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Container Service for Kubernetes:Network Element Configuration for Express Connect Environments

Last Updated:Mar 26, 2026

ACK Edge clusters connect on-premises IDC servers to Alibaba Cloud through Express Connect. Before adding edge nodes to a cluster, configure the required network elements on each device in the connectivity path. This topic covers the network architecture, device-by-device configuration, required ports, and endpoint allowlists for Express Connect environments.

Network architecture

image

On-premises IDC network topology

A typical on-premises IDC network uses a three-tier architecture. Servers and switches form a Layer 2 local area network (LAN). Multiple Layer 2 LANs combine into a Layer 3 network domain, giving the IDC a private CIDR block of 10.0.0.0/8.

Cloud-based VPC topology

The cloud-based Virtual Private Cloud (VPC) uses a virtualized network. Compute instances such as Elastic Compute Service (ECS) and Elastic Container Instance (ECI) connect directly to vSwitches and communicate through them. Some Alibaba Cloud services use the 100.0.0.0/8 CIDR block, which is accessible by default through vSwitches inside the VPC.

Express Connect network

Express Connect access points are available in multiple regions. Select an access point location based on proximity. Use your IDC core switch to connect to a Virtual Border Router (VBR) associated with an Express Connect access point through a network firewall. Then use an Express Connect Router (ECR) or a Cloud Enterprise Network (CEN) instance to connect to your VPC.

Prerequisites

Before you begin, confirm that:

  • Your IDC core switch and its subnets have completed Layer 3 network configuration and are interconnected.

  • You have provisioned an Express Connect circuit and associated it with a VBR.

  • You have an ECR or CEN instance to connect the VBR to your VPC. For details, see Alibaba Cloud Express Connect.

Network element configuration

All upstream routes go from your on-premises IDC toward the cloud VPC or Alibaba Cloud services. All downstream routes go from the cloud VPC back to your on-premises IDC.

CNI plug-in impact on configuration

The network plug-in your ACK Edge cluster uses affects several configuration steps. Identify your plug-in before you start:

CNI plug-in Additional upstream/downstream routes Additional firewall and security group rules
Terway Edge Add the edge container CIDR block (172.16.0.0/12) to downstream routes on the VBR, ECR or CEN, and VPC route table. Configure BGP on the IDC core switch and access switches. None
Flannel None Allow UDP 8472 in both directions on the IDC network firewall and cloud VPC security group. Source: VPC CIDR block. Destination: host CIDR block in the on-premises IDC.

Sample network configuration

This topic uses the following CIDR blocks as examples. The China (Hangzhou) region is used throughout.

Network CIDR block
Cloud VPC 192.168.0.0/16
On-premises IDC 10.0.0.0/8
Alibaba Cloud internal services 100.0.0.0/8
Edge container network (Terway Edge only) 172.16.0.0/12

If the 100.0.0.0/8 CIDR block is too broad for your environment, replace it with the specific IP ranges for your region. The table below lists the key service endpoints for China (Hangzhou):

Service CIDR blocks or endpoint
Object Storage Service (OSS) 100.118.28.0/24, 100.114.102.0/24, 100.98.170.0/24, 100.118.31.0/24
Container Registry (ACR) 100.103.9.188/32, 100.103.7.181/32
ACK management cs-anony-vpc.cn-hangzhou.aliyuncs.com (resolves to 100.103.42.233 inside the VPC)

For the complete list of service endpoints and their route CIDR blocks, see Endpoints and corresponding route CIDR blocks for Express Connect mode.

IDC core switch

Configuration item Description Notes
Upstream routes Add routes to the cloud VPC CIDR block (192.168.0.0/16) and the Alibaba Cloud service CIDR block (100.0.0.0/8). Point them to the Express Connect VBR through the ECR. If your cluster uses Terway Edge, configure BGP on your IDC core switch and access switches so the network plug-in can advertise container routes. For details, see Use the Terway Edge network plug-in and Configure Terway Edge for container communication.
Downstream routes Add routes from the Express Connect VBR to your IDC servers. This topic assumes your core switch has already completed server network configuration.

IDC network firewall

Direction Allow list Notes
Outbound Cloud VPC CIDR block (192.168.0.0/16) and Alibaba Cloud service CIDR block (100.0.0.0/8). For fine-grained control, also allow: OSS endpoint CIDR blocks, ACR endpoint CIDR blocks, TCP 443 or 80 for the ACK management endpoint, and TCP 6443 for the API server. If your cluster uses Flannel, allow UDP 8472 in both directions. Source: cloud VPC CIDR block. Destination: host CIDR block in your on-premises IDC.
Inbound Cloud VPC CIDR block (192.168.0.0/16) and Alibaba Cloud service CIDR block (100.0.0.0/8). For fine-grained control, also allow inbound traffic on kubelet TCP ports 10250 and 10255, and Node Exporter TCP ports 9100 and 9445.

Virtual Border Router (VBR)

Configuration item Description Notes
Upstream routes Add routes to the cloud VPC CIDR block (192.168.0.0/16) and Alibaba Cloud service CIDR block (100.0.0.0/8), pointing to the VPC. Use a direct VPC connection, an ECR, or a CEN instance.
Downstream routes Add a route to the IDC server CIDR block (10.0.0.0/8), pointing to the core switch through Express Connect and the IDC network firewall. If your cluster uses Terway Edge, also add the edge container CIDR block (172.16.0.0/12) to the VBR's downstream routes.

Express Connect Router (ECR) or Cloud Enterprise Network (CEN)

Configuration item Description Notes
Upstream routes In the ECR or CEN forwarding route table, add routes to the cloud VPC CIDR block (192.168.0.0/16) and Alibaba Cloud service CIDR block (100.0.0.0/8), pointing to the VPC.
Downstream routes In the ECR or CEN forwarding route table, add a route to the IDC server CIDR block (10.0.0.0/8), pointing to the VBR. If your cluster uses Terway Edge, also add the edge container CIDR block (172.16.0.0/12) to the ECR or CEN's downstream routes.

VPC route table

Configuration item Description Notes
Upstream routes The cloud VPC uses default network configuration and forwards requests from your IDC to their destination addresses.
Downstream routes Add a route to the IDC server CIDR block (10.0.0.0/8), pointing to CEN, ECR, or VBR. If your cluster uses Terway Edge, also add the edge container CIDR block (172.16.0.0/12) to the VPC route table's downstream routes.

Cloud VPC security group

Direction Allow list Notes
Outbound IDC server CIDR block (10.0.0.0/8). For fine-grained port control, also allow outbound traffic on kubelet TCP ports 10250 and 10255, and Node Exporter TCP ports 9100 and 9445. If your cluster uses Flannel, allow UDP 8472 in both directions. Source: cloud VPC CIDR block. Destination: host CIDR block in your on-premises IDC.
Inbound IDC CIDR block (10.0.0.0/8). For fine-grained port control, also allow inbound traffic on API server TCP port 6443.

Ports required for inbound access to edge nodes

Configure these inbound ports on edge nodes to allow cloud-initiated access.

Protocol Port Source Purpose Used by
TCP 10250, 10255 VPC CIDR block (optional — scope to your cluster's vSwitch CIDR block for tighter control) kubelet API API server (O&M operations), Metrics Server (metric collection)
TCP 9100, 9445 VPC CIDR block (optional — scope to your cluster's vSwitch CIDR block for tighter control) Node Exporter metrics Prometheus
UDP 8472 VPC CIDR block and node address or node CIDR block (required only for Flannel clusters) VXLAN tunnel Flannel

Domain names and ports required for outbound access from edge nodes

Configure the following endpoints to allow edge nodes to reach Alibaba Cloud services over Express Connect. Replace {region} with your cluster's region ID (for example, cn-hangzhou for China (Hangzhou)). For a complete list of region IDs, see Regions where Alibaba Cloud services are available.

Target Endpoint Port Required Description
Container Service control plane cs-anony-vpc.{region}.aliyuncs.com TCP 443 (clusters v1.26 or later); TCP 80 (clusters earlier than v1.26) Required ACK management endpoint
OSS installation packages aliacs-k8s-{region}.oss-{region}-internal.aliyuncs.com TCP 443 (clusters v1.26 or later); TCP 80 and 443 (clusters earlier than v1.26) Required Download edgeadm, kubelet, CNI, runtime, and edgehub installation packages from OSS
Internal API server endpoint View on the Basic Information tab of the cluster details page TCP 6443 Required Communication with kube-apiserver
NTP ntp1.aliyun.com, cn.ntp.org.cn UDP 123 (typically) Optional — skip if selfHostNtpServer is set to true Clock synchronization
System component image registry dockerauth-vpc.{region}.aliyuncs.com; dockerauth-ee-vpc.{region}.aliyuncs.com (not available in all regions); registry-{region}-vpc.ack.aliyuncs.com TCP 443 Required Pull system component images. For corresponding IP ranges, see Endpoints and corresponding route CIDR blocks for Express Connect mode.
System tools No additional domains required N/A Required if tools are absent The node registration process checks for net-tools, iproute, chrony (or ntpdate), crontabs, pciutils, socat, ebtables, iptables, and conntrack-tools. Missing tools are installed via apt-get (Ubuntu) or yum (CentOS) using the node's existing package source configuration.

Endpoints and corresponding route CIDR blocks for Express Connect mode

On-premises IDC devices access ACK component image registries over the internal network. You can connect your VPC internal network using CEN, Express Connect, dedicated lines, or VPN. Configure routes to the following registry endpoints and their associated OSS CIDR blocks, because ACK images are stored in OSS.

Internal image registry endpoints and route CIDR blocks for ACK components

Public cloud regions

Region Region ID VPC endpoint Route CIDR blocks
China (Hangzhou) cn-hangzhou registry-cn-hangzhou-vpc.ack.aliyuncs.com 100.103.9.188/32, 100.103.7.181/32
China (Shanghai) cn-shanghai registry-cn-shanghai-vpc.ack.aliyuncs.com 100.103.94.158/32, 100.103.7.57/32, 100.100.80.231/32
China (Fuzhou - Local Region) cn-fuzhou registry-cn-fuzhou-vpc.ack.aliyuncs.com 100.100.0.43/32, 100.100.0.28/32
China (Qingdao) cn-qingdao registry-cn-qingdao-vpc.ack.aliyuncs.com 100.100.0.172/32, 100.100.0.207/32
China (Beijing) cn-beijing registry-cn-beijing-vpc.ack.aliyuncs.com 100.103.99.73/32, 100.103.0.251/32, 100.103.6.63/32
China (Zhangjiakou) cn-zhangjiakou registry-cn-zhangjiakou-vpc.ack.aliyuncs.com 100.100.1.179/32, 100.100.80.152/32
China (Hohhot) cn-huhehaote registry-cn-huhehaote-vpc.ack.aliyuncs.com 100.100.0.194/32, 100.100.80.55/32
China (Ulanqab) cn-wulanchabu registry-cn-wulanchabu-vpc.ack.aliyuncs.com 100.100.0.122/32, 100.100.0.58/32
China (Shenzhen) cn-shenzhen registry-cn-shenzhen-vpc.ack.aliyuncs.com 100.103.96.139/32, 100.103.6.153/32, 100.103.26.52/32
China (Heyuan) cn-heyuan registry-cn-heyuan-vpc.ack.aliyuncs.com 100.100.0.150/32, 100.100.0.193/32
China (Guangzhou) cn-guangzhou registry-cn-guangzhou-vpc.ack.aliyuncs.com 100.100.0.101/32, 100.100.0.21/32
China (Chengdu) cn-chengdu registry-cn-chengdu-vpc.ack.aliyuncs.com 100.100.0.48/32, 100.100.0.64/32
Zhengzhou (CUCC Joint Venture) cn-zhengzhou-jva registry-cn-zhengzhou-jva-vpc.ack.aliyuncs.com 100.100.0.111/32, 100.100.0.84/32
China (Hong Kong) cn-hongkong registry-cn-hongkong-vpc.ack.aliyuncs.com 100.103.85.19/32, 100.100.80.157/32
US (Silicon Valley) us-west-1 registry-us-west-1-vpc.ack.aliyuncs.com 100.103.13.55/32, 100.100.80.93/32
US (Virginia) us-east-1 registry-us-east-1-vpc.ack.aliyuncs.com 100.103.12.19/32, 100.100.80.11/32
Japan (Tokyo) ap-northeast-1 registry-ap-northeast-1-vpc.ack.aliyuncs.com 100.100.0.167/32, 100.100.80.198/32
South Korea (Seoul) ap-northeast-2 registry-ap-northeast-2-vpc.ack.aliyuncs.com 100.100.0.71/32, 100.100.0.33/32
Singapore ap-southeast-1 registry-ap-southeast-1-vpc.ack.aliyuncs.com 100.103.103.254/32, 100.100.80.136/32
Malaysia (Kuala Lumpur) ap-southeast-3 registry-ap-southeast-3-vpc.ack.aliyuncs.com 100.100.0.17/32, 100.100.80.137/32
Indonesia (Jakarta) ap-southeast-5 registry-ap-southeast-5-vpc.ack.aliyuncs.com 100.100.0.226/32, 100.100.80.200/32
Philippines (Manila) ap-southeast-6 registry-ap-southeast-6-vpc.ack.aliyuncs.com 100.100.0.75/32, 100.100.0.24/32
Thailand (Bangkok) ap-southeast-7 registry-ap-southeast-7-vpc.ack.aliyuncs.com 100.100.0.62/32, 100.100.0.34/32
Germany (Frankfurt) eu-central-1 registry-eu-central-1-vpc.ack.aliyuncs.com 100.100.0.92/32, 100.100.80.155/32
UK (London) eu-west-1 registry-eu-west-1-vpc.ack.aliyuncs.com 100.100.0.175/32, 100.100.0.18/32
SAU (Riyadh - Partner Region) me-central-1 registry-me-central-1-vpc.ack.aliyuncs.com 100.100.0.109/32, 100.100.0.18/32

OSS internal endpoints and VIP CIDR blocks

Public cloud

Important

Due to a policy change to improve compliance and security, starting March 20, 2025, new OSS users must use a custom domain name (CNAME) to perform data API operations on OSS buckets in Chinese mainland regions. Default public endpoints are restricted for these operations. Refer to the official announcement for the complete list of affected operations. If you access your data via HTTPS, bind a valid SSL certificate to your custom domain. This is mandatory for OSS Console access, as the console enforces HTTPS.

The names of some regions outside the Chinese mainland may differ between the OSS pricing page and the resource plan purchase page. However, these different names refer to the same physical location. For example, the US (Silicon Valley) region may be displayed as US West 1 or US West. For more information, see OSS Pricing or Purchase a resource plan.

Asia-Pacific - China
Region Region ID Public endpoint Internal endpoint Dual-stack endpoint Internal VIP CIDR blocks
China (Hangzhou) cn-hangzhou oss-cn-hangzhou.aliyuncs.com oss-cn-hangzhou-internal.aliyuncs.com cn-hangzhou.oss.aliyuncs.com 100.118.28.0/24, 100.114.102.0/24, 100.98.170.0/24, 100.118.31.0/24
China (Shanghai) cn-shanghai oss-cn-shanghai.aliyuncs.com oss-cn-shanghai-internal.aliyuncs.com cn-shanghai.oss.aliyuncs.com 100.98.35.0/24, 100.98.110.0/24, 100.98.169.0/24, 100.118.102.0/24
China (Nanjing - Local Region) Closing Down cn-nanjing oss-cn-nanjing.aliyuncs.com oss-cn-nanjing-internal.aliyuncs.com Not supported 100.114.142.0/24
China (Qingdao) cn-qingdao oss-cn-qingdao.aliyuncs.com oss-cn-qingdao-internal.aliyuncs.com cn-qingdao.oss.aliyuncs.com 100.115.173.0/24, 100.99.113.0/24, 100.99.114.0/24, 100.99.115.0/24
China (Beijing) cn-beijing oss-cn-beijing.aliyuncs.com oss-cn-beijing-internal.aliyuncs.com cn-beijing.oss.aliyuncs.com 100.118.58.0/24, 100.118.167.0/24, 100.118.170.0/24, 100.118.171.0/24, 100.118.172.0/24, 100.118.173.0/24
China (Zhangjiakou) cn-zhangjiakou oss-cn-zhangjiakou.aliyuncs.com oss-cn-zhangjiakou-internal.aliyuncs.com cn-zhangjiakou.oss.aliyuncs.com 100.118.90.0/24, 100.98.159.0/24, 100.114.0.0/24, 100.114.1.0/24
China (Hohhot) cn-huhehaote oss-cn-huhehaote.aliyuncs.com oss-cn-huhehaote-internal.aliyuncs.com cn-huhehaote.oss.aliyuncs.com 100.118.195.0/24, 100.99.110.0/24, 100.99.111.0/24, 100.99.112.0/24
China (Ulanqab) cn-wulanchabu oss-cn-wulanchabu.aliyuncs.com oss-cn-wulanchabu-internal.aliyuncs.com cn-wulanchabu.oss.aliyuncs.com 100.114.11.0/24, 100.114.12.0/24, 100.114.100.0/24, 100.118.214.0/24
China (Shenzhen) cn-shenzhen oss-cn-shenzhen.aliyuncs.com oss-cn-shenzhen-internal.aliyuncs.com cn-shenzhen.oss.aliyuncs.com 100.118.78.0/24, 100.118.203.0/24, 100.118.204.0/24, 100.118.217.0/24
China (Heyuan) cn-heyuan oss-cn-heyuan.aliyuncs.com oss-cn-heyuan-internal.aliyuncs.com cn-heyuan.oss.aliyuncs.com 100.98.83.0/24, 100.118.174.0/24
China (Guangzhou) cn-guangzhou oss-cn-guangzhou.aliyuncs.com oss-cn-guangzhou-internal.aliyuncs.com cn-guangzhou.oss.aliyuncs.com 100.115.33.0/24, 100.114.101.0/24
China (Chengdu) cn-chengdu oss-cn-chengdu.aliyuncs.com oss-cn-chengdu-internal.aliyuncs.com cn-chengdu.oss.aliyuncs.com 100.115.155.0/24, 100.99.107.0/24, 100.99.108.0/24, 100.99.109.0/24
China (Hong Kong) cn-hongkong oss-cn-hongkong.aliyuncs.com oss-cn-hongkong-internal.aliyuncs.com cn-hongkong.oss.aliyuncs.com 100.115.61.0/24, 100.99.103.0/24, 100.99.104.0/24, 100.99.106.0/24
Asia-Pacific - Other
Region Region ID Public endpoint Internal endpoint Dual-stack endpoint Internal VIP CIDR blocks
Japan (Tokyo) ap-northeast-1 oss-ap-northeast-1.aliyuncs.com oss-ap-northeast-1-internal.aliyuncs.com Not supported 100.114.211.0/24, 100.114.114.0/25
South Korea (Seoul) ap-northeast-2 oss-ap-northeast-2.aliyuncs.com oss-ap-northeast-2-internal.aliyuncs.com Not supported 100.99.119.0/24
Singapore ap-southeast-1 oss-ap-southeast-1.aliyuncs.com oss-ap-southeast-1-internal.aliyuncs.com Not supported 100.118.219.0/24, 100.99.213.0/24, 100.99.116.0/24, 100.99.117.0/24
Malaysia (Kuala Lumpur) ap-southeast-3 oss-ap-southeast-3.aliyuncs.com oss-ap-southeast-3-internal.aliyuncs.com Not supported 100.118.165.0/24, 100.99.125.0/24, 100.99.130.0/24, 100.99.131.0/24
Indonesia (Jakarta) ap-southeast-5 oss-ap-southeast-5.aliyuncs.com oss-ap-southeast-5-internal.aliyuncs.com Not supported 100.114.98.0/24
Philippines (Manila) ap-southeast-6 oss-ap-southeast-6.aliyuncs.com oss-ap-southeast-6-internal.aliyuncs.com Not supported 100.115.16.0/24
Thailand (Bangkok) ap-southeast-7 oss-ap-southeast-7.aliyuncs.com oss-ap-southeast-7-internal.aliyuncs.com Not supported 100.98.249.0/24
Europe and Americas
Region Region ID Public endpoint Internal endpoint Dual-stack endpoint Internal VIP CIDR blocks
Germany (Frankfurt) eu-central-1 oss-eu-central-1.aliyuncs.com oss-eu-central-1-internal.aliyuncs.com eu-central-1.oss.aliyuncs.com 100.115.154.0/24
UK (London) eu-west-1 oss-eu-west-1.aliyuncs.com oss-eu-west-1-internal.aliyuncs.com Not supported 100.114.114.128/25
US (Silicon Valley) us-west-1 oss-us-west-1.aliyuncs.com oss-us-west-1-internal.aliyuncs.com Not supported 100.115.107.0/24
US (Virginia) us-east-1 oss-us-east-1.aliyuncs.com oss-us-east-1-internal.aliyuncs.com Not supported 100.115.60.0/24, 100.99.100.0/24, 100.99.101.0/24, 100.99.102.0/24
Mexico na-south-1 oss-na-south-1.aliyuncs.com oss-na-south-1-internal.aliyuncs.com Not supported 100.115.112.0/27
Middle East
Region Region ID Public endpoint Internal endpoint Dual-stack endpoint Internal VIP CIDR blocks
UAE (Dubai) me-east-1 oss-me-east-1.aliyuncs.com oss-me-east-1-internal.aliyuncs.com Not supported 100.99.235.0/24
SAU (Riyadh - Partner Region) me-central-1 oss-me-central-1.aliyuncs.com oss-me-central-1-internal.aliyuncs.com Not supported 100.99.121.0/24