前言

该集群包含三个节点，启动后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，阻塞节点将会在此选举产生新的leader，从而保证服务的高可用。为保证通信安全，这里采用x509证书和私钥，kube-controller-manager在与apiserver的安全端口（http 10252）通信使用；

创建kube-controller-manager证书和私钥

创建证书签名请求

cd /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",

        "10.0.20.11",

        "10.0.20.12",

        "10.0.20.13",

        "node01.k8s.com",

        "node02.k8s.com",

        "node03.k8s.com"

    ],

    "names": [

      {

        "C": "CN",

        "ST": "BeiJing",

        "L": "BeiJing",

        "O": "system:kube-controller-manager",

        "OU": "4Paradigm"

      }

    ]

}

EOF

host列表包含所有的kube-controller-manager节点IP(VIP不需要输入)
CN和O均为system:kube-controller-manager，kubernetes内置的ClusterRoleBindings system:kube-controller-manager赋予kube-controller-manager工作所需权限

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-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

cd /opt/k8s/work

source /opt/k8s/bin/environment.sh

for node_ip in ${MASTER_IPS[@]}

  do

    echo ">>> ${node_ip}"

    scp kube-controller-manager*.pem root@${node_ip}:/etc/kubernetes/cert/

  done

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

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=${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

cd /opt/k8s/work

source /opt/k8s/bin/environment.sh

for node_ip in ${MASTER_IPS[@]}

  do

    echo ">>> ${node_ip}"

    scp kube-controller-manager.kubeconfig root@${node_ip}:/etc/kubernetes/

  done

创建 kube-controller-manager 启动文件

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=0.0.0.0 \\

  #--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="" \\

  --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

参数解释

–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；

替换启动文件，并分发脚本

cd /opt/k8s/work

source /opt/k8s/bin/environment.sh

for (( i=0; i < 3; i++ ))

  do

    sed -e "s/##NODE_NAME##/${MASTER_NAMES[i]}/" -e "s/##NODE_IP##/${MASTER_IPS[i]}/" kube-controller-manager.service.template > kube-controller-manager-${MASTER_IPS[i]}.service

  done

ls kube-controller-manager*.service

分发到所有master节点

cd /opt/k8s/work

source /opt/k8s/bin/environment.sh

for node_ip in ${MASTER_IPS[@]}

  do

    echo ">>> ${node_ip}"

    scp kube-controller-manager-${node_ip}.service root@${node_ip}:/etc/systemd/system/kube-controller-manager.service

  done

启动服务

source /opt/k8s/bin/environment.sh

for node_ip in ${MASTER_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

检查运行状态

source /opt/k8s/bin/environment.sh

for node_ip in ${MASTER_IPS[@]}

  do

    echo ">>> ${node_ip}"

    ssh root@${node_ip} "systemctl status kube-controller-manager|grep Active"

  done

检查服务端口

for node_ip in ${MASTER_IPS[@]}

  do

    echo ">>> ${node_ip}"

    ssh root@${node_ip} "netstat -lnpt | grep kube-controlle"

  done

输出结果

[root@node01 work]# for node_ip in ${MASTER_IPS[@]}

>   do

>     echo ">>> ${node_ip}"

>     ssh root@${node_ip} "netstat -lnpt | grep kube-controlle"

>   done

>>> 10.0.20.11

tcp6       0      0 :::10252                :::*                    LISTEN      6127/kube-controlle

tcp6       0      0 :::10257                :::*                    LISTEN      6127/kube-controlle

>>> 10.0.20.12

tcp6       0      0 :::10252                :::*                    LISTEN      2914/kube-controlle

tcp6       0      0 :::10257                :::*                    LISTEN      2914/kube-controlle

>>> 10.0.20.13

tcp6       0      0 :::10252                :::*                    LISTEN      2952/kube-controlle

tcp6       0      0 :::10257                :::*                    LISTEN      2952/kube-controlle

查看 kube-controller-manager 创建权限

ClusteRole system:kube-controller-manager的权限太小，只能创建secret、serviceaccount等资源,将controller的权限分散到ClusterRole system:controller:xxx中

[root@node01 work]# kubectl describe clusterrole system:kube-controller-manager

Name:         system:kube-controller-manager

Labels:       kubernetes.io/bootstrapping=rbac-defaults

Annotations:  rbac.authorization.kubernetes.io/autoupdate: true

PolicyRule:

  Resources                                  Non-Resource URLs  Resource Names  Verbs

  ---------                                  -----------------  --------------  -----

  secrets                                    []                 []              [create delete get update]

  endpoints                                  []                 []              [create get update]

  serviceaccounts                            []                 []              [create get update]

  events                                     []                 []              [create patch update]

  serviceaccounts/token                      []                 []              [create]

  tokenreviews.authentication.k8s.io         []                 []              [create]

  subjectaccessreviews.authorization.k8s.io  []                 []              [create]

  configmaps                                 []                 []              [get]

  namespaces                                 []                 []              [get]

  *.*                                        []                 []              [list watch]

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。

[root@node01 work]# kubectl get clusterrole|grep controller

system:controller:attachdetach-controller                              122m

system:controller:certificate-controller                               122m

system:controller:clusterrole-aggregation-controller                   122m

system:controller:cronjob-controller                                   122m

system:controller:daemon-set-controller                                122m

system:controller:deployment-controller                                122m

system:controller:disruption-controller                                122m

system:controller:endpoint-controller                                  122m

system:controller:expand-controller                                    122m

system:controller:generic-garbage-collector                            122m

system:controller:horizontal-pod-autoscaler                            122m

system:controller:job-controller                                       122m

system:controller:namespace-controller                                 122m

system:controller:node-controller                                      122m

system:controller:persistent-volume-binder                             122m

system:controller:pod-garbage-collector                                122m

system:controller:pv-protection-controller                             122m

system:controller:pvc-protection-controller                            122m

system:controller:replicaset-controller                                122m

system:controller:replication-controller                               122m

system:controller:resourcequota-controller                             122m

system:controller:route-controller                                     122m

system:controller:service-account-controller                           122m

system:controller:service-controller                                   122m

system:controller:statefulset-controller                               122m

system:controller:ttl-controller                                       122m

system:kube-controller-manager                                         122m

以 deployment controller 为例：

[root@node01 work]# kubectl describe clusterrole system:controller:deployment-controller

Name:         system:controller:deployment-controller

Labels:       kubernetes.io/bootstrapping=rbac-defaults

Annotations:  rbac.authorization.kubernetes.io/autoupdate: true

PolicyRule:

  Resources                          Non-Resource URLs  Resource Names  Verbs

  ---------                          -----------------  --------------  -----

  replicasets.apps                   []                 []              [create delete get list patch update watch]

  replicasets.extensions             []                 []              [create delete get list patch update watch]

  events                             []                 []              [create patch update]

  pods                               []                 []              [get list update watch]

  deployments.apps                   []                 []              [get list update watch]

  deployments.extensions             []                 []              [get list update watch]

  deployments.apps/finalizers        []                 []              [update]

  deployments.apps/status            []                 []              [update]

  deployments.extensions/finalizers  []                 []              [update]

  deployments.extensions/status      []                 []              [update]

通过apiserver查看controller-manager状态

[root@node01 work]# kubectl get cs

NAME                 STATUS      MESSAGE                                                                                     ERROR

scheduler            Unhealthy   Get http://127.0.0.1:10251/healthz: dial tcp 127.0.0.1:10251: connect: connection refused

controller-manager   Healthy     ok

etcd-0               Healthy     {"health":"true"}

etcd-2               Healthy     {"health":"true"}

etcd-1               Healthy     {"health":"true"}

这里看到 controller-manager 的状态已经是 ok 了，在测试访问apiserver状态看到的还是 scheduler 是会一样的。

巴特西

部署 kube-controller-manager 高可用集群

前言