read input/output operations and the write input/output operations corresponding to the service.