1. Kubernetes 1.20 集群部署全景解读
作为容器编排领域的事实标准,Kubernetes 1.20版本带来了多项重要特性更新。本教程将从零开始构建生产级集群,重点解析以下核心改进:
- 废弃Docker运行时支持带来的CRI选择策略
- API优先级与公平性(APF)的实践配置
- 增强的Volume快照功能集成方案
我们将采用kubeadm工具链,基于containerd运行时,在Ubuntu 20.04 LTS上构建高可用集群架构。这个方案经过笔者在金融、物联网等多个行业的实际生产验证,特别适合需要长期稳定运行的企业级环境。
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2. 基础环境准备
2.1 硬件资源配置建议
生产环境最低配置要求:
- 控制平面节点:4核CPU/8GB内存/50GB磁盘
- Worker节点:根据工作负载动态扩展
- 负载均衡器:至少2台用于API Server高可用
重要提示:所有节点需要确保时钟同步(chrony/NTP)和主机名解析正常,跨节点SSH互信建议通过Ansible批量配置。
2.2 操作系统调优
执行以下内核参数优化(所有节点):
bash复制cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
net.ipv4.ip_forward = 1
net.bridge.bridge-nf-call-iptables = 1
fs.inotify.max_user_watches = 1048576
vm.swappiness = 10
EOF
sudo sysctl --system
禁用swap并安装基础依赖:
bash复制sudo swapoff -a
sudo sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab
sudo apt-get update && sudo apt-get install -y apt-transport-https ca-certificates curl gnupg lsb-release
3. 容器运行时部署
3.1 containerd深度配置
由于Kubernetes 1.20开始逐步弃用Docker支持,我们选择containerd作为生产级运行时:
bash复制# 安装containerd
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg
echo "deb [arch=amd64 signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
sudo apt-get update && sudo apt-get install -y containerd.io
# 生成默认配置并启用SystemdCgroup
sudo mkdir -p /etc/containerd
containerd config default | sudo tee /etc/containerd/config.toml
sudo sed -i 's/SystemdCgroup = false/SystemdCgroup = true/g' /etc/containerd/config.toml
sudo systemctl restart containerd
3.2 CRI工具链集成
安装crictl用于容器调试:
bash复制VERSION="v1.20.0"
wget https://github.com/kubernetes-sigs/cri-tools/releases/download/$VERSION/crictl-$VERSION-linux-amd64.tar.gz
sudo tar zxvf crictl-$VERSION-linux-amd64.tar.gz -C /usr/local/bin
rm -f crictl-$VERSION-linux-amd64.tar.gz
4. Kubernetes组件安装
4.1 关键组件部署
配置Kubernetes源并安装三件套:
bash复制sudo curl -fsSLo /usr/share/keyrings/kubernetes-archive-keyring.gpg https://packages.cloud.google.com/apt/doc/apt-key.gpg
echo "deb [signed-by=/usr/share/keyrings/kubernetes-archive-keyring.gpg] https://apt.kubernetes.io/ kubernetes-xenial main" | sudo tee /etc/apt/sources.list.d/kubernetes.list
sudo apt-get update && sudo apt-get install -y kubelet=1.20.15-00 kubeadm=1.20.15-00 kubectl=1.20.15-00
sudo apt-mark hold kubelet kubeadm kubectl
4.2 集群初始化
主节点初始化命令(注意替换API Server证书SAN):
bash复制sudo kubeadm init \
--control-plane-endpoint "k8s-api.example.com:6443" \
--upload-certs \
--pod-network-cidr=10.244.0.0/16 \
--service-cidr=10.96.0.0/12 \
--kubernetes-version v1.20.15 \
--image-repository registry.aliyuncs.com/google_containers
初始化完成后务必保存join命令输出。配置kubectl访问:
bash复制mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
5. 网络插件与扩展组件
5.1 Calico网络部署
选择与1.20版本兼容的Calico v3.18:
bash复制kubectl apply -f https://docs.projectcalico.org/archive/v3.18/manifests/calico.yaml
验证网络健康状态:
bash复制kubectl get pods -n kube-system -l k8s-app=calico-node
kubectl get pods -n kube-system -l k8s-app=calico-kube-controllers
5.2 Metrics Server配置
部署资源监控组件:
bash复制kubectl apply -f https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml
修改部署参数以兼容私有证书:
bash复制kubectl -n kube-system edit deploy metrics-server
# 在args部分添加:
# - --kubelet-insecure-tls
6. 高可用架构实现
6.1 控制平面扩展
在其他控制节点执行保存的join命令:
bash复制sudo kubeadm join k8s-api.example.com:6443 \
--token <token> \
--discovery-token-ca-cert-hash <hash> \
--control-plane \
--certificate-key <key>
6.2 负载均衡配置
使用HAProxy实现API Server负载均衡示例配置:
haproxy复制frontend k8s-api
bind *:6443
mode tcp
option tcplog
default_backend k8s-api-servers
backend k8s-api-servers
mode tcp
balance roundrobin
option tcp-check
server k8s-master-1 192.168.1.101:6443 check
server k8s-master-2 192.168.1.102:6443 check
server k8s-master-3 192.168.1.103:6443 check
7. 关键特性实践
7.1 Volume快照功能
- 安装Snapshot Controller:
bash复制kubectl apply -f https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/release-3.0/client/config/crd/snapshot.storage.k8s.io_volumesnapshotclasses.yaml
kubectl apply -f https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/release-3.0/client/config/crd/snapshot.storage.k8s.io_volumesnapshotcontents.yaml
kubectl apply -f https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/release-3.0/client/config/crd/snapshot.storage.k8s.io_volumesnapshots.yaml
- 创建示例快照:
yaml复制apiVersion: snapshot.storage.k8s.io/v1
kind: VolumeSnapshot
metadata:
name: test-snapshot
spec:
volumeSnapshotClassName: csi-hostpath-snapclass
source:
persistentVolumeClaimName: test-pvc
7.2 API优先级配置
启用APF特性门控:
yaml复制# /etc/kubernetes/manifests/kube-apiserver.yaml 追加:
- --feature-gates=APIPriorityAndFairness=true
- --runtime-config=flowcontrol.apiserver.k8s.io/v1alpha1=true
定义优先级配置:
yaml复制apiVersion: flowcontrol.apiserver.k8s.io/v1alpha1
kind: PriorityLevelConfiguration
metadata:
name: high-priority
spec:
limited:
assuredConcurrencyShares: 100
limitResponse:
type: Queue
queuing:
queueLengthLimit: 100
handSize: 6
queues: 64
8. 生产环境验证
8.1 集群健康检查
综合验证命令集:
bash复制# 节点状态
kubectl get nodes -o wide
# 组件健康
kubectl get cs
# 事件监控
kubectl get events --sort-by='.metadata.creationTimestamp' -A
# DNS测试
kubectl run -it --rm --restart=Never busybox --image=busybox -- nslookup kubernetes.default
8.2 性能压力测试
使用kube-bench进行CIS合规检查:
bash复制docker run --rm --pid=host -v /etc:/etc:ro -v /var:/var:ro -v $(which kubectl):/usr/local/mount-from-host/bin/kubectl -v ~/.kube:/.kube -e KUBECONFIG=/.kube/config aquasec/kube-bench:latest run --targets=master,node
创建测试负载:
bash复制kubectl create deployment stress-test --image=stress --replicas=50 -- stress --cpu 4 --vm 2 --vm-bytes 512M
9. 运维管理技巧
9.1 证书自动续期
1.20版本改进了证书管理机制,建议配置定期检查:
bash复制# 检查证书有效期
kubeadm certs check-expiration
# 手动更新证书
kubeadm certs renew all
9.2 关键日志收集
配置journald持久化:
bash复制mkdir -p /var/log/journal
systemd-tmpfiles --create --prefix /var/log/journal
systemctl restart systemd-journald
重要的日志监控点:
- /var/log/kubelet.log
- /var/log/kube-apiserver.log
- journalctl -u kubelet -f
10. 故障排查指南
常见问题处理速查表:
| 故障现象 | 诊断命令 | 解决方案 |
|---|---|---|
| Pod一直Pending | kubectl describe pod <name> |
检查资源配额、节点选择器、PV绑定状态 |
| Node状态NotReady | journalctl -u kubelet -n 100 |
检查kubelet日志,通常与CNI或证书过期有关 |
| API连接超时 | telnet <api-endpoint> 6443 |
验证负载均衡器和防火墙规则 |
| DNS解析失败 | kubectl get endpoints kube-dns -n kube-system |
检查CoreDNS Pod状态和网络策略 |
网络问题深度排查流程:
- 检查Calico BGP对等状态(如使用BGP后端)
- 验证iptables/nftables规则链
- 使用nsenter进入Pod网络命名空间测试
- 捕获CNI插件执行日志(设置calico-node日志级别为debug)
