On Tue, Apr 6, 2021 at 1:04 AM Amnon Ilan ailan@redhat.com wrote:
On Tue, Mar 30, 2021 at 2:50 AM Eric Ernst eric.g.ernst@gmail.com wrote:
Ya'll,
I'd like to see if we can create a pattern in upstream Kata Containers to help facilitate directly assigning volumes to the VM via virtio-blk, skipping any mounts on the host, and avoiding needing to use a shared file-system for the particular volume. Some of the benefits in doing this:
- we can better isolate the host (no mounted filesystem),
- more efficient and much faster data path that non-dax virtiofs.
- avoid inode caching/memory overheads of virtiofs on the host.
In Kubernetes today, there is not a direct communication channel between CSI and the runtime. To make this work on a shorter timeline, therefore, we need to come up with a less traditional way to communicate between the user, CSI and the runtime. I have a proposal in place that "works" today, and I'd like to get feedback on how to improve it, and see if it could be a good fit for upstream. Please see: the proposal at [1], and the PR associated with that proposal at [2].
I'm not an expert here, but why not use raw block rather than adding the annotation skip-hostmount https://kubernetes.io/blog/2019/03/07/raw-block-volume-support-to-beta/
+Orit Wasserman owasserm@redhat.com
Hey Amnon,
Raw block is supported well in Kata today (it just works); the problem is that the workload/user would then need to utilize a raw block, when in most cases, they want a mounted filesystem to interact with.
The direct-assignment work's goal is to provide a mounted filesystem to the container workload.
Eric
Thanks, Amnon
Please let me know if you:
- have any suggestions on the pattern
- you are a user that would find this pattern helpful for their
use-cases
Thanks, Eric
[1] - https://github.com/egernst/kata-containers/blob/da-proposal/docs/design/dire... [2] - https://github.com/kata-containers/kata-containers/pull/1568
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