配置kubelet
kubelet 运行在每个 worker 节点上,接收 kube-apiserver 发送的请求,管理 Pod 容器,执行交互式命令,如 exec、run、logs 等。
kubelet 启动时自动向 kube-apiserver 注册节点信息,内置的 cadvisor 统计和监控节点的资源使用情况。
为确保安全,部署时关闭了 kubelet 的非安全 http 端口,对请求进行认证和授权,拒绝未授权的访问(如 apiserver、heapster 的请求)。
- 创建 kubelet bootstrap kubeconfig 文件
cd /opt/k8s/work export KUBE_APISERVER=https://192.168.0.107:6443 export node_name=slave export BOOTSTRAP_TOKEN=$(kubeadm token create --description kubelet-bootstrap-token --groups system:bootstrappers:${node_name} --kubeconfig ~/.kube/config) # 设置集群参数 kubectl config set-cluster kubernetes --certificate-authority=/etc/kubernetes/cert/ca.pem --embed-certs=true --server=${KUBE_APISERVER} --kubeconfig=kubelet-bootstrap.kubeconfig # 设置客户端认证参数 kubectl config set-credentials kubelet-bootstrap --token=${BOOTSTRAP_TOKEN} --kubeconfig=kubelet-bootstrap.kubeconfig # 设置上下文参数 kubectl config set-context default --cluster=kubernetes --user=kubelet-bootstrap --kubeconfig=kubelet-bootstrap.kubeconfig # 设置默认上下文 kubectl config use-context default --kubeconfig=kubelet-bootstrap.kubeconfig
- 向 kubeconfig 写入的是 token,bootstrap 结束后 kube-controller-manager 为 kubelet 创建 client 和 server 证书
- kube-apiserver 接收 kubelet 的 bootstrap token 后,将请求的 user 设置为 system:bootstrap:,group 设置为 system:bootstrappers,后续将为这个 group 设置 ClusterRoleBinding
- 分发 bootstrap kubeconfig 文件到所有 worker 节点
cd /opt/k8s/work export node_ip=192.168.0.114 scp kubelet-bootstrap.kubeconfig [email protected]${node_ip}:/etc/kubernetes/kubelet-bootstrap.kubeconfig
- 创建和分发 kubelet 参数配置文件
从 v1.10 开始,部分 kubelet 参数需在配置文件中配置,kubelet --help 会提示
cd /opt/k8s/work export CLUSTER_CIDR="172.30.0.0/16" export NODE_IP=192.168.0.114 export CLUSTER_DNS_SVC_IP="10.254.0.2" cat > kubelet-config.yaml <<EOF kind: KubeletConfiguration apiVersion: kubelet.config.k8s.io/v1beta1 address: ${NODE_IP} staticPodPath: "/etc/kubernetes/manifests" syncFrequency: 1m fileCheckFrequency: 20s httpCheckFrequency: 20s staticPodURL: "" port: 10250 readOnlyPort: 0 rotateCertificates: true serverTLSBootstrap: true authentication: anonymous: enabled: false webhook: enabled: true x509: clientCAFile: "/etc/kubernetes/cert/ca.pem" authorization: mode: Webhook registryPullQPS: 0 registryBurst: 20 eventRecordQPS: 0 eventBurst: 20 enableDebuggingHandlers: true enableContentionProfiling: true healthzPort: 10248 healthzBindAddress: ${NODE_IP} clusterDomain: "cluster.local" clusterDNS: - "${CLUSTER_DNS_SVC_IP}" nodeStatusUpdateFrequency: 10s nodeStatusReportFrequency: 1m imageMinimumGCAge: 2m imageGCHighThresholdPercent: 85 imageGCLowThresholdPercent: 80 volumeStatsAggPeriod: 1m kubeletCgroups: "" systemCgroups: "" cgroupRoot: "" cgroupsPerQOS: true cgroupDriver: cgroupfs runtimeRequestTimeout: 10m hairpinMode: promiscuous-bridge maxPods: 220 podCIDR: "${CLUSTER_CIDR}" podPidsLimit: -1 resolvConf: /run/systemd/resolve/resolv.conf maxOpenFiles: 1000000 kubeAPIQPS: 1000 kubeAPIBurst: 2000 serializeImagePulls: false evictionHard: memory.available: "100Mi" nodefs.available: "10%" nodefs.inodesFree: "5%" imagefs.available: "15%" evictionSoft: {} enableControllerAttachDetach: true failSwapOn: true containerLogMaxSize: 20Mi containerLogMaxFiles: 10 systemReserved: {} kubeReserved: {} systemReservedCgroup: "" kubeReservedCgroup: "" enforceNodeAllocatable: ["pods"] EOF
- address:kubelet 安全端口(https,10250)监听的地址,不能为 127.0.0.1,否则 kube-apiserver、heapster 等不能调用 kubelet 的 API;
- readOnlyPort=0:关闭只读端口(默认 10255),等效为未指定;
- authentication.anonymous.enabled:设置为 false,不允许匿名访问 10250 端口;
- authentication.x509.clientCAFile:指定签名客户端证书的 CA 证书,开启 HTTP 证书认证;
- authentication.webhook.enabled=true:开启 HTTPs bearer token 认证;
对于未通过 x509 证书和 webhook 认证的请求(kube-apiserver 或其他客户端),将被拒绝,提示 Unauthorized;
- authroization.mode=Webhook:kubelet 使用 SubjectAccessReview API 查询 kube-apiserver 某 user、group 是否具有操作资源的权限(RBAC);
- featureGates.RotateKubeletClientCertificate、featureGates.RotateKubeletServerCertificate:自动 rotate 证书,证书的有效期取决于 kube-controller-manager 的 --experimental-cluster-signing-duration 参数
- 为各节点创建和分发 kubelet 配置文件
cd /opt/k8s/work export node_ip=192.168.0.114 scp kubelet-config.yaml [email protected]${node_ip}:/etc/kubernetes/kubelet-config.yaml
- 创建和分发 kubelet 服务启动文件
cd /opt/k8s/work export K8S_DIR=/data/k8s/k8s export NODE_NAME=slave cat > kubelet.service <<EOF [Unit] Description=Kubernetes Kubelet Documentation=https://github.com/GoogleCloudPlatform/kubernetes After=docker.service Requires=docker.service [Service] WorkingDirectory=${K8S_DIR}/kubelet ExecStart=/opt/k8s/bin/kubelet \ --bootstrap-kubeconfig=/etc/kubernetes/kubelet-bootstrap.kubeconfig \ --cert-dir=/etc/kubernetes/cert \ --root-dir=${K8S_DIR}/kubelet \ --kubeconfig=/etc/kubernetes/kubelet.kubeconfig \ --config=/etc/kubernetes/kubelet-config.yaml \ --hostname-override=${NODE_NAME} \ --image-pull-progress-deadline=15m \ --volume-plugin-dir=${K8S_DIR}/kubelet/kubelet-plugins/volume/exec/ \ --logtostderr=true \ --v=2 Restart=always RestartSec=5 StartLimitInterval=0 [Install] WantedBy=multi-user.target EOF
- 如果设置了 --hostname-override 选项,则 kube-proxy 也需要设置该选项,否则会出现找不到 Node 的情况;
- --bootstrap-kubeconfig:指向 bootstrap kubeconfig 文件,kubelet 使用该文件中的用户名和 token 向 kube-apiserver 发送 TLS Bootstrapping 请求;
- K8S approve kubelet 的 csr 请求后,在 --cert-dir 目录创建证书和私钥文件,然后写入 --kubeconfig 文件
- 安装分发kubelet服务文件
cd /opt/k8s/work export node_ip=192.168.0.114 scp kubelet.service [email protected]${node_ip}:/etc/systemd/system/kubelet.service
- 授予 kube-apiserver 访问 kubelet API 的权限
在执行 kubectl exec、run、logs 等命令时,apiserver 会将请求转发到 kubelet 的 https 端口。这里定义 RBAC 规则,授权 apiserver 使用的证书(kubernetes.pem)对应的用户(CN:kubernetes-api)访问 kubelet API 的权限,详情参考kubelet-auth:
kubectl create clusterrolebinding kube-apiserver:kubelet-apis --clusterrole=system:kubelet-api-admin --user kubernetes-api
- Bootstrap Token Auth 和授予权限
kubelet 启动时查找 --kubeletconfig 参数对应的文件是否存在,如果不存在则使用 --bootstrap-kubeconfig 指定的 kubeconfig 文件向 kube-apiserver 发送证书签名请求 (CSR)。
kube-apiserver 收到 CSR 请求后,对其中的 Token 进行认证,认证通过后将请求的 user 设置为 system:bootstrap:,group 设置为 system:bootstrappers,这一过程称为 Bootstrap Token Auth。
默认情况下,这个 user 和 group 没有创建 CSR 的权限, 需要创建一个 clusterrolebinding,将 group system:bootstrappers 和 clusterrole system:node-bootstrapper 绑定:
kubectl create clusterrolebinding kubelet-bootstrap --clusterrole=system:node-bootstrapper --group=system:bootstrappers
- 启动 kubelet 服务
export K8S_DIR=/data/k8s/k8s export node_ip=192.168.0.114 ssh [email protected]${node_ip} "mkdir -p ${K8S_DIR}/kubelet/kubelet-plugins/volume/exec/" ssh [email protected]${node_ip} "systemctl daemon-reload && systemctl enable kubelet && systemctl restart kubelet"
- kubelet 启动后使用 --bootstrap-kubeconfig 向 kube-apiserver 发送 CSR 请求,当这个 CSR 被 approve 后,kube-controller-manager 为 kubelet 创建 TLS 客户端证书、私钥和 --kubeletconfig 文件。
- 注意:kube-controller-manager 需要配置 --cluster-signing-cert-file 和 --cluster-signing-key-file 参数,才会为 TLS Bootstrap 创建证书和私钥。
- 遇到问题
- 启动kubelet后,使用 kubectl get csr 没有结果,查看kubelet出现错误
journalctl -u kubelet -a |grep -A 2 ‘certificate_manager.go‘ Failed while requesting a signed certificate from the master: cannot create certificate signing request: Unauthorized
查看kube-api服务日志
[email protected]:/opt/k8s/work# journalctl -eu kube-apiserver Unable to authenticate the request due to an error: invalid bearer token
原因,在kube-apiserver服务的启动文件中丢掉了下面的配置
--enable-bootstrap-token-auth \
追加上,重新启动kube-apiserver后解决
- kubelet 启动后持续不断的产生csr,手动approve后还继续产生
原因是kube-controller-manager服务停止掉了,重新启动后解决
- kubelet服务出问题后 要删除对应节点的/etc/kubernetes/kubelet.kubeconfig和/etc/kubernetes/cert/kubelet-client-current*.pem、/etc/kubernetes/cert/kubelet-client-current*.pem,之后再重新启动kubelet
- 启动kubelet后,使用 kubectl get csr 没有结果,查看kubelet出现错误
- 查看 kubelet 情况
[email protected]:/opt/k8s/work# kubectl get csr NAME AGE REQUESTOR CONDITION csr-kl5mg 49s system:bootstrap:5t989l Pending csr-mrmkf 2m1s system:bootstrap:5t989l Pending csr-ql68g 13s system:bootstrap:5t989l Pending csr-rvl2v 84s system:bootstrap:5t989l Pending
- 执行时,在手动approve之前会一直追加csr
- 手动 approve csr
[email protected]:/opt/k8s/work# kubectl get csr | grep Pending | awk ‘{print $1}‘ | xargs kubectl certificate approve certificatesigningrequest.certificates.k8s.io/csr-kl5mg approved certificatesigningrequest.certificates.k8s.io/csr-mrmkf approved certificatesigningrequest.certificates.k8s.io/csr-ql68g approved certificatesigningrequest.certificates.k8s.io/csr-rvl2v approved [email protected]:/opt/k8s/work# kubectl get csr | grep Pending | awk ‘{print $1}‘ | xargs kubectl certificate approve certificatesigningrequest.certificates.k8s.io/csr-f4smx approved
- 查看node信息
[email protected]:/opt/k8s/work# kubectl get nodes NAME STATUS ROLES AGE VERSION slave Ready <none> 10m v1.17.2
- 查看kubelet服务状态
export node_ip=192.168.0.114 [email protected]:/opt/k8s/work# ssh [email protected]${node_ip} "systemctl status kubelet.service" ● kubelet.service - Kubernetes Kubelet Loaded: loaded (/etc/systemd/system/kubelet.service; enabled; vendor preset: enabled) Active: active (running) since Mon 2020-02-10 22:48:41 CST; 12min ago Docs: https://github.com/GoogleCloudPlatform/kubernetes Main PID: 15529 (kubelet) Tasks: 19 (limit: 4541) CGroup: /system.slice/kubelet.service └─15529 /opt/k8s/bin/kubelet --bootstrap-kubeconfig=/etc/kubernetes/kubelet-bootstrap.kubeconfig --cert-dir=/etc/kubernetes/cert --root-dir=/data/k8s/k8s/kubelet --kubeconfig=/etc/kubernetes/kubelet.kubeconfig --config=/etc/kubernetes/kubelet-config.yaml --hostname-override=slave --image-pull-progress-deadline=15m --volume-plugin-dir=/data/k8s/k8s/kubelet/kubelet-plugins/volume/exec/ --logtostderr=true --v=2 2月 10 22:49:04 slave kubelet[15529]: I0210 22:49:04.846285 15529 kubelet_node_status.go:73] Successfully registered node slave 2月 10 22:49:04 slave kubelet[15529]: I0210 22:49:04.930745 15529 certificate_manager.go:402] Rotating certificates 2月 10 22:49:14 slave kubelet[15529]: I0210 22:49:14.966351 15529 kubelet_node_status.go:486] Recording NodeReady event message for node slave 2月 10 22:49:29 slave kubelet[15529]: I0210 22:49:29.580410 15529 certificate_manager.go:531] Certificate expiration is 2030-02-06 04:19:00 +0000 UTC, rotation deadline is 2029-01-21 13:08:18.850930128 +0000 UTC 2月 10 22:49:29 slave kubelet[15529]: I0210 22:49:29.580484 15529 certificate_manager.go:281] Waiting 78430h18m49.270459727s for next certificate rotation 2月 10 22:49:30 slave kubelet[15529]: I0210 22:49:30.580981 15529 certificate_manager.go:531] Certificate expiration is 2030-02-06 04:19:00 +0000 UTC, rotation deadline is 2027-07-14 16:09:26.990162158 +0000 UTC 2月 10 22:49:30 slave kubelet[15529]: I0210 22:49:30.581096 15529 certificate_manager.go:281] Waiting 65065h19m56.409078053s for next certificate rotation 2月 10 22:53:44 slave kubelet[15529]: I0210 22:53:44.911705 15529 kubelet.go:1312] Image garbage collection succeeded 2月 10 22:53:45 slave kubelet[15529]: I0210 22:53:45.053792 15529 container_manager_linux.go:469] [ContainerManager]: Discovered runtime cgroups name: /system.slice/docker.service 2月 10 22:58:45 slave kubelet[15529]: I0210 22:58:45.054225 15529 container_manager_linux.go:469] [ContainerManager]: Discovered runtime cgroups name: /system.slice/docker.servic
配置kube-proxy 组件
- 创建 kube-proxy 证书和私钥
- 创建证书签名请求文件
cd /opt/k8s/work cat > kube-proxy-csr.json <<EOF { "CN": "system:kube-proxy", "key": { "algo": "rsa", "size": 2048 }, "names": [ { "C": "CN", "ST": "NanJing", "L": "NanJing", "O": "system:kube-proxy", "OU": "system" } ] } EOF
- CN:指定该证书的 User 为 system:kube-proxy;
- 预定义的 RoleBinding system:node-proxier 将User system:kube-proxy 与 Role system:node-proxier 绑定,该 Role 授予了调用 kube-apiserver Proxy 相关 API 的权限。
- 生成证书和私钥
cd /opt/k8s/work cfssl gencert -ca=/opt/k8s/work/ca.pem -ca-key=/opt/k8s/work/ca-key.pem -config=/opt/k8s/work/ca-config.json -profile=kubernetes kube-proxy-csr.json | cfssljson -bare kube-proxy ls kube-proxy*pem
- 安装证书
cd /opt/k8s/work export node_ip=192.168.0.114 scp kube-proxy*.pem [email protected]${node_ip}:/etc/kubernetes/cert/
- 创建证书签名请求文件
- 创建 kubeconfig 文件
- kube-proxy 使用此文件访问apiserver,该文件提供了 apiserver 地址、嵌入的 CA 证书和 kube-proxy证书等信息
cd /opt/k8s/work export KUBE_APISERVER=https://192.168.0.107:6443 kubectl config set-cluster kubernetes --certificate-authority=/opt/k8s/work/ca.pem --embed-certs=true --server=${KUBE_APISERVER} --kubeconfig=kube-proxy.kubeconfig kubectl config set-credentials kube-proxy --client-certificate=kube-proxy.pem --client-key=kube-proxy-key.pem --embed-certs=true --kubeconfig=kube-proxy.kubeconfig kubectl config set-context default --cluster=kubernetes --user=kube-proxy --kubeconfig=kube-proxy.kubeconfig kubectl config use-context default --kubeconfig=kube-proxy.kubeconfig
- 分发 kubeconfig
cd /opt/k8s/work export node_ip=192.168.0.114 scp kube-proxy.kubeconfig [email protected]${node_ip}:/etc/kubernetes/kube-proxy.kubeconfig
- 创建 kube-proxy 配置文件
cd /opt/k8s/work export CLUSTER_CIDR="172.30.0.0/16" export NODE_IP=192.168.0.114 export NODE_NAME=slave cat > kube-proxy-config.yaml <<EOF kind: KubeProxyConfiguration apiVersion: kubeproxy.config.k8s.io/v1alpha1 clientConnection: burst: 200 kubeconfig: "/etc/kubernetes/kube-proxy.kubeconfig" qps: 100 bindAddress: ${NODE_IP} healthzBindAddress: ${NODE_IP}:10256 metricsBindAddress: ${NODE_IP}:10249 enableProfiling: true clusterCIDR: ${CLUSTER_CIDR} hostnameOverride: ${NODE_NAME} mode: "ipvs" portRange: "" iptables: masqueradeAll: false ipvs: scheduler: rr excludeCIDRs: [] EOF
- bindAddress: 监听地址;
- clientConnection.kubeconfig: 连接 apiserver 的 kubeconfig 文件;
- clusterCIDR: kube-proxy 根据 --cluster-cidr 判断集群内部和外部流量,指定 --cluster-cidr 或 --masquerade-all 选项后 kube-proxy 才会对访问 Service IP 的请求做 SNAT;
- hostnameOverride: 参数值必须与 kubelet 的值一致,否则 kube-proxy 启动后会找不到该 Node,从而不会创建任何 ipvs 规则;
- mode: 使用 ipvs 模式;
- 分发kube-proxy 配置文件
cd /opt/k8s/work export node_ip=192.168.0.114 scp kube-proxy-config.yaml [email protected]${node_ip}:/etc/kubernetes/kube-proxy-config.yaml
- 创建kube-proxy服务启动文件
cd /opt/k8s/work export K8S_DIR=/data/k8s/k8s cat > kube-proxy.service <<EOF [Unit] Description=Kubernetes Kube-Proxy Server Documentation=https://github.com/GoogleCloudPlatform/kubernetes After=network.target [Service] WorkingDirectory=${K8S_DIR}/kube-proxy ExecStart=/opt/k8s/bin/kube-proxy \ --config=/etc/kubernetes/kube-proxy-config.yaml \ --logtostderr=true \ --v=2 Restart=on-failure RestartSec=5 LimitNOFILE=65536 [Install] WantedBy=multi-user.target EOF
- 分发 kube-proxy服务启动文件:
export node_ip=192.168.0.114 scp kube-proxy.service [email protected]${node_ip}:/etc/systemd/system/
- 启动 kube-proxy服务
export node_ip=192.168.0.114 export K8S_DIR=/data/k8s/k8s ssh [email protected]${node_ip} "mkdir -p ${K8S_DIR}/kube-proxy" ssh [email protected]${node_ip} "modprobe ip_vs_rr" ssh [email protected]${node_ip} "systemctl daemon-reload && systemctl enable kube-proxy && systemctl restart kube-proxy"
- 检查启动结果
export node_ip=192.168.0.114 ssh [email protected]${node_ip} "systemctl status kube-proxy |grep Active"
- 确保状态为 active (running),否则查看日志,确认原因
- 如果出现异常,通过如下命令查看
journalctl -u kube-proxy
- 查看状态
[email protected]:~# netstat -lnpt|grep kube-prox tcp 0 0 192.168.0.114:10256 0.0.0.0:* LISTEN 23078/kube-proxy tcp 0 0 192.168.0.114:10249 0.0.0.0:* LISTEN 23078/kube-proxy [email protected]:~# ipvsadm -ln IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConn TCP 10.254.0.1:443 rr -> 192.168.0.107:6443 Masq 1 0 0
原文地址:https://www.cnblogs.com/gaofeng-henu/p/12594633.html