二进制搭建kubernetes多master集群【三、配置k8s master及高可用】

前面两篇文章已经配置好了etcd和flannel的网络,现在开始配置k8s master集群。

etcd集群配置参考:二进制搭建kubernetes多master集群【一、使用TLS证书搭建etcd集群】

flannel网络配置参考:二进制搭建kubernetes多master集群【二、配置flannel网络】

本文在以下主机上操作部署k8s集群

k8s-master1:192.168.80.7

k8s-master2:192.168.80.8

k8s-master3:192.168.80.9

配置Kubernetes master集群

kubernetes master 节点包含的组件:

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

目前这三个组件需要部署在同一台机器上。

  • kube-schedulerkube-controller-manager 和 kube-apiserver 三者的功能紧密相关;
  • 同时只能有一个 kube-schedulerkube-controller-manager 进程处于工作状态,如果运行多个,则需要通过选举产生一个 leader;

一、部署kubectl命令工具

kubectl 是 kubernetes 集群的命令行管理工具,本文档介绍安装和配置它的步骤。

kubectl 默认从 ~/.kube/config 文件读取 kube-apiserver 地址、证书、用户名等信息,如果没有配置,执行 kubectl 命令时可能会出错。

~/.kube/config只需要部署一次,然后拷贝到其他的master。

1、下载kubectl

wget https://dl.k8s.io/v1.12.3/kubernetes-server-linux-amd64.tar.gz
tar -xzvf kubernetes-server-linux-amd64.tar.gz
cd kubernetes/server/bin/
cp kube-apiserver kubeadm kube-controller-manager kubectl kube-scheduler /usr/local/bin

2、创建请求证书

[root@k8s-master1 ssl]# cat > admin-csr.json <<EOF
{
"CN": "admin",
"hosts": [],
"key": {
"algo": "rsa",
"size":
},
"names": [
{
"C": "CN",
"ST": "BeiJing",
"L": "BeiJing",
"O": "system:masters",
"OU": "4Paradigm"
}
]
}
EOF
  • O 为 system:masters,kube-apiserver 收到该证书后将请求的 Group 设置为 system:masters;
  • 预定义的 ClusterRoleBinding cluster-admin 将 Group system:masters 与 Role cluster-admin 绑定,该 Role 授予所有 API的权限;
  • 该证书只会被 kubectl 当做 client 证书使用,所以 hosts 字段为空;

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 admin-csr.json | cfssljson -bare admin

3、创建~/.kube/config文件

kubectl config set-cluster kubernetes \
--certificate-authority=/etc/kubernetes/cert/ca.pem \
--embed-certs=true \
--server=https://114.67.81.105:8443 \
--kubeconfig=kubectl.kubeconfig # 设置客户端认证参数
kubectl config set-credentials admin \
--client-certificate=admin.pem \
--client-key=admin-key.pem \
--embed-certs=true \
--kubeconfig=kubectl.kubeconfig # 设置上下文参数
kubectl config set-context kubernetes \
--cluster=kubernetes \
--user=admin \
--kubeconfig=kubectl.kubeconfig # 设置默认上下文
kubectl config use-context kubernetes --kubeconfig=kubectl.kubeconfig

4、分发~/.kube/config文件

[root@k8s-master1 temp]# cp kubectl.kubeconfig ~/.kube/config
[root@k8s-master1 temp]# scp kubectl.kubeconfig k8s-master2:~/.kube/config
kubectl.kubeconfig % .2MB/s :
[root@k8s-master1 temp]# scp kubectl.kubeconfig k8s-master3:~/.kube/config
kubectl.kubeconfig

二、部署api-server

1、创建kube-apiserver的证书签名请求:


[root@k8s-master1 ssl]# cat > kubernetes-csr.json <<EOF
{
"CN": "kubernetes",
"hosts": [
"127.0.0.1",
"192.168.80.7",
"192.168.80.8",
"192.168.80.9",
"192.168.80.13",
"114.67.81.105",
"kubernetes",
"kubernetes.default",
"kubernetes.default.svc",
"kubernetes.default.svc.cluster",
"kubernetes.default.svc.cluster.local"
],
"key": {
"algo": "rsa",
"size":
},
"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 或域名列表,这里列出了 VIP 、apiserver 节点 IP、kubernetes 服务 IP 和域名;
  • 域名最后字符不能是 .(如不能为 kubernetes.default.svc.cluster.local.),否则解析时失败,提示: x509: cannot parse dnsName "kubernetes.default.svc.cluster.local."
  • 如果使用非 cluster.local 域名,如 bqding.com,则需要修改域名列表中的最后两个域名为:kubernetes.default.svc.bqdingkubernetes.default.svc.bqding.com
  • 红色的主机依次为master节点的ip,以及负载均衡器的内网和公网IP。

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 kubernetes-csr.json | cfssljson -bare kubernetes

2、将生成的证书和私钥文件拷贝到 master 节点:

[root@k8s-master1 ssl]# cp kubernetes*.pem /etc/kubernetes/cert/
[root@k8s-master1 ssl]# scp kubernetes*.pem k8s-master2:/etc/kubernetes/cert/
[root@k8s-master1 ssl]# scp kubernetes*.pem k8s-master3:/etc/kubernetes/cert/

3、创建加密配置文件

[root@k8s-master1 ssl]# cat > encryption-config.yaml <<EOF
kind: EncryptionConfig
apiVersion: v1
resources:
- resources:
- secrets
providers:
- aescbc:
keys:
- name: key1
secret: $(head -c /dev/urandom | base64)
- identity: {}
EOF

4、分发加密配置文件到master节点

[root@k8s-master1 ssl]# cp encryption-config.yaml /etc/kubernetes/cert/
[root@k8s-master1 ssl]# scp encryption-config.yaml k8s-master2:/etc/kubernetes/cert/
[root@k8s-master1 ssl]# scp encryption-config.yaml k8s-master3:/etc/kubernetes/cert/

5、创建kube-apiserver systemd unit文件

[root@k8s-master1 ssl]# cat > /etc/systemd/system/kube-apiserver.service << EOF
[Unit]
Description=Kubernetes API Server
Documentation=https://github.com/GoogleCloudPlatform/kubernetes
After=network.target [Service]
ExecStart=/usr/local/bin/kube-apiserver \
--enable-admission-plugins=Initializers,NamespaceLifecycle,NodeRestriction,LimitRanger,ServiceAccount,DefaultStorageClass,ResourceQuota \
--anonymous-auth=false \
--experimental-encryption-provider-config=/etc/kubernetes/cert/encryption-config.yaml \
--advertise-address=192.168.80.7 \
--bind-address=192.168.80.7 \
--insecure-port= \
--authorization-mode=Node,RBAC \
--runtime-config=api/all \
--enable-bootstrap-token-auth \
--service-cluster-ip-range=10.254.0.0/ \
--service-node-port-range=- \
--tls-cert-file=/etc/kubernetes/cert/kubernetes.pem \
--tls-private-key-file=/etc/kubernetes/cert/kubernetes-key.pem \
--client-ca-file=/etc/kubernetes/cert/ca.pem \
--kubelet-client-certificate=/etc/kubernetes/cert/kubernetes.pem \
--kubelet-client-key=/etc/kubernetes/cert/kubernetes-key.pem \
--service-account-key-file=/etc/kubernetes/cert/ca-key.pem \
--etcd-cafile=/etc/kubernetes/cert/ca.pem \
--etcd-certfile=/etc/kubernetes/cert/kubernetes.pem \
--etcd-keyfile=/etc/kubernetes/cert/kubernetes-key.pem \
--etcd-servers=https://192.168.80.4:2379,https://192.168.80.5:2379,https://192.168.80.6:2379 \
--enable-swagger-ui=true \
--allow-privileged=true \
--apiserver-count= \
--audit-log-maxage= \
--audit-log-maxbackup= \
--audit-log-maxsize= \
--audit-log-path=/var/log/kube-apiserver-audit.log \
--event-ttl=1h \
--alsologtostderr=true \
--logtostderr=false \
--log-dir=/var/log/kubernetes \
--v=
Restart=on-failure
RestartSec=
Type=notify
LimitNOFILE= [Install]
WantedBy=multi-user.targe
EOF
  • --experimental-encryption-provider-config:启用加密特性;
  • --authorization-mode=Node,RBAC: 开启 Node 和 RBAC 授权模式,拒绝未授权的请求;
  • --enable-admission-plugins:启用 ServiceAccount 和 NodeRestriction
  • --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;
  • --tls-*-file:指定 apiserver 使用的证书、私钥和 CA 文件。--client-ca-file 用于验证 client (kue-controller-manager、kube-scheduler、kubelet、kube-proxy 等)请求所带的证书;
  • --kubelet-client-certificate--kubelet-client-key: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;
  • --bind-address: 不能为 127.0.0.1,否则外界不能访问它的安全端口 6443;
  • --insecure-port=0:关闭监听非安全端口(8080);
  • --service-cluster-ip-range: 指定 Service Cluster IP 地址段;
  • --service-node-port-range: 指定 NodePort 的端口范围;
  • --runtime-config=api/all=true: 启用所有版本的 APIs,如 autoscaling/v2alpha1;
  • --enable-bootstrap-token-auth:启用 kubelet bootstrap 的 token 认证;
  • --apiserver-count=3:指定集群运行模式,多台 kube-apiserver 会通过 leader 选举产生一个工作节点,其它节点处于阻塞状态;
  • 红色部分为各个master主机部分

6、分发kube-apiserver.service文件到其他master

[root@k8s-master1 ssl]# scp /etc/systemd/system/kube-apiserver.service k8s-master2:/etc/systemd/system/kube-apiserver.service
[root@k8s-master1 ssl]# scp /etc/systemd/system/kube-apiserver.service k8s-master3:/etc/systemd/system/kube-apiserver.service

7、创建日志目录

mkdir -p /var/log/kubernetes

8、启动api-server服务

[root@k8s-master1 ssl]# systemctl daemon-reload
[root@k8s-master1 ssl]# systemctl enable kube-apiserver
[root@k8s-master1 ssl]# systemctl start kube-apiserver

9、检查api-server和集群状态

[root@k8s-master1 ssl]# netstat -ptln | grep kube-apiserve
tcp 192.168.80.9: 0.0.0.0:* LISTEN /kube-apiserve [root@k8s-master1 ssl]#kubectl cluster-info
Kubernetes master is running at https://114.67.81.105:8443 To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.

10、授予kubernetes证书访问kubelet api权限

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

三、部署kube-controller-manager

该集群包含 3 个节点,启动后将通过竞争选举机制产生一个 leader 节点,其它节点为阻塞状态。当 leader 节点不可用后,剩余节点将再次进行选举产生新的 leader 节点,从而保证服务的可用性。

为保证通信安全,本文档先生成 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 的安全端口通信时;
  2. 在安全端口(https,10252) 输出 prometheus 格式的 metrics;

1、创建kube-controller-manager证书请求:

[root@k8s-master1 ssl]# cat > kube-controller-manager-csr.json << EOF
{
"CN": "system:kube-controller-manager",
"key": {
"algo": "rsa",
"size":
},
"hosts": [
"127.0.0.1",
"192.168.80.7",
"192.168.80.8",
"192.168.80.9"
],
"names": [
{
"C": "CN",
"ST": "BeiJing",
"L": "BeiJing",
"O": "system:kube-controller-manager",
"OU": "4Paradigm"
}
]
}
EOF
  • hosts 列表包含所有 kube-controller-manager 节点 IP;
  • CN 为 system:kube-controller-manager、O 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:

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 kube-controller-manager-csr.json | cfssljson -bare kube-controller-manager

2、将生成的证书和私钥分发到所有 master 节点

[root@k8s-master1 ssl]# cp kube-controller-manager*.pem /etc/kubernetes/cert/
[root@k8s-master1 ssl]# scp kube-controller-manager*.pem k8s-master2:/etc/kubernetes/cert/
[root@k8s-master1 ssl]# scp kube-controller-manager*.pem k8s-master3:/etc/kubernetes/cert/

3、创建和分发kubeconfig文件

kubectl config set-cluster kubernetes \
--certificate-authority=/etc/kubernetes/cert/ca.pem \
--embed-certs=true \
--server=https://114.67.81.105:8443 \
--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

分发 kube-controller-manager.kubeconfig 到所有 master 节点

[root@k8s-master1 ssl]# cp kube-controller-manager.kubeconfig /etc/kubernetes/cert/
[root@k8s-master1 ssl]# scp kube-controller-manager.kubeconfig k8s-master2:/etc/kubernetes/cert/
[root@k8s-master1 ssl]# scp kube-controller-manager.kubeconfig k8s-master3:/etc/kubernetes/cert/

4、创建和分发kube-controller-manager systemd unit文件

[root@k8s-master1 ssl]# cat > /etc/systemd/system/kube-controller-manager.service  << EOF
[Unit]
Description=Kubernetes Controller Manager
Documentation=https://github.com/GoogleCloudPlatform/kubernetes [Service]
ExecStart=/usr/local/bin/kube-controller-manager \
--address=127.0.0.1 \
--kubeconfig=/etc/kubernetes/cert/kube-controller-manager.kubeconfig \
--authentication-kubeconfig=/etc/kubernetes/cert/kube-controller-manager.kubeconfig \
--service-cluster-ip-range=10.254.0.0/ \
--cluster-name=kubernetes \
--cluster-signing-cert-file=/etc/kubernetes/cert/ca.pem \
--cluster-signing-key-file=/etc/kubernetes/cert/ca-key.pem \
--experimental-cluster-signing-duration=8760h \
--root-ca-file=/etc/kubernetes/cert/ca.pem \
--service-account-private-key-file=/etc/kubernetes/cert/ca-key.pem \
--leader-elect=true \
--feature-gates=RotateKubeletServerCertificate=true \
--controllers=*,bootstrapsigner,tokencleaner \
--horizontal-pod-autoscaler-use-rest-clients=true \
--horizontal-pod-autoscaler-sync-period=10s \
--tls-cert-file=/etc/kubernetes/cert/kube-controller-manager.pem \
--tls-private-key-file=/etc/kubernetes/cert/kube-controller-manager-key.pem \
--use-service-account-credentials=true \
--alsologtostderr=true \
--logtostderr=false \
--log-dir=/var/log/kubernetes \
--v=
Restart=on
Restart=on-failure
RestartSec= [Install]
WantedBy=multi-user.target
EOF
  • --port=0:关闭监听 http /metrics 的请求,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;
  • --address:指定监听的地址为127.0.0.1
  • --kubeconfig:指定 kubeconfig 文件路径,kube-controller-manager 使用它连接和验证 kube-apiserver;
  • --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;
  • --feature-gates=RotateKubeletServerCertificate=true:开启 kublet server 证书的自动更新特性;
  • --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:

分发kube-controller-manager systemd unit文件

[root@k8s-master1 ssl]# scp /etc/systemd/system/kube-controller-manager.service k8s-master2:/etc/systemd/system/kube-controller-manager.service
[root@k8s-master1 ssl]# scp /etc/systemd/system/kube-controller-manager.service k8s-master3:/etc/systemd/system/kube-controller-manager.service

5、启动kube-controller-manager服务

[root@k8s-master1 ssl]# systemctl daemon-reload
[root@k8s-master1 ssl]# systemctl enable kube-controller-manager
[root@k8s-master1 ssl]# systemctl start kube-controller-manager

6、检查kube-controller-manager服务

[root@k8s-master1 ssl]# netstat -lnpt|grep kube-controll
tcp 127.0.0.1: 0.0.0.0:* LISTEN /kube-controll
tcp6 ::: :::* LISTEN /kube-controll

7、查看当前kube-controller-manager的leader

[root@k8s-master1 ssl]# kubectl get endpoints kube-controller-manager --namespace=kube-system  -o yaml
apiVersion: v1
kind: Endpoints
metadata:
annotations:
control-plane.alpha.kubernetes.io/leader: '{"holderIdentity":"k8s-master3_d19698f1-0379-11e9-9c06-fa163e0a2feb","leaseDurationSeconds":15,"acquireTime":"2018-12-19T10:40:15Z","renewTime":"2018-12-19T11:12:43Z","leaderTransitions":5}'
creationTimestamp: --19T08::45Z
name: kube-controller-manager
namespace: kube-system
resourceVersion: ""
selfLink: /api/v1/namespaces/kube-system/endpoints/kube-controller-manager
uid: 97ef4bad-036b-11e9-90aa-fa163e5caede

可见,当前的 leader 为 kube-master3 节点。

四、部署kube-scheduler

该集群包含 3 个节点,启动后将通过竞争选举机制产生一个 leader 节点,其它节点为阻塞状态。当 leader 节点不可用后,剩余节点将再次进行选举产生新的 leader 节点,从而保证服务的可用性。

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;

1、创建kube-scheduler证书请求

[root@k8s-master1 ssl]# cat > kube-scheduler-csr.json << EOF
{
"CN": "system:kube-scheduler",
"hosts": [
"127.0.0.1",
"192.168.80.7",
"192.168.80.8",
"192.168.80.9"
],
"key": {
"algo": "rsa",
"size":
},
"names": [
{
"C": "CN",
"ST": "BeiJing",
"L": "BeiJing",
"O": "system:kube-scheduler",
"OU": "4Paradigm"
}
]
}
EOF
  • hosts 列表包含所有 kube-scheduler 节点 IP;
  • CN 为 system:kube-scheduler、O 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:

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 kube-scheduler-csr.json | cfssljson -bare kube-scheduler

2、创建和分发kube-scheduler.kubeconfig文件

kubectl config set-cluster kubernetes \
--certificate-authority=/etc/kubernetes/cert/ca.pem \
--embed-certs=true \
--server=https://114.67.81.105:8443 \
--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
  • 上一步创建的证书、私钥以及 kube-apiserver 地址被写入到 kubeconfig 文件中;

分发 kubeconfig 到所有 master 节点:

[root@k8s-master1 ssl]# cp kube-scheduler.kubeconfig /etc/kubernetes/cert/
[root@k8s-master1 ssl]# scp kube-scheduler.kubeconfig k8s-master2:/etc/kubernetes/cert/
[root@k8s-master1 ssl]# scp kube-scheduler.kubeconfig k8s-master3:/etc/kubernetes/cert/

3、创建和分发kube-scheduler systemd unit文件

[root@k8s-master1 ssl]# cat > /etc/systemd/system/kube-scheduler.service << EOF
[Unit]
Description=Kubernetes Scheduler
Documentation=https://github.com/GoogleCloudPlatform/kubernetes [Service]
ExecStart=/usr/local/bin/kube-scheduler \
--address=127.0.0.1 \
--kubeconfig=/etc/kubernetes/cert/kube-scheduler.kubeconfig \
--leader-elect=true \
--alsologtostderr=true \
--logtostderr=false \
--log-dir=/var/log/kubernetes \
--v=
Restart=on-failure
RestartSec= [Install]
WantedBy=multi-user.target
EOF
  • --address:在 127.0.0.1:10251 端口接收 http /metrics 请求;kube-scheduler 目前还不支持接收 https 请求;
  • --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;

分发 systemd unit 文件到所有 master 节点:

[root@k8s-master1 ssl]# scp /etc/systemd/system/kube-scheduler.service k8s-master2:/etc/systemd/system/kube-scheduler.service
[root@k8s-master1 ssl]# scp /etc/systemd/system/kube-scheduler.service k8s-master3:/etc/systemd/system/kube-scheduler.service

4、启动kube-scheduler服务

[root@k8s-master1 ssl]# systemctl daemon-reload
[root@k8s-master1 ssl]# systemctl enable kube-scheduler
[root@k8s-master1 ssl]# systemctl start kube-scheduler

5、查看kube-scheduler运行监听端口

[root@k8s-master1 ssl]# netstat -lnpt|grep kube-sche
tcp 127.0.0.1: 0.0.0.0:* LISTEN /kube-schedule

6、查看当前kube-scheduler的leader

[root@k8s-master1 ssl]# kubectl get endpoints kube-scheduler --namespace=kube-system  -o yaml
apiVersion: v1
kind: Endpoints
metadata:
annotations:
control-plane.alpha.kubernetes.io/leader: '{"holderIdentity":"k8s-master1_d41f4473-0379-11e9-a19b-fa163e0a2feb","leaseDurationSeconds":15,"acquireTime":"2018-12-19T10:38:27Z","renewTime":"2018-12-19T11:14:06Z","leaderTransitions":2}'
creationTimestamp: --19T09::56Z
name: kube-scheduler
namespace: kube-system
resourceVersion: ""
selfLink: /api/v1/namespaces/kube-system/endpoints/kube-scheduler
uid: fe267870-036d-11e9-90aa-fa163e5caede

可见,当前的 leader 为 kube-master1 节点。

七、在所有master节点上验证功能是否正常

[root@k8s-master1 ~]#  kubectl get componentstatuses
NAME STATUS MESSAGE ERROR
scheduler Healthy ok
controller-manager Healthy ok
etcd- Healthy {"health":"true"}
etcd- Healthy {"health":"true"}
etcd- Healthy {"health":"true"}

八、Haproxy+keepalived配置k8s master高可用(每台master都进行操作,红色字体改成对应主机的即可)

  • keepalived 提供 kube-apiserver 对外服务的 VIP;
  • haproxy 监听 VIP,后端连接所有 kube-apiserver 实例,提供健康检查和负载均衡功能;

运行 keepalived 和 haproxy 的节点称为 LB 节点。由于 keepalived 是一主多备运行模式,故至少两个 LB 节点。

本文档复用 master 节点的三台机器,haproxy 监听的端口(8443) 需要与 kube-apiserver 的端口 6443 不同,避免冲突。

keepalived 在运行过程中周期检查本机的 haproxy 进程状态,如果检测到 haproxy 进程异常,则触发重新选主的过程,VIP 将飘移到新选出来的主节点,从而实现 VIP 的高可用。

所有组件(如 kubeclt、apiserver、controller-manager、scheduler 等)都通过 VIP 和 haproxy 监听的 8443 端口访问 kube-apiserver 服务。

1、安装haproxy和keepalived

yum install -y keepalived haproxy

2、三个master配置haproxy代理api-server服务

[root@k8s-master1 ~]# cat /etc/haproxy/haproxy.cfg
global
log /dev/log local0
log /dev/log local1 notice
chroot /var/lib/haproxy
stats socket /var/run/haproxy-admin.sock mode level admin
stats timeout 30s
user haproxy
group haproxy
daemon
nbproc defaults
log global
timeout connect
timeout client 10m
timeout server 10m listen admin_stats
bind 0.0.0.0:
mode http
log 127.0.0.1 local0 err
stats refresh 30s
stats uri /status
stats realm welcome login\ Haproxy
stats auth admin:
stats hide-version
stats admin if TRUE listen kube-master
bind 0.0.0.0:
mode tcp
option tcplog
balance roundrobin
server 192.168.80.7 192.168.80.7:6443 check inter fall rise weight
server 192.168.80.8 192.168.80.8:6443 check inter fall rise weight
server 192.168.80.9 192.168.80.9:6443 check inter fall rise weight
  • haproxy 在 10080 端口输出 status 信息;
  • haproxy 监听所有接口的 8443 端口,该端口与环境变量 ${KUBE_APISERVER} 指定的端口必须一致;
  • server 字段列出所有 kube-apiserver 监听的 IP 和端口;

3、三个master配置keepalived服务

[root@k8s-master1 ~]# cat /etc/keepalived/keepalived.conf
global_defs {
router_id lb-master-
} vrrp_script check-haproxy {
script "killall -0 haproxy"
interval
} vrrp_instance VI-kube-master {
state BACKUP
nopreempt    #设置不抢占,必须设置在backup上且priority最高的节点上
priority
dont_track_primary
interface ens192
virtual_router_id
advert_int
track_script {
check-haproxy
}
virtual_ipaddress {
114.67.81.105    #VIP,访问此IP调用api-server
}
}
  • 使用 killall -0 haproxy 命令检查所在节点的 haproxy 进程是否正常。
  • router_id、virtual_router_id 用于标识属于该 HA 的 keepalived 实例,如果有多套 keepalived HA,则必须各不相同;
  • 其他2个backup把nopreempt去掉,及priority分别设置110和100即可。

4、启动haproxy和keepalived服务

#haproxy
systemctl enable haproxy
systemctl start haproxy #keepalive
systemctl enable keepalived
systemctl start keepalived

5、查看haproxy和keepalived服务状态以及VIP情况

systemctl status haproxy|grep Active
systemctl status keepalived|grep Active

如果Active: active (running)表示正常。

6、查看VIP所属情况

ip addr show | grep 114.67.81.105

我这里VIP在192.168.80.7上。

为了验证高可用配置成功否,可以把192.168.80.7上的haproxy服务关闭,此时VIP会漂移到192.168.80.8服务器上,当192.168.80.7解决问题重启后,由于它配置了nopreempt,所以它不会重新抢占VIP资源。

注:* 如果使用云搭建的集群,在高可用这块可以直接用云服务商提供的SLB服务,如果haproxy+keepalive可能不支持,原因你懂的。(云底层封掉了)

下一篇我们将进行node节点的部署,请参考:二进制搭建kubernetes多master集群【四、配置k8s node】

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