mirror of https://github.com/easzlab/kubeasz.git
264 lines
9.4 KiB
Markdown
264 lines
9.4 KiB
Markdown
# calico 配置 BGP Route Reflectors
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`Calico`作为`k8s`的一个流行网络插件，它依赖`BGP`路由协议实现集群节点上的`POD`路由互通；而路由互通的前提是节点间建立 BGP Peer 连接。BGP 路由反射器（Route Reflectors，简称 RR）可以简化集群BGP Peer的连接方式，它是解决BGP扩展性问题的有效方式；具体来说：
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- 没有 RR 时，所有节点之间需要两两建立连接（IBGP全互联），节点数量增加将导致连接数剧增、资源占用剧增
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- 引入 RR 后，其他 BGP 路由器只需要与它建立连接并交换路由信息，节点数量增加连接数只是线性增加，节省系统资源
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calico-node 版本 v3.3 开始支持内建路由反射器，非常方便，因此使用 calico 作为网络插件可以支持大规模节点数的`K8S`集群。
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本文档主要讲解配置 BGP Route Reflectors，建议首先阅读[基础calico文档](calico.md)。
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## 前提条件
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实验环境为按照kubeasz安装的2主2从集群，calico 版本 v3.3.2
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```
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$ kubectl get node
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NAME STATUS ROLES AGE VERSION
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192.168.1.1 Ready,SchedulingDisabled master 178m v1.13.1
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192.168.1.2 Ready,SchedulingDisabled master 178m v1.13.1
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192.168.1.3 Ready node 178m v1.13.1
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192.168.1.4 Ready node 178m v1.13.1
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$ kubectl get pod -n kube-system -o wide | grep calico
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calico-kube-controllers-77487546bd-jqrlc 1/1 Running 0 179m 192.168.1.3 192.168.1.3 <none> <none>
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calico-node-67t5m 2/2 Running 0 179m 192.168.1.1 192.168.1.1 <none> <none>
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calico-node-drmhq 2/2 Running 0 179m 192.168.1.2 192.168.1.2 <none> <none>
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calico-node-rjtkv 2/2 Running 0 179m 192.168.1.4 192.168.1.4 <none> <none>
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calico-node-xtspl 2/2 Running 0 179m 192.168.1.3 192.168.1.3 <none> <none>
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```
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查看当前集群中BGP连接情况：可以看到集群中4个节点两两建立了 BGP 连接
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```
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$ ansible all -m shell -a '/opt/kube/bin/calicoctl node status'
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192.168.1.3 | SUCCESS | rc=0 >>
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Calico process is running.
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IPv4 BGP status
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+--------------+-------------------+-------+----------+-------------+
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| PEER ADDRESS | PEER TYPE | STATE | SINCE | INFO |
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+--------------+-------------------+-------+----------+-------------+
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| 192.168.1.1 | node-to-node mesh | up | 03:08:20 | Established |
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| 192.168.1.2 | node-to-node mesh | up | 03:08:18 | Established |
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| 192.168.1.4 | node-to-node mesh | up | 03:08:19 | Established |
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+--------------+-------------------+-------+----------+-------------+
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IPv6 BGP status
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No IPv6 peers found.
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192.168.1.2 | SUCCESS | rc=0 >>
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Calico process is running.
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IPv4 BGP status
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+--------------+-------------------+-------+----------+-------------+
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| PEER ADDRESS | PEER TYPE | STATE | SINCE | INFO |
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+--------------+-------------------+-------+----------+-------------+
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| 192.168.1.4 | node-to-node mesh | up | 03:08:17 | Established |
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| 192.168.1.3 | node-to-node mesh | up | 03:08:18 | Established |
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| 192.168.1.1 | node-to-node mesh | up | 03:08:20 | Established |
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+--------------+-------------------+-------+----------+-------------+
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IPv6 BGP status
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No IPv6 peers found.
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192.168.1.1 | SUCCESS | rc=0 >>
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Calico process is running.
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IPv4 BGP status
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+--------------+-------------------+-------+----------+-------------+
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| PEER ADDRESS | PEER TYPE | STATE | SINCE | INFO |
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+--------------+-------------------+-------+----------+-------------+
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| 192.168.1.2 | node-to-node mesh | up | 03:08:21 | Established |
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| 192.168.1.3 | node-to-node mesh | up | 03:08:21 | Established |
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| 192.168.1.4 | node-to-node mesh | up | 03:08:21 | Established |
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+--------------+-------------------+-------+----------+-------------+
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IPv6 BGP status
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No IPv6 peers found.
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192.168.1.4 | SUCCESS | rc=0 >>
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Calico process is running.
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IPv4 BGP status
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+--------------+-------------------+-------+----------+-------------+
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| PEER ADDRESS | PEER TYPE | STATE | SINCE | INFO |
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+--------------+-------------------+-------+----------+-------------+
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| 192.168.1.2 | node-to-node mesh | up | 03:08:17 | Established |
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| 192.168.1.3 | node-to-node mesh | up | 03:08:19 | Established |
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| 192.168.1.1 | node-to-node mesh | up | 03:08:20 | Established |
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+--------------+-------------------+-------+----------+-------------+
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IPv6 BGP status
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No IPv6 peers found.
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```
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## 配置全局禁用全连接（BGP full mesh）
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```
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$ cat << EOF | calicoctl create -f -
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apiVersion: projectcalico.org/v3
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kind: BGPConfiguration
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metadata:
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name: default
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spec:
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logSeverityScreen: Info
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nodeToNodeMeshEnabled: false
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asNumber: 64512
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EOF
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```
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上述命令配置完成后，再次使用命令`ansible all -m shell -a '/opt/kube/bin/calicoctl node status'`查看，可以看到之前所有的bgp连接都消失了。
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## 配置 BGP node 与 Route Reflector 的连接建立规则
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``` bash
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$ cat << EOF | calicoctl create -f -
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kind: BGPPeer
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apiVersion: projectcalico.org/v3
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metadata:
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name: peer-to-rrs
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spec:
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# 规则1：普通 bgp node 与 rr 建立连接
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nodeSelector: !has(i-am-a-route-reflector)
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peerSelector: has(i-am-a-route-reflector)
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---
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kind: BGPPeer
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apiVersion: projectcalico.org/v3
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metadata:
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name: rr-mesh
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spec:
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# 规则2：route reflectors 之间也建立连接
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nodeSelector: has(i-am-a-route-reflector)
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peerSelector: has(i-am-a-route-reflector)
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EOF
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```
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上述命令配置完成后，使用命令：`calicoctl get bgppeer` `calicoctl get bgppeer rr-mesh -o yaml` 检查配置是否正确。
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## 选择并配置 Route Reflector 节点
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首先查看当前集群中的节点：
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```
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$ calicoctl get node -o wide
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NAME ASN IPV4 IPV6
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k8s401 (64512) 192.168.1.1/24
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k8s402 (64512) 192.168.1.2/24
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k8s403 (64512) 192.168.1.3/24
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k8s404 (64512) 192.168.1.4/24
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```
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可以在集群中选择1个或多个节点作为 rr 节点，这里先选择节点：k8s401
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``` bash
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# 1.先导出 node k8s401 的配置，准备修改
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$ calicoctl get node k8s401 --export -o yaml |tee rr01.yml
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apiVersion: projectcalico.org/v3
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kind: Node
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metadata:
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creationTimestamp: null
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name: k8s401
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spec:
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bgp:
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ipv4Address: 192.168.1.1/24
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ipv4IPIPTunnelAddr: 172.20.7.128
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orchRefs:
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- nodeName: 192.168.1.1
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orchestrator: k8s
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# 2.修改上述 rr01.yml 的配置如下
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apiVersion: projectcalico.org/v3
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kind: Node
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metadata:
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creationTimestamp: null
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name: k8s401
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labels:
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# 设置标签
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i-am-a-route-reflector: true
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spec:
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bgp:
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ipv4Address: 192.168.1.1/24
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ipv4IPIPTunnelAddr: 172.20.7.128
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# 设置集群ID
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routeReflectorClusterID: 224.0.0.1
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orchRefs:
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- nodeName: 192.168.1.1
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orchestrator: k8s
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# 3.应用修改后的 rr node 配置
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$ calicoctl apply -f rr01.yml
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```
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## 查看增加 rr 之后的bgp 连接情况
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```
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$ ansible all -m shell -a '/opt/kube/bin/calicoctl node status'
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192.168.1.4 | SUCCESS | rc=0 >>
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Calico process is running.
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IPv4 BGP status
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+--------------+-----------+-------+----------+-------------+
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| PEER ADDRESS | PEER TYPE | STATE | SINCE | INFO |
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+--------------+-----------+-------+----------+-------------+
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| 192.168.1.1 | global | up | 11:02:55 | Established |
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+--------------+-----------+-------+----------+-------------+
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IPv6 BGP status
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No IPv6 peers found.
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192.168.1.3 | SUCCESS | rc=0 >>
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Calico process is running.
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IPv4 BGP status
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+--------------+-----------+-------+----------+-------------+
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| PEER ADDRESS | PEER TYPE | STATE | SINCE | INFO |
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+--------------+-----------+-------+----------+-------------+
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| 192.168.1.1 | global | up | 11:02:55 | Established |
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+--------------+-----------+-------+----------+-------------+
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IPv6 BGP status
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No IPv6 peers found.
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192.168.1.1 | SUCCESS | rc=0 >>
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Calico process is running.
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IPv4 BGP status
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+--------------+---------------+-------+----------+-------------+
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| PEER ADDRESS | PEER TYPE | STATE | SINCE | INFO |
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+--------------+---------------+-------+----------+-------------+
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| 192.168.1.2 | node specific | up | 11:02:55 | Established |
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| 192.168.1.3 | node specific | up | 11:02:55 | Established |
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| 192.168.1.4 | node specific | up | 11:02:55 | Established |
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+--------------+---------------+-------+----------+-------------+
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IPv6 BGP status
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No IPv6 peers found.
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192.168.1.2 | SUCCESS | rc=0 >>
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Calico process is running.
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IPv4 BGP status
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+--------------+-----------+-------+----------+-------------+
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| PEER ADDRESS | PEER TYPE | STATE | SINCE | INFO |
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+--------------+-----------+-------+----------+-------------+
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| 192.168.1.1 | global | up | 11:02:55 | Established |
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+--------------+-----------+-------+----------+-------------+
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IPv6 BGP status
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No IPv6 peers found.
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```
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可以看到所有其他节点都与所选rr节点建立bgp连接。
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## 再增加一个 rr 节点
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步骤同上述选择第1个 rr 节点，这里省略；添加成功后可以看到所有其他节点都与两个rr节点建立bgp连接，两个rr节点之间也建立bgp连接。
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- 对于节点数较多的`K8S`集群建议配置3-4个 RR 节点
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## 参考文档
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- 1.[Calico 使用指南：Route Reflectors](https://docs.projectcalico.org/v3.3/usage/routereflector)
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- 2.[BGP路由反射器基础](https://www.sohu.com/a/140033025_761420)
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更多 BGP 路由协议相关知识请查阅思科/华为相关网络文档。
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