Configure Flannel to route pod traffic across nodes via VPC custom routes.
How it works
The pod CIDR block is separate from the VPC CIDR block. ACK divides the pod CIDR block into per-node subnets based on a subnet mask, and each pod receives an IP address from its node's subnet.
Usage notes
Route table management
Cloud Controller Manager manages the VPC default route table for Flannel clusters, with one route entry per node.
Do not modify the VPC default route table unless necessary. Cloud Controller Manager automatically deletes conflicting route entries. See Cloud Controller Manager.
Multiple route tables
Flannel clusters do not support multiple VPC route tables by default. If your VPC has multiple route tables, see Use multiple route tables in a VPC.
If you use Alibaba Cloud NAT firewalls, add the VPC system route table to the multiple route table list after the firewall is created. Skipping this step may affect cluster scale-out.
Select Flannel when creating a cluster
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On the Create Kubernetes Cluster page, set Forwarding Mode to Flannel.
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Configure the following network parameters:
Parameter Description VPC The VPC for the cluster. vSwitch The vSwitch for the cluster nodes. Pods per Node The maximum number of pods per node. Pod CIDR Block The pod CIDR block. See Plan CIDR blocks for ACK managed clusters. Service CIDR Block The service CIDR block. See Plan CIDR blocks for ACK managed clusters. -
Complete the remaining cluster configuration. See Create an ACK managed cluster or Create an ACK dedicated cluster (no longer available for creation).
VPC quota limits
Each node consumes one route entry in the VPC route table. The default limit is 200 route entries per VPC. For clusters with more than 200 nodes, request a quota increase in Quota Center.
See Limits and Quotas.