Cilium vs Network Service Mesh

Cilium is an open-source, cloud-native system for providing, securing, and observing network connectivity between workloads using eBPF. Its networking capabilities include CNI, Layer 4 load balancing, Cluster Mesh, kube-proxy replacement, BGP, service mesh, Gateway API, IPv6, host firewall, and ingress. Network policies can enforce identity-aware rules from L3 through L7, including DNS- and HTTP-aware filtering. Security features include runtime protection and transparent encryption of managed host and endpoint traffic using IPsec, WireGuard, or ztunnel; ztunnel support is marked beta. For visibility, Cilium lists service maps, metrics and tracing export, network flow logs, and protocol visibility. Hubble, built on Cilium and eBPF, provides visibility into service communication and behavior. Documentation describes Prometheus and Grafana integrations and Kubernetes support for services including GKE, AKS, EKS, OpenShift, RKE, k3s, and Alibaba ACK. Its container image requires AMD64 or AArch64 hosts running Linux kernel 5.10 or later, or an equivalent kernel such as 4.18 on RHEL 8.10. For environments above 500 nodes, the quick installation guide directs readers to large-environment guidance or specific datapath modes.

Network Service Mesh connects workloads across clusters and clouds through a hybrid, multi-cloud IP service mesh. Each workload can connect independently to zero or more Network Services, regardless of where it runs. The project says it works with an existing CNI without requiring changes to Kubernetes or workloads. Services can provide connectivity, security, and observability at Layer 3 and above, carrying IP or Ethernet payloads.

Clients may be Kubernetes pods, virtual machines, or physical servers. They authenticate independently, currently using SPIFFE IDs, and need authorization to attach. Clients request and close virtual wires over gRPC and can monitor connection status through a streaming call. Endpoint selection offers composition, selective composition, topology awareness, and scale from zero. A service may also provide domain-scoped DNS for connected pods. The architecture describes integration with Istio, Linkerd, Consul, and Kuma. Network Service Mesh is a CNCF sandbox project and is free and open source. Its run guide lists Docker, Go, a Kubernetes cluster, and kubectl as prerequisites; most examples require at least two worker nodes.