-
Notifications
You must be signed in to change notification settings - Fork 368
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Signed-off-by: Hongliang Liu <[email protected]>
- Loading branch information
1 parent
5cee770
commit 2bd84a2
Showing
1 changed file
with
223 additions
and
0 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,223 @@ | ||
| # BGPPolicy | ||
|
|
||
| ## Table of Contents | ||
|
|
||
| <!-- toc --> | ||
| - [What is BGPPolicy?](#what-is-bgppolicy) | ||
| - [Prerequisites](#prerequisites) | ||
| - [The BGPPolicy resource](#the-bgppolicy-resource) | ||
| - [NodeSelector](#nodeselector) | ||
| - [LocalASN](#localasn) | ||
| - [ListenPort](#listenport) | ||
| - [Advertisements](#advertisements) | ||
| - [BGPPeers](#bgppeers) | ||
| - [BGP router ID](#bgp-router-id) | ||
| - [BGP Authentication](#bgp-authentication) | ||
| - [Example Usage](#example-usage) | ||
| - [Combined Advertisements of Service, Pod, and Egress IPs](#combined-advertisements-of-service-pod-and-egress-ips) | ||
| - [Advertise Egress IPs to external BGP peers with more than one hop](#advertise-egress-ips-to-external-bgp-peers-with-more-than-one-hop) | ||
| - [Limitations](#limitations) | ||
| <!-- /toc --> | ||
|
|
||
| ## What is BGPPolicy? | ||
|
|
||
| `BGPPolicy` is a custom resource that allows users to run a BGP process on selected Kubernetes Nodes and advertise | ||
| Service IPs, Pod IPs, and Egress IPs to remote BGP peers, facilitating the integration of Kubernetes workloads with an | ||
| external BGP-enabled network. | ||
|
|
||
| ## Prerequisites | ||
|
|
||
| BGPPolicy was introduced in Antrea v2.1 as an alpha feature. A feature gate, `BGPPolicy`, must be enabled on antrea-agent | ||
| in the `antrea-config` ConfigMap for the feature to work, like the following: | ||
|
|
||
| ```yaml | ||
| kind: ConfigMap | ||
| apiVersion: v1 | ||
| metadata: | ||
| name: antrea-config | ||
| namespace: kube-system | ||
| data: | ||
| antrea-agent.conf: | | ||
| featureGates: | ||
| BGPPolicy: true | ||
| ``` | ||
| ## The BGPPolicy resource | ||
| A BGPPolicy in Kubernetes is a Custom Resource Definition (CRD) object. | ||
| The following manifest creates a BGPPolicy object. It will start a BGP process with ASN `64512`, listening on port `179`, | ||
| on Nodes labeled with `bgp=enabled`. The process will advertise ClusterIPs, LoadBalancerIPs, and ExternalIPs to a BGP | ||
| peer at IP address `192.168.77.200`, which has ASN `65001` and listens on port `179`: | ||
|
|
||
| ```yaml | ||
| apiVersion: crd.antrea.io/v1alpha1 | ||
| kind: BGPPolicy | ||
| metadata: | ||
| name: example-bgp-policy | ||
| spec: | ||
| nodeSelector: | ||
| matchLabels: | ||
| bgp: enabled | ||
| localASN: 64512 | ||
| listenPort: 179 | ||
| advertisements: | ||
| service: | ||
| ipTypes: [ClusterIP, ExternalIP, LoadBalancerIP] | ||
| bgpPeers: | ||
| - address: 192.168.77.200 | ||
| asn: 65001 | ||
| port: 179 | ||
| ``` | ||
|
|
||
| ### NodeSelector | ||
|
|
||
| The `nodeSelector` field selects which Kubernetes Nodes the BGPPolicy applies to based on the Node labels. The field is | ||
| mandatory. | ||
|
|
||
| **Note**: If multiple BGPPolicy objects select the same Node, the one with the earliest creation time will be chosen | ||
| as the effective BGPPolicy. | ||
|
|
||
| ### LocalASN | ||
|
|
||
| The `localASN` field defines the Autonomous System Number (ASN) that the local BGP process uses. The available private | ||
| ASN range is `64512-65535`. The field is mandatory. | ||
|
|
||
| ### ListenPort | ||
|
|
||
| The `listenPort` field specifies the port on which the BGP process listens. The default value is 179. The valid port | ||
| range is `1-65535`. | ||
|
|
||
| ### Advertisements | ||
|
|
||
| The `advertisements` field configures which IPs are advertised to BGP peers. | ||
|
|
||
| - `pod`: Specifies how to advertise Pod IPs. The Node IPAM Pod CIDRs will be advertised by setting `pod:{}`. Note that | ||
| IPs allocated by Antrea Flexible IPAM are not yet supported.. | ||
| - `egress`: Specifies how to advertise Egress IPs. All Egress IPs will be advertised by setting `egress:{}`. A Node will | ||
| only advertise Egress IPs which are local (i.e., assigned to the Node). | ||
| - `service`: Specifies how to advertise Service IPs. The `ipTypes` field lists the types of Service IPs to be advertised, | ||
| which can include `ClusterIP`, `ExternalIP`, and `LoadBalancerIP`. | ||
| - All Nodes can advertise all ClusterIPs, respecting `internalTrafficPolicy`. If `internalTrafficPolicy` is set to | ||
| `Local`, a Node will only advertise ClusterIPs with at least one local Endpoint. | ||
| - All Nodes can advertise all ExternalIPs and LoadBalancerIPs, respecting `externalTrafficPolicy`. If | ||
| `externalTrafficPolicy` is set to `Local`, a Node will only advertise IPs with at least one local Endpoint. | ||
|
|
||
| ### BGPPeers | ||
|
|
||
| The `bgpPeers` field lists the BGP peers to which the advertisements are sent. | ||
|
|
||
| - `address`: The IP address of the BGP peer. | ||
| - `asn`: The Autonomous System Number of the BGP peer. | ||
| - `port`: The port number on which the BGP peer listens. The default value is 179. | ||
| - `multihopTTL`: The Time To Live (TTL) value used in BGP packets sent to the BGP peer, with a range of 1 to 255. | ||
| The default value is 1. | ||
| - `gracefulRestartTimeSeconds`: Specifies how long the BGP peer waits for the BGP session to re-establish after a | ||
| restart before deleting stale routes, with a range of 1 to 3600 seconds. The default value is 120 seconds. | ||
|
|
||
| ## BGP router ID | ||
|
|
||
| The BGP router identifier (ID) is a 4-byte field that is usually represented as an IPv4 address. Antrea uses the following | ||
| steps to choose the BGP router ID: | ||
|
|
||
| 1. If the `node.antrea.io/bgp-router-id` annotation is present on the Node and its value is a valid IPv4 address string, | ||
| we will use the provided value. | ||
| 2. Otherwise, for an IPv4-only or dual-stack Kubernetes cluster, the Node's IPv4 address (assigned to the transport | ||
| interface) is used. | ||
| 3. Otherwise, for IPv6-only clusters, a 32-bit integer will be generated by hashing the Node name, then converted to the | ||
| string representation of an IPv4 address. | ||
|
|
||
| After this selection process, the `node.antrea.io/bgp-router-id` annotation is added / updated as necessary to reflect | ||
| the selected BGP router ID. | ||
|
|
||
| ## BGP Authentication | ||
|
|
||
| BGP authentication ensures that BGP sessions are established and maintained only with legitimate peers. Users can provide | ||
| authentication passwords for different BGP peering sessions by storing them in a Kubernetes Secret. The Secret must | ||
| be defined in the same Namespace as Antrea (`kube-system` by default) and must be named `antrea-bgp-passwords`. | ||
|
|
||
| By default, this Secret is not created, and BGP authentication is considered unconfigured for all BGP peers. If the | ||
| Secret is created like in the following example, each entry should have a key that is the concatenated string of the BGP | ||
| peer IP address and ASN (e.g., `192.168.77.100-65000`, `2001:db8::1-65000`), with the value being the password for that | ||
| BGP peer. If a given BGP peer does not have a corresponding key in the Secret data, then authentication is considered | ||
| disabled for that peer. | ||
|
|
||
| ```yaml | ||
| apiVersion: v1 | ||
| kind: Secret | ||
| metadata: | ||
| name: antrea-bgp-passwords | ||
| namespace: kube-system | ||
| stringData: | ||
| 192.168.77.100-65000: "password" | ||
| 2001:db8::1-65000: "password" | ||
| type: Opaque | ||
| ``` | ||
|
|
||
| ## Example Usage | ||
|
|
||
| ### Combined Advertisements of Service, Pod, and Egress IPs | ||
|
|
||
| In this example, we will advertise Service IPs of types ClusterIP and LoadBalancerIP, along with Pod CIDRs and Egress | ||
| IPs from the selected Nodes to multiple remote BGP peers. | ||
|
|
||
| ```yaml | ||
| apiVersion: crd.antrea.io/v1alpha1 | ||
| kind: BGPPolicy | ||
| metadata: | ||
| name: advertise-all-ips | ||
| spec: | ||
| nodeSelector: | ||
| matchLabels: | ||
| bgp: enabled | ||
| localASN: 64512 | ||
| listenPort: 179 | ||
| advertisements: | ||
| service: | ||
| ipTypes: [ClusterIP, LoadBalancerIP] | ||
| pod: {} | ||
| egress: {} | ||
| bgpPeers: | ||
| - address: 192.168.77.200 | ||
| asn: 65001 | ||
| port: 179 | ||
| - address: 192.168.77.201 | ||
| asn: 65001 | ||
| port: 179 | ||
| ``` | ||
|
|
||
| ### Advertise Egress IPs to external BGP peers with more than one hop | ||
|
|
||
| In this example, we configure the BGPPolicy to advertise Egress IPs from selected Nodes to a remote BGP peer located | ||
| multiple hops away from the cluster. It's crucial to set the `multihopTTL` to a value equal to or greater than the | ||
| number of hops, allowing BGP packets to traverse multiple hops to reach the peer. | ||
|
|
||
| ```yaml | ||
| apiVersion: crd.antrea.io/v1alpha1 | ||
| kind: BGPPolicy | ||
| metadata: | ||
| name: advertise-all-egress-ips | ||
| spec: | ||
| nodeSelector: | ||
| matchLabels: | ||
| bgp: enabled | ||
| localASN: 64512 | ||
| listenPort: 179 | ||
| advertisements: | ||
| egress: {} | ||
| bgpPeers: | ||
| - address: 192.168.78.201 | ||
| asn: 65001 | ||
| port: 179 | ||
| multihopTTL: 2 | ||
| ``` | ||
|
|
||
| ## Limitations | ||
|
|
||
| - The routes received from remote BGP peers will not be installed. Therefore, you must ensure that the path from Nodes | ||
| to the remote BGP network is properly configured and routable. This involves configuring your network infrastructure | ||
| to handle the routing of traffic between your Kubernetes cluster and the remote BGP network. | ||
| - Only Linux Nodes are supported. The feature has not been validated on Windows Nodes, though theoretically it can work | ||
| with Windows Nodes. | ||
| - Advanced BGP features such as BGP communities, route filtering, route reflection, confederations, and other BGP policy | ||
| mechanisms defined in BGP RFCs are not supported. |