Antrea Feature Gates

This page contains an overview of the various features an administrator can turn on or off for Antrea components. We follow the same convention as the Kubernetes feature gates.

In particular:

• a feature in the Alpha stage will be disabled by default but can be enabled by editing the appropriate .conf entry in the Antrea manifest.
• a feature in the Beta stage will be enabled by default but can be disabled by editing the appropriate .conf entry in the Antrea manifest.
• a feature in the GA stage will be enabled by default and cannot be disabled.

Some features are specific to the Agent, others are specific to the Controller, and some apply to both and should be enabled / disabled consistently in both .conf entries.

To enable / disable a feature, edit the Antrea manifest appropriately. For example, to enable AntreaProxy on Linux, edit the Agent configuration in the antrea ConfigMap as follows:

  antrea-agent.conf: |
    # FeatureGates is a map of feature names to bools that enable or disable experimental features.
    featureGates:
    # Enable antrea proxy which provides ServiceLB for in-cluster Services in antrea agent.
    # It should be enabled on Windows, otherwise NetworkPolicy will not take effect on
    # Service traffic.
      AntreaProxy: true    

List of Available Features

Description and Requirements of Features

AntreaProxy

AntreaProxy implements Service load-balancing for ClusterIP Services as part of the OVS pipeline, as opposed to relying on kube-proxy. This only applies to traffic originating from Pods, and destined to ClusterIP Services. In particular, it does not apply to NodePort Services. Please note that due to some restrictions on the implementation of Services in Antrea, the maximum number of Endpoints that Antrea can support at the moment is 800. If the number of Endpoints for a given Service exceeds 800, extra Endpoints will be dropped.

Note that this feature must be enabled for Windows. The Antrea Windows YAML manifest provided as part of releases enables this feature by default. If you edit the manifest, make sure you do not disable it, as it is needed for correct NetworkPolicy implementation for Pod-to-Service traffic.

Please refer to this document for extra information on AntreaProxy and how it can be configured.

Requirements for this Feature

When using the OVS built-in kernel module (which is the most common case), your kernel version must be >= 4.6 (as opposed to >= 4.4 without this feature).

EndpointSlice

EndpointSlice enables Service EndpointSlice support in AntreaProxy. The EndpointSlice API was introduced in Kubernetes 1.16 (alpha) and it is enabled by default in Kubernetes 1.17 (beta), promoted to GA in Kubernetes 1.21. The EndpointSlice feature will take no effect if AntreaProxy is not enabled. Refer to this link for more information about EndpointSlice. If this feature is enabled but the EndpointSlice v1 API is not available (Kubernetes version is lower than 1.21), Antrea Agent will log a message and fallback to the Endpoints API.

Requirements for this Feature

• EndpointSlice v1 API is available (Kubernetes version >=1.21).
• AntreaProxy is enabled.

TopologyAwareHints

TopologyAwareHints enables TopologyAwareHints support in AntreaProxy. For AntreaProxy, traffic can be routed to the Endpoint which is closer to where it originated when this feature is enabled. Refer to this link for more information about TopologyAwareHints.

Requirements for this Feature

• AntreaProxy is enabled.
• EndpointSlice is enabled.

LoadBalancerModeDSR

LoadBalancerModeDSR allows users to specify the load balancer mode as DSR (Direct Server Return). The load balancer mode determines how external traffic destined to LoadBalancerIPs and ExternalIPs of Services is processed when it’s load balanced across Nodes. In DSR mode, external traffic is never SNAT’d and backend Pods running on Nodes that are not the ingress Node can reply to clients directly, bypassing the ingress Node. Therefore, DSR mode can preserve client IP of requests, and usually has lower latency and higher throughput. It’s only meaningful to use this feature when AntreaProxy is enabled and configured to proxy external traffic (proxyAll=true). Refer to this link for more information about load balancer mode.

Requirements for this Feature

• AntreaProxy with proxyAll is enabled.
• IPv4 only.
• Linux Nodes only.
• Encap mode only.

CleanupStaleUDPSvcConntrack

CleanupStaleUDPSvcConntrack enables support for cleaning up stale UDP Service conntrack connections in AntreaProxy.

Requirements for this Feature

• AntreaProxy is enabled.

AntreaPolicy

AntreaPolicy enables Antrea ClusterNetworkPolicy and Antrea NetworkPolicy CRDs to be handled by Antrea controller. ClusterNetworkPolicy is an Antrea-specific extension to K8s NetworkPolicies, which enables cluster admins to define security policies which apply to the entire cluster. Antrea NetworkPolicy also complements K8s NetworkPolicies by supporting policy priorities and rule actions. Refer to this document for more information.

Requirements for this Feature

None

Traceflow

Traceflow enables a CRD API for Antrea that supports generating tracing requests for traffic going through the Antrea-managed Pod network. This is useful for troubleshooting connectivity issues, e.g. determining if a NetworkPolicy is responsible for traffic drops between two Pods. Refer to this document for more information.

Requirements for this Feature

Until Antrea v0.11, this feature could only be used in “encap” mode, with the Geneve tunnel type (default configuration for both Linux and Windows). In v0.11, this feature was graduated to Beta (enabled by default) and this requirement was lifted.

In order to support cluster Services as the destination for tracing requests, AntreaProxy should be enabled, which is the default starting with Antrea v0.11.

Flow Exporter

Flow Exporter is a feature that runs as part of the Antrea Agent, and enables network flow visibility into a Kubernetes cluster. Flow exporter sends IPFIX flow records that are built from observed connections in Conntrack module to a flow collector. Refer to this document for more information.

Requirements for this Feature

This feature is currently only supported for Nodes running Linux. Windows support will be added in the future.

NetworkPolicyStats

NetworkPolicyStats enables collecting NetworkPolicy statistics from antrea-agents and exposing them through Antrea Stats API, which can be accessed by kubectl get commands, e.g. kubectl get networkpolicystats. The statistical data includes total number of sessions, packets, and bytes allowed or denied by a NetworkPolicy. It is collected asynchronously so there may be a delay of up to 1 minute for changes to be reflected in API responses. The feature supports K8s NetworkPolicies and Antrea native policies, the latter of which requires AntreaPolicy to be enabled. Usage examples:

# List stats of all K8s NetworkPolicies.
> kubectl get networkpolicystats -A
NAMESPACE     NAME                  SESSIONS   PACKETS   BYTES   CREATED AT
default       access-nginx          3          36        5199    2020-09-07T13:19:38Z
kube-system   access-dns            1          12        1221    2020-09-07T13:22:42Z

# List stats of all Antrea ClusterNetworkPolicies.
> kubectl get antreaclusternetworkpolicystats
NAME                  SESSIONS   PACKETS   BYTES   CREATED AT
cluster-deny-egress   3          36        5199    2020-09-07T13:19:38Z
cluster-access-dns    10         120       12210   2020-09-07T13:22:42Z

# List stats of all Antrea NetworkPolicies.
> kubectl get antreanetworkpolicystats -A
NAMESPACE     NAME                  SESSIONS   PACKETS   BYTES   CREATED AT
default       access-http           3          36        5199    2020-09-07T13:19:38Z
foo           bar                   1          12        1221    2020-09-07T13:22:42Z

# List per-rule statistics for Antrea ClusterNetworkPolicy cluster-access-dns.
# Both Antrea NetworkPolicy and Antrea ClusterNetworkPolicy support per-rule statistics.
> kubectl get antreaclusternetworkpolicystats cluster-access-dns -o json
{
    "apiVersion": "stats.antrea.io/v1alpha1",
    "kind": "AntreaClusterNetworkPolicyStats",
    "metadata": {
        "creationTimestamp": "2022-02-24T09:04:53Z",
        "name": "cluster-access-dns",
        "uid": "940cf76a-d836-4e76-b773-d275370b9328"
    },
    "ruleTrafficStats": [
        {
            "name": "rule1",
            "trafficStats": {
                "bytes": 392,
                "packets": 4,
                "sessions": 1
            }
        },
        {
            "name": "rule2",
            "trafficStats": {
                "bytes": 111,
                "packets": 2,
                "sessions": 1
            }
        }
    ],
    "trafficStats": {
        "bytes": 503,
        "packets": 6,
        "sessions": 2
    }
}

Requirements for this Feature

None

NodePortLocal

NodePortLocal (NPL) is a feature that runs as part of the Antrea Agent, through which each port of a Service backend Pod can be reached from the external network using a port of the Node on which the Pod is running. NPL enables better integration with external Load Balancers which can take advantage of the feature: instead of relying on NodePort Services implemented by kube-proxy, external Load-Balancers can consume NPL port mappings published by the Antrea Agent (as K8s Pod annotations) and load-balance Service traffic directly to backend Pods. Refer to this document for more information.

Requirements for this Feature

This feature is currently only supported for Nodes running Linux with IPv4 addresses. Only TCP & UDP Service ports are supported (not SCTP).

Egress

Egress enables a CRD API for Antrea that supports specifying which egress (SNAT) IP the traffic from the selected Pods to the external network should use. When a selected Pod accesses the external network, the egress traffic will be tunneled to the Node that hosts the egress IP if it’s different from the Node that the Pod runs on and will be SNATed to the egress IP when leaving that Node. Refer to this document for more information.

Requirements for this Feature

This feature is currently only supported for Nodes running Linux and “encap” mode. The support for Windows and other traffic modes will be added in the future.

NodeIPAM

NodeIPAM runs a Node IPAM Controller similar to the one in Kubernetes that allocates Pod CIDRs for Nodes. Running Node IPAM Controller with Antrea is useful in environments where Kubernetes Controller Manager does not run the Node IPAM Controller, and Antrea has to handle the CIDR allocation.

Requirements for this Feature

This feature requires the Node IPAM Controller to be disabled in Kubernetes Controller Manager. When Antrea and Kubernetes both run Node IPAM Controller there is a risk of conflicts in CIDR allocation between the two.

AntreaIPAM

AntreaIPAM feature allocates IP addresses from IPPools. It is required by bridging mode Pods. The bridging mode allows flexible control over Pod IP addressing. The desired set of IP ranges, optionally with VLANs, are defined with IPPool CRD. An IPPool can be annotated to Namespace, Pod and PodTemplate of StatefulSet/Deployment. Then, Antrea will manage IP address assignment for corresponding Pods according to IPPool spec. On a Node, cross-Node/VLAN traffic of AntreaIPAM Pods is sent to the underlay network, and forwarded/routed by the underlay network. For more information, please refer to the Antrea IPAM document.

This feature gate also needs to be enabled to use Antrea for IPAM when configuring secondary network interfaces with Multus, in which case Antrea works as an IPAM plugin and allocates IP addresses for Pods' secondary networks, again from the configured IPPools of a secondary network. Refer to the secondary network IPAM document to learn more information.

Requirements for this Feature

Both bridging mode and secondary network IPAM are supported only on Linux Nodes.

The bridging mode works only with system OVS datapath type; and noEncap, noSNAT traffic mode. At the moment, it supports only IPv4. The IPs in an IP range without a VLAN must be in the same underlay subnet as the Node IPs, because inter-Node traffic of AntreaIPAM Pods is forwarded by the Node network. IP ranges with a VLAN must not overlap with other network subnets, and the underlay network router should provide the network connectivity for these VLANs.

Multicast

The Multicast feature enables forwarding multicast traffic within the cluster network (i.e., between Pods) and between the external network and the cluster network. Refer to this document for more information.

Requirements for this Feature

This feature is only supported:

• on Linux Nodes
• for IPv4 traffic
• in noEncap and encap traffic modes

SecondaryNetwork

The SecondaryNetwork feature enables support for provisioning secondary network interfaces for Pods, by annotating them appropriately.

More documentation will be coming in the future.

Requirements for this Feature

At the moment, Antrea can only create secondary network interfaces using SR-IOV VFs on baremetal Linux Nodes.

ServiceExternalIP

The ServiceExternalIP feature enables a controller which can allocate external IPs for Services with type LoadBalancer. External IPs are allocated from an ExternalIPPool resource and each IP gets assigned to a Node selected by the nodeSelector of the pool automatically. That Node will receive Service traffic destined to that IP and distribute it among the backend Endpoints for the Service (through kube-proxy). To enable external IP allocation for a LoadBalancer Service, you need to annotate the Service with "service.antrea.io/external-ip-pool": "<externalIPPool name>" and define the appropriate ExternalIPPool resource. Refer to this document for more information.

Requirements for this Feature

This feature is currently only supported for Nodes running Linux.

TrafficControl

TrafficControl enables a CRD API for Antrea that controls and manipulates the transmission of Pod traffic. It allows users to mirror or redirect traffic originating from specific Pods or destined for specific Pods to a local network device or a remote destination via a tunnel of various types. It enables a monitoring solution to get full visibility into network traffic, including both north-south and east-west traffic. Refer to this document for more information.

Multicluster

The Multicluster feature gate of Antrea Agent enables Antrea Multi-cluster Gateways which route Multi-cluster Service and Pod traffic through tunnels across clusters, and support for Multi-cluster NetworkPolicy ingress rules. The Multicluster feature gate of Antrea Controller enables support for Multi-cluster NetworkPolicy.

Requirements for this Feature

Antrea Multi-cluster Controller must be deployed and the cluster must join a Multi-cluster ClusterSet to configure Antrea Multi-cluster features. Refer to Antrea Multi-cluster user guide for more information about Multi-cluster configuration. At the moment, Antrea Multi-cluster supports only IPv4.

ExternalNode

The ExternalNode feature enables Antrea Agent runs on a virtual machine or a bare-metal server which is not a Kubernetes Node, and enforces Antrea NetworkPolicy for the VM/BM. Antrea Agent supports the ExternalNode feature on both Linux and Windows.

Refer to this document for more information.

Requirements for this Feature

Since Antrea Agent is running on an unmanaged VM/BM when this feature is enabled, features designed for K8s Pods are disabled. As of now, this feature requires that AntreaProxy and NetworkPolicyStats are also enabled.

OVS is required to be installed on the virtual machine or the bare-metal server before running Antrea Agent, and the OVS version must be >= 2.13.0.

SupportBundleCollection

SupportBundleCollection feature enables a CRD API for Antrea to collect support bundle files on any Node or ExternalNode, and upload to a user defined file server.

More documentation will be coming in the future.

Requirements for this Feature

User should provide a file server with this feature, and store its authentication credential in a Secret. Antrea Controller is required to be configured with the permission to read the Secret.

L7NetworkPolicy

L7NetworkPolicy enables users to protect their applications by specifying how they are allowed to communicate with others, taking into account application context, providing fine-grained control over the network traffic beyond IP, transport protocol, and port. Refer to this document for more information.

Requirements for this Feature

This feature is currently only supported for Nodes running Linux, and TX checksum offloading must be disabled. Refer to this document for more information and how it can be configured.

AdminNetworkPolicy

The AdminNetworkPolicy API (which currently includes the AdminNetworkPolicy and BaselineAdminNetworkPolicy objects) complements the Antrea-native policies and help cluster administrators to set security postures in a portable manner.