Abstract: Container migration is provided. A comparison of a second image and a third image is performed to detect data changes made by write input/output operations occurring between a second timestamp and a third timestamp. It is determined whether a set of data changes exists in the third image that occurred between the second timestamp and the third timestamp. In response to determining that the set of data changes does exist in the third image that occurred between the second timestamp and the third timestamp, a copy of the set of data changes is sent to a second host node. The set of data changes are merged into the second host node. The write input/output operations are resumed to the second host node using previously queued write input/output operations and new incoming write input/output operations so that the second host node is processing read input/output operations and the write input/output operations.

Abstract: VM file management includes detecting a user request to access to a virtual machine (VM) and searching a pre-defined list to determine whether the user requesting access is identified on the list. If so, a file-level snapshot is generated prior to enabling modification of a VM file by the user. The file-level snapshot includes a user attribute and is added as the top layer of a stack. The user attribute indicates a role of the user for whom the file-level snapshot is created. Each layer of the stack contains one or more other file-level snapshots. The VM file is written in the file's entirety to the snapshot in response to the user modifying the VM file. Based on the user attribute of each snapshot, a set of snapshots is selected from the stack, and the VM is modified by merging the VM files belonging to the set of snapshots selected.

Abstract: A computer implemented method manages an image. A number of processor units identifies a set of base files in a set of image layers for a candidate file in a container layer in response to a request to create a new image with the candidate file. The number of processor units identifies delta data between the candidate file and the set of base files. The number of processor units creates the new image with a new top image layer using the delta data identified for the candidate file in the container layer. According to other illustrative embodiments, a computer system, and a computer program product for managing an image are provided. As a result, the illustrative embodiments provide a technical effect of reducing the size of images and reducing storage space used to store the images.

Abstract: VM file management includes detecting a user request to access to a virtual machine (VM) and searching a pre-defined list to determine whether the user requesting access is identified on the list. If so, a file-level snapshot is generated prior to enabling modification of a VM file by the user. The file-level snapshot includes a user attribute and is added as the top layer of a stack. The user attribute indicates a role of the user for whom the file-level snapshot is created. Each layer of the stack contains one or more other file-level snapshots. The VM file is written in the file's entirety to the snapshot in response to the user modifying the VM file. Based on the user attribute of each snapshot, a set of snapshots is selected from the stack, and the VM is modified by merging the VM files belonging to the set of snapshots selected.