一部署master节点
1.1master节点服务
kubernetes master 节点运行如下组件：
- kube-apiserver
- kube-scheduler
- kube-controller-manager
- kube-nginx
kube-apiserver、kube-scheduler 和 kube-controller-manager 均以多实例模式运行：
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。
kube-apiserver 是无状态的，需要通过 kube-nginx 进行代理访问，从而保证服务可用性。
1.2安装Kubernetes
1 [root@k8smaster01 ~]# cd /opt/k8s/work 2 [root@k8smaster01 work]# wget https://dl.k8s.io/v1.14.2/kubernetes-server-linux-amd64.tar.gz 3 [root@k8smaster01 work]# tar -xzvf kubernetes-server-linux-amd64.tar.gz 4 [root@k8smaster01 work]# cd kubernetes 5 [root@k8smaster01 kubernetes]# tar -xzvf kubernetes-src.tar.gz
1.3分发Kubernetes
1 [root@k8smaster01 ~]# cd /opt/k8s/work 2 [root@k8smaster01 work]# source /opt/k8s/bin/environment.sh 3 [root@k8smaster01 work]# for master_ip in ${MASTER_IPS[@]} 4 do 5 echo ">>> ${master_ip}" 6 scp kubernetes/server/bin/{apiextensions-apiserver,cloud-controller-manager,kube-apiserver,kube-controller-manager,kube-proxy,kube-scheduler,kubeadm,kubectl,kubelet,mounter} root@${master_ip}:/opt/k8s/bin/ 7 ssh root@${master_ip} "chmod +x /opt/k8s/bin/*" 8 done
二部署高可用kube-apiserver
2.1高可用apiserver介绍
本实验部署一个三实例 kube-apiserver 集群的步骤，它们通过 kube-nginx 进行代理访问，从而保证服务可用性。
2.2创建Kubernetes证书和私钥
1 [root@k8smaster01 ~]# cd /opt/k8s/work 2 [root@k8smaster01 work]# cat > kubernetes-csr.json <<EOF 3 { 4 "CN": "kubernetes", 5 "hosts": [ 6 "127.0.0.1", 7 "172.24.8.71", 8 "172.24.8.72", 9 "172.24.8.73", 10 "${CLUSTER_KUBERNETES_SVC_IP}", 11 "kubernetes", 12 "kubernetes.default", 13 "kubernetes.default.svc", 14 "kubernetes.default.svc.cluster", 15 "kubernetes.default.svc.cluster.local." 16 ], 17 "key": { 18 "algo": "rsa", 19 "size": 2048 20 }, 21 "names": [ 22 { 23 "C": "CN", 24 "ST": "Shanghai", 25 "L": "Shanghai", 26 "O": "k8s", 27 "OU": "System" 28 } 29 ] 30 } 31 EOF 32 #创建Kubernetes的CA证书请求文件
解释：
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：
1 # kubectl get svc kubernetes1 [root@k8smaster01 ~]# cd /opt/k8s/work 2 [root@k8smaster01 work]# cfssl gencert -ca=/opt/k8s/work/ca.pem \ 3 -ca-key=/opt/k8s/work/ca-key.pem -config=/opt/k8s/work/ca-config.json \ 4 -profile=kubernetes kubernetes-csr.json | cfssljson -bare kubernetes #生成CA密钥（ca-key.pem）和证书（ca.pem）
2.3分发证书和私钥
1 [root@k8smaster01 ~]# cd /opt/k8s/work 2 [root@k8smaster01 work]# source /opt/k8s/bin/environment.sh 3 [root@k8smaster01 work]# for master_ip in ${MASTER_IPS[@]} 4 do 5 echo ">>> ${master_ip}" 6 ssh root@${master_ip} "mkdir -p /etc/kubernetes/cert" 7 scp kubernetes*.pem root@${master_ip}:/etc/kubernetes/cert/ 8 done
2.4创建加密配置文件
1 [root@k8smaster01 ~]# cd /opt/k8s/work 2 [root@k8smaster01 work]# source /opt/k8s/bin/environment.sh 3 [root@k8smaster01 work]# cat > encryption-config.yaml <<EOF 4 kind: EncryptionConfig 5 apiVersion: v1 6 resources: 7 - resources: 8 - secrets 9 providers: 10 - aescbc: 11 keys: 12 - name: key1 13 secret: ${ENCRYPTION_KEY} 14 - identity: {} 15 EOF
2.5分发加密配置文件
1 [root@k8smaster01 ~]# cd /opt/k8s/work 2 [root@k8smaster01 work]# source /opt/k8s/bin/environment.sh 3 [root@k8smaster01 work]# for master_ip in ${MASTER_IPS[@]} 4 do 5 echo ">>> ${master_ip}" 6 scp encryption-config.yaml root@${master_ip}:/etc/kubernetes/ 7 done
2.6创建审计策略文件
1 [root@k8smaster01 ~]# cd /opt/k8s/work 2 [root@k8smaster01 work]# source /opt/k8s/bin/environment.sh 3 [root@k8smaster01 work]# cat > audit-policy.yaml <<EOF 4 apiVersion: audit.k8s.io/v1beta1 5 kind: Policy 6 rules: 7 # The following requests were manually identified as high-volume and low-risk, so drop them. 8 - level: None 9 resources: 10 - group: "" 11 resources: 12 - endpoints 13 - services 14 - services/status 15 users: 16 - 'system:kube-proxy' 17 verbs: 18 - watch 19 20 - level: None 21 resources: 22 - group: "" 23 resources: 24 - nodes 25 - nodes/status 26 userGroups: 27 - 'system:nodes' 28 verbs: 29 - get 30 31 - level: None 32 namespaces: 33 - kube-system 34 resources: 35 - group: "" 36 resources: 37 - endpoints 38 users: 39 - 'system:kube-controller-manager' 40 - 'system:kube-scheduler' 41 - 'system:serviceaccount:kube-system:endpoint-controller' 42 verbs: 43 - get 44 - update 45 46 - level: None 47 resources: 48 - group: "" 49 resources: 50 - namespaces 51 - namespaces/status 52 - namespaces/finalize 53 users: 54 - 'system:apiserver' 55 verbs: 56 - get 57 58 # Don't log HPA fetching metrics. 59 - level: None 60 resources: 61 - group: metrics.k8s.io 62 users: 63 - 'system:kube-controller-manager' 64 verbs: 65 - get 66 - list 67 68 # Don't log these read-only URLs. 69 - level: None 70 nonResourceURLs: 71 - '/healthz*' 72 - /version 73 - '/swagger*' 74 75 # Don't log events requests. 76 - level: None 77 resources: 78 - group: "" 79 resources: 80 - events 81 82 # node and pod status calls from nodes are high-volume and can be large, don't log responses for expected updates from nodes 83 - level: Request 84 omitStages: 85 - RequestReceived 86 resources: 87 - group: "" 88 resources: 89 - nodes/status 90 - pods/status 91 users: 92 - kubelet 93 - 'system:node-problem-detector' 94 - 'system:serviceaccount:kube-system:node-problem-detector' 95 verbs: 96 - update 97 - patch 98 99 - level: Request 100 omitStages: 101 - RequestReceived 102 resources: 103 - group: "" 104 resources: 105 - nodes/status 106 - pods/status 107 userGroups: 108 - 'system:nodes' 109 verbs: 110 - update 111 - patch 112 113 # deletecollection calls can be large, don't log responses for expected namespace deletions 114 - level: Request 115 omitStages: 116 - RequestReceived 117 users: 118 - 'system:serviceaccount:kube-system:namespace-controller' 119 verbs: 120 - deletecollection 121 122 # Secrets, ConfigMaps, and TokenReviews can contain sensitive & binary data, 123 # so only log at the Metadata level. 124 - level: Metadata 125 omitStages: 126 - RequestReceived 127 resources: 128 - group: "" 129 resources: 130 - secrets 131 - configmaps 132 - group: authentication.k8s.io 133 resources: 134 - tokenreviews 135 # Get repsonses can be large; skip them. 136 - level: Request 137 omitStages: 138 - RequestReceived 139 resources: 140 - group: "" 141 - group: admissionregistration.k8s.io 142 - group: apiextensions.k8s.io 143 - group: apiregistration.k8s.io 144 - group: apps 145 - group: authentication.k8s.io 146 - group: authorization.k8s.io 147 - group: autoscaling 148 - group: batch 149 - group: certificates.k8s.io 150 - group: extensions 151 - group: metrics.k8s.io 152 - group: networking.k8s.io 153 - group: policy 154 - group: rbac.authorization.k8s.io 155 - group: scheduling.k8s.io 156 - group: settings.k8s.io 157 - group: storage.k8s.io 158 verbs: 159 - get 160 - list 161 - watch 162 163 # Default level for known APIs 164 - level: RequestResponse 165 omitStages: 166 - RequestReceived 167 resources: 168 - group: "" 169 - group: admissionregistration.k8s.io 170 - group: apiextensions.k8s.io 171 - group: apiregistration.k8s.io 172 - group: apps 173 - group: authentication.k8s.io 174 - group: authorization.k8s.io 175 - group: autoscaling 176 - group: batch 177 - group: certificates.k8s.io 178 - group: extensions 179 - group: metrics.k8s.io 180 - group: networking.k8s.io 181 - group: policy 182 - group: rbac.authorization.k8s.io 183 - group: scheduling.k8s.io 184 - group: settings.k8s.io 185 - group: storage.k8s.io 186 187 # Default level for all other requests. 188 - level: Metadata 189 omitStages: 190 - RequestReceived 191 EOF
2.7分发策略文件
1 [root@k8smaster01 ~]# cd /opt/k8s/work 2 [root@k8smaster01 work]# source /opt/k8s/bin/environment.sh 3 [root@k8smaster01 work]# for master_ip in ${MASTER_IPS[@]} 4 do 5 echo ">>> ${master_ip}" 6 scp audit-policy.yaml root@${master_ip}:/etc/kubernetes/audit-policy.yaml 7 done
2.8创建访问 metrics-server的证书和密钥
1 [root@k8smaster01 ~]# cd /opt/k8s/work 2 [root@k8smaster01 work]# cat > proxy-client-csr.json <<EOF 3 { 4 "CN": "aggregator", 5 "hosts": [], 6 "key": { 7 "algo": "rsa", 8 "size": 2048 9 }, 10 "names": [ 11 { 12 "C": "CN", 13 "ST": "Shanghai", 14 "L": "Shanghai", 15 "O": "k8s", 16 "OU": "System" 17 } 18 ] 19 } 20 EOF 21 #创建metrics-server的CA证书请求文件
解释：
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。
1 [root@k8smaster01 ~]# cd /opt/k8s/work 2 [root@k8smaster01 work]# cfssl gencert -ca=/opt/k8s/work/ca.pem \ 3 -ca-key=/opt/k8s/work/ca-key.pem -config=/opt/k8s/work/ca-config.json \ 4 -profile=kubernetes proxy-client-csr.json | cfssljson -bare proxy-client #生成CA密钥（ca-key.pem）和证书（ca.pem）
2.9分发证书和私钥
1 [root@k8smaster01 ~]# cd /opt/k8s/work 2 [root@k8smaster01 work]# source /opt/k8s/bin/environment.sh 3 [root@k8smaster01 work]# for master_ip in ${MASTER_IPS[@]} 4 do 5 echo ">>> ${master_ip}" 6 scp proxy-client*.pem root@${master_ip}:/etc/kubernetes/cert/ 7 done
2.10创建kube-apiserver的systemd
1 [root@k8smaster01 ~]# cd /opt/k8s/work 2 [root@k8smaster01 work]# source /opt/k8s/bin/environment.sh 3 [root@k8smaster01 work]# cat > kube-apiserver.service.template <<EOF 4 [Unit] 5 Description=Kubernetes API Server 6 Documentation=https://github.com/GoogleCloudPlatform/kubernetes 7 After=network.target 8 9 [Service] 10 WorkingDirectory=${K8S_DIR}/kube-apiserver 11 ExecStart=/opt/k8s/bin/kube-apiserver \\ 12 --advertise-address=##MASTER_IP## \\ 13 --default-not-ready-toleration-seconds=360 \\ 14 --default-unreachable-toleration-seconds=360 \\ 15 --feature-gates=DynamicAuditing=true \\ 16 --max-mutating-requests-inflight=2000 \\ 17 --max-requests-inflight=4000 \\ 18 --default-watch-cache-size=200 \\ 19 --delete-collection-workers=2 \\ 20 --encryption-provider-config=/etc/kubernetes/encryption-config.yaml \\ 21 --etcd-cafile=/etc/kubernetes/cert/ca.pem \\ 22 --etcd-certfile=/etc/kubernetes/cert/kubernetes.pem \\ 23 --etcd-keyfile=/etc/kubernetes/cert/kubernetes-key.pem \\ 24 --etcd-servers=${ETCD_ENDPOINTS} \\ 25 --bind-address=##MASTER_IP## \\ 26 --secure-port=6443 \\ 27 --tls-cert-file=/etc/kubernetes/cert/kubernetes.pem \\ 28 --tls-private-key-file=/etc/kubernetes/cert/kubernetes-key.pem \\ 29 --insecure-port=0 \\ 30 --audit-dynamic-configuration \\ 31 --audit-log-maxage=15 \\ 32 --audit-log-maxbackup=3 \\ 33 --audit-log-maxsize=100 \\ 34 --audit-log-mode=batch \\ 35 --audit-log-truncate-enabled \\ 36 --audit-log-batch-buffer-size=20000 \\ 37 --audit-log-batch-max-size=2 \\ 38 --audit-log-path=${K8S_DIR}/kube-apiserver/audit.log \\ 39 --audit-policy-file=/etc/kubernetes/audit-policy.yaml \\ 40 --profiling \\ 41 --anonymous-auth=false \\ 42 --client-ca-file=/etc/kubernetes/cert/ca.pem \\ 43 --enable-bootstrap-token-auth \\ 44 --requestheader-allowed-names="aggregator" \\ 45 --requestheader-client-ca-file=/etc/kubernetes/cert/ca.pem \\ 46 --requestheader-extra-headers-prefix="X-Remote-Extra-" \\ 47 --requestheader-group-headers=X-Remote-Group \\ 48 --requestheader-username-headers=X-Remote-User \\ 49 --service-account-key-file=/etc/kubernetes/cert/ca.pem \\ 50 --authorization-mode=Node,RBAC \\ 51 --runtime-config=api/all=true \\ 52 --enable-admission-plugins=NodeRestriction \\ 53 --allow-privileged=true \\ 54 --apiserver-count=3 \\ 55 --event-ttl=168h \\ 56 --kubelet-certificate-authority=/etc/kubernetes/cert/ca.pem \\ 57 --kubelet-client-certificate=/etc/kubernetes/cert/kubernetes.pem \\ 58 --kubelet-client-key=/etc/kubernetes/cert/kubernetes-key.pem \\ 59 --kubelet-https=true \\ 60 --kubelet-timeout=10s \\ 61 --proxy-client-cert-file=/etc/kubernetes/cert/proxy-client.pem \\ 62 --proxy-client-key-file=/etc/kubernetes/cert/proxy-client-key.pem \\ 63 --service-cluster-ip-range=${SERVICE_CIDR} \\ 64 --service-node-port-range=${NODE_PORT_RANGE} \\ 65 --logtostderr=true \\ 66 --v=2 67 Restart=on-failure 68 RestartSec=10 69 Type=notify 70 LimitNOFILE=65536 71 72 [Install] 73 WantedBy=multi-user.target 74 EOF
解释：
- --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。
提示：如果 kube-apiserver 机器没有运行 kube-proxy，则还需要添加 --enable-aggregator-routing=true 参数。
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：
1 [root@zhangjun-k8s01 1.8+]# kubectl top nodes 2 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 3
2.11分发systemd
1 [root@k8smaster01 ~]# cd /opt/k8s/work 2 [root@k8smaster01 work]# source /opt/k8s/bin/environment.sh 3 [root@k8smaster01 work]# for (( i=0; i < 3; i++ )) 4 do 5 sed -e "s/##MASTER_NAME##/${MASTER_NAMES[i]}/" -e "s/##MASTER_IP##/${MASTER_IPS[i]}/" kube-apiserver.service.template > kube-apiserver-${MASTER_IPS[i]}.service 6 done 7 [root@k8smaster01 work]# ls kube-apiserver*.service #替换相应的IP 8 [root@k8smaster01 ~]# cd /opt/k8s/work 9 [root@k8smaster01 work]# source /opt/k8s/bin/environment.sh 10 [root@k8smaster01 work]# for master_ip in ${MASTER_IPS[@]} 11 do 12 echo ">>> ${master_ip}" 13 scp kube-apiserver-${master_ip}.service root@${master_ip}:/etc/systemd/system/kube-apiserver.service 14 done #分发systemd
三启动并验证
3.1启动kube-apiserver服务
1 [root@k8smaster01 ~]# source /opt/k8s/bin/environment.sh 2 [root@k8smaster01 ~]# for master_ip in ${MASTER_IPS[@]} 3 do 4 echo ">>> ${master_ip}" 5 ssh root@${master_ip} "mkdir -p ${K8S_DIR}/kube-apiserver" 6 ssh root@${master_ip} "systemctl daemon-reload && systemctl enable kube-apiserver && systemctl restart kube-apiserver" 7 done
3.2检查kube-apiserver服务
1 [root@k8smaster01 ~]# source /opt/k8s/bin/environment.sh 2 [root@k8smaster01 ~]# for master_ip in ${MASTER_IPS[@]} 3 do 4 echo ">>> ${master_ip}" 5 ssh root@${master_ip} "systemctl status kube-apiserver |grep 'Active:'" 6 done
3.3查看kube-apiserver写入etcd的数据
1 [root@k8smaster01 ~]# source /opt/k8s/bin/environment.sh 2 [root@k8smaster01 ~]# ETCDCTL_API=3 etcdctl \ 3 --endpoints=${ETCD_ENDPOINTS} \ 4 --cacert=/opt/k8s/work/ca.pem \ 5 --cert=/opt/k8s/work/etcd.pem \ 6 --key=/opt/k8s/work/etcd-key.pem \ 7 get /registry/ --prefix --keys-only
3.4检查集群信息
1 [root@k8smaster01 ~]# kubectl cluster-info 2 [root@k8smaster01 ~]# kubectl get all --all-namespaces 3 [root@k8smaster01 ~]# kubectl get componentstatuses 4 [root@k8smaster01 ~]# sudo netstat -lnpt|grep kube #检查 kube-apiserver 监听的端口
提示：
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；
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。
3.5授权
授予 kube-apiserver 访问 kubelet API 的权限。
在执行 kubectl exec、run、logs 等命令时，apiserver 会将请求转发到 kubelet 的 https 端口。本实验定义 RBAC 规则，授权 apiserver 使用的证书（kubernetes.pem）用户名（CN：kuberntes）访问 kubelet API 的权限：
1 [root@k8smaster01 ~]# kubectl create clusterrolebinding kube-apiserver:kubelet-apis --clusterrole=system:kubelet-api-admin --user kubernetes