kubeasz/docs/setup/network-plugin/calico-bgp-rr.md

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# 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
- 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
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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)。
## 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 <none> <none>
calico-node-67t5m 2/2 Running 0 179m 192.168.1.1 192.168.1.1 <none> <none>
calico-node-drmhq 2/2 Running 0 179m 192.168.1.2 192.168.1.2 <none> <none>
calico-node-rjtkv 2/2 Running 0 179m 192.168.1.4 192.168.1.4 <none> <none>
calico-node-xtspl 2/2 Running 0 179m 192.168.1.3 192.168.1.3 <none> <none>
```
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
```
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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。
## 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2route reflectors 之间也建立连接
nodeSelector: has(i-am-a-route-reflector)
peerSelector: has(i-am-a-route-reflector)
EOF
```
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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。
## 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 | global | 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 | global | 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 | global | up | 11:02:55 | Established |
+--------------+-----------+-------+----------+-------------+
IPv6 BGP status
No IPv6 peers found.
```
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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。
## 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。
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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
## 参考文档
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- 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)
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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。