Submariner

Spec sheet

Purpose

Submariner connects Pods and Services across Kubernetes clusters on-premises or in the cloud.Read 3 Oct 2026 · submariner.io

Audience

Submariner is aimed at teams operating multiple Kubernetes clusters across clouds, data centers, or regions.Read 3 Oct 2026 · submariner.io

Deployment

Submariner is installed and managed through a Kubernetes Operator, with subctl and Helm charts as deployment tools; the docs recommend subctl.Read 3 Oct 2026 · submariner.io

Security

The Broker deployment generates a broker-info.subm file containing an API endpoint, CA certificate, service-account token, and random IPsec pre-shared key.Read 3 Oct 2026 · submariner.io

Support

The project directs users to GitHub, Kubernetes Slack, community meetings, and the submariner-dev and submariner-users mailing lists for help and discussion.Read 3 Oct 2026 · submariner.io

License

Contributions to Submariner projects other than the website must be made available under Apache License 2.0.Read 3 Oct 2026 · submariner.io

Administrative requirements

Deployment requires administrative setup, including configuring firewall rules in the underlying infrastructure.Read 2 Oct 2026 · submariner.io

Calico limitation

Submariner is validated with Calico when it uses VXLAN encapsulation, and Calico requires configuration to avoid NAT on remote cluster subnets.Read 2 Oct 2026 · submariner.io

Community support

The project offers community help through GitHub, Kubernetes Slack, open community meetings, and user and developer mailing lists.Read 2 Oct 2026 · submariner.io

Connectivity

It provides cross-cluster Layer 3 connectivity using encrypted or unencrypted connections.Read 2 Oct 2026 · submariner.io

Deployment tool

The project includes subctl, a command-line utility that simplifies deployment and management.Read 2 Oct 2026 · submariner.io

External connectivity

Access to external applications or endpoints outside Kubernetes is described as experimental and potentially less mature or stable than core features.Read 2 Oct 2026 · submariner.io

High availability

The Gateway Engine supports active/passive high availability, with standby instances ready to take over if the active instance fails.Read 3 Oct 2026 · submariner.io

Limit

Load Balancer mode is marked experimental and is not yet tested across all cloud providers or failover scenarios.Read 3 Oct 2026 · submariner.io

Network plugins

Submariner is designed to be CNI-agnostic and documents working alongside network plugins including Calico and Flannel.Read 2 Oct 2026 · submariner.io

Networking

It provides cross-cluster Layer 3 connectivity using encrypted or unencrypted connections.Read 3 Oct 2026 · submariner.io

Open source

The project describes Submariner as completely open source and network-plugin agnostic.Read 3 Oct 2026 · submariner.io

Overlapping CIDRs

Globalnet provides an optional way to connect clusters with overlapping CIDRs; by default, clusters need distinct, non-overlapping ServiceCIDR and ClusterCIDR ranges.Read 3 Oct 2026 · submariner.io

Project status

Submariner is a Cloud Native Computing Foundation sandbox project.Read 2 Oct 2026 · submariner.io

Service discovery

Lighthouse provides DNS discovery for Kubernetes clusters connected by Submariner and implements Kubernetes Multi-Cluster Service APIs.Read 3 Oct 2026 · submariner.io

Tunnel options

The Gateway Engine supports IPsec using Libreswan by default, WireGuard, and unencrypted VXLAN tunnels.Read 3 Oct 2026 · submariner.io

Use case

It supports applications spanning cloud providers, data centers, and regions for needs such as geo-redundancy, scale, and fault isolation.Read 3 Oct 2026 · submariner.io

Where Specifiction places it

• Container Networking Software#23 of 286.7