【k8s部署】5. 部署 master 节点

如果没有特殊指明，所有操作均在 zhaoyixin-k8s-01 节点上执行。

kubernetes master 节点运行如下组件：

• kube-apiserver
• kube-scheduler
• kube-controller-manager

这三个组件均以多实例模式运行：

1. kube-scheduler 和 kube-controller-manager 会自动选举产生一个 leader 实例，其它实例处于阻塞模式，当 leader 挂了后，重新选举产生新的 leader，从而保证服务可用性；
2. kube-apiserver 是无状态的，可以通过 kube-nginx 进行代理访问，从而保证服务可用性。

0.下载二进制文件

cd /opt/k8s/work
wget https://dl.k8s.io/v1.16.6/kubernetes-server-linux-amd64.tar.gz
tar -xzvf kubernetes-server-linux-amd64.tar.gz
cd kubernetes
tar -xzvf  kubernetes-src.tar.gz

将二进制文件拷贝到所有 master 节点：

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    scp kubernetes/server/bin/{apiextensions-apiserver,kube-apiserver,kube-controller-manager,kube-proxy,kube-scheduler,kubeadm,kubectl,kubelet,mounter} root@${node_ip}:/opt/k8s/bin/
    ssh root@${node_ip} "chmod +x /opt/k8s/bin/*"
  done

1.部署 kube-apiserver 集群

本节部署一个三实例 kube-apiserver 集群。

创建 kubernetes-master 证书和私钥

创建证书签名请求：

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
cat > kubernetes-csr.json <<EOF
{
  "CN": "kubernetes-master",
  "hosts": [
    "127.0.0.1",
    "192.168.16.8",
    "192.168.16.10",
    "192.168.16.6",
    "${CLUSTER_KUBERNETES_SVC_IP}",
    "kubernetes",
    "kubernetes.default",
    "kubernetes.default.svc",
    "kubernetes.default.svc.cluster",
    "kubernetes.default.svc.cluster.local.",
    "kubernetes.default.svc.${CLUSTER_DNS_DOMAIN}."
  ],
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "ST": "BeiJing",
      "L": "BeiJing",
      "O": "k8s",
      "OU": "zhaoyixin"
    }
  ]
}
EOF

• hosts 字段指定授权使用该证书的 IP 和域名列表，这里列出了 master 节点 IP、kubernetes 服务的 IP 和域名。

生成证书和私钥：

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 kubernetes-csr.json | cfssljson -bare kubernetes
ls kubernetes*pem

将证书和私钥拷贝到所有 master 节点：

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 /etc/kubernetes/cert"
    scp kubernetes*.pem root@${node_ip}:/etc/kubernetes/cert/
  done

创建加密配置文件

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
cat > encryption-config.yaml <<EOF
kind: EncryptionConfig
apiVersion: v1
resources:
  - resources:
      - secrets
    providers:
      - aescbc:
          keys:
            - name: key1
              secret: ${ENCRYPTION_KEY}
      - identity: {}
EOF

将加密配置文件拷贝到 master 节点：

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    scp encryption-config.yaml root@${node_ip}:/etc/kubernetes/
  done

创建审计策略文件

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
cat > audit-policy.yaml <<EOF
apiVersion: audit.k8s.io/v1beta1
kind: Policy
rules:
  # The following requests were manually identified as high-volume and low-risk, so drop them.
  - level: None
    resources:
      - group: ""
        resources:
          - endpoints
          - services
          - services/status
    users:
      - 'system:kube-proxy'
    verbs:
      - watch

  - level: None
    resources:
      - group: ""
        resources:
          - nodes
          - nodes/status
    userGroups:
      - 'system:nodes'
    verbs:
      - get

  - level: None
    namespaces:
      - kube-system
    resources:
      - group: ""
        resources:
          - endpoints
    users:
      - 'system:kube-controller-manager'
      - 'system:kube-scheduler'
      - 'system:serviceaccount:kube-system:endpoint-controller'
    verbs:
      - get
      - update

  - level: None
    resources:
      - group: ""
        resources:
          - namespaces
          - namespaces/status
          - namespaces/finalize
    users:
      - 'system:apiserver'
    verbs:
      - get

  # Don't log HPA fetching metrics.
  - level: None
    resources:
      - group: metrics.k8s.io
    users:
      - 'system:kube-controller-manager'
    verbs:
      - get
      - list

  # Don't log these read-only URLs.
  - level: None
    nonResourceURLs:
      - '/healthz*'
      - /version
      - '/swagger*'

  # Don't log events requests.
  - level: None
    resources:
      - group: ""
        resources:
          - events

  # node and pod status calls from nodes are high-volume and can be large, don't log responses
  # for expected updates from nodes
  - level: Request
    omitStages:
      - RequestReceived
    resources:
      - group: ""
        resources:
          - nodes/status
          - pods/status
    users:
      - kubelet
      - 'system:node-problem-detector'
      - 'system:serviceaccount:kube-system:node-problem-detector'
    verbs:
      - update
      - patch

  - level: Request
    omitStages:
      - RequestReceived
    resources:
      - group: ""
        resources:
          - nodes/status
          - pods/status
    userGroups:
      - 'system:nodes'
    verbs:
      - update
      - patch

  # deletecollection calls can be large, don't log responses for expected namespace deletions
  - level: Request
    omitStages:
      - RequestReceived
    users:
      - 'system:serviceaccount:kube-system:namespace-controller'
    verbs:
      - deletecollection

  # Secrets, ConfigMaps, and TokenReviews can contain sensitive & binary data,
  # so only log at the Metadata level.
  - level: Metadata
    omitStages:
      - RequestReceived
    resources:
      - group: ""
        resources:
          - secrets
          - configmaps
      - group: authentication.k8s.io
        resources:
          - tokenreviews
  # Get repsonses can be large; skip them.
  - level: Request
    omitStages:
      - RequestReceived
    resources:
      - group: ""
      - group: admissionregistration.k8s.io
      - group: apiextensions.k8s.io
      - group: apiregistration.k8s.io
      - group: apps
      - group: authentication.k8s.io
      - group: authorization.k8s.io
      - group: autoscaling
      - group: batch
      - group: certificates.k8s.io
      - group: extensions
      - group: metrics.k8s.io
      - group: networking.k8s.io
      - group: policy
      - group: rbac.authorization.k8s.io
      - group: scheduling.k8s.io
      - group: settings.k8s.io
      - group: storage.k8s.io
    verbs:
      - get
      - list
      - watch

  # Default level for known APIs
  - level: RequestResponse
    omitStages:
      - RequestReceived
    resources:
      - group: ""
      - group: admissionregistration.k8s.io
      - group: apiextensions.k8s.io
      - group: apiregistration.k8s.io
      - group: apps
      - group: authentication.k8s.io
      - group: authorization.k8s.io
      - group: autoscaling
      - group: batch
      - group: certificates.k8s.io
      - group: extensions
      - group: metrics.k8s.io
      - group: networking.k8s.io
      - group: policy
      - group: rbac.authorization.k8s.io
      - group: scheduling.k8s.io
      - group: settings.k8s.io
      - group: storage.k8s.io
      
  # Default level for all other requests.
  - level: Metadata
    omitStages:
      - RequestReceived
EOF

分发审计策略文件：

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    scp audit-policy.yaml root@${node_ip}:/etc/kubernetes/audit-policy.yaml
  done

创建访问 metrics-server 或 kube-prometheus 使用的证书

创建证书签名请求:

cd /opt/k8s/work
cat > proxy-client-csr.json <<EOF
{
  "CN": "aggregator",
  "hosts": [],
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "ST": "BeiJing",
      "L": "BeiJing",
      "O": "k8s",
      "OU": "zhaoyixin"
    }
  ]
}
EOF

• CN 名称需要位于 kube-apiserver 的 --requestheader-allowed-names 参数中，否则后续访问 metrics 时会提示权限不足。

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 proxy-client-csr.json | cfssljson -bare proxy-client
ls proxy-client*.pem

拷贝生成的证书和私钥文件

source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    scp proxy-client*.pem root@${node_ip}:/etc/kubernetes/cert/
  done

创建 kube-apiserver systemd unit 模板文件

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
cat > kube-apiserver.service.template <<EOF
[Unit]
Description=Kubernetes API Server
Documentation=https://github.com/GoogleCloudPlatform/kubernetes
After=network.target

[Service]
WorkingDirectory=${K8S_DIR}/kube-apiserver
ExecStart=/opt/k8s/bin/kube-apiserver \
  --advertise-address=##NODE_IP## \
  --default-not-ready-toleration-seconds=360 \
  --default-unreachable-toleration-seconds=360 \
  --feature-gates=DynamicAuditing=true \
  --max-mutating-requests-inflight=2000 \
  --max-requests-inflight=4000 \
  --default-watch-cache-size=200 \
  --delete-collection-workers=2 \
  --encryption-provider-config=/etc/kubernetes/encryption-config.yaml \
  --etcd-cafile=/etc/kubernetes/cert/ca.pem \
  --etcd-certfile=/etc/kubernetes/cert/kubernetes.pem \
  --etcd-keyfile=/etc/kubernetes/cert/kubernetes-key.pem \
  --etcd-servers=${ETCD_ENDPOINTS} \
  --bind-address=##NODE_IP## \
  --secure-port=6443 \
  --tls-cert-file=/etc/kubernetes/cert/kubernetes.pem \
  --tls-private-key-file=/etc/kubernetes/cert/kubernetes-key.pem \
  --insecure-port=0 \
  --audit-dynamic-configuration \
  --audit-log-maxage=15 \
  --audit-log-maxbackup=3 \
  --audit-log-maxsize=100 \
  --audit-log-truncate-enabled \
  --audit-log-path=${K8S_DIR}/kube-apiserver/audit.log \
  --audit-policy-file=/etc/kubernetes/audit-policy.yaml \
  --profiling \
  --anonymous-auth=false \
  --client-ca-file=/etc/kubernetes/cert/ca.pem \
  --enable-bootstrap-token-auth \
  --requestheader-allowed-names="aggregator" \
  --requestheader-client-ca-file=/etc/kubernetes/cert/ca.pem \
  --requestheader-extra-headers-prefix="X-Remote-Extra-" \
  --requestheader-group-headers=X-Remote-Group \
  --requestheader-username-headers=X-Remote-User \
  --service-account-key-file=/etc/kubernetes/cert/ca.pem \
  --authorization-mode=Node,RBAC \
  --runtime-config=api/all=true \
  --enable-admission-plugins=NodeRestriction \
  --allow-privileged=true \
  --apiserver-count=3 \
  --event-ttl=168h \
  --kubelet-certificate-authority=/etc/kubernetes/cert/ca.pem \
  --kubelet-client-certificate=/etc/kubernetes/cert/kubernetes.pem \
  --kubelet-client-key=/etc/kubernetes/cert/kubernetes-key.pem \
  --kubelet-https=true \
  --kubelet-timeout=10s \
  --proxy-client-cert-file=/etc/kubernetes/cert/proxy-client.pem \
  --proxy-client-key-file=/etc/kubernetes/cert/proxy-client-key.pem \
  --service-cluster-ip-range=${SERVICE_CIDR} \
  --service-node-port-range=${NODE_PORT_RANGE} \
  --logtostderr=true \
  --v=2
Restart=on-failure
RestartSec=10
Type=notify
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target
EOF

• --advertise-address：apiserver 对外通告的 IP（kubernetes 服务后端节点 IP）；
• --default-*-toleration-seconds：设置节点异常相关的阈值；
• --max-*-requests-inflight：请求相关的最大阈值；
• --etcd-*：访问 etcd 的证书和 etcd 服务器地址；
• --bind-address： https 监听的 IP，不能为 127.0.0.1，否则外界不能访问它的安全端口 6443；
• --secret-port：https 监听端口；
• --insecure-port=0：关闭监听 http 非安全端口(8080)；
• --tls-*-file：指定 apiserver 使用的证书、私钥和 CA 文件；
• --audit-*：配置审计策略和审计日志文件相关的参数；
• --client-ca-file：验证 client (kue-controller-manager、kube-scheduler、kubelet、kube-proxy 等)请求所带的证书；
• --enable-bootstrap-token-auth：启用 kubelet bootstrap 的 token 认证；
• --requestheader-*：kube-apiserver 的 aggregator layer 相关的配置参数，proxy-client & HPA 需要使用；
• --requestheader-client-ca-file：用于签名 --proxy-client-cert-file 和 --proxy-client-key-file 指定的证书；在启用了 metric aggregator 时使用；
• --requestheader-allowed-names：不能为空，值为逗号分割的 --proxy-client-cert-file 证书的 CN 名称，这里设置为 "aggregator"；
• --service-account-key-file：签名 ServiceAccount Token 的公钥文件，kube-controller-manager 的 --service-account-private-key-file 指定私钥文件，两者配对使用；
• --runtime-config=api/all=true： 启用所有版本的 APIs，如 autoscaling/v2alpha1；
• --authorization-mode=Node,RBAC、--anonymous-auth=false： 开启 Node 和 RBAC 授权模式，拒绝未授权的请求；
• --enable-admission-plugins：启用一些默认关闭的 plugins；
• --allow-privileged：运行执行 privileged 权限的容器；
• --apiserver-count=3：指定 apiserver 实例的数量；
• --event-ttl：指定 events 的保存时间；
• --kubelet-*：如果指定，则使用 https 访问 kubelet APIs；需要为证书对应的用户(上面 kubernetes*.pem 证书的用户为 kubernetes) 用户定义 RBAC 规则，否则访问 kubelet API 时提示未授权；
• --proxy-client-*：apiserver 访问 metrics-server 使用的证书；
• --service-cluster-ip-range： 指定 Service Cluster IP 地址段；
• --service-node-port-range： 指定 NodePort 的端口范围；

如果 kube-apiserver 机器没有运行 kube-proxy，则还需要添加 --enable-aggregator-routing=true 参数；

1.--requestheader-client-ca-file 指定的 CA 证书，必须具有 client auth and server auth
2.如果 --requestheader-allowed-names 不为空,且 --proxy-client-cert-file 证书的 CN 名称不在 allowed-names 中，则后续查看 node 或 pods 的 metrics 失败

创建和分发 kube-apiserver systemd unit 文件

替换模板文件中的变量，为各节点生成 systemd unit 文件：

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-apiserver.service.template > kube-apiserver-${NODE_IPS[i]}.service 
  done
ls kube-apiserver*.service

分发生成的 systemd unit 文件：

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    scp kube-apiserver-${node_ip}.service root@${node_ip}:/etc/systemd/system/kube-apiserver.service
  done

启动并检查 kube-apiserver 服务

source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "mkdir -p ${K8S_DIR}/kube-apiserver"
    ssh root@${node_ip} "systemctl daemon-reload && systemctl enable kube-apiserver && systemctl restart kube-apiserver"
  done

查看运行状态

source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "systemctl status kube-apiserver |grep 'Active:'"
  done

确保状态是active (running)，否则通过journalctl -u kube-apiserver查看日志，找出原因。

检查集群状态

$ kubectl cluster-info
Kubernetes master is running at https://192.168.16.8:6443

To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.

$ kubectl get all --all-namespaces
NAMESPACE   NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
default     service/kubernetes   ClusterIP   10.254.0.1   <none>        443/TCP   60s

$ kubectl get componentstatuses
NAME                 AGE
controller-manager   <unknown>
scheduler            <unknown>
etcd-0               <unknown>
etcd-2               <unknown>
etcd-1               <unknown>

检查 kube-apiserver 监听的端口

$ sudo netstat -lnpt|grep kube
tcp        0      0 192.168.16.8:6443       0.0.0.0:*               LISTEN      13722/kube-apiserve 

• 6443: 接收 https 请求的安全端口，对所有请求做认证和授权；
• 由于关闭了非安全端口，故没有监听 8080；

2.部署 kube-controller-manager 集群

本节部署一个三节点 kube-controller-manager 集群。

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;
2. 在安全端口(https，10252) 输出 prometheus 格式的 metrics；

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",
      "192.168.16.8",
      "192.168.16.10",
      "192.168.16.6"
    ],
    "names": [
      {
        "C": "CN",
        "ST": "BeiJing",
        "L": "BeiJing",
        "O": "system:kube-controller-manager",
        "OU": "zhaoyixin"
      }
    ]
}
EOF

• host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 ClusterRoleBindings system:kube-controller-manager 赋予 kube-controller-manager 工作所需的权限。

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-controller-manager-csr.json | cfssljson -bare kube-controller-manager
ls kube-controller-manager*pem

分发生成的证书和私钥

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

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：

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

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

创建 kube-controller-manager systemd unit 模板文件

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=${K8S_DIR}/kube-controller-manager
ExecStart=/opt/k8s/bin/kube-controller-manager \
  --profiling \
  --cluster-name=kubernetes \
  --controllers=*,bootstrapsigner,tokencleaner \
  --kube-api-qps=1000 \
  --kube-api-burst=2000 \
  --leader-elect \
  --use-service-account-credentials\
  --concurrent-service-syncs=2 \
  --bind-address=##NODE_IP## \
  --secure-port=10252 \
  --tls-cert-file=/etc/kubernetes/cert/kube-controller-manager.pem \
  --tls-private-key-file=/etc/kubernetes/cert/kube-controller-manager-key.pem \
  --port=0 \
  --authentication-kubeconfig=/etc/kubernetes/kube-controller-manager.kubeconfig \
  --client-ca-file=/etc/kubernetes/cert/ca.pem \
  --requestheader-allowed-names="aggregator" \
  --requestheader-client-ca-file=/etc/kubernetes/cert/ca.pem \
  --requestheader-extra-headers-prefix="X-Remote-Extra-" \
  --requestheader-group-headers=X-Remote-Group \
  --requestheader-username-headers=X-Remote-User \
  --authorization-kubeconfig=/etc/kubernetes/kube-controller-manager.kubeconfig \
  --cluster-signing-cert-file=/etc/kubernetes/cert/ca.pem \
  --cluster-signing-key-file=/etc/kubernetes/cert/ca-key.pem \
  --experimental-cluster-signing-duration=876000h \
  --horizontal-pod-autoscaler-sync-period=10s \
  --concurrent-deployment-syncs=10 \
  --concurrent-gc-syncs=30 \
  --node-cidr-mask-size=24 \
  --service-cluster-ip-range=${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；

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：

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
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 ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    scp kube-controller-manager-${node_ip}.service root@${node_ip}:/etc/systemd/system/kube-controller-manager.service
  done

启动并检查 kube-controller-manager 服务

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

检查服务运行状态

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

确保状态为 active (running)，否则通过journalctl -u kube-controller-manager查看日志，找出原因。

kube-controller-manager 监听 10252 端口，接收 https 请求：

$ sudo netstat -lnpt | grep kube-cont
tcp        0      0 192.168.16.8:10252      0.0.0.0:*               LISTEN      27533/kube-controll

查看 metrics 和 leader

$ curl -s --cacert /opt/k8s/work/ca.pem --cert /opt/k8s/work/admin.pem --key /opt/k8s/work/admin-key.pem https://172.27.138.251:10252/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

$ kubectl get endpoints kube-controller-manager --namespace=kube-system  -o yaml
apiVersion: v1
kind: Endpoints
metadata:
  annotations:
    control-plane.alpha.kubernetes.io/leader: '{"holderIdentity":"zhaoyixin-k8s-01_4b717180-fdc3-42d1-8e9e-08d8bc0708b2","leaseDurationSeconds":15,"acquireTime":"2020-05-21T07:05:08Z","renewTime":"2020-05-21T07:06:29Z","leaderTransitions":0}'
  creationTimestamp: "2020-05-21T07:05:08Z"
  name: kube-controller-manager
  namespace: kube-system
  resourceVersion: "23373"
  selfLink: /api/v1/namespaces/kube-system/endpoints/kube-controller-manager
  uid: cdd98142-9541-4418-9e8f-c2f77c5009e6

可见，当前的 leader 为 zhaoyixin-k8s-01 节点。

3.部署 kube-scheduler 集群

本节部署一个三节点 kube-scheduler 集群。

为保证通信安全，本文档先生成 x509 证书和私钥，kube-scheduler 在如下两种情况下使用该证书：

1. 与 kube-apiserver 的安全端口通信;
2. 在安全端口(https，10251) 输出 prometheus 格式的 metrics；

创建 kube-scheduler 证书和私钥

创建证书签名请求：

cd /opt/k8s/work
cat > kube-scheduler-csr.json <<EOF
{
    "CN": "system:kube-scheduler",
    "hosts": [
      "127.0.0.1",
      "192.168.16.8",
      "192.168.16.10",
      "192.168.16.6"
    ],
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "names": [
      {
        "C": "CN",
        "ST": "BeiJing",
        "L": "BeiJing",
        "O": "system:kube-scheduler",
        "OU": "zhaoyixin"
      }
    ]
}
EOF

• hosts 列表包含所有 kube-scheduler 节点 IP；
• CN 和 O 均为 system:kube-scheduler，kubernetes 内置的 ClusterRoleBindings system:kube-scheduler 将赋予 kube-scheduler 工作所需的权限；

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-scheduler-csr.json | cfssljson -bare kube-scheduler
ls kube-scheduler*pem

分发证书和私钥

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    scp kube-scheduler*.pem root@${node_ip}:/etc/kubernetes/cert/
  done

创建和分发 kubeconfig 文件

kube-scheduler 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-scheduler 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="https://##NODE_IP##:6443" 
  --kubeconfig=kube-scheduler.kubeconfig

kubectl config set-credentials system:kube-scheduler 
  --client-certificate=kube-scheduler.pem 
  --client-key=kube-scheduler-key.pem 
  --embed-certs=true 
  --kubeconfig=kube-scheduler.kubeconfig

kubectl config set-context system:kube-scheduler 
  --cluster=kubernetes 
  --user=system:kube-scheduler 
  --kubeconfig=kube-scheduler.kubeconfig

kubectl config use-context system:kube-scheduler --kubeconfig=kube-scheduler.kubeconfig

分发 kubeconfig 到所有 master 节点：

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-scheduler.kubeconfig > kube-scheduler-${node_ip}.kubeconfig
    scp kube-scheduler-${node_ip}.kubeconfig root@${node_ip}:/etc/kubernetes/kube-scheduler.kubeconfig
  done

创建 kube-scheduler 配置文件

cd /opt/k8s/work
cat >kube-scheduler.yaml.template <<EOF
apiVersion: kubescheduler.config.k8s.io/v1alpha1
kind: KubeSchedulerConfiguration
bindTimeoutSeconds: 600
clientConnection:
  burst: 200
  kubeconfig: "/etc/kubernetes/kube-scheduler.kubeconfig"
  qps: 100
enableContentionProfiling: false
enableProfiling: true
hardPodAffinitySymmetricWeight: 1
healthzBindAddress: ##NODE_IP##:10251
leaderElection:
  leaderElect: true
metricsBindAddress: ##NODE_IP##:10251
EOF

• --kubeconfig：指定 kubeconfig 文件路径，kube-scheduler 使用它连接和验证 kube-apiserver；
• --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；

替换模板文件中的变量：

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-scheduler.yaml.template > kube-scheduler-${NODE_IPS[i]}.yaml
  done
ls kube-scheduler*.yaml

• NODE_NAMES 和 NODE_IPS 为相同长度的 bash 数组，分别为节点名称和对应的 IP；

分发 kube-scheduler 配置文件到所有 master 节点，并重名命名为 kube-scheduler.yaml。

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    scp kube-scheduler-${node_ip}.yaml root@${node_ip}:/etc/kubernetes/kube-scheduler.yaml
  done

创建 kube-scheduler systemd unit 模板文件

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
cat > kube-scheduler.service.template <<EOF
[Unit]
Description=Kubernetes Scheduler
Documentation=https://github.com/GoogleCloudPlatform/kubernetes

[Service]
WorkingDirectory=${K8S_DIR}/kube-scheduler
ExecStart=/opt/k8s/bin/kube-scheduler \
  --config=/etc/kubernetes/kube-scheduler.yaml \
  --bind-address=##NODE_IP## \
  --secure-port=10259 \
  --port=0 \
  --tls-cert-file=/etc/kubernetes/cert/kube-scheduler.pem \
  --tls-private-key-file=/etc/kubernetes/cert/kube-scheduler-key.pem \
  --authentication-kubeconfig=/etc/kubernetes/kube-scheduler.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-scheduler.kubeconfig \
  --logtostderr=true \
  --v=2
Restart=always
RestartSec=5
StartLimitInterval=0

[Install]
WantedBy=multi-user.target
EOF

创建和分发 kube-scheduler systemd unit 文件

替换模板文件中的变量，为各节点创建 systemd unit 文件：

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-scheduler.service.template > kube-scheduler-${NODE_IPS[i]}.service 
  done
ls kube-scheduler*.service

分发 systemd unit 文件到所有 master 节点：

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    scp kube-scheduler-${node_ip}.service root@${node_ip}:/etc/systemd/system/kube-scheduler.service
  done

启动并检查 kube-scheduler 服务

source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "mkdir -p ${K8S_DIR}/kube-scheduler"
    ssh root@${node_ip} "systemctl daemon-reload && systemctl enable kube-scheduler && systemctl restart kube-scheduler"
  done

检查服务运行状态

source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "systemctl status kube-scheduler|grep Active"
  done

确保状态为 active (running)，否则通过journalctl -u kube-scheduler查看日志，找出原因。

查看 metrics 和 leader

kube-scheduler 监听 10251 和 10259 端口：

• 10251：接收 http 请求，非安全端口，不需要认证授权；
• 10259：接收 https 请求，安全端口，需要认证授权；

两个接口都对外提供 /metrics 和 /healthz 的访问。

$ sudo netstat -lnpt |grep kube-sch
tcp        0      0 192.168.16.8:10259      0.0.0.0:*               LISTEN      3605/kube-scheduler 
tcp        0      0 192.168.16.8:10251      0.0.0.0:*               LISTEN      3605/kube-scheduler

$ curl -s http://192.168.16.8:10251/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

$ curl -s --cacert /opt/k8s/work/ca.pem --cert /opt/k8s/work/admin.pem --key /opt/k8s/work/admin-key.pem https://192.168.16.8:10259/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

查看当前的 leader

$ kubectl get endpoints kube-scheduler --namespace=kube-system  -o yaml
apiVersion: v1
kind: Endpoints
metadata:
  annotations:
    control-plane.alpha.kubernetes.io/leader: '{"holderIdentity":"zhaoyixin-k8s-01_463d86ce-7c3f-478f-b03f-79282fd97565","leaseDurationSeconds":15,"acquireTime":"2020-05-29T03:23:30Z","renewTime":"2020-05-29T03:26:14Z","leaderTransitions":0}'
  creationTimestamp: "2020-05-29T03:23:30Z"
  name: kube-scheduler
  namespace: kube-system
  resourceVersion: "559017"
  selfLink: /api/v1/namespaces/kube-system/endpoints/kube-scheduler
  uid: 6ca6bd7b-b3ee-49bb-9efb-f180511022df

可见，当前的 leader 为 zhaoyixin-k8s-01 节点。

参考

opsnull/follow-me-install-kubernetes-cluster