kube-apiserver 集群服務安裝

目錄

• 創建 kube-apiserver 證書
  • 生成證書和私鑰
• 創建加密配置文件
• 創建審計策略文件
• 分發 kube-apiserver 二進制文件
• 創建后續訪問 metrics-server 使用的證書
• 創建 kube-apiserver systemd unit 模板文件
  • 為各節點創建和分發 kube-apiserver systemd unit 文件
  • 啟動apiserver
  • 打印kube-apiserver寫入etcd數據

下面的操作依托於上一篇文章

• 部署前期准備工作
• kube-nginx 和 keepalived 部署安裝

創建 kube-apiserver 證書

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
cat > kubernetes-csr.json <<EOF
{
  "CN": "kubernetes",
  "hosts": [
    "127.0.0.1",
    "10.0.20.10",
    "10.0.20.11",
    "10.0.20.12",
    "10.0.20.13",
    "vip.k8s.com",
    "node01.k8s.com",
    "node02.k8s.com",
    "node03.k8s.com",
    "10.254.0.1",
    "kubernetes",
    "kubernetes.default",
    "kubernetes.default.svc",
    "kubernetes.default.svc.cluster",
    "kubernetes.default.svc.cluster.local."
  ],
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "ST": "BeiJing",
      "L": "BeiJing",
      "O": "k8s",
      "OU": "4Paradigm"
    }
  ]
}
EOF

#需要將集群的所有IP及VIP添域名加進去
#如果要添加注意最后的逗號，不要忘記添加，否則下一步報錯

hosts 字段指定授權使用該證書的IP和域名列表，這里列出了master節點IP、kubernetes服務的IP和域名

kubernetes serviceIP是apiserver自動創建的，一般是–service-cluster-ip-range參數指定的網段的第一個IP

$ kubectl get svc kubernetes
NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
kubernetes   ClusterIP   10.254.0.1           443/TCP   31d

生成證書和私鑰

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
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

將生成的證書和私鑰文件拷貝到所有master節點

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

創建加密配置文件

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

將加密配置文件拷貝到master節點的/etc/kubernetes目錄下

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

創建審計策略文件

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

分發審計策略文件：

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

分發 kube-apiserver 二進制文件

把 kube-apiserver 二進制執行文件分發到所有 master 節點上

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

創建后續訪問 metrics-server 使用的證書

創建證書簽名請求:

cat > proxy-client-csr.json <<EOF
{
  "CN": "aggregator",
  "hosts": [],
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "ST": "BeiJing",
      "L": "BeiJing",
      "O": "k8s",
      "OU": "4Paradigm"
    }
  ]
}
EOF

• CN 名稱需要位於 kube-apiserver 的 --requestheader-allowed-names 參數中，否則后續訪問 metrics 時會提示權限不足。

生成證書和私鑰：

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

將生成的證書和私鑰文件拷貝到所有 master 節點：

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

創建 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 對外通告的 IP（kubernetes 服務后端節點 IP）；
• --default-*-toleration-seconds：設置節點異常相關的閾值；
• --max-*-requests-inflight：請求相關的最大閾值；
• --etcd-*：訪問 etcd 的證書和 etcd 服務器地址；
• --experimental-encryption-provider-config：指定用於加密 etcd 中 secret 的配置；
• --bind-address： https 監聽的 IP，不能為 127.0.0.1，否則外界不能訪問它的安全端口 6443；
• --secret-port：https 監聽端口；
• --insecure-port=0：關閉監聽 http 非安全端口(8080)；
• --tls-*-file：指定 apiserver 使用的證書、私鑰和 CA 文件；
• --audit-*：配置審計策略和審計日志文件相關的參數；
• --client-ca-file：驗證 client (kue-controller-manager、kube-scheduler、kubelet、kube-proxy 等)請求所帶的證書；
• --enable-bootstrap-token-auth：啟用 kubelet bootstrap 的 token 認證；
• --requestheader-*：kube-apiserver 的 aggregator layer 相關的配置參數，proxy-client & HPA 需要使用；
• --requestheader-client-ca-file：用於簽名 --proxy-client-cert-file 和 --proxy-client-key-file 指定的證書；在啟用了 metric aggregator 時使用；
• --requestheader-allowed-names：不能為空，值為逗號分割的 --proxy-client-cert-file 證書的 CN 名稱，這里設置為 "aggregator"；
• --service-account-key-file：簽名 ServiceAccount Token 的公鑰文件，kube-controller-manager 的 * * --service-account-private-key-file` 指定私鑰文件，兩者配對使用；
• --runtime-config=api/all=true： 啟用所有版本的 APIs，如 autoscaling/v2alpha1；
• --authorization-mode=Node,RBAC、--anonymous-auth=false： 開啟 Node 和 RBAC 授權模式，拒絕未授權的請求；
• --enable-admission-plugins：啟用一些默認關閉的 plugins；
• --allow-privileged：運行執行 privileged 權限的容器；
• --apiserver-count=3：指定 apiserver 實例的數量；
• --event-ttl：指定 events 的保存時間；
• --kubelet-*：如果指定，則使用 https 訪問 kubelet APIs；需要為證書對應的用戶(上面 kubernetes*.pem 證書的用戶為 kubernetes) 用戶定義 RBAC 規則，否則訪問 kubelet API 時提示未授權；
• --proxy-client-*：apiserver 訪問 metrics-server 使用的證書；
• --service-cluster-ip-range： 指定 Service Cluster IP 地址段；
• --service-node-port-range： 指定 NodePort 的端口范圍；

如果 kube-apiserver 機器沒有運行 kube-proxy，則還需要添加 --enable-aggregator-routing=true 參數；

關於 --requestheader-XXX 相關參數，參考：

• https://github.com/kubernetes-incubator/apiserver-builder/blob/master/docs/concepts/auth.md
• https://docs.bitnami.com/kubernetes/how-to/configure-autoscaling-custom-metrics/

注意：

1. requestheader-client-ca-file 指定的 CA 證書，必須具有 client auth and server auth；
2. 如果 --requestheader-allowed-names 不為空，且 --proxy-client-cert-file 證書的 CN 名稱不在 allowed-names 中，則后續查看 node 或 pods 的 metrics 失敗，提示：

[root@zhangjun-k8s01 1.8+]# kubectl top nodes
Error from server (Forbidden): nodes.metrics.k8s.io is forbidden: User "aggregator" cannot list resource "nodes" in API group "metrics.k8s.io" at the cluster scope

為各節點創建和分發 kube-apiserver 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

• NODE_NAMES 和 NODE_IPS 為相同長度的 bash 數組，分別為節點名稱和對應的 IP；

分發生成的 systemd unit 文件：

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

• 文件重命名為 kube-apiserver.service;

啟動apiserver

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

檢查服務是否正常

for node_ip in ${MASTER_IPS[@]}
  do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "systemctl status kube-apiserver |grep 'Active:'"
  done

輸出結果如下

[root@node01 work]# for node_ip in ${MASTER_IPS[@]}
>   do
>     echo ">>> ${node_ip}"
>     ssh root@${node_ip} "systemctl status kube-apiserver |grep 'Active:'"
>   done
>>> 10.0.20.11
   Active: active (running) since Thu 2019-12-05 14:29:01 CST; 29s ago
>>> 10.0.20.12
   Active: active (running) since Thu 2019-12-05 14:29:27 CST; 3s ago
>>> 10.0.20.13
   Active: active (running) since Thu 2019-12-05 14:29:27 CST; 3s ago

查看端口apiserver 啟動的端口:

for node_ip in ${MASTER_IPS[@]}
  do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "netstat -lntup|grep kube-apiserver |grep '6443'"
  done

[root@node01 work]# for node_ip in ${MASTER_IPS[@]}
>   do
>     echo ">>> ${node_ip}"
>     ssh root@${node_ip} "netstat -lntup|grep kube-apiserver |grep '6443'"
>   done
>>> 10.0.20.11
tcp        0      0 10.0.20.11:6443         0.0.0.0:*               LISTEN      2891/kube-apiserver 
>>> 10.0.20.12
tcp        0      0 10.0.20.12:6443         0.0.0.0:*               LISTEN      2391/kube-apiserver 
>>> 10.0.20.13
tcp        0      0 10.0.20.13:6443         0.0.0.0:*               LISTEN      2436/kube-apiserver 

打印kube-apiserver寫入etcd數據

source /opt/k8s/bin/environment.sh
ETCDCTL_API=3 etcdctl \
    --endpoints=${ETCD_ENDPOINTS} \
    --cacert=/opt/k8s/work/ca.pem \
    --cert=/opt/k8s/work/etcd.pem \
    --key=/opt/k8s/work/etcd-key.pem \
    get /registry/ --prefix --keys-only