养浩然之气,做博学之人
部署高可用 kube-controller-manager 集群,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,其它节点为阻塞状态。当 leader 节点不可用后,剩余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,先生成 x509 证书和私钥,kube-controller-manager 在如下两种情况下使用该证书:
(1)与 kube-apiserver 的安全端口通信时;
(2)在安全端口(https,10252) 输出 prometheus 格式的 metrics;
下载最新版本的二进制文件、安装和配置 flanneld 参考:06-0.部署master节点.md
创建证书签名请求:
cat> kube-controller-manager-csr.json<< EOF { "CN": "system:kube-controller-manager", "key": { "algo": "rsa", "size": 2048 }, "hosts": [ "127.0.0.1", "192.168.1.110", "192.168.1.111" ], "names": [ { "C": "CN", "ST": "BeiJing", "L": "BeiJing", "O": "system:kube-controller-manager", "OU": "xiaowangyun" } ] } EOF
#hosts 列表包含所有 kube-controller-manager 节点 IP;
#CN 为 system:kube-controller-manager、O 为 system:kube-controller-manager,kubernetes 内置的 ClusterRoleBindings system:kube-controller-manager 赋予 kube-controller-manager 工作所需的权限。
生成证书和私钥:
cfssl gencert -ca=/etc/kubernetes/cert/ca.pem -ca-key=/etc/kubernetes/cert/ca-key.pem -config=/etc/kubernetes/cert/ca-config.json -profile=kubernetes kube-controller-manager-csr.json | cfssljson -bare kube-controller-manager
将生成的证书和私钥分发到所有 master 节点:
source /opt/k8s/bin/environment.sh for node_ip in ${MASTER_IPS[@]} do echo ">>> ${node_ip}" scp kube-controller-manager*.pem k8s@${node_ip}:/etc/kubernetes/cert/ done
kubeconfig 文件包含访问 apiserver 的所有信息,如 apiserver 地址、CA 证书和自身使用的证书;
source /opt/k8s/bin/environment.sh kubectl config set-cluster kubernetes --certificate-authority=/etc/kubernetes/cert/ca.pem --embed-certs=true --server=${KUBE_APISERVER} --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
分发 kubeconfig 到所有 master 节点:
source /opt/k8s/bin/environment.sh for node_ip in ${MASTER_IPS[@]} do echo ">>> ${node_ip}" scp kube-controller-manager.kubeconfig k8s@${node_ip}:/etc/kubernetes/ done
source /opt/k8s/bin/environment.sh cat > kube-controller-manager.service <<EOF [Unit] Description=Kubernetes Controller Manager Documentation=https://github.com/GoogleCloudPlatform/kubernetes [Service] ExecStart=/opt/k8s/bin/kube-controller-manager \ --port=0 \ --secure-port=10252 \ --bind-address=127.0.0.1 \ --kubeconfig=/etc/kubernetes/kube-controller-manager.kubeconfig \ --service-cluster-ip-range=${SERVICE_CIDR} \ --cluster-name=kubernetes \ --cluster-signing-cert-file=/etc/kubernetes/cert/ca.pem \ --cluster-signing-key-file=/etc/kubernetes/cert/ca-key.pem \ --experimental-cluster-signing-duration=8760h \ --root-ca-file=/etc/kubernetes/cert/ca.pem \ --service-account-private-key-file=/etc/kubernetes/cert/ca-key.pem \ --leader-elect=true \ --feature-gates=RotateKubeletServerCertificate=true \ --controllers=*,bootstrapsigner,tokencleaner \ --horizontal-pod-autoscaler-use-rest-clients=true \ --horizontal-pod-autoscaler-sync-period=10s \ --tls-cert-file=/etc/kubernetes/cert/kube-controller-manager.pem \ --tls-private-key-file=/etc/kubernetes/cert/kube-controller-manager-key.pem \ --use-service-account-credentials=true \ --alsologtostderr=true \ --logtostderr=false \ --log-dir=/var/log/kubernetes \ --v=2 Restart=on Restart=on-failure RestartSec=5 User=k8s [Install] WantedBy=multi-user.target EOF
#--port=0:关闭监听 http /metrics 的请求,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;
#--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;
#--feature-gates=RotateKubeletServerCertificate=true:开启 kublet server 证书的自动更新特性;
#--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:
#User=k8s:使用 k8s 账户运行;
##kube-controller-manager 不对请求 https metrics 的 Client 证书进行校验,故不需要指定 --tls-ca-file 参数,而且该参数已被淘汰。
分发 systemd unit 文件到所有 master 节点:
source /opt/k8s/bin/environment.sh for node_ip in ${MASTER_IPS[@]} do echo ">>> ${node_ip}" scp kube-controller-manager.service root@${node_ip}:/etc/systemd/system/ done
ClusteRole: system:kube-controller-manager 的权限很小,只能创建 secret、serviceaccount 等资源对象,各 controller 的权限分散到 ClusterRole system:controller:XXX 中。
需要在 kube-controller-manager 的启动参数中添加 --use-service-account-credentials=true 参数,这样 main controller 会为各 controller 创建对应的 ServiceAccount XXX-controller。
内置的 ClusterRoleBinding system:controller:XXX 将赋予各 XXX-controller ServiceAccount 对应的 ClusterRole system:controller:XXX 权限。
source /opt/k8s/bin/environment.sh for node_ip in ${MASTER_IPS[@]} do echo ">>> ${node_ip}" ssh root@${node_ip} "mkdir -p /var/log/kubernetes && chown -R k8s /var/log/kubernetes" ssh root@${node_ip} "systemctl daemon-reload && systemctl enable kube-controller-manager && systemctl restart kube-controller-manager" done
#必须先创建日志目录;
source /opt/k8s/bin/environment.sh for node_ip in ${MASTER_IPS[@]} do echo ">>> ${node_ip}" ssh k8s@${node_ip} "systemctl status kube-controller-manager|grep Active" done
确保状态为 active (running),否则查看日志,确认原因:journalctl -u kube-controller-manager
#注意:以下命令在 kube-controller-manager 节点上执行。
#kube-controller-manager 监听 10252 端口,接收 https 请求:
sudo netstat -lnpt|grep kube-controll #tcp 0 0 127.0.0.1:10252 0.0.0.0:* LISTEN 7402/kube-controlle
curl -s --cacert /etc/kubernetes/cert/ca.pem https://127.0.0.1:10252/metrics |head
输出:
# HELP ClusterRoleAggregator_adds Total number of adds handled by workqueue: ClusterRoleAggregator
# TYPE ClusterRoleAggregator_adds counter
ClusterRoleAggregator_adds 3
# HELP ClusterRoleAggregator_depth Current depth of workqueue: ClusterRoleAggregator
# TYPE ClusterRoleAggregator_depth gauge
ClusterRoleAggregator_depth 0
# HELP ClusterRoleAggregator_queue_latency How long an item stays in workqueueClusterRoleAggregator before being requested.
# TYPE ClusterRoleAggregator_queue_latency summary
ClusterRoleAggregator_queue_latency{quantile="0.5"} 19720
ClusterRoleAggregator_queue_latency{quantile="0.9"} 20032
curl --cacert CA 证书用来验证 kube-controller-manager https server 证书;
查看当前的 leader
kubectl get endpoints kube-controller-manager --namespace=kube-system -o yaml
当前leader是dokcer110:"holderIdentity":"docker110_8065545f-9ddc-11e8-a04b-000c2931fef9"
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。
systemctl stop kube-controller-manager
再次查看leader可见,当前的 leader 为 docker112 :"holderIdentity":"docker112_81cc39d8-9ddc-11e8-885f-000c29761448"
参考:
https://www.kubernetes.org.cn/3063.html
https://www.kubernetes.org.cn/3096.html
https://github.com/opsnull/follow-me-install-kubernetes-cluster
http://www.imooc.com/article/23355
https://www.docker.com/
编辑:孙小北
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