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· 阅读需 3 分钟

KubeEdge v1.17 is now available! This latest release introduces several new features and enhancements, including support for edge pods using InClusterConfig to access the Kubernetes API server, video streaming data reporting in Mappers, auto-restarting for EdgeCore modules, and more.

1.17 What's New

Release Highlights

Support Edge Pods Using InClusterConfig to Access Kube-APIServer

The InClusterConfig mechanism enables cloud pods to directly access the Kubernetes API server. With this release, KubeEdge now supports edge pods using the InClusterConfig mechanism to access the Kube-APIServer directly, even when the edge and cloud are in different network environments.

Refer to the link for more details. (#5524, #5541)

Mapper Supports Video Streaming Data Reporting

Previously, Mappers could only process structured device data. In v1.17, video stream data processing features have been added to the Mapper-Framework.

  • Edge Camera Device Management

    v1.17 provides a built-in Mapper based on the Onvif protocol, which can manage Onvif network camera devices into the KubeEdge cluster and obtain the camera's authentication file and RTSP video stream.

  • Video Stream Data Processing

    Video stream data processing capabilities have been introduced to the Mapper-Framework data plane. The video stream reported by edge camera devices can be saved as frame files or video files.

Refer to the link for more details. (#5448, #5514, mappers-go/#127)

Support Auto-Restarting for Edge Modules

EdgeCore modules could previously fail to start due to non-configurable and recoverable matters like process start order issues. In v1.17, the BeeHive framework has been improved to support automatically restarting modules. Users can now configure EdgeCore modules to automatically restart instead of restarting the entire component.

Refer to the link for more details. (#5509, #5513)

Introduce keadm ctl Command to Support Pods Query and Restart at Edge

The new keadm ctl command has been introduced in v1.17, allowing users to query and restart pods on edge nodes when they are offline:

  • Query: keadm ctl get pod [flags]
  • Restart: keadm ctl restart pod [flags]

Refer to the link for more details. (#5504)

Keadm Enhancements

Several enhancements were made to the keadm installation tool:

  • Refactored the keadm init command
  • Changed the command keadm generate to keadm manifest
  • Added image-repository flag to keadm join to support customization
  • Split the keadm reset command into keadm reset cloud and keadm reset edge.

Refer to the link for more details. (#5317)

Add MySQL to Mapper Framework

The Mapper Framework data plane now includes MySQL database support in its pushMethod. When using MySQL, basic configuration parameters for the MySQL client need to be added in the DeviceInstance.

Refer to the link for more details. (#5376)

Upgrade Kubernetes Dependency to v1.28.6

The vendored Kubernetes version has been upgraded to v1.28.6, users are now able to use the latest features on both the cloud and edge side.

Refer to the link for more details. (#5412)

Important Steps before Upgrading

  • To use the InClusterConfig feature for edge pods, you need to enable the metaServer and dynamicController switches, and set featureGates.requireAuthorization=true in the CloudCore and EdgeCore configuration files.

  • To use the Auto-Restarting for Edge Modules feature, you must enable the moduleRestart feature gate in EdgeCore.

Download the v1.17.0 release from the release page and upgrade today to take advantage of these new capabilities!

· 阅读需 3 分钟

On July 1, 2023, KubeEdge released v1.14. The new version introduces several enhanced features, significantly improving security, reliability, and user experience.

v1.14 What's New

Release Highlights

Support Authentication and Authorization for Kube-API Endpoint for Applications On Edge Nodes

The Kube-API endpoint for edge applications is implemented through MetaServer in edegcore. However, in previous versions, the authentication and authorization of Kube-API endpoint are performed in the cloud, which prevents authentication and authorization especially in offline scenarios on the edge node.

In this release, the authentication and authorization functionalities are implemented within the MetaServer at edge, which allows for limiting the access permissions of edge applications when accessing Kube-API endpoint at edge.

Refer to the link for more details. (#4802)

Support Cluster Scope Resource Reliable Delivery to Edge Node

The cluster scope resource can guarantee deliver to the edge side reliably since this release, especially include using list-watch global resources, the cluster scope resource can be delivered to the edge side reliably, and the edge applications can work normally.

Refer to the link for more details. (#4758)

Upgrade Kubernetes Dependency to v1.24.14

Upgrade the vendered kubernetes version to v1.24.14, users are now able to use the feature of new version on the cloud and on the edge side.

备注

The dockershim has been removed, which means users can't use docker runtime directly in this release.

Refer to the link for more details. (#4789)

Support Kubectl Attach to Container Running on Edge Node

KubeEdge already support kubectl logs/exe command, kubectl attach is supported in this release. kubectl attach command can attach to a running container at edge node. Users can execute these commands in the cloud and no need to operate on the edge nodes.

Refer to the link for more details. (#4734)

Alpha version of KubeEdge Dashboard

KubeEdge dashboard provides a graphical user interface (GUI) for managing and monitoring your KubeEdge clusters. It allows users to manage edge applications running in the cluster and troubleshoot them.

Refer to the link for more details. (https://github.com/kubeedge/dashboard)

Important Steps before Upgrading

  • On KubeEdge v1.14, EdgeCore has removed the dockeshim support, so users can only use remote type runtime, and uses containerd runtime by default. If you want to use docker runtime, you must first set edged.containerRuntime=remote and corresponding docker configuration like RemoteRuntimeEndpoint and RemoteImageEndpoint in EdgeCore, then install the cri-dockerd tools as docs below: https://github.com/kubeedge/kubeedge/issues/4843

· 阅读需 3 分钟

On Jan 18, 2023, KubeEdge released v1.13. The new version introduces several enhanced features, significantly improving performance, security, and edge device management.

v1.13 What's New

Performance Improvement

  • CloudCore memory usage is reduced by 40%, through unified generic Informer and reduce unnecessary cache. (#4375, #4377)

  • List-watch dynamicController processing optimization, each watcher has a separate channel and goroutine processing to improve processing efficiency (#4506)

  • Added list-watch synchronization mechanism between cloud and edge and add dynamicController watch gc mechanism (#4484)

  • Removed 10s hard delay when offline nodes turn online (#4490)

  • Added prometheus monitor server and a metric connected_nodes to cloudHub. This metric tallies the number of connected nodes each cloudhub instance (#3646)

  • Added pprof for visualization and analysis of profiling data (#3646)

  • CloudCore configuration is now automatically adjusted according to nodeLimit to adapt to the number of nodes of different scales (#4376)

Security Improvement

  • KubeEdge is proud to announce that we are digitally signing all release artifacts (including binary artifacts and container images). Signing artifacts provides end users a chance to verify the integrity of the downloaded resource. It allows to mitigate man-in-the-middle attacks directly on the client side and therefore ensures the trustfulness of the remote serving the artifacts. By doing this, we reached the SLSA security assessment level L3 (#4285)

  • Remove the token field in the edge node configuration file edgecore.yaml to eliminate the risk of edge information leakage (#4488)

Upgrade Kubernetes Dependency to v1.23.15

Upgrade the vendered kubernetes version to v1.23.15, users are now able to use the feature of new version on the cloud and on the edge side.

Refer to the link for more details. (#4509)

Modbus Mapper based on DMI

Modbus Device Mapper based on DMI is provided, which is used to access Modbus protocol devices and uses DMI to synchronize the management plane messages of devices with edgecore.

Refer to the link for more details. (mappers-go#79)

Support Rolling Upgrade for Edge Nodes from Cloud

Users now able to trigger rolling upgrade for edge nodes from cloud, and specify number of concurrent upgrade nodes with nodeupgradejob.spec.concurrency. The default Concurrency value is 1, which means upgrade edge nodes one by one.

Refer to the link for more details. (#4476)

Test Runner for conformance test

KubeEdge has provided the runner of the conformance test, which contains the scripts and related files of the conformance test.

Refer to the link for more details. (#4411)

EdgeMesh: Added configurable field TunnelLimitConfig to edge-tunnel module

The tunnel stream of the edge-tunnel module is used to manage the data stream state of the tunnel. Users can obtain a stable and configurable tunnel stream to ensure the reliability of user application traffic forwarding.

Users can configure the cache size of tunnel stream according to TunnelLimitConfig to support larger application relay traffic.

Refer to the link for more details. (#399)

Cancel the restrictions on the relay to ensure the stability of the user's streaming application or long link application.

Refer to the link for more details. (#400)

Important Steps before Upgrading

  • EdgeCore now uses containerd runtime by default on KubeEdge v1.13. If you want to use docker runtime, you must set edged.containerRuntime=docker and corresponding docker configuration like DockerEndpoint, RemoteRuntimeEndpoint and RemoteImageEndpoint in EdgeCore.

· 阅读需 3 分钟

The KubeEdge community is thrilled to announce the release of KubeEdge v1.12! This release introduces several exciting new features and enhancements, including alpha implementation of the next-generation Cloud Native Device Management Interface (DMI), a new version of the lightweight Edged engine, high-availability mode for EdgeMesh, edge node upgrades from the cloud, authorization for the Edge Kube-API endpoint, and more.

What's New in KubeEdge v1.12

Alpha Implementation of Next-Gen Cloud Native Device Management Interface (DMI)

DMI makes KubeEdge's IoT device management more pluggable and modular in a cloud-native way, covering Device Lifecycle Management, Device Operation, and Device Data Management.

  • Device Lifecycle Management: Simplifies IoT device lifecycle management, making it as easy as managing a pod.

  • Device Operation: Provides the ability to operate devices through the Kubernetes API.

  • Device Data Management: Separates device data management from device management, allowing data to be consumed by local applications or synchronized to the cloud through a special tunnel.

Next-Gen Edged Graduates to GA: Suitable for More Scenarios

The new version of the lightweight Edged engine, optimized from Kubelet and integrated into EdgeCore, has graduated to General Availability (GA) in this release. The new Edged will continue to communicate with the cloud through a reliable transmission tunnel, making it suitable for a wider range of scenarios.

Introducing High-Availability Mode for EdgeMesh

KubeEdge v1.12 introduces a high-availability mode for EdgeMesh. Unlike the previous centralized relay mode, the EdgeMesh HA mode can set up multiple relay nodes. When some relay nodes fail, other relay nodes can continue to provide relay services, avoiding single points of failure and improving system stability.

Support Edge Node Upgrade from the Cloud

KubeEdge v1.12 introduces the NodeUpgradeJob v1alpha1 API to upgrade edge nodes from the cloud. With this API and its associated controller, users can upgrade selected edge nodes from the cloud and roll back to the original version if the upgrade fails.

Support Authorization for Edge Kube-API Endpoint

Authorization for the Edge Kube-API Endpoint is now available in KubeEdge v1.12. Third-party plugins and applications that depend on Kubernetes APIs on edge nodes must use a bearer token to communicate with the kube-apiserver via the HTTPS server in MetaServer.

New GigE Mapper

KubeEdge v1.12 includes a new GigE Device Mapper with a Golang implementation, which is used to access GigE Vision protocol cameras.

Important Steps Before Upgrading

  • If you want to upgrade KubeEdge to v1.12, the configuration file in EdgeCore has been upgraded to v1alpha2. You must modify your configuration file for Edged in EdgeCore to adapt to the new Edged.

  • If you want to use authorization for the Edge Kube-API Endpoint, please enable the RequireAuthorization feature through the feature gate in both CloudCore and EdgeCore. If the RequireAuthorization feature is enabled, MetaServer will only serve HTTPS requests.

  • If you want to upgrade EdgeMesh to v1.12, you do not need to deploy the existing EdgeMesh-server, but you need to configure relayNodes.

  • If you want to run EdgeMesh v1.12 on KubeEdge v1.12 and use HTTPS requests to communicate with KubeEdge, you must set kubeAPIConfig.metaServer.security.enable=true.

KubeEdge v1.12 brings exciting new features and improvements to the edge computing ecosystem. We invite you to explore the release and provide feedback to the community. Happy edge computing!

· 阅读需 13 分钟
Wack Xu

Abstract

The population of KubeEdge brings in community interests in the scalability and scale of KubeEdge. Now, Kubernetes clusters powered by KubeEdge, as fully tested, can stably support 100,000 concurrent edge nodes and manage more than one million pods. This report introduces the metrics used in the test, the test procedure, and the method to connect to an ocean of edge nodes.

Background

Fast growing technologies, such as 5G networks, industrial Internet, and AI, are giving edge computing an important role in driving digital transformation. Cities, transportation, healthcare, manufacturing, and many other fields are becoming smart thanks to edge computing. According to Gartner, by 2023, the number of intelligent edge devices may be more than 20 times that of traditional IT devices. By 2028, the embedding of sensors, storage, computing, and advanced AI functions in edge devices will grow steadily. IoT devices are of various types and in large quantities. The increasing connected IoT devices are challenging management and O&M.

At the same time, users in the KubeEdge community are expecting large-scale edge deployment. There are already some successful use cases for KubeEdge. In unmanned toll stations across China, there are nearly 100,000 edge nodes and more than 500,000 edge applications in this project, and the numbers keep growing. Another case is a vehicle-cloud collaboration platform, the industry-first cloud-edge-device system. It enables fast software upgrade and iteration for software-defined vehicles. On this platform, each vehicle is connected as an edge node, and the number of edge nodes will reach millions.

Introduction to KubeEdge

KubeEdge is the industry's first cloud native edge computing framework designed for edge-cloud collaboration. Complementing Kubernetes for container orchestration and scheduling, KubeEdge allows applications, resources, data, and devices to collaborate between edges and the cloud. Devices, edges, and the cloud are now fully connected in edge computing.

In the KubeEdge architecture, the cloud is a unified control plane, which includes native Kubernetes management components and KubeEdge-developed CloudCore components. It listens to cloud resource changes and provides reliable, efficient cloud-edge messaging. At the edge side lie the EdgeCore components, including Edged, MetaManager, and EdgeHub. They receive messages from the cloud and manage the lifecycle of containers. The device mapper and event bus are responsible for device access.

kubeedge-arch

Based on the Kubernetes control plane, KubeEdge allows nodes to be deployed more remotely and thereby extends edge-cloud collaboration. Kubernetes supports 5,000 nodes and 150,000 pods, which are far from enough for edge computing in Internet of Everything (IoE). The access of a large number of edge devices demands a scalable, centralized edge computing platform. To help users cost less and manage more in an easier way, KubeEdge, fully compatible with Kubernetes, optimizes the cloud-edge messaging and provides access support for mass edge nodes.

SLIs/SLOs

Scalability and performance are important features of Kubernetes clusters. Before performing the large-scale performance test, we need to define the measurement metrics. The Kubernetes community defines the following SLIs (Service Level Indicators) and SLOs (Service Level Objectives) to measure the cluster service quality.

  1. API Call Latency
StatusSLISLO
OfficialLatency of mutating API calls for single objects for every (resource, verb) pair, measured as 99th percentile over last 5 minutesIn default Kubernetes installation, for every (resource, verb) pair, excluding virtual and aggregated resources and Custom Resource Definitions, 99th percentile per cluster-day <= 1s
OfficialLatency of non-streaming read-only API calls for every (resource, scope) pair, measured as 99th percentile over last 5 minutesIn default Kubernetes installation, for every (resource, scope) pair, excluding virtual and aggregated resources and Custom Resource Definitions, 99th percentile per cluster-day: (a) <= 1s if scope=resource (b) <= 30s5 otherwise (if scope=namespace or scope=cluster)
  1. Pod Startup Latency
StatusSLISLO
OfficialStartup latency of schedulable stateless pods, excluding time to pull images and run init containers, measured from pod creation timestamp to when all its containers are reported as started and observed via watch, measured as 99th percentile over last 5 minutesIn default Kubernetes installation, 99th percentile per cluster-day <= 5s
WIPStartup latency of schedulable stateful pods, excluding time to pull images, run init containers, provision volumes (in delayed binding mode) and unmount/detach volumes (from previous pod if needed), measured from pod creation timestamp to when all its containers are reported as started and observed via watch, measured as 99th percentile over last 5 minutesTBD

The community also defines indicators such as in-cluster network programming latency (latency for Service updates or changes in ready pods to be reflected to iptables/IPVS rules), in-cluster network latency, DNS programming latency (latency for Service updates or changes in ready pods to be reflected to the DNS server), and DNS latency. These indicators have not yet been quantified. This test was conducted to satisfy all SLIs/SLOs in the official state.

Kubernetes Scalability Dimensions and Thresholds

Kubernetes scalability does not just mean the number of nodes (Scalability != #Nodes). Other dimensions include the number of namespaces, pods, Services, secrets, and ConfigMaps. Configurations that Kubernetes supports create the Scalability Envelope (which keeps evolving):

k8s-scalability

Obviously, it is impossible for a Kubernetes cluster to expand resource objects without limitation while satisfying SLIs/SLOs. Therefore, the industry defines the upper limits of Kubernetes resource objects.

1. Pods/node 30
2. Backends <= 50k & Services <= 10k & Backends/service <= 250
3. Pod churn 20/s
4. Secret & configmap/node 30
5. Namespaces <= 10k & Pods <= 150k & Pods/namespace <= 3k
6. ​ …..

Dimensions are sometimes not independent. As you move farther along one dimension, your cross-section wrt other dimensions gets smaller. For example, if 5000 nodes are expanded to 10,000 nodes, the specifications of other dimensions will be affected. A heavy workload is required if all scenarios are tested. In this test, we focus on the typical scenarios. We manage to host 100k edge nodes and 1000k pods in a single cluster while satisfying the SLIs/SLOs.

Test Tools

ClusterLoader2

ClusterLoader2 is an open source Kubernetes cluster performance test tool. It can test the Kubernetes SLIs/SLOs to check whether the cluster meets the service quality standards. It also visualizes data for locating cluster problems and optimizing cluster performance. After the test, users get a performance report with detailed test results.

Clusterloader2 performance metrics:

  • APIResponsivenessPrometheusSimple
  • APIResponsivenessPrometheus
  • CPUProfile
  • EtcdMetrics
  • MemoryProfile
  • MetricsForE2E
  • PodStartupLatency
  • ResourceUsageSummary
  • SchedulingMetrics
  • SchedulingThroughput
  • WaitForControlledPodsRunning
  • WaitForRunningPods

Edgemark

Edgemark is a performance test tool similar to Kubemark. It simulates deploying KubeEdge edge nodes in the KubeEdge cluster scalability test to build ultra-large Kubernetes clusters, powered by KubeEdge, with limited resources. The objective is to expose the cluster control plane downsides that occur only in large-scale deployments. The following figure illustrates the Edgemark deployment:

edgemark-deploy

  • K8s master: the master node of the Kubernetes cluster
  • Edgemark master: the master node of the simulated Kubernetes cluster
  • CloudCore: the KubeEdge cloud management component, which is responsible for edge node access
  • hollow pod: a pod started in the actual cluster. It registers with the Edgemark master as a virtual edge node by starting Edgemark in it. The Edgemark master can schedule pods to this virtual edge node.
  • hollow edgeNode: a virtual node in the simulated cluster, registered from a hollow pod

Cluster Deployment Scheme for the Test

deploy

The Kubernetes control plane is deployed with one master node. The etcd, kube-apiserver, kube-scheduler, and kube-controller are deployed as single-instance. The KubeEdge control plane is deployed with five CloudCore instances and connects to the kube-apiserver through the IP address of the master node. Hollow EdgeNodes are exposed by a load balancer and randomly connect to a CloudCore instance based on the round-robin policy of the load balancer.

Test Environment Information

Control Plane OS Version

CentOS 7.9 64bit 3.10.0-1160.15.2.el7.x86_64

Kubernetes Version

Major:"1", Minor:"23", GitVersion:"v1.23.4", GitCommit:"e6c093d87ea4cbb530a7b2ae91e54c0842d8308a", GitTreeState:"clean", BuildDate:"2022-02-16T12:38:05Z", GoVersion:"go1.17.7", Compiler:"gc", Platform:"linux/amd64"

KubeEdge Version

KubeEdge v1.11.0-alpha.0

Master Node Configurations

  • CPU
Architecture:          x86_64
CPU op-mode(s): 32-bit, 64-bit
Byte Order: Little Endian
CPU(s): 128
On-line CPU(s) list: 0-127
Thread(s) per core: 2
Core(s) per socket: 32
Socket(s): 2
NUMA node(s): 2
Vendor ID: GenuineIntel
CPU family: 6
Model: 106
Model name: Intel(R) Xeon(R) Platinum 8378A CPU @ 3.00GHz
Stepping: 6
CPU MHz: 2999.998
  • MEMORY
Total online memory:   256G
  • ETCD DISK
Type:   SAS_SSD
Size: 300GB

CloudCore Node Configurations

  • CPU
Architecture:          x86_64
CPU op-mode(s): 32-bit, 64-bit
Byte Order: Little Endian
CPU(s): 12
On-line CPU(s) list: 0-11
Thread(s) per core: 2
Core(s) per socket: 6
Socket(s): 1
NUMA node(s): 1
Vendor ID: GenuineIntel
CPU family: 6
Model: 106
Model name: Intel(R) Xeon(R) Platinum 8378A CPU @ 3.00GHz
Stepping: 6
CPU MHz: 2999.998
  • MEMORY
Total online memory:   48G

Component Parameter Configurations

1. kube-apiserver

--max-requests-inflight=2000
--max-mutating-requests-inflight=1000

2. kube-controller-manager

--kube-api-qps=100
--kube-api-burst=100

3. kube-scheduler

--kube-api-qps=200
--kube-api-burst=400

4. CloudCore

apiVersion: cloudcore.config.kubeedge.io/v1alpha1
kind: CloudCore
kubeAPIConfig:
kubeConfig: ""
master: ""
qps: 60000
burst: 80000
modules:
cloudHub:
advertiseAddress:
- xx.xx.xx.xx
nodeLimit: 30000
tlsCAFile: /etc/kubeedge/ca/rootCA.crt
tlsCertFile: /etc/kubeedge/certs/server.crt
tlsPrivateKeyFile: /etc/kubeedge/certs/server.key
unixsocket:
address: unix:///var/lib/kubeedge/kubeedge.sock
enable: false
websocket:
address: 0.0.0.0
enable: true
port: 10000
cloudStream:
enable: false
deviceController:
enable: false
dynamicController:
enable: false
edgeController:
buffer:
configMapEvent: 102400
deletePod: 10240
endpointsEvent: 1
podEvent: 102400
queryConfigMap: 10240
queryEndpoints: 1
queryNode: 10240
queryPersistentVolume: 1
queryPersistentVolumeClaim: 1
querySecret: 10240
queryService: 1
queryVolumeAttachment: 1
ruleEndpointsEvent: 1
rulesEvent: 1
secretEvent: 1
serviceEvent: 10240
updateNode: 15240
updateNodeStatus: 30000
updatePodStatus: 102400
enable: true
load:
deletePodWorkers: 5000
queryConfigMapWorkers: 1000
queryEndpointsWorkers: 1
queryNodeWorkers: 5000
queryPersistentVolumeClaimWorkers: 1
queryPersistentVolumeWorkers: 1
querySecretWorkers: 1000
queryServiceWorkers: 1
queryVolumeAttachmentWorkers: 1
updateNodeStatusWorkers: 10000
updateNodeWorkers: 5000
updatePodStatusWorkers: 20000
ServiceAccountTokenWorkers: 10000
nodeUpdateFrequency: 60
router:
enable: false
syncController:
enable: true

Density Test

Test Execution

Before using ClusterLoader2 to perform the performance test, we defined the test policy using the configuration file. In this test, we used the official Kubernetes density case. The configuration file we used can be obtained here:

https://github.com/kubernetes/perf-tests/blob/master/clusterloader2/testing/density/config.yaml

The following table describes the detailed Kubernetes resource configurations:

Maximum typeMaximum value
Number of Nodes100,000
Number of Pods1,000,000
Number of Pods per node10
Number of Namespaces400
Number of Pods per Namespace2,500

For details about the test method and procedure, see the following links:

https://github.com/kubeedge/kubeedge/tree/master/build/edgemark

https://github.com/kubernetes/perf-tests/blob/master/clusterloader2/docs/GETTING_STARTED.md

Test Results

APIResponsivenessPrometheusSimple

  1. mutating API latency(threshold=1s):

    mutating-api-latency

  2. Read-only API call latency(scope=resource, threshold=1s)

    read-only-api-call-resource

  3. Read-only API call latency(scope=namespace, threshold=5s)

    read-only-api-call-namespace

  4. Read-only API call latency(scope=cluster, threshold=30s)

    read-only-api-call-cluster

PodStartupLatency

metricp50(ms)p90(ms)p99(ms)SLO(ms)
pod_startup1688275140875000
create_to_schedule001000N/A
schedule_to_run100010001000N/A
run_to_watch108716742265N/A
schedule_to_watch165727243070N/A

Note: Theoretically, the latency should always be greater than 0. Because kube-apiserver does not support RFC339NANO, the timestamp precision can only be seconds. Therefore, when the latency is low, some values collected by ClusterLoader2 are 0 due to precision loss.

Conclusion and Analysis

From the preceding test results, the API call latency and pod startup latency meet the SLIs/SLOs defined by the Kubernetes community. Therefore, the KubeEdge-powered Kubernetes clusters can stably support 100,000 concurrent edge nodes and more than one million pods. In production, the network between edge nodes and the cloud is connected according to O&M requirements due to reasons such as network security and partition management. Therefore, the number of edge nodes that can be managed by a single cluster can increase proportionally based on the proportion of offline edge nodes to online ones. In addition, data fragmentation is used on the Kubernetes control plane to store different resources to the corresponding etcd space, which allows for a larger service deployment scale.

KubeEdge's Support for Large-Scale Edge Node Access

1. Efficient Cloud-Edge Messaging

List-watch is a unified mechanism for asynchronous messaging of Kubernetes components. The list operation calls the list API of a resource to obtain full resource data through non-persistent HTTP connections. The watch operation calls the watch API of a resource to monitor resource change events and obtain incremental change data through persistent HTTP connections and block-based transmission encoding. In Kubernetes, in addition to the list-watch of a node, pods allocated to the node, and full service metadata, kubelet must also watch (by default) the running pods mounted with secrets and ConfigMaps as data volumes. The number of list-watch operations could explode with increasing nodes and pods, which heavily burdens kube-apiserver.

KubeEdge uses the two-way multiplexing edge-cloud message channel and supports the WebSocket (default) and QUIC protocols. EdgeCore at the edge initiates a connection request to CloudCore on the cloud. CloudCore list-watches Kubernetes resource changes, and delivers metadata to the edge through this two-way channel. EdgeCore uploads the metadata, such as edge node status and application status, to CloudCore through this channel. CloudCore reports the received metadata to kube-apiserver.

CloudCore aggregates the upstream and downstream data. kube-apiserver processes only several list-watch requests from CloudCore. It can be effectively unburdened and the cluster performance gets improved.

Memory usage when the native Kubernetes kube-apiserver is used under the same node and pod scales:

kube-apiserver-usage

Memory usage when kube-apiserver is used in a KubeEdge-powered Kubernetes cluster:

kubeedge-kube-apiserver-usage

2. Reliable Incremental Cloud-Edge Data Transmission

In the case of complex edge network topology or poor networking quality, cloud-edge communication may be compromised by high network latency, intermittent/frequent disconnection, and other issues. When the network recovers and edge nodes want to reconnect to the cloud, a large number of full list requests will be generated, pressuring kube-apiserver. Large-scale deployments may amplify this challenge to system stability. To solve it, KubeEdge records the version of the metadata successfully sent to the edge. When the cloud-edge network is reconnected, the cloud sends incremental metadata starting from the recorded metadata version.

3. Lightweight Edge + Edge-Cloud Messaging Optimization

EdgeCore removes native kubelet features that are not used in edge deployments, such as in-tree volume and cloud-provider, trims the status information reported by nodes, and optimizes resource usage of edge agent software. EdgeCore can run with a minimum of 70 MB memory on edge devices whose memory is as minimum as 100 MB. The WebSocket channel, edge-cloud message combination, and data trim greatly reduces the communication pressure on the edge and cloud and the access pressure on the control plane. They ensure that the system can work properly even in the case of high latency and jitter.

When 100,000 edge nodes are connected, the number of ELB connections is 100,000.

connect-number

When 100,000 edge nodes and more than 1,000,000 pods are deployed, the inbound rate of the ELB network is about 3 MB/s, and the average uplink bandwidth to each edge node is about 0.25 kbit/s.

network

Next Steps

Targeted tests will be performed on edge devices, edge-cloud messaging, and edge service mesh. In addition, for some edge scenarios, such as large-scale node network disconnection and reconnection, high latency of edge networks, and intermittent disconnection, new SLIs/SLOs need to be introduced to measure the cluster service quality and perform large-scale tests.