Flannel vs Spiderpool

Flannel is a free network fabric for containers designed for Kubernetes. A small flanneld agent on each host allocates a subnet lease from a configured address space, then forwards packets between hosts using a selected backend. Documented choices include VXLAN, host-gw, WireGuard and UDP, with VXLAN recommended. WireGuard encapsulates and encrypts packets using the in-kernel WireGuard implementation. Network configuration and subnet allocations can be stored in the Kubernetes API or directly in etcd. The project documents Kubernetes and Docker deployments, with Linux and Windows build instructions. Flannel does not enforce network policies itself, though its Helm chart can deploy a Kubernetes SIGs network policy controller alongside it. It runs as a privileged daemonset with access to the host network, so the security policy advises least privilege and keeping it updated. Security fixes are maintained for the latest release only, and the backend documentation says not to change a selected backend at runtime.

Spiderpool is a free, open-source Kubernetes networking solution for underlay networking and RDMA on bare metal, virtual machines, and public clouds. Its CRD-based IPAM handles dual-stack networks, shared or exclusive address pools, and static addresses for stateful applications. The project supports Macvlan, IPvlan, and SR-IOV, while its IPAM can pair with compatible CNIs such as Calico and Weave. Pods may use multiple underlay interfaces or combine underlay and overlay interfaces, with policy routing across them. Documented connectivity includes Pod-to-host access, conflict detection, gateway checks, and service access through kube-proxy or an eBPF replacement. RDMA works with RoCE and InfiniBand in shared or exclusive device modes. Use cases include storage, middleware, observability, AI training, latency-sensitive workloads, and separate bandwidth needs. It supports AMD64 and ARM64 nodes, with SpiderSubnet requiring Kubernetes 1.21 or later. Spiderpool is Apache 2.0 licensed and a CNCF sandbox project.