手动部署k8s(八)-部署 master 节点

原教程来自 github/opsnull, 现在此基础上记录自己搭建遇到的问题

kubernetes master运行如下组件

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

kube-apiserver,kubekube-scheduler,kube-controller-manager均以多实例模式运行

1. kubekube-scheduler和kubekube-controller-manager会自动选举产生一个leader示例,其它示例处于阻塞模式,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,需要通过kubekube-nginx进行代理访问,从而保证服务可用性

安装和配置kube-nginx

参考 apiserver高可用之nginx代理

下载最新版本二进制文件

从 CHANGELOG 页面 下载二进制 tar 文件并解压

cd /opt/k8s/work
wget https://dl.k8s.io/v1.14.2/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 ">>> ${node_ip}"
    scp kubernetes/server/bin/{apiextensions-apiserver,cloud-controller-manager,kube-apiserver,kube-controller-manager,kube-proxy,kube-scheduler,kubeadm,kubectl,kubelet,mounter} root@${node_ip}:/opt/k8s/bin/
    ssh root@${node_ip} "chmod +x /opt/k8s/bin/*"
  done

部署高可用 kube-apiserver 集群

准备工作

下载最新版本的二进制文件、安装和配置 flanneld 参考 部署flannel网络

创建 kubernetes 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",
  "hosts": [
    "127.0.0.1",
    "192.168.1.31",
    "192.168.1.32",
    "192.168.1.33",
    "${CLUSTER_KUBERNETES_SVC_IP}",
    "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

• 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

• kubernetes 服务 IP 是 apiserver 自动创建的，一般是 --service-cluster-ip-range 参数指定的网段的第一个IP，后续可以通过下面命令获取

  $ kubectl get svc kubernetes
  NAME         CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
  kubernetes   10.254.0.1   <none>        443/TCP   1d

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

将生成的证书和私钥文件拷贝到所有 master 节点

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    ssh root@${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 节点的 /etc/kubernetes 目录下

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

创建后续访问 metrics-server 使用的证书

创建证书签名请求

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

将生成的证书和私钥文件拷贝到所有 master 节点

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；
• --experimental-encryption-provider-config：指定用于加密 etcd 中 secret 的配置；
• --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

关于 --requestheader-XXX 相关参数，参考

• 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

• requestheader-client-ca-file 指定的 CA 证书，必须具有 client auth and server auth；

• 如果 --requestheader-allowed-names 为空，或者 --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，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

为各节点创建和分发 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

• 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

• 文件重命名为 kube-apiserver.service

启动 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

• 启动服务前必须先创建工作目录

检查 kube-apiserver 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

确保状态为 active (running)，否则查看日志，确认原因

journalctl -u kube-apiserver

打印 kube-apiserver 写入 etcd 的数据

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

检查集群信息

这里我访问失败了,报错如下

[root@ _76_ /opt/k8s/work]# kubectl cluster-info

To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.
The connection to the server 127.0.0.1:8443 was refused - did you specify the right host or port?

查看到8443是在nginx代理时监听的地址,原来是nginx没有启动

再次检查集群信息

[root@ _122_ /opt/k8s/work]# kubectl cluster-info
Kubernetes master is running at https://127.0.0.1:8443

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

[root@ _123_ /opt/k8s/work]# 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   28m


NAME                 STATUS      MESSAGE                                                                                     ERROR
controller-manager   Unhealthy   Get http://127.0.0.1:10252/healthz: dial tcp 127.0.0.1:10252: connect: connection refused
scheduler            Unhealthy   Get http://127.0.0.1:10251/healthz: dial tcp 127.0.0.1:10251: connect: connection refused
etcd-0               Healthy     {"health":"true"}
etcd-2               Healthy     {"health":"true"}
etcd-1               Healthy     {"health":"true"}

• 如果执行 kubectl 命令式时输出如下错误信息，则说明使用的 ~/.kube/config 文件不对，请切换到正确的账户后再执行该命令：

  The connection to the server localhost:8080 was refused - did you specify the right host or port?

  执行 kubectl get componentstatuses 命令时，apiserver 默认向 127.0.0.1 发送请求。当 - controller-manager、scheduler 以集群模式运行时，有可能和 kube-apiserver 不在一台机器上，这时 controller-manager 或 scheduler 的状态为 Unhealthy，但实际上它们工作正常。

检查 kube-apiserver 监听的端口

$ sudo netstat -lnpt|grep kube
tcp        0      0 172.27.137.240:6443     0.0.0.0:*               LISTEN      101442/kube-apiserv

• 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；

授予 kube-apiserver 访问 kubelet API 的权限

kubectl create clusterrolebinding kube-apiserver:kubelet-apis --clusterrole=system:kubelet-api-admin --user kubernetes