- Fix erros when run tox -edocs (except one spec - cinder-integration.rst, will be fixed when merge patch set [1]) - Update urls. [1] https://review.openstack.org/#/c/468658/ Change-Id: I05865708ef356f17a388eace234ac004dd1a364f
3.6 KiB
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
Introduce a new CLI command to enable a user to take a snapshot of a running container instance:
$ zun commit <container-name> <image-name> $ zun help commit usage: zun commit <container-name> <image-name> Create a new image by taking a snapshot of a running container. Positional arguments: <container-name> Name or ID of container. <image-name> Name of snapshot.
Extend docker driver to enable “docker commit” command to create a new image.
The new image should be accessable from other hosts. There are two options to support this:
- 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
- Using linked volumes to persistent changes in a container.
- 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:
- The container must exist.
- User can only create a new image from the container when its status is Running, Stopped, and Paused.
- The connection to the Image service is valid.
POST /containers/<ID>/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.