Kubernetes安裝之八：配置master之scheduler

dessler發表於2019-02-14
AST

都是3臺伺服器需要操作的

1.建立證書

mkdir -p /etc/ssl/kube-scheduler
cat > /etc/ssl/kube-scheduler/kube-scheduler-csr.json <<EOF
{
    "CN": "system:kube-scheduler",
    "hosts": [
      "127.0.0.1",
      "192.168.1.40",
      "192.168.1.41",
      "192.168.1.42"
    ],
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "names": [
      {
        "C": "CN",
        "ST": "ChengDu",
        "L": "ChengDu",
        "O": "system:kube-scheduler",
        "OU": "dessler"
      }
    ]
}
EOF
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cfssl gencert -ca=/etc/ssl/ca.pem \
  -ca-key=/etc/ssl/ca-key.pem \
  -config=/etc/ssl/ca-config.json \
  -profile=kubernetes kube-scheduler-csr.json | cfssljson -bare kube-scheduler
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ls
kube-scheduler.csr  kube-scheduler-csr.json  kube-scheduler-key.pem  kube-scheduler.pem
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  • 說明：
  • hosts 列表包含所有kube-scheduler 節點 IP
  • CN 為 system:kube-scheduler、O 為 system:kube-scheduler，kubernetes 內建的 ClusterRoleBindings system:kube-scheduler 將賦予 kube-scheduler 工作所需的許可權

2.建立kubeconfig 檔案

kubectl config set-cluster kubernetes \
>   --certificate-authority=/etc/ssl/ca.pem \
>   --embed-certs=true \
>   --server=https://192.168.1.43:8443 \
>   --kubeconfig=kube-scheduler.kubeconfig
Cluster "kubernetes" set.
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kubectl config set-credentials system:kube-scheduler \
>   --client-certificate=/etc/ssl/kube-scheduler/kube-scheduler.pem \
>   --client-key=/etc/ssl/kube-scheduler/kube-scheduler-key.pem \
>   --embed-certs=true \
>   --kubeconfig=kube-scheduler.kubeconfig
User "system:kube-scheduler" set.
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kubectl config set-context system:kube-scheduler \
>   --cluster=kubernetes \
>   --user=system:kube-scheduler \
>   --kubeconfig=kube-scheduler.kubeconfig
Context "system:kube-scheduler" created.
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kubectl config use-context system:kube-scheduler --kubeconfig=kube-scheduler.kubeconfig
Switched to context "system:kube-scheduler".
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3.分發配置檔案證書二進位制檔案

4.配置kube-scheduler服務

cat > /usr/lib/systemd/system/kube-scheduler.service <<EOF
[Unit]
Description=Kubernetes Scheduler
Documentation=https://github.com/GoogleCloudPlatform/kubernetes

[Service]
ExecStart=/opt/kubernetes/bin/kube-scheduler \\
  --address=127.0.0.1 \\
  --kubeconfig=/opt/kubernetes/cfg/kube-scheduler.kubeconfig \\
  --leader-elect=true \\
  --alsologtostderr=true \\
  --logtostderr=false \\
  --log-dir=/var/log/kubernetes \\
  --v=2
Restart=on-failure
RestartSec=5
#User=k8s

[Install]
WantedBy=multi-user.target
EOF
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  • 說明：
  • --address：在0.0.1:10251 埠接收 http /metrics 請求；kube-scheduler 目前還不支援接收 https 請求
  • --kubeconfig：指定 kubeconfig 檔案路徑，kube-scheduler 使用它連線和驗證 kube-apiserver
  • --leader-elect=true：叢集執行模式，啟用選舉功能；被選為 leader 的節點負責處理工作，其它節點為阻塞狀態
  • User=k8s：使用 k8s 賬戶執行

5.啟動服務

systemctl daemon-reload
systemctl enable kube-scheduler
systemctl restart kube-scheduler
systemctl status kube-scheduler
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6.檢查服務

curl -s http://127.0.0.1:10251/metrics |head
# HELP apiserver_audit_event_total 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 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 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="21600"} 0
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 kubectl get endpoints kube-scheduler --namespace=kube-system  -o yaml
apiVersion: v1
kind: Endpoints
metadata:
  annotations:
    control-plane.alpha.kubernetes.io/leader: '{"holderIdentity":"host22_11b7b315-2f42-11e9-b608-525400a73b99","leaseDurationSeconds":15,"acquireTime":"2019-02-13T05:39:32Z","renewTime":"2019-02-14T06:30:41Z","leaderTransitions":5}'
  creationTimestamp: "2019-01-30T08:32:08Z"
  name: kube-scheduler
  namespace: kube-system
  resourceVersion: "1737721"
  selfLink: /api/v1/namespaces/kube-system/endpoints/kube-scheduler
  uid: 87dbdef5-2469-11e9-a032-525400c6cc24
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7.配置自動approve kubelet CSR 請求

cat > /opt/kubernetes/cfg/csr-crb.yaml <<EOF
 # Approve all CSRs for the group "system:bootstrappers"
 kind: ClusterRoleBinding
 apiVersion: rbac.authorization.k8s.io/v1
 metadata:
   name: auto-approve-csrs-for-group
 subjects:
 - kind: Group
   name: system:bootstrappers
   apiGroup: rbac.authorization.k8s.io
 roleRef:
   kind: ClusterRole
   name: system:certificates.k8s.io:certificatesigningrequests:nodeclient
   apiGroup: rbac.authorization.k8s.io
---
 # To let a node of the group "system:nodes" renew its own credentials
 kind: ClusterRoleBinding
 apiVersion: rbac.authorization.k8s.io/v1
 metadata:
   name: node-client-cert-renewal
 subjects:
 - kind: Group
   name: system:nodes
   apiGroup: rbac.authorization.k8s.io
 roleRef:
   kind: ClusterRole
   name: system:certificates.k8s.io:certificatesigningrequests:selfnodeclient
   apiGroup: rbac.authorization.k8s.io
---
# A ClusterRole which instructs the CSR approver to approve a node requesting a
# serving cert matching its client cert.
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: approve-node-server-renewal-csr
rules:
- apiGroups: ["certificates.k8s.io"]
  resources: ["certificatesigningrequests/selfnodeserver"]
  verbs: ["create"]
---
 # To let a node of the group "system:nodes" renew its own server credentials
 kind: ClusterRoleBinding
 apiVersion: rbac.authorization.k8s.io/v1
 metadata:
   name: node-server-cert-renewal
 subjects:
 - kind: Group
   name: system:nodes
   apiGroup: rbac.authorization.k8s.io
 roleRef:
   kind: ClusterRole
   name: approve-node-server-renewal-csr
   apiGroup: rbac.authorization.k8s.io
EOF
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kubectl apply -f /opt/kubernetes/cfg/csr-crb.yaml
clusterrolebinding.rbac.authorization.k8s.io/auto-approve-csrs-for-group created
clusterrolebinding.rbac.authorization.k8s.io/node-client-cert-renewal created
clusterrole.rbac.authorization.k8s.io/approve-node-server-renewal-csr created
clusterrolebinding.rbac.authorization.k8s.io/node-server-cert-renewal created

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  • 說明：
  • kubelet 啟動後使用 --bootstrap-kubeconfig 向 kube-apiserver 傳送 CSR 請求，當這個 CSR 被 approve 後，kube-controller-manager 為 kubelet 建立 TLS 客戶端證書、私鑰和 --kubeletconfig 檔案。
  • 注意：kube-controller-manager 需要配置--cluster-signing-cert-file 和 --cluster-signing-key-file引數，才會為 TLS Bootstrap 建立證書和私鑰。


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