.. This work is licensed under a Creative Commons Attribution 3.0 Unported License. https://creativecommons.org/licenses/by/3.0/legalcode ================== Container Snapshot ================== Related Launchpad Blueprint: https://blueprints.launchpad.net/zun/+spec/container-snapshot Zun needs to snapshot a running container, and make it available to user. Potentially, a user can restore the container from this snapshot image. Problem description =================== It is a common requirement from users of containers to save the changes of a current running container to a new image. Zun currently does not support taking a snapshot of a container. Proposed change =============== 1. Introduce a new CLI command to enable a user to take a snapshot of a running container instance. zun commit # zun help commit usage: zun commit Create a new image by taking a snapshot of a running container. Positional arguments: Name or ID of container. Name of snapshot. 2. Extend docker driver to enable “docker commit” command to create a new image. 3. The new image should be accessable from other hosts. There are two options to support this: a) upload the image to glance b) upload the image to docker hub Option a) will be implemented as default; future enhancement can be done to support option b). Design Principles ================= Similar user experience between VMs and containers. In particular, the ways to snapshot a container should be similar as the VM equivalent. Alternatives ============ 1. Using linked volumes to persistent changes in a container. 2. Use docker cp to copy data from the container onto the host machine. Data model impact ================= None REST API impact =============== Creates an image from a container. Specify the image name in the request body. After making this request, a user typically must keep polling the status of the created image from glance to determine whether the request succeeded. If the operation succeeds, the created image has a status of active. User can also see the new image in the image back end that OpenStack Image service manages. Preconditions: 1. The container must exist. 2. User can only create a new image from the container when its status is Running, Stopped, and Paused. 3. The connection to the Image service is valid. POST /containers//commit: commit a container Example commit { "image-name" : "foo-image" } Response: If successful, this method does not return content in the response body. Normal response codes: 202 Error response codes: badRequest(400), unauthorized(401), forbidden(403), itemNotFound(404) Security impact =============== None Notifications impact ==================== None Other end user impact ===================== None Performance Impact ================== None Other deployer impact ===================== None Developer impact ================ None Implementation ============== Assignee(s) Primary assignee: Bin Zhou Other contributors: Work Items 1. Expend docker driver to enable “docker commit”. 2. Upload the generated image to glance. 3. Implement a new API endpoint for createImage. 4. Implement unit/integration test. Dependencies ============ None Testing ======= Each patch will have unit tests, and Tempest functional tests covered. Documentation Impact ==================== A set of documentation for this new feature will be required.