edge-hub is a node-level proxy that runs on each node in an ACK Edge cluster. It sits between edge-side components (kubelet, kube-proxy, Flannel, and CoreDNS) and kube-apiserver in the cloud, enabling edge nodes to function reliably even when the cloud connection is unstable or lost.
In edge-hub 0.12.0 and later, the deployment form depends on where it runs: a systemd service in edge node pools, and a DaemonSet named cloud-hub in cloud node pools.
How it works
Native Kubernetes assumes stable network connectivity between nodes and kube-apiserver. In edge computing environments, this assumption breaks — cloud-edge links are often unreliable, and pods on edge nodes can fail to start or lose access to cluster services during disconnections.
edge-hub addresses these problems through four capabilities:
Data caching: Native Kubernetes pods cannot retrieve resources from kube-apiserver when the cloud connection drops, causing restarts to fail. edge-hub caches data received from the cloud locally on each edge node, so pods restart against cached data instead of failing.
kube-apiserver access: In cloud-edge topologies, pods cannot reach kube-apiserver directly through inClusterConfig because the cloud network is not accessible from the edge. edge-hub acts as a local proxy, allowing pods to use inClusterConfig without any pod-level changes.
Service topology-based routing: Without topology awareness, Services can route traffic to backend pods in remote node pools, causing high-latency or failed connections at the edge. edge-hub filters EndpointSlices to generate a service topology, so Services route traffic only to backend pods in the same node pool.
Automatic image registry selection: edge-hub switches between private and public image registries automatically. When nodes connect through Express Connect circuits, private registries are used; when nodes have direct internet access, public registries are used.
Deployment modes
edge-hub runs differently depending on the node pool type:
| Deployment context | Form | Name |
|---|---|---|
| Edge node pool | systemd service (static pod in versions before 0.12.0) | edge-hub |
| Cloud node pool | DaemonSet | cloud-hub |
Usage notes
For configuration procedures, see:
Release notes
December 2024
v0.12.3 — released 2024-12-19 — no impact on workloads
Supports ACK Edge clusters running 1.26.3-aliyun.1, 1.28.9-aliyun.1, and 1.30.7-aliyun.1.
Adds support for the local caching feature in terway-edge.
Image: registry.cn-hangzhou.aliyuncs.com/acs/edge-hub:v0.12.3
November 2023
v0.12.0 — released 2023-11-28 — no impact on workloads
Supports ACK Edge clusters running 1.26.3-aliyun.1.
Changes the deployment mode: edge-hub now runs as a systemd service in edge node pools, and as a DaemonSet named cloud-hub in cloud node pools.
Image: registry.cn-hangzhou.aliyuncs.com/acs/edge-hub:v0.12.0
August 2023
v0.11.0 — released 2023-08-03 — no impact on workloads
Supports ACK Edge clusters running 1.24.6-aliyunedge.1.
Image: registry.cn-hangzhou.aliyuncs.com/acs/edge-hub:v0.11.0
December 2022
v0.10.3 — released 2022-12-07 — no impact on workloads
Supports ACK Edge clusters running 1.22-aliyunedge.1.
Image: registry.cn-hangzhou.aliyuncs.com/acs/edge-hub:v0.10.3
January 2022
v0.10.0 — released 2022-01-27 — no impact on workloads
First release supporting ACK Edge clusters running 1.20.11-aliyunedge.1.
Health checks: Fixes an issue where edge-hub continued sending heartbeats after kubelet stopped.
Node certificate management: When a node certificate is not deleted after a node disconnects, edge-hub now automatically updates the certificate when the node joins another cluster.
Traffic statistics: View traffic statistics for edge node requests at
http://127.0.0.1:10267/metrics.Stability: Fixes a data race that occurred when edge nodes processed large numbers of concurrent requests.
Image: registry.cn-hangzhou.aliyuncs.com/acs/edge-hub:v0.10.0
November 2021
v0.9.5 — released 2021-11-15 — no impact on workloads
Fixes an issue where edge requests without an Accept header were rejected.
Image: registry.cn-hangzhou.aliyuncs.com/acs/edge-hub:v0.9.5
v0.9.4 — released 2021-11-01 — no impact on workloads
Fixes inconsistent key usages in HTTPS server certificates across programming languages.
Image: registry.cn-hangzhou.aliyuncs.com/acs/edge-hub:v0.9.4
October 2021
v0.9.3 — released 2021-10-27 — no impact on workloads
Fixes truncation of large-sized data in data filters.
Filtering can now be disabled for requests from LoadBalancer Services.
Image: registry.cn-hangzhou.aliyuncs.com/acs/edge-hub:v0.9.3
v0.9.2 — released 2021-10-12 — no impact on existing workloads; to use new features on existing workloads, recreate the pods
Adds HTTPS server support on port 10268.
Adds the data filtering framework for edge nodes.
Image: registry.cn-hangzhou.aliyuncs.com/acs/edge-hub:v0.9.2
September 2021
v0.9.1 — released 2021-09-23 — no impact on workloads
Adds support for edge nodes running Windows.
Image: registry.cn-hangzhou.aliyuncs.com/acs/edge-hub:v0.9.1
July 2021
v0.9.0 — released 2021-07-12 — no impact on workloads
First release for ACK Edge clusters running 1.18.8-aliyunedge.1.
Image: registry.cn-hangzhou.aliyuncs.com/acs/edge-hub:v0.9.0