Nydus
Get faster pull times with Nydus on CoreWeave
Note
Nydus on CoreWeave Cloud is currently in alpha with limited availability. In order to make use of Nydus, Workloads must be scheduled onto Nydus-enabled nodes using anti-affinity.
Embedding machine learning models directly into images has become a popular ease-of-use technique, but it has made image pull times slower due to the increased size of container images. As a result, pulling images is often the most time-consuming aspect of spinning up new containers, and for those who rely on fast autoscaling to respond to changes in demand, the time it takes to create new containers can pose as a major hurdle.
It's for this reason that CoreWeave Cloud supports Nydus, for dramatically shorter container image pull times.
Nydus is an external plugin for containerd leveraging the Nydus container image service, which implements a content-addressable filesystem on top of a RAFS format for container images. This formatting allows for major improvements to the current OCI image specification in terms of container launching speed, image space, network bandwidth efficiency, and data integrity.
- a method called "lazy pulling," container images are downloaded on-demand in "chunks," which significantly boosts container startup times,
- content-addressable data deduplication, which minimizes storage, transmission, and memory footprints,
- a merged filesystem tree, which allows all intermediate layers to be removed,
- compatibility with the OCI artifacts and distribution specs, so Nydus images may be stored in any regular container registry
For clients who would like to bake machine learning models directly into their images, or who otherwise have very large container images, Nydus provides a solution that significantly shortens pull times of hefty container images.
Additional Resources
Nydus configures the container runtime (containerd), to inspect the given container image at runtime. If Nydus recognizes the image as a Nydus-formatted image, then it will pull it using the Nydus image service.
Nydus is also backwards-compatible - if Nydus recognizes that the image being pulled is a standard OCI image, then it will pull it normally; just as a normal configuration of the containerd runtime would.
To use Nydus on CoreWeave Cloud, it is not required to change the Kubernetes manifests, but the base images must be reformatted to the Nydus format.
To convert the images to Nydus format, use the Nydusify conversion tool. Converting base images is as easy as either targeting an OCI image in a repository:
nydusify convert \
--source myregistry/repo:tag \
--target myregistry/repo:tag-nydus
Or, a local dictionary may be packed as a Nydus-formatted image:
nydusify pack \
--bootstrap target.bootstrap \
--target-dir /path/to/target \
--output-dir /path/to/output
Important
At this time, using Nydus images on CoreWeave requires that:
- base images are converted manually using Nydusify
- images must be stored in a public repository
Nydus is only available on some nodes on CoreWeave Cloud. To use Nydus, Workloads must be scheduled on Nydus-enabled nodes using a Kubernetes anti-affinity that explicitly prevents Workloads from being scheduled onto nodes running Cloud version
1.20.0, 1.19.1, or 1.18.0: affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: node.coreweave.cloud/version
operator: NotIn
values:
- 1.20.0
- 1.19.1
- 1.18.0
A more complete example of this same manifest might look like:
kind: Pod
apiVersion: v1
metadata:
name: nydus-image
spec:
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: node.coreweave.cloud/version
operator: NotIn
values:
- 1.20.0
- 1.19.1
- 1.18.0
containers:
- name: nydus-image
image: {registry}:{tag}
ports:
- containerPort: 80
Last modified 19d ago