ovn lb select the local chassis's backend prefer

[changluyi]

Pull Request

• Make sure you have followed Kube-OVN Code Style.

What type of this PR

Examples of user facing changes:

• Features
• Bug fixes
• Docs
• Tests

目前只改了ovn 部分代码，kube-ovn 代码还在开发，可以暂时使用slr的配置：配置模板入下：

kind: SwitchLBRule
metadata:
  name:  cjh-slr-nginx
spec:
  vip: 1.1.1.1
  sessionAffinity: ClientIP
  namespace: default
  selector:
    - app:nginx
  ports:
  - name: http
    port: 80
    targetPort: 80
    protocol: TCP
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx
  labels:
    app: nginx
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      affinity:
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            - labelSelector:
                matchExpressions:
                  - key: "app"
                    operator: In
                    values:
                      - nginx
              topologyKey: "kubernetes.io/hostname"
      containers:
      - name: nginx-container
        image: nginx:alpine
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 80

实现原理是获取到vip backend的 chassis ， 新增加流表入下：

is_chassis_resident("nginx-6f55f97f94-8kvlx.default") , 其中 nginx-6f55f97f94-8kvlx.default 是某个vip 的backend下的任意一个lsp，backends=10.16.0.3:80 表示这个lb 在这个chassis下的所有backendip: port 。

  table=13(ls_in_lb           ), priority=140  , match=(ct.new && ip4.dst == 1.1.1.1 && tcp.dst == 80 && is_chassis_resident("nginx-6f55f97f94-8kvlx.default")), action=(ct_lb_mark(backends=10.16.0.3:80; hash_fields="ip_src");)
  table=13(ls_in_lb           ), priority=140  , match=(ct.new && ip4.dst == 1.1.1.1 && tcp.dst == 80 && is_chassis_resident("nginx-6f55f97f94-zlr4p.default")), action=(ct_lb_mark(backends=10.16.0.2:80; hash_fields="ip_src");)

如果hit不到以上流表，就会走原来的ovn lb 规则。

该功能需要配置Load_balancer的 两个字段
option:prefer_local_backend

option:prefer_local_backend=true

ip_port_mappings

"10.16.0.10"="nginx-6f55f97f94-m4bxx.default:10.16.0.4", "10.16.0.2"="nginx-6f55f97f94-zlr4p.default:10.16.0.4", "10.16.0.3"="nginx-6f55f97f94-8kvlx.default:10.16.0.4", "10.16.0.5"="nginx-6f55f97f94-ns9th.default:10.16.0.4"

Which issue(s) this PR fixes

Fixes #(issue-number)

[coveralls]

Pull Request Test Coverage Report for Build 12684623577

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.004%) to 22.083%

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Totals
Change from base Build 12674528419:	0.004%
Covered Lines:	10166
Relevant Lines:	46035

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💛 - Coveralls