# calico 配置 BGP Route Reflectors `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： - 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 - 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 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。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)。 ## 前提条件实验环境为按照kubeasz安装的2主2从集群，calico 版本 v3.3.2 ``` $ kubectl get node NAME STATUS ROLES AGE VERSION 192.168.1.1 Ready,SchedulingDisabled master 178m v1.13.1 192.168.1.2 Ready,SchedulingDisabled master 178m v1.13.1 192.168.1.3 Ready node 178m v1.13.1 192.168.1.4 Ready node 178m v1.13.1 $ kubectl get pod -n kube-system -o wide | grep calico calico-kube-controllers-77487546bd-jqrlc 1/1 Running 0 179m 192.168.1.3 192.168.1.3 calico-node-67t5m 2/2 Running 0 179m 192.168.1.1 192.168.1.1 calico-node-drmhq 2/2 Running 0 179m 192.168.1.2 192.168.1.2 calico-node-rjtkv 2/2 Running 0 179m 192.168.1.4 192.168.1.4 calico-node-xtspl 2/2 Running 0 179m 192.168.1.3 192.168.1.3 ``` 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 ``` $ ansible all -m shell -a '/opt/kube/bin/calicoctl node status' 192.168.1.3 | SUCCESS | rc=0 >> Calico process is running. IPv4 BGP status +--------------+-------------------+-------+----------+-------------+ | PEER ADDRESS | PEER TYPE | STATE | SINCE | INFO | +--------------+-------------------+-------+----------+-------------+ | 192.168.1.1 | node-to-node mesh | up | 03:08:20 | Established | | 192.168.1.2 | node-to-node mesh | up | 03:08:18 | Established | | 192.168.1.4 | node-to-node mesh | up | 03:08:19 | Established | +--------------+-------------------+-------+----------+-------------+ IPv6 BGP status No IPv6 peers found. 192.168.1.2 | SUCCESS | rc=0 >> Calico process is running. IPv4 BGP status +--------------+-------------------+-------+----------+-------------+ | PEER ADDRESS | PEER TYPE | STATE | SINCE | INFO | +--------------+-------------------+-------+----------+-------------+ | 192.168.1.4 | node-to-node mesh | up | 03:08:17 | Established | | 192.168.1.3 | node-to-node mesh | up | 03:08:18 | Established | | 192.168.1.1 | node-to-node mesh | up | 03:08:20 | Established | +--------------+-------------------+-------+----------+-------------+ IPv6 BGP status No IPv6 peers found. 192.168.1.1 | SUCCESS | rc=0 >> Calico process is running. IPv4 BGP status +--------------+-------------------+-------+----------+-------------+ | PEER ADDRESS | PEER TYPE | STATE | SINCE | INFO | +--------------+-------------------+-------+----------+-------------+ | 192.168.1.2 | node-to-node mesh | up | 03:08:21 | Established | | 192.168.1.3 | node-to-node mesh | up | 03:08:21 | Established | | 192.168.1.4 | node-to-node mesh | up | 03:08:21 | Established | +--------------+-------------------+-------+----------+-------------+ IPv6 BGP status No IPv6 peers found. 192.168.1.4 | SUCCESS | rc=0 >> Calico process is running. IPv4 BGP status +--------------+-------------------+-------+----------+-------------+ | PEER ADDRESS | PEER TYPE | STATE | SINCE | INFO | +--------------+-------------------+-------+----------+-------------+ | 192.168.1.2 | node-to-node mesh | up | 03:08:17 | Established | | 192.168.1.3 | node-to-node mesh | up | 03:08:19 | Established | | 192.168.1.1 | node-to-node mesh | up | 03:08:20 | Established | +--------------+-------------------+-------+----------+-------------+ IPv6 BGP status No IPv6 peers found. ``` ## 配置全局禁用全连接（BGP full mesh） ``` $ cat << EOF | calicoctl create -f - apiVersion: projectcalico.org/v3 kind: BGPConfiguration metadata: name: default spec: logSeverityScreen: Info nodeToNodeMeshEnabled: false asNumber: 64512 EOF ``` 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。 ## 配置 BGP node 与 Route Reflector 的连接建立规则 ``` bash $ cat << EOF | calicoctl create -f - kind: BGPPeer apiVersion: projectcalico.org/v3 metadata: name: peer-to-rrs spec: # 规则1：普通 bgp node 与 rr 建立连接 nodeSelector: "!has(i-am-a-route-reflector)" peerSelector: has(i-am-a-route-reflector) --- kind: BGPPeer apiVersion: projectcalico.org/v3 metadata: name: rr-mesh spec: # 规则2：route reflectors 之间也建立连接 nodeSelector: has(i-am-a-route-reflector) peerSelector: has(i-am-a-route-reflector) EOF ``` 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。 ## 选择并配置 Route Reflector 节点首先查看当前集群中的节点： ``` $ calicoctl get node -o wide NAME ASN IPV4 IPV6 k8s401 (64512) 192.168.1.1/24 k8s402 (64512) 192.168.1.2/24 k8s403 (64512) 192.168.1.3/24 k8s404 (64512) 192.168.1.4/24 ``` 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 ``` bash # 1.先导出 node k8s401 的配置，准备修改 $ calicoctl get node k8s401 --export -o yaml |tee rr01.yml apiVersion: projectcalico.org/v3 kind: Node metadata: creationTimestamp: null name: k8s401 spec: bgp: ipv4Address: 192.168.1.1/24 ipv4IPIPTunnelAddr: 172.20.7.128 orchRefs: - nodeName: 192.168.1.1 orchestrator: k8s # 2.修改上述 rr01.yml 的配置如下 apiVersion: projectcalico.org/v3 kind: Node metadata: creationTimestamp: null name: k8s401 labels: # 设置标签 i-am-a-route-reflector: true spec: bgp: ipv4Address: 192.168.1.1/24 ipv4IPIPTunnelAddr: 172.20.7.128 # 设置集群ID routeReflectorClusterID: 224.0.0.1 orchRefs: - nodeName: 192.168.1.1 orchestrator: k8s # 3.应用修改后的 rr node 配置 $ calicoctl apply -f rr01.yml ``` ## 查看增加 rr 之后的bgp 连接情况 ``` $ ansible all -m shell -a '/opt/kube/bin/calicoctl node status' 192.168.1.4 | SUCCESS | rc=0 >> Calico process is running. IPv4 BGP status +--------------+-----------+-------+----------+-------------+ | PEER ADDRESS | PEER TYPE | STATE | SINCE | INFO | +--------------+-----------+-------+----------+-------------+ | 192.168.1.1 | node specific | up | 11:02:55 | Established | +--------------+-----------+-------+----------+-------------+ IPv6 BGP status No IPv6 peers found. 192.168.1.3 | SUCCESS | rc=0 >> Calico process is running. IPv4 BGP status +--------------+-----------+-------+----------+-------------+ | PEER ADDRESS | PEER TYPE | STATE | SINCE | INFO | +--------------+-----------+-------+----------+-------------+ | 192.168.1.1 | node specific | up | 11:02:55 | Established | +--------------+-----------+-------+----------+-------------+ IPv6 BGP status No IPv6 peers found. 192.168.1.1 | SUCCESS | rc=0 >> Calico process is running. IPv4 BGP status +--------------+---------------+-------+----------+-------------+ | PEER ADDRESS | PEER TYPE | STATE | SINCE | INFO | +--------------+---------------+-------+----------+-------------+ | 192.168.1.2 | node specific | up | 11:02:55 | Established | | 192.168.1.3 | node specific | up | 11:02:55 | Established | | 192.168.1.4 | node specific | up | 11:02:55 | Established | +--------------+---------------+-------+----------+-------------+ IPv6 BGP status No IPv6 peers found. 192.168.1.2 | SUCCESS | rc=0 >> Calico process is running. IPv4 BGP status +--------------+-----------+-------+----------+-------------+ | PEER ADDRESS | PEER TYPE | STATE | SINCE | INFO | +--------------+-----------+-------+----------+-------------+ | 192.168.1.1 | node specific | up | 11:02:55 | Established | +--------------+-----------+-------+----------+-------------+ IPv6 BGP status No IPv6 peers found. ``` 可以看到所有其他节点都与所选rr节点建立bgp连接。 ## 再增加一个 rr 节点步骤同上述选择第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。 - 对于节点数较多的`K8S`集群建议配置3-4个 RR 节点 ## 参考文档 - 1.[Calico 使用指南：Route Reflectors](https://docs.projectcalico.org/v3.3/usage/routereflector) - 2.[BGP路由反射器基础](https://www.sohu.com/a/140033025_761420) 更多 BGP 路由协议相关知识请查阅思科/华为相关网络文档。