本文档介绍部署高可用 kube-controller-manager 集群的步骤。
该集群包含3个节点,启动后将通过竞争选举机制产生一个leader节点,其他节点为阻塞状态。当leader节点不可用时,阻塞的节点将再次进行选举产生新的leader节点,从而保证服务的可用性。
为保证通信安全,本文档先生成 x509 证书和秘钥,kube-controller-manager 在如下两种情况下使用该证书:
- 与 kube-apiserver 的安全端口通信;
- 在安全端口(https,10252) 输出 prometheus 格式的 metrics;
注意:如果没有特殊指明,本文档的所有操作均在 k8s-01 节点上执行。
一、创建 kube-controller-manager 证书和私钥
创建证书签名请求:
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27cd /opt/k8s/work cat > kube-controller-manager-csr.json <<EOF { "CN": "system:kube-controller-manager", "key": { "algo": "rsa", "size": 2048 }, "hosts": [ "127.0.0.1", "192.168.0.71", "192.168.0.72", "192.168.0.73" ], "names": [ { "C": "CN", "ST": "BeiJing", "L": "BeiJing", "O": "system:kube-controller-manager", "OU": "opsnull" } ] } EOF
- hosts 列表包含所有 kube-controller-manager 节点 IP;
- CN 和 O 均为
system:kube-controller-manager
,kubernetes 内置的 ClusterRoleBindingssystem:kube-controller-manager
赋予 kube-controller-manager 工作所需的权限。
生成证书和私钥:
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9$ 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-controller-manager-csr.json | cfssljson -bare kube-controller-manager $ ls kube-controller-manager*pem
将生成的证书和私钥分发到所有 master 节点:
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11cat > deploy.sh << "EOF" #!/bin/bash cd /opt/k8s/work source /opt/k8s/bin/environment.sh for node_ip in ${NODE_IPS[@]} do echo ">>> ${node_ip}" scp kube-controller-manager*.pem root@${node_ip}:/etc/kubernetes/cert/ done EOF
二、创建和分发 kubeconfig 文件
kube-controller-manager 使用 kubeconfig 文件访问 apiserver,该文件提供了 apiserver 地址、嵌入的 CA 证书和 kube-controller-manager 证书等信息:
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22$ cd /opt/k8s/work $ source /opt/k8s/bin/environment.sh $ kubectl config set-cluster kubernetes --certificate-authority=/opt/k8s/work/ca.pem --embed-certs=true --server="https://##NODE_IP##:6443" --kubeconfig=kube-controller-manager.kubeconfig $ kubectl config set-credentials system:kube-controller-manager --client-certificate=kube-controller-manager.pem --client-key=kube-controller-manager-key.pem --embed-certs=true --kubeconfig=kube-controller-manager.kubeconfig $ kubectl config set-context system:kube-controller-manager --cluster=kubernetes --user=system:kube-controller-manager --kubeconfig=kube-controller-manager.kubeconfig $ kubectl config use-context system:kube-controller-manager --kubeconfig=kube-controller-manager.kubeconfig
- kube-controller-manager 与 kube-apiserver 混布,故直接通过节点 IP 访问 kube-apiserver;
分发 kubeconfig 到所有 master 节点:
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12cat > deploy.sh << "EOF" #!/bin/bash cd /opt/k8s/work source /opt/k8s/bin/environment.sh for node_ip in ${NODE_IPS[@]} do echo ">>> ${node_ip}" sed -e "s/##NODE_IP##/${node_ip}/" kube-controller-manager.kubeconfig > kube-controller-manager-${node_ip}.kubeconfig scp kube-controller-manager-${node_ip}.kubeconfig root@${node_ip}:/etc/kubernetes/kube-controller-manager.kubeconfig done EOF
三、 创建 kube-controller-manager systemd unit 模板文件
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54$ cd /opt/k8s/work $ source /opt/k8s/bin/environment.sh $ cat > kube-controller-manager.service.template <<EOF [Unit] Description=Kubernetes Controller Manager Documentation=https://github.com/GoogleCloudPlatform/kubernetes [Service] WorkingDirectory=${K8S_DIR}/kube-controller-manager ExecStart=/opt/k8s/bin/kube-controller-manager \ --profiling \ --cluster-name=kubernetes \ --controllers=*,bootstrapsigner,tokencleaner \ --kube-api-qps=1000 \ --kube-api-burst=2000 \ --leader-elect \ --use-service-account-credentials\ --concurrent-service-syncs=2 \ --bind-address=##NODE_IP## \ --secure-port=10252 \ --tls-cert-file=/etc/kubernetes/cert/kube-controller-manager.pem \ --tls-private-key-file=/etc/kubernetes/cert/kube-controller-manager-key.pem \ --port=0 \ --authentication-kubeconfig=/etc/kubernetes/kube-controller-manager.kubeconfig \ --client-ca-file=/etc/kubernetes/cert/ca.pem \ --requestheader-allowed-names="aggregator" \ --requestheader-client-ca-file=/etc/kubernetes/cert/ca.pem \ --requestheader-extra-headers-prefix="X-Remote-Extra-" \ --requestheader-group-headers=X-Remote-Group \ --requestheader-username-headers=X-Remote-User \ --authorization-kubeconfig=/etc/kubernetes/kube-controller-manager.kubeconfig \ --cluster-signing-cert-file=/etc/kubernetes/cert/ca.pem \ --cluster-signing-key-file=/etc/kubernetes/cert/ca-key.pem \ --experimental-cluster-signing-duration=876000h \ --horizontal-pod-autoscaler-sync-period=10s \ --concurrent-deployment-syncs=10 \ --concurrent-gc-syncs=30 \ --node-cidr-mask-size=24 \ --service-cluster-ip-range=${SERVICE_CIDR} \ --pod-eviction-timeout=6m \ --terminated-pod-gc-threshold=10000 \ --root-ca-file=/etc/kubernetes/cert/ca.pem \ --service-account-private-key-file=/etc/kubernetes/cert/ca-key.pem \ --kubeconfig=/etc/kubernetes/kube-controller-manager.kubeconfig \ --logtostderr=true \ --v=2 Restart=on-failure RestartSec=5 [Install] WantedBy=multi-user.target EOF
--port=0
:关闭监听非安全端口(http),同时--address
参数无效,--bind-address
参数有效;--secure-port=10252
、--bind-address=0.0.0.0
: 在所有网络接口监听 10252 端口的 https /metrics 请求;--kubeconfig
:指定 kubeconfig 文件路径,kube-controller-manager 使用它连接和验证 kube-apiserver;--authentication-kubeconfig
和--authorization-kubeconfig
:kube-controller-manager 使用它连接 apiserver,对 client 的请求进行认证和授权。kube-controller-manager
不再使用--tls-ca-file
对请求 https metrics 的 Client 证书进行校验。如果没有配置这两个 kubeconfig 参数,则 client 连接 kube-controller-manager https 端口的请求会被拒绝(提示权限不足)。--cluster-signing-*-file
:签名 TLS Bootstrap 创建的证书;--experimental-cluster-signing-duration
:指定 TLS Bootstrap 证书的有效期;--root-ca-file
:放置到容器 ServiceAccount 中的 CA 证书,用来对 kube-apiserver 的证书进行校验;--service-account-private-key-file
:签名 ServiceAccount 中 Token 的私钥文件,必须和 kube-apiserver 的--service-account-key-file
指定的公钥文件配对使用;--service-cluster-ip-range
:指定 Service Cluster IP 网段,必须和 kube-apiserver 中的同名参数一致;--leader-elect=true
:集群运行模式,启用选举功能;被选为 leader 的节点负责处理工作,其它节点为阻塞状态;--controllers=*,bootstrapsigner,tokencleaner
:启用的控制器列表,tokencleaner 用于自动清理过期的 Bootstrap token;--horizontal-pod-autoscaler-*
:custom metrics 相关参数,支持 autoscaling/v2alpha1;--tls-cert-file
、--tls-private-key-file
:使用 https 输出 metrics 时使用的 Server 证书和秘钥;--use-service-account-credentials=true
: kube-controller-manager 中各 controller 使用 serviceaccount 访问 kube-apiserver;
四、 为各节点创建和分发 kube-controller-mananger systemd unit 文件
替换模板文件中的变量,为各节点创建 systemd unit 文件:
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12$ cat > deploy.sh << "EOF" #!/bin/bash cd /opt/k8s/work source /opt/k8s/bin/environment.sh for (( i=0; i < 3; i++ )) do sed -e "s/##NODE_NAME##/${NODE_NAMES[i]}/" -e "s/##NODE_IP##/${NODE_IPS[i]}/" kube-controller-manager.service.template > kube-controller-manager-${NODE_IPS[i]}.service done EOF $ ls kube-controller-manager*.service
分发到所有 master 节点:
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11cat > deploy.sh << "EOF" #!/bin/bash cd /opt/k8s/work source /opt/k8s/bin/environment.sh for node_ip in ${NODE_IPS[@]} do echo ">>> ${node_ip}" scp kube-controller-manager-${node_ip}.service root@${node_ip}:/etc/systemd/system/kube-controller-manager.service done EOF
五、启动 kube-controller-manager 服务
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13cat > deploy.sh << "EOF" #!/bin/bash cd /opt/k8s/work source /opt/k8s/bin/environment.sh for node_ip in ${NODE_IPS[@]} do echo ">>> ${node_ip}" ssh root@${node_ip} "mkdir -p ${K8S_DIR}/kube-controller-manager" ssh root@${node_ip} "systemctl daemon-reload && systemctl enable kube-controller-manager && systemctl restart kube-controller-manager" done EOF
六、检查服务运行状态
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12cat > deploy.sh << "EOF" #!/bin/bash cd /opt/k8s/work source /opt/k8s/bin/environment.sh for node_ip in ${NODE_IPS[@]} do echo ">>> ${node_ip}" ssh root@${node_ip} "systemctl status kube-controller-manager|grep Active" done EOF
输出内容如下:
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9$ ./deploy.sh >>> 192.168.0.71 Active: active (running) since Fri 2020-04-24 13:31:47 CST; 1min 3s ago >>> 192.168.0.72 Active: active (running) since Fri 2020-04-24 13:31:51 CST; 1min 3s ago >>> 192.168.0.73 Active: active (running) since Fri 2020-04-24 13:31:52 CST; 1min 2s ago
确保状态为 active (running)
,否则通过如下命令查看日志,确认原因:
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3journalctl -u kube-controller-manager
kube-controller-manager 监听 10252 端口,接收 https 请求:
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4$ sudo netstat -lnpt | grep kube-cont tcp 0 0 192.168.0.71:10252 0.0.0.0:* LISTEN 26653/kube-controll
七、查看输出的metrics
注意:以下命令在 kube-controller-manager 节点上执行。
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13$ curl -s --cacert /opt/k8s/work/ca.pem --cert /opt/k8s/work/admin.pem --key /opt/k8s/work/admin-key.pem https://192.168.0.71:10252/metrics |head # HELP apiserver_audit_event_total [ALPHA] Counter of audit events generated and sent to the audit backend. # TYPE apiserver_audit_event_total counter apiserver_audit_event_total 0 # HELP apiserver_audit_requests_rejected_total [ALPHA] Counter of apiserver requests rejected due to an error in audit logging backend. # TYPE apiserver_audit_requests_rejected_total counter apiserver_audit_requests_rejected_total 0 # HELP apiserver_client_certificate_expiration_seconds [ALPHA] Distribution of the remaining lifetime on the certificate used to authenticate a request. # TYPE apiserver_client_certificate_expiration_seconds histogram apiserver_client_certificate_expiration_seconds_bucket{le="0"} 0 apiserver_client_certificate_expiration_seconds_bucket{le="1800"} 0
八、查看当前的leader
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14$ kubectl get endpoints kube-controller-manager --namespace=kube-system -o yaml apiVersion: v1 kind: Endpoints metadata: annotations: control-plane.alpha.kubernetes.io/leader: '{"holderIdentity":"k8s-01_130e5bf0-8d2a-42d5-86a4-9ef84c16e641","leaseDurationSeconds":15,"acquireTime":"2020-04-24T05:31:47Z","renewTime":"2020-04-24T05:42:44Z","leaderTransitions":0}' creationTimestamp: "2020-04-24T05:31:47Z" name: kube-controller-manager namespace: kube-system resourceVersion: "3489" selfLink: /api/v1/namespaces/kube-system/endpoints/kube-controller-manager uid: 395decb9-a8fb-4c91-89a5-d31fb0bdfc0e
可以看到,当前的 leader 为k8s-01 节点。
九、测试 kube-controller-manager 集群的高可用
停掉一个或两个节点的 kube-controller-manager 服务,观察其它节点的日志,看是否获取了 leader 权限。
现在停掉 k8s-01节点上的kube-controller-manager。
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5$ systemctl stop kube-controller-manager $ systemctl status kube-controller-manager |grep Active Active: inactive (dead) since Fri 2020-04-24 13:48:36 CST; 46s ago
再查看一下当前的leader:
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14$ kubectl get endpoints kube-controller-manager --namespace=kube-system -o yaml apiVersion: v1 kind: Endpoints metadata: annotations: control-plane.alpha.kubernetes.io/leader: '{"holderIdentity":"k8s-02_59ba72de-6138-475b-90e8-b2807cab5bbf","leaseDurationSeconds":15,"acquireTime":"2020-04-24T05:48:58Z","renewTime":"2020-04-24T05:49:28Z","leaderTransitions":1}' creationTimestamp: "2020-04-24T05:31:47Z" name: kube-controller-manager namespace: kube-system resourceVersion: "3802" selfLink: /api/v1/namespaces/kube-system/endpoints/kube-controller-manager uid: 395decb9-a8fb-4c91-89a5-d31fb0bdfc0e
可以看到现在的leader是k8s-02了。
参考文章:
-
关于 controller 权限和 use-service-account-credentials 参数:https://github.com/kubernetes/kubernetes/issues/48208
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kubelet 认证和授权:https://kubernetes.io/docs/admin/kubelet-authentication-authorization/#kubelet-authorization
最后
以上就是拼搏保温杯最近收集整理的关于手动搭建k8s-1.16.6高可用集群之部署master节点-部署高可用kube-controller-manager集群的全部内容,更多相关手动搭建k8s-1内容请搜索靠谱客的其他文章。
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