Flannel Add-On beta

Flannel implements the Container Network Interface (CNI) to enable pod networking in a Kubernetes cluster. Flannel runs a small, single binary agent called flanneld in a Pod on each host, and is responsible for allocating a subnet lease to each host out of a larger, preconfigured address space. Flannel uses the Kubernetes API directly to store the network configuration, the allocated subnets, and any auxiliary data (such as the host's public IP). Packets are forwarded using VXLAN encapsulation.

Advanced Install Options

spec:
  flannel:
    version: "0.20.0"
    podCIDR: "10.32.0.0/22"
    podCIDRRange: "/22"

Flag Usage
version The version of Flannel to be installed.
podCIDR The subnet used by Pods.
podCIDRRange The size of the subnet used by Pods.

System Requirements

The following additional ports must be open between nodes for multi-node clusters:

Primary Nodes:

Protocol Direction Port Range Purpose Used By
UDP Inbound 8472 Flannel VXLAN All

Secondary Nodes:

Protocol Direction Port Range Purpose Used By
UDP Inbound 8472 Flannel VXLAN All

Custom Pod Subnet

The Pod subnet will default to 10.32.0.0/20 if available. If not available, the installer will attempt to find an available range with prefix bits 20 in the 10.32.0.0/16 or 10.0.0.0/8 address spaces. This can be overridden using the podCIDR to specify a specific address space, or podCIDRRange to specify a different prefix bits.

Limitations

  • Migrations from Weave CNI are not supported
  • Migrations from Antrea CNI are not supported
  • Network Policies are not supported
  • IPv6 and dual stack networks are not supported
  • Encryption is not supported