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Snapshotting is a feature based on checkpointing and ploop shapshots. It allows to save a complete state of container file system. Plus, if the container is running, it’s in-memory state (as in checkpointing). Note that snapshot functionality is only working for containers on ploop device.
snapshot CTID [--id uuid] [--name name] [--description desc]
Creates a container snapshot, i.e. saves the current container state, including its file system state, running processes state, and configuration file.
If a container is running, and
--skip-suspend option is not specified, a container is checkpointed and then restored, and CT memory dump becomes the part of snapshot.
--skip-config option is given, container configuration file is saved to the snapshot.
If uuid is not specified, it is auto-generated. Options
--description can be used to specify the snapshot name and description, respectively. Name is displayed by
snapshot-switch CTID [--skip-resume | --must-resume] [--skip-config] --id uuid
Switches the container to a snapshot identified by uuid, restoring its file system state, configuration (if available) and its running state (if available).
Note that the current state of a container (including its file system state and its configuration file) is lost!
--skip-resume is used to ignore a CT memory dump file in a snapshot, as a result the container will end up being in a stopped state (same as if a snapshot has been taken with
--must-resume is set, absense of a memory dump is treated as an error, and the inability to restore from the memory dump is treated as an error rather than warning.
--skip-config is used to ignore the CT configuration file in a snapshot, i.e. the current configuration file will be left as is.
snapshot-delete CTID --id uuid
Removes a specified snapshot.
snapshot-mount CTID --id uuid --target directory
Mounts a snapshot specified by uuid to a directory. Note this mount is read-only.
snapshot-umount CTID --id uuid
Unmounts a specified snapshot.
snapshot-list CTID [-H] [-o field[,field...] [--id uuid]
List container’s snapshots.
You can suppress displaying header using -H option.
You can use the -o option to display only the specified field(s). List of available fields can be obtained using -L option.