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.

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.

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). The EndpointSlice feature gate will take no effect if AntreaProxy is not enabled. The endpoint conditions of Serving and Terminating are not supported currently. ServiceTopology is not supported either. Refer to this link for more information. The EndpointSlice API version that AntreaProxy supports is v1beta1 currently, and other EndpointSlice API versions are not supported. If EndpointSlice is enabled in AntreaProxy, but EndpointSlice API is disabled in Kubernetes or EndpointSlice API version v1beta1 is not supported in Kubernetes, Antrea Agent will log an error message and will not implement Cluster IP functionality as expected.

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).

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

Requirements for this Feature

None

NodePortLocal

NodePortLocal is a feature that runs as part of the Antrea Agent, through which each port of a Pod can be reached from external network using a port in the Node on which the Pod is running. In addition to enabling NodePortLocal feature gate, the value of nplPortRange can be set in Antrea Agent configuration through ConfigMap. Ports from a Node will be allocated from the range of ports specified in nplPortRange. If the value of nplPortRange is not specified, the range 40000-41000 will be used as default.

Pods can be selected for NodePortLocal by tagging a Service with Annotation: nodeportlocal.antrea.io/enabled: "true". Consequently, NodePortLocal is enabled for all the Pods which are selected by the Service through a selector, and the ports of these Pods will be reachable through Node ports allocated from the nplPortRange.

The selected Pods will be annotated with the details about allocated Node port(s) for the Pod. For example:

apiVersion: v1
kind: Pod
metadata:
  annotations:
    nodeportlocal.antrea.io: '[{"podPort":8080,"nodeIP":"10.10.10.10","nodePort":40002}]'

This annotation denotes that the port 8080 of the Pod can be reached through port 40002 of the Node with IP Address 10.10.10.10.

Requirements for this Feature

This feature is currently only supported for Nodes running Linux with IPv4 addresses.

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. Usage example:

apiVersion: crd.antrea.io/v1alpha2
kind: Egress
metadata:
  name: egress-web
spec:
  appliedTo:
    podSelector:
      matchLabels:
        role: web
    namespaceSelector:
      matchLabels:
        env: prod
  egressIP: 10.0.10.8

The appliedTo field specifies the grouping criteria of Pods to which the Egress applies to. Pods can be selected cluster-wide using podSelector. If set with a namespaceSelector, Pods from Namespaces selected by the namespaceSelector will be selected. Empty appliedTo selects nothing. The field is mandatory.

The egressIP field specifies the egress (SNAT) IP the traffic from the selected Pods to the external network should use. The IP must be assigned to an arbitrary interface of one Node, and one Node only. It must be reachable from all Nodes. For IPv4 cluster, it must be an IPv4 address; for IPv6 cluster, it must be an IPv6 address. The field is mandatory.

Note: If more than one Egress applies to a Pod and they specify different egressIP, the effective egress IP will be selected randomly.

In the above example, the Egress applies to Pods which match the labels “role=web” from Namespaces which match the labels “env=prod”. The source IPs of their egress traffic to external network will be translated to 10.0.10.8.

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.