Traffic Encryption with Antrea

Antrea supports encrypting traffic across Linux Nodes with IPsec ESP or WireGuard. Traffic encryption is not supported on Windows Nodes yet.

IPsec

IPsec encryption works for all tunnel types supported by OVS including Geneve, GRE, VXLAN, and STT tunnel.

Note that GRE is not supported for IPv6 clusters (IPv6-only or dual-stack clusters). For such clusters, please choose a different tunnel type such as Geneve or VXLAN.

Prerequisites

IPsec requires a set of Linux kernel modules. Check the required kernel modules listed in the strongSwan documentation. Make sure the required kernel modules are loaded on the Kubernetes Nodes before deploying Antrea with IPsec encryption enabled.

If you want to enable IPsec with Geneve, please make sure this commit is included in the kernel. For Ubuntu 18.04, kernel version should be at least 4.15.0-128. For Ubuntu 20.04, kernel version should be at least 5.4.70.

Antrea installation

You can simply apply the Antrea IPsec deployment yaml to deploy Antrea with IPsec encryption enabled. To deploy a released version of Antrea, pick a version from the list of releases. Note that IPsec support was added in release 0.3.0, which means you can not pick a release older than 0.3.0. For any given release <TAG> (e.g. v0.3.0), get the Antrea IPsec deployment yaml at:

https://github.com/antrea-io/antrea/releases/download/<TAG>/antrea-ipsec.yml

To deploy the latest version of Antrea (built from the main branch), get the IPsec deployment yaml at:

https://raw.githubusercontent.com/antrea-io/antrea/main/build/yamls/antrea-ipsec.yml

Antrea leverages strongSwan as the IKE daemon, and supports using pre-shared key (PSK) for IKE authentication. The deployment yaml creates a Kubernetes Secret antrea-ipsec to store the PSK string. For security consideration, we recommend to change the default PSK string in the yaml file. You can edit the yaml file, and update the psk field in the antrea-ipsec Secret spec to any string you want to use. Check the antrea-ipsec Secret spec below:

---
apiVersion: v1
kind: Secret
metadata:
  name: antrea-ipsec
  namespace: kube-system
stringData:
  psk: changeme
type: Opaque

After updating the PSK value, deploy Antrea with:

kubectl apply -f antrea-ipsec.yml

By default, the deployment yaml uses GRE as the tunnel type, which you can change by editing the file. You will need to change the tunnel type to another one if your cluster supports IPv6.

WireGuard

Antrea can leverage WireGuard to encrypt Pod traffic between Nodes. WireGuard encryption works like another tunnel type, and when it is enabled the tunnelType parameter in the antrea-agent configuration file will be ignored.

Prerequisites

WireGuard encryption requires the wireguard kernel module be present on the Kubernetes Nodes. wireguard module is part of mainline kernel since Linux 5.6. Or, you can compile the module from source code with a kernel version >= 3.10. This WireGuard installation guide documents how to install WireGuard together with the kernel module on various operating systems.

Antrea installation

First, download the Antrea deployment yaml. To deploy a released version of Antrea, pick a version from the list of releases. Note that WireGuard support was added in release 1.3.0, which means you can not pick a release older than 1.3.0. For any given release <TAG> (e.g. v1.3.0), get the Antrea deployment yaml at:

https://github.com/antrea-io/antrea/releases/download/<TAG>/antrea.yml

To deploy the latest version of Antrea (built from the main branch), get the deployment yaml at:

https://raw.githubusercontent.com/antrea-io/antrea/main/build/yamls/antrea.yml

To enable WireGuard encryption, the trafficEncryptionMode config parameter of antrea-agent to wireGuard. The trafficEncryptionMode config parameter is defined in antrea-agent.conf of antrea ConfigMap in the Antrea deployment yaml:

kind: ConfigMap
apiVersion: v1
metadata:
  name: antrea-config
  namespace: kube-system
data:
  antrea-agent.conf: |
        trafficEncryptionMode: wireGuard

After saving the yaml file change, deploy Antrea with:

kubectl apply -f antrea.yml