K8s进阶之MetalLB实现LoadBalancer
<h2 id="概述">概述</h2><p>LoadBalancer官网文档：https://kubernetes.io/zh-cn/docs/concepts/services-networking/service/#loadbalancer<br>
MetalLB官网地址：https://metallb.universe.tf/installation/<br>
MetalLB仓库地址：https://github.com/metallb/metallb</p>
<p>LoadBalancer是实现负载均衡的Service，主要应用场景是云厂商环境，它能够为服务提供外部可访问的 IP 地址。这种类型的服务通过云服务提供商的负载均衡器实现，允许外部流量进入集群中的 Pod。<br>
<img src="https://img2024.cnblogs.com/blog/3468887/202505/3468887-20250514212024308-747651103.png" alt="image" loading="lazy"></p>
<p>MetalLB 是一个为 Kubernetes 集群提供负载均衡的开源项目。在裸机环境中，Kubernetes 原生的 LoadBalancer 服务类型无法直接使用，因为云厂商的负载均衡器在裸机环境中不可用。MetalLB 通过实现标准的负载均衡器行为，填补了这一空白。</p>
<h2 id="metallb主要功能">MetalLB主要功能</h2>
<ul>
<li>地址分配：MetalLB 可以从预配置的 IP 地址池中分配 IP 地址给 LoadBalancer 类型的服务。</li>
<li>负载均衡实现：支持两种主要的负载均衡模式：
<ul>
<li>Layer 2 模式：通过 ARP/NDP 协议响应，将流量直接转发到节点。</li>
<li>BGP 模式：通过边界网关协议与网络设备交换路由信息。</li>
</ul>
</li>
<li>健康检查：自动检测节点健康状态，确保流量不会被发送到不可用的节点。</li>
</ul>
<h2 id="部署metallb">部署MetalLB</h2>
<pre><code># 下载
# wget https://raw.githubusercontent.com/metallb/metallb/v0.14.9/config/manifests/metallb-frr.yaml
# 配置镜像源，解决镜像拉不下来
# sed -i s#quay.io#quay.m.daocloud.io#g metallb-frr.yaml
# 应用资源文件
# kubectl apply -f metallb-frr.yaml
# 检查各种资源的启动状态
# kubectl get all -o wide -n metallb-system
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
pod/controller-749d99c9bf-89jdj 1/1 Running 1 (83s ago) 6m3s 100.95.185.241 node02 <none> <none>
pod/speaker-69stl 4/4 Running 0 11m 10.0.0.31 node01 <none> <none>
pod/speaker-lg2fp 4/4 Running 0 11m 10.0.0.30 master01 <none> <none>
pod/speaker-xhh4v 4/4 Running 0 11m 10.0.0.32 node02 <none> <none>
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
service/metallb-webhook-service ClusterIP 10.96.3.91 <none> 443/TCP 11m component=controller
NAME DESIRED CURRENT READY UP-TO-DATE AVAILABLE NODE SELECTOR AGE CONTAINERS IMAGES SELECTOR
daemonset.apps/speaker 3 3 3 3 3 kubernetes.io/os=linux 11m frr,reloader,frr-metrics,speaker quay.m.daocloud.io/frrouting/frr:9.1.0,quay.m.daocloud.io/frrouting/frr:9.1.0,quay.m.daocloud.io/frrouting/frr:9.1.0,quay.m.daocloud.io/metallb/speaker:v0.14.9 app=metallb,component=speaker
NAME READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR
deployment.apps/controller 1/1 1 1 11m controller quay.m.daocloud.io/metallb/controller:v0.14.9 app=metallb,component=controller
NAME DESIRED CURRENT READY AGE CONTAINERS IMAGES SELECTOR
replicaset.apps/controller-749d99c9bf 1 1 1 11m controller quay.m.daocloud.io/metallb/controller:v0.14.9 app=metallb,component=controller,pod-template-hash=749d99c9bf
</code></pre>
<h3 id="创建地址池配置">创建地址池配置</h3>
<pre><code># 定义清单文件
# cat ippool.yaml
apiVersion: metallb.io/v1beta1
kind: IPAddressPool
metadata:
name: first-pool
namespace: metallb-system
spec:
addresses:
# 注意改为你自己为MetalLB分配的IP地址
- 10.0.0.150-10.0.0.180
# 创建地址池
# kubectl apply -f ippool.yaml
ipaddresspool.metallb.io/first-pool created
# 检查配置
# kubectl get IPAddressPool -n metallb-system
NAME AUTO ASSIGN AVOID BUGGY IPS ADDRESSES
first-pool true false ["10.0.0.150-10.0.0.180"]
</code></pre>
<h3 id="创建l2广告配置">创建L2广告配置</h3>
<pre><code># 定义资源文件
# cat l2.yaml
apiVersion: metallb.io/v1beta1
kind: L2Advertisement
metadata:
name: example
# 注意名称空间
namespace: metallb-system
spec:
ipAddressPools:
# 地址池的名称
- first-pool
# 创建l2广告配置
# kubectl apply -f l2.yaml
l2advertisement.metallb.io/example created
# 获取l2的配置
# kubectl get L2Advertisement -n metallb-system
NAME IPADDRESSPOOLS IPADDRESSPOOL SELECTORS INTERFACES
example ["first-pool"]
</code></pre>
<h2 id="创建deploy">创建deploy</h2>
<pre><code># 定义资源清单
# cat deploy-nginx.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: deployment-nginx
namespace: default
spec:
# 设置Pod的副本数量
replicas: 3
selector:
# 标签匹配规则
matchLabels:
app: nginx
template:
metadata:
name: pod-nginx
labels:
app: nginx
spec:
containers:
- name: container-nginx
image: nginx:1.14.1
restartPolicy: Always
# 创建deploy
# kubectl apply -f deploy-nginx.yaml
deployment.apps/deployment-nginx created
# 检查是否启动
# kubectl get deploy
NAME READY UP-TO-DATE AVAILABLE AGE
deployment-nginx 3/3 3 3 108s
</code></pre>
<h2 id="创建loadbalancer的service">创建LoadBalancer的service</h2>
<pre><code># cat service-loadbanlacer.yaml
apiVersion: v1
kind: Service
metadata:
name: loadbalancer-svc
spec:
# 指定svc的类型为LoadBalancer
type: LoadBalancer
selector:
app: nginx
ports:
- port: 80
targetPort: 80
nodePort: 32000
# kubectl apply -f service-loadbanlacer.yaml
service/loadbalancer-svc created
# 注意EXTERNAL-IP这一列，IP地址会在MetalLB分配的IP地址范围之内
# kubectl get svc loadbalancer-svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
loadbalancer-svc LoadBalancer 10.96.0.141 10.0.0.150 80:32000/TCP 19s
</code></pre>
<h2 id="访问测试">访问测试</h2>
<h3 id="在宿主机上进行curl访问">在宿主机上进行curl访问</h3>
<pre><code># curl 10.0.0.150:80
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>
</code></pre>
<h3 id="通过浏览器访问">通过浏览器访问</h3>
<p>http://10.0.0.150/<br>
<img src="https://img2024.cnblogs.com/blog/3468887/202505/3468887-20250516222933048-1584935583.png" alt="image" loading="lazy"></p>
<p>结尾：想要了解service的其它类型可以查看这篇文章：K8s新手系列之Service资源</p>
</div>
<div id="MySignature" role="contentinfo">
<p>本文来自博客园，作者：huangSir-devops，转载请注明原文链接：https://www.cnblogs.com/huangSir-devops/p/18876710，微信Vac6666666，欢迎交流</p><br><br>
来源：https://www.cnblogs.com/huangSir-devops/p/18876710
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