Antrea Feature Gates

    In particular:

    • a feature in the Alpha stage will be disabled by default but can be enabled by editing the appropriate 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:

    Description and Requirements of Features

    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 for extra information on AntreaProxy and how it can be configured.

    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 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).

    TopologyAwareHints

    TopologyAwareHints enables TopologyAwareHints support in AntreaProxy. The feature TopologyAwareHints is at beta stage in Kubernetes 1.23 (beta), and it is enabled by default in Kubernetes 1.24. For AntreaProxy, traffic can be routed to the Endpoint which is closer to its origin with this feature. Refer to this link for more information.

    Requirements for this Feature

    Feature EndpointSlice is enabled.

    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 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

    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 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 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:

    1. # List stats of all K8s NetworkPolicies.
    2. > kubectl get networkpolicystats -A
    3. NAMESPACE     NAME                  SESSIONS   PACKETS   BYTES   CREATED AT
    4. default       access-nginx          3          36        5199    2020-09-07T13:19:38Z
    5. kube-system   access-dns            1          12        1221    2020-09-07T13:22:42Z
    7. # List stats of all Antrea ClusterNetworkPolicies.
    8. > kubectl get antreaclusternetworkpolicystats
    9. NAME                  SESSIONS   PACKETS   BYTES   CREATED AT
    10. cluster-deny-egress   3          36        5199    2020-09-07T13:19:38Z
    11. cluster-access-dns    10         120       12210   2020-09-07T13:22:42Z
    13. # List stats of all Antrea NetworkPolicies.
    14. > kubectl get antreanetworkpolicystats -A
    15. NAMESPACE     NAME                  SESSIONS   PACKETS   BYTES   CREATED AT
    16. default       access-http           3          36        5199    2020-09-07T13:19:38Z
    17. foo           bar                   1          12        1221    2020-09-07T13:22:42Z
    19. # List per-rule statistics for Antrea ClusterNetworkPolicy cluster-access-dns.
    20. # Both Antrea NetworkPolicy and Antrea ClusterNetworkPolicy support per-rule statistics.
    21. > kubectl get antreaclusternetworkpolicystats cluster-access-dns -o json
    22. {
    23.     "apiVersion": "stats.antrea.io/v1alpha1",
    24.     "kind": "AntreaClusterNetworkPolicyStats",
    25.         "creationTimestamp": "2022-02-24T09:04:53Z",
    26.         "name": "cluster-access-dns",
    27.         "uid": "940cf76a-d836-4e76-b773-d275370b9328"
    28.     },
    29.     "ruleTrafficStats": [
    30.         {
    31.             "name": "rule1",
    32.             "trafficStats": {
    34.                 "packets": 4,
    35.                 "sessions": 1
    36.             }
    37.         },
    38.         {
    39.             "name": "rule2",
    40.             "trafficStats": {
    41.                 "bytes": 111,
    42.                 "packets": 2,
    43.                 "sessions": 1
    44.             }
    45.         }
    46.     ],
    47.     "trafficStats": {
    48.         "bytes": 503,
    49.         "packets": 6,
    50.         "sessions": 2
    51.     }
    52. }

    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 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 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 to learn more information.

    Requirements for this Feature

    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.

    More documentation will be coming in the future.

    Requirements for this Feature

    This feature is only supported:

    • on Linux Nodes
    • in noEncap mode

    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 for more information.

    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.

    More documentation will be coming in the future.

    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 and NetworkPolicyStats are also enabled.