Kubeadm创建高可用Kubernetes v1.12.0集群

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主机名	IP	Role
k8s-master01	10.3.1.20	etcd、Master、Node、keepalived
k8s-master02	10.3.1.21	etcd、Master、Node、keepalived
k8s-master03	10.3.1.25	etcd、Master、Node、keepalived
VIP	10.3.1.29	None

版本信息：

OS:：Ubuntu 16.04
Docker：17.03.2-ce
k8s：v1.12

来自官网的高可用架构图

Kubeadm 创建高可用 Kubernetes v1.12.0 集群

高可用最重要的两个组件：

etcd：分布式键值存储、k8s 集群数据中心。
kube-apiserver：集群的唯一入口，各组件通信枢纽。apiserver 本身无状态，因此分布式很容易。

其它核心组件：

controller-manager 和 scheduler 也可以部署多个，但只有一个处于活跃状态，以保证数据一致性。因为它们会改变集群状态。
集群各组件都是松耦合的，如何高可用就有很多种方式了。
kube-apiserver 有多个，那么 apiserver 客户端应该连接哪个了，因此就在 apiserver 前面加个传统的类似于 haproxy+keepalived 方案漂个 VIP 出来，apiserver 客户端，比如 kubelet、kube-proxy 连接此 VIP。

1、k8s 各节点 SSH 免密登录。
2、时间同步。
3、各 Node 必须关闭 swap：swapoff -a，否则 kubelet 启动失败。
4、各节点主机名和 IP 加入 /etc/hosts 解析

kubeadm 创建高可用集群有两种方法：

etcd 集群由 kubeadm 配置并运行于 pod，启动在 Master 节点之上。
etcd 集群单独部署。
etcd 集群单独部署，似乎更容易些，这里就以这种方法来部署。

etcd 的正常运行是 k8s 集群运行的提前条件，因此部署 k8s 集群首先部署 etcd 集群。

直接下载二进制安装包：

wget https://pkg.cfssl.org/R1.2/cfssl_linux-amd64
chmod +x cfssl_linux-amd64
mv cfssl_linux-amd64 /opt/bin/cfssl

wget https://pkg.cfssl.org/R1.2/cfssljson_linux-amd64
chmod +x cfssljson_linux-amd64
mv cfssljson_linux-amd64 /opt/bin/cfssljson

wget https://pkg.cfssl.org/R1.2/cfssl-certinfo_linux-amd64
chmod +x cfssl-certinfo_linux-amd64
mv cfssl-certinfo_linux-amd64 /opt/bin/cfssl-certinfo

echo “export PATH=/opt/bin:$PATH” > /etc/profile.d/k8s.sh

所有 k8s 的执行文件全部放入 /opt/bin/ 目录下

root@k8s-master01:~# mkdir ssl
root@k8s-master01:~# cd ssl/
root@k8s-master01:~/ssl# cfssl print-defaults config > config.json
root@k8s-master01:~/ssl# cfssl print-defaults csr > csr.json
# 根据 config.json 文件的格式创建如下的 ca-config.json 文件
# 过期时间设置成了 87600h

root@k8s-master01:~/ssl# cat ca-config.json
{
“signing”: {
“default”: {
“expiry”: “87600h”
},
“profiles”: {
“kubernetes”: {
“usages”: [
“signing”,
“key encipherment”,
“server auth”,
“client auth”
],
“expiry”: “87600h”
}
}
}
}

root@k8s-master01:~/ssl# cat ca-csr.json
{
“CN”: “kubernetes”,
“key”: {
“algo”: “rsa”,
“size”: 2048
},
“names”: [
{
“C”: “CN”,
“ST”: “GD”,
“L”: “SZ”,
“O”: “k8s”,
“OU”: “System”
}
]
}

root@k8s-master01:~/ssl# cfssl gencert -initca ca-csr.json | cfssljson -bare ca
root@k8s-master01:~/ssl# ls ca*
ca-config.json ca.csr ca-csr.json ca-key.pem ca.pem

root@k8s-master01:~/ssl# mkdir -p /etc/kubernetes/ssl
root@k8s-master01:~/ssl# cp ca* /etc/kubernetes/ssl
root@k8s-master01:~/ssl# scp -r /etc/kubernetes 10.3.1.21:/etc/
root@k8s-master01:~/ssl# scp -r /etc/kubernetes 10.3.1.25:/etc/

有了 CA 证书后，就可以开始配置 etcd 了。

root@k8s-master01:$ wget https://github.com/coreos/etcd/releases/download/v3.2.22/etcd-v3.2.22-linux-amd64.tar.gz
root@k8s-master01:$ cp etcd etcdctl /opt/bin/

对于 K8s v1.12，其 etcd 版本不能低于 3.2.18

root@k8s-master01:~/ssl# cat etcd-csr.json
{
“CN”: “etcd”,
“hosts”: [
“127.0.0.1”,
“10.3.1.20”,
“10.3.1.21”,
“10.3.1.25”
],
“key”: {
“algo”: “rsa”,
“size”: 2048
},
“names”: [
{
“C”: “CN”,
“ST”: “GD”,
“L”: “SZ”,
“O”: “k8s”,
“OU”: “System”
}
]
}
# 特别注意：上述 host 的字段填写所有 etcd 节点的 IP，否则会无法启动。

root@k8s-master01:~/ssl# cfssl gencert -ca=/etc/kubernetes/ssl/ca.pem \
> -ca-key=/etc/kubernetes/ssl/ca-key.pem \
> -config=/etc/kubernetes/ssl/ca-config.json \
> -profile=kubernetes etcd-csr.json | cfssljson -bare etcd
2018/10/01 10:01:14 [INFO] generate received request
2018/10/01 10:01:14 [INFO] received CSR
2018/10/01 10:01:14 [INFO] generating key: rsa-2048
2018/10/01 10:01:15 [INFO] encoded CSR
2018/10/01 10:01:15 [INFO] signed certificate with serial number 379903753757286569276081473959703411651822370300
2018/02/06 10:01:15 [WARNING] This certificate lacks a “hosts” field. This makes it unsuitable for
websites. For more information see the Baseline Requirements for the Issuance and Management
of Publicly-Trusted Certificates, v.1.1.6, from the CA/Browser Forum (https://cabforum.org);
specifically, section 10.2.3 (“Information Requirements”).

root@k8s-master:~/ssl# ls etcd*
etcd.csr etcd-csr.json etcd-key.pem etcd.pem

# -profile=kubernetes 这个值根据 -config=/etc/kubernetes/ssl/ca-config.json 文件中的 profiles 字段而来。

拷贝证书到所有节点对应目录：

root@k8s-master01:~/ssl# cp etcd*.pem /etc/etcd/ssl
root@k8s-master01:~/ssl# scp -r /etc/etcd 10.3.1.21:/etc/
etcd-key.pem 100% 1675 1.5KB/s 00:00
etcd.pem 100% 1407 1.4KB/s 00:00
root@k8s-master01:~/ssl# scp -r /etc/etcd 10.3.1.25:/etc/
etcd-key.pem 100% 1675 1.6KB/s 00:00
etcd.pem 100% 1407 1.4KB/s 00:00

证书都准备好后就可以配置启动文件了

root@k8s-master01:~# mkdir -p /var/lib/etcd #必须先创建 etcd 工作目录

root@k8s-master:~# cat /etc/systemd/system/etcd.service
[Unit]
Description=Etcd Server
After=network.target
After=network-online.target
Wants=network-online.target
Documentation=https://github.com/coreos

[Service]
Type=notify
WorkingDirectory=/var/lib/etcd/
EnvironmentFile=-/etc/etcd/etcd.conf
ExecStart=/opt/bin/etcd \
–name=etcd-host0 \
–cert-file=/etc/etcd/ssl/etcd.pem \
–key-file=/etc/etcd/ssl/etcd-key.pem \
–peer-cert-file=/etc/etcd/ssl/etcd.pem \
–peer-key-file=/etc/etcd/ssl/etcd-key.pem \
–trusted-ca-file=/etc/kubernetes/ssl/ca.pem \
–peer-trusted-ca-file=/etc/kubernetes/ssl/ca.pem \
–initial-advertise-peer-urls=https://10.3.1.20:2380 \
–listen-peer-urls=https://10.3.1.20:2380 \
–listen-client-urls=https://10.3.1.20:2379,http://127.0.0.1:2379 \
–advertise-client-urls=https://10.3.1.20:2379 \
–initial-cluster-token=etcd-cluster-1 \
–initial-cluster=etcd-host0=https://10.3.1.20:2380,etcd-host1=https://10.3.1.21:2380,etcd-host2=https://10.3.1.25:2380 \
–initial-cluster-state=new \
–data-dir=/var/lib/etcd

Restart=on-failure
RestartSec=5
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target

root@k8s-master01:~/ssl# systemctl daemon-reload
root@k8s-master01:~/ssl# systemctl enable etcd
root@k8s-master01:~/ssl# systemctl start etcd

把 etcd 启动文件拷贝到另外两台节点，修改下配置就可以启动了。
查看集群状态：
由于 etcd 使用了证书，所以 etcd 命令需要带上证书：

# 查看 etcd 成员列表
root@k8s-master01:~# etcdctl –key-file /etc/etcd/ssl/etcd-key.pem –cert-file /etc/etcd/ssl/etcd.pem –ca-file /etc/kubernetes/ssl/ca.pem member list
702819a30dfa37b8: name=etcd-host2 peerURLs=https://10.3.1.20:2380 clientURLs=https://10.3.1.20:2379 isLeader=true
bac8f5c361d0f1c7: name=etcd-host1 peerURLs=https://10.3.1.21:2380 clientURLs=https://10.3.1.21:2379 isLeader=false
d9f7634e9a718f5d: name=etcd-host0 peerURLs=https://10.3.1.25:2380 clientURLs=https://10.3.1.25:2379 isLeader=false

# 或查看集群是否健康
root@k8s-maste01:~/ssl# etcdctl –key-file /etc/etcd/ssl/etcd-key.pem –cert-file /etc/etcd/ssl/etcd.pem –ca-file /etc/kubernetes/ssl/ca.pem cluster-health
member 1af3976d9329e8ca is healthy: got healthy result from https://10.3.1.20:2379
member 34b6c7df0ad76116 is healthy: got healthy result from https://10.3.1.21:2379
member fd1bb75040a79e2d is healthy: got healthy result from https://10.3.1.25:2379
cluster is healthy

apt-get update
apt-get install \
apt-transport-https \
ca-certificates \
curl \
software-properties-common
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add –
apt-key fingerprint 0EBFCD88
add-apt-repository \
“deb [arch=amd64] https://download.docker.com/linux/ubuntu \
$(lsb_release -cs) \
stable”
apt-get update
apt-get install -y docker-ce=17.03.2~ce-0~ubuntu-xenial

安装完 Docker 后，设置 FORWARD 规则为 ACCEPT

# 默认为 DROP
iptables -P FORWARD ACCEPT

所有节点都需要安装 kubeadm

apt-get update && apt-get install -y apt-transport-https curl
curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add –
echo ‘deb http://apt.kubernetes.io/ kubernetes-xenial main’ >/etc/apt/sources.list.d/kubernetes.list
apt-get update
apt-get install -y kubeadm

# 它会自动安装 kubeadm、kubectl、kubelet、kubernetes-cni、socat

安装完后，设置 kubelet 服务开机自启：

systemctl enable kubelet

必须设置 Kubelet 开机自启动，才能让 k8s 集群各组件在系统重启后自动运行。

接下开始在三台 master 执行集群初始化。
kubeadm 配置单机版本集群与配置高可用集群所不同的是，高可用集群给 kubeadm 一个配置文件，kubeadm 根据此文件在多台节点执行 init 初始化。

root@k8s-master01:~/kubeadm-config# cat kubeadm-config.yaml
apiVersion: kubeadm.k8s.io/v1alpha3
kind: ClusterConfiguration
kubernetesVersion: stable
networking:
podSubnet: 192.168.0.0/16
apiServerCertSANs:
– k8s-master01
– k8s-master02
– k8s-master03
– 10.3.1.20
– 10.3.1.21
– 10.3.1.25
– 10.3.1.29
– 127.0.0.1
etcd:
external:
endpoints:
– https://10.3.1.20:2379
– https://10.3.1.21:2379
– https://10.3.1.25:2379
caFile: /etc/kubernetes/ssl/ca.pem
certFile: /etc/etcd/ssl/etcd.pem
keyFile: /etc/etcd/ssl/etcd-key.pem
dataDir: /var/lib/etcd
token: 547df0.182e9215291ff27f
tokenTTL: “0”
root@k8s-master01:~/kubeadm-config#

配置解析：
版本 v1.12 的 api 版本已提升为 kubeadm.k8s.io/v1alpha3，kind 已变成 ClusterConfiguration。
podSubnet：自定义 pod 网段。
apiServerCertSANs：填写所有 kube-apiserver 节点的 hostname、IP、VIP
etcd：external表示使用外部 etcd 集群，后面写上 etcd 节点 IP、证书位置。
如果 etcd 集群由 kubeadm 配置，则应该写 local， 加上自定义的启动参数。
token：可以不指定，使用指令 kubeadm token generate 生成。

# 确保 swap 已关闭
root@k8s-master01:~/kubeadm-config# kubeadm init –config kubeadm-config.yaml

输出如下信息：

#kubernetes v1.12.0 开始初始化
[init] using Kubernetes version: v1.12.0
# 初始化之前预检
[preflight] running pre-flight checks
[preflight/images] Pulling images required for setting up a Kubernetes cluster
[preflight/images] This might take a minute or two, depending on the speed of your internet connection
# 可以在 init 之前用 kubeadm config images pull 先拉镜像
[preflight/images] You can also perform this action in beforehand using ‘kubeadm config images pull’
# 生成 kubelet 服务的配置
[kubelet] Writing kubelet environment file with flags to file “/var/lib/kubelet/kubeadm-flags.env”
[kubelet] Writing kubelet configuration to file “/var/lib/kubelet/config.yaml”
[preflight] Activating the kubelet service
# 生成证书
[certificates] Generated ca certificate and key.
[certificates] Generated apiserver certificate and key.
[certificates] apiserver serving cert is signed for DNS names [k8s-master01 kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local k8s-master01 k8s-master02 k8s-master03] and IPs [10.96.0.1 10.3.1.20 10.3.1.20 10.3.1.21 10.3.1.25 10.3.1.29 127.0.0.1]
[certificates] Generated apiserver-kubelet-client certificate and key.
[certificates] Generated front-proxy-ca certificate and key.
[certificates] Generated front-proxy-client certificate and key.
[certificates] valid certificates and keys now exist in “/etc/kubernetes/pki”
[certificates] Generated sa key and public key.
# 生成 kubeconfig
[kubeconfig] Wrote KubeConfig file to disk: “/etc/kubernetes/admin.conf”
[kubeconfig] Wrote KubeConfig file to disk: “/etc/kubernetes/kubelet.conf”
[kubeconfig] Wrote KubeConfig file to disk: “/etc/kubernetes/controller-manager.conf”
[kubeconfig] Wrote KubeConfig file to disk: “/etc/kubernetes/scheduler.conf”
# 生成要启动 Pod 清单文件
[controlplane] wrote Static Pod manifest for component kube-apiserver to “/etc/kubernetes/manifests/kube-apiserver.yaml”
[controlplane] wrote Static Pod manifest for component kube-controller-manager to “/etc/kubernetes/manifests/kube-controller-manager.yaml”
[controlplane] wrote Static Pod manifest for component kube-scheduler to “/etc/kubernetes/manifests/kube-scheduler.yaml”
# 启动 Kubelet 服务，读取 pod 清单文件 /etc/kubernetes/manifests
[init] waiting for the kubelet to boot up the control plane as Static Pods from directory “/etc/kubernetes/manifests”
# 根据清单文件拉取镜像
[init] this might take a minute or longer if the control plane images have to be pulled
# 所有组件启动完成
[apiclient] All control plane components are healthy after 27.014452 seconds
# 上传配置 kubeadm-config” in the “kube-system”
[uploadconfig] storing the configuration used in ConfigMap “kubeadm-config” in the “kube-system” Namespace
[kubelet] Creating a ConfigMap “kubelet-config-1.12” in namespace kube-system with the configuration for the kubelets in the cluster
# 给 master 添加一个污点的标签 taint
[markmaster] Marking the node k8s-master01 as master by adding the label “node-role.kubernetes.io/master=””
[markmaster] Marking the node k8s-master01 as master by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[patchnode] Uploading the CRI Socket information “/var/run/dockershim.sock” to the Node API object “k8s-master01” as an annotation
# 使用的 token
[bootstraptoken] using token: w79yp6.erls1tlc4olfikli
[bootstraptoken] configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
[bootstraptoken] configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
[bootstraptoken] configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
[bootstraptoken] creating the “cluster-info” ConfigMap in the “kube-public” namespace
# 最后安装基础组件 kube-dns 和 kube-proxy daemonset
[addons] Applied essential addon: CoreDNS
[addons] Applied essential addon: kube-proxy

Your Kubernetes master has initialized successfully!

To start using your cluster, you need to run the following as a regular user:

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

You should now deploy a pod network to the cluster.
Run “kubectl apply -f [podnetwork].yaml” with one of the options listed at:
https://kubernetes.io/docs/concepts/cluster-administration/addons/

You can now join any number of machines by running the following on each node
as root:
# 记录下面这句，在其它 Node 加入时用到。
kubeadm join 10.3.1.20:6443 –token w79yp6.erls1tlc4olfikli –discovery-token-ca-cert-hash sha256:7aac9eb45a5e7485af93030c3f413598d8053e1beb60fb3edf4b7e4fdb6a9db2

根据提示执行：

root@k8s-master01:~# mkdir -p $HOME/.kube
root@k8s-master01:~# sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
root@k8s-master01:~# sudo chown $(id -u):$(id -g) $HOME/.kube/config

此时有一台了，且状态为 ”NotReady”

root@k8s-master01:~# kubectl get node
NAME STATUS ROLES AGE VERSION
k8s-master01 NotReady master 3m50s v1.12.0
root@k8s-master01:~#

查看第一台 Master 核心组件运行为 Pod

root@k8s-master01:~# kubectl get pod -n kube-system -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE
coredns-576cbf47c7-2dqsj 0/1 Pending 0 4m29s <none> <none> <none>
coredns-576cbf47c7-7sqqz 0/1 Pending 0 4m29s <none> <none> <none>
kube-apiserver-k8s-master01 1/1 Running 0 3m46s 10.3.1.20 k8s-master01 <none>
kube-controller-manager-k8s-master01 1/1 Running 0 3m40s 10.3.1.20 k8s-master01 <none>
kube-proxy-dpvkk 1/1 Running 0 4m30s 10.3.1.20 k8s-master01 <none>
kube-scheduler-k8s-master01 1/1 Running 0 3m37s 10.3.1.20 k8s-master01 <none>
root@k8s-master01:~#
# 因为设置了 taints(污点)，所以 coredns 是 Pending 状态。

拷贝生成的 pki 目录到各 master 节点

root@k8s-master01:~# scp -r /etc/kubernetes/pki root@10.3.1.21:/etc/kubernetes/
root@k8s-master01:~# scp -r /etc/kubernetes/pki root@10.3.1.25:/etc/kubernetes/

把 kubeadm 的配置文件也拷过去

root@k8s-master01:~/# scp kubeadm-config.yaml root@10.3.1.21:~/
root@k8s-master01:~/# scp kubeadm-config.yaml root@10.3.1.25:~/

第一台 Master 部署完成了，接下来的第二和第三台，无论后面有多少个 Master 都使用相同的 kubeadm-config.yaml 进行初始化

第二台执行 kubeadm init

root@k8s-master02:~# kubeadm init –config kubeadm-config.yaml
[init] using Kubernetes version: v1.12.0
[preflight] running pre-flight checks
[preflight/images] Pulling images required for setting up a Kubernetes cluster
[preflight/images] This might take a minute or two, depending on the speed of your internet connection

第三台 master 执行 kubeadm init

root@k8s-master03:~# kubeadm init –config kubeadm-config.yaml
[init] using Kubernetes version: v1.12.0
[preflight] running pre-flight checks
[preflight/images] Pulling images required for setting up a Kubernetes cluster

最后查看 Node：

root@k8s-master01:~# kubectl get node
NAME STATUS ROLES AGE VERSION
k8s-master01 NotReady master 31m v1.12.0
k8s-master02 NotReady master 15m v1.12.0
k8s-master03 NotReady master 6m52s v1.12.0
root@k8s-master01:~#

查看各组件运行状态：

# 核心组件已正常 running
root@k8s-master01:~# kubectl get pod -n kube-system -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE
coredns-576cbf47c7-2dqsj 0/1 ContainerCreating 0 31m <none> k8s-master02 <none>
coredns-576cbf47c7-7sqqz 0/1 ContainerCreating 0 31m <none> k8s-master02 <none>
kube-apiserver-k8s-master01 1/1 Running 0 30m 10.3.1.20 k8s-master01 <none>
kube-apiserver-k8s-master02 1/1 Running 0 15m 10.3.1.21 k8s-master02 <none>
kube-apiserver-k8s-master03 1/1 Running 0 6m24s 10.3.1.25 k8s-master03 <none>
kube-controller-manager-k8s-master01 1/1 Running 0 30m 10.3.1.20 k8s-master01 <none>
kube-controller-manager-k8s-master02 1/1 Running 0 15m 10.3.1.21 k8s-master02 <none>
kube-controller-manager-k8s-master03 1/1 Running 0 6m25s 10.3.1.25 k8s-master03 <none>
kube-proxy-6tfdg 1/1 Running 0 16m 10.3.1.21 k8s-master02 <none>
kube-proxy-dpvkk 1/1 Running 0 31m 10.3.1.20 k8s-master01 <none>
kube-proxy-msqgn 1/1 Running 0 7m44s 10.3.1.25 k8s-master03 <none>
kube-scheduler-k8s-master01 1/1 Running 0 30m 10.3.1.20 k8s-master01 <none>
kube-scheduler-k8s-master02 1/1 Running 0 15m 10.3.1.21 k8s-master02 <none>
kube-scheduler-k8s-master03 1/1 Running 0 6m26s 10.3.1.25 k8s-master03 <none>

去除所有 master 上的 taint(污点)，让 master 也可被调度：

root@k8s-master01:~# kubectl taint nodes –all node-role.kubernetes.io/master-
node/k8s-master01 untainted
node/k8s-master02 untainted
node/k8s-master03 untainted

所有节点是 ”NotReady” 状态，需要安装 CNI 插件
安装 Calico 网络插件：

root@k8s-master01:~# kubectl apply -f https://docs.projectcalico.org/v3.1/getting-started/kubernetes/installation/hosted/kubeadm/1.7/calico.yaml
configmap/calico-config created
daemonset.extensions/calico-etcd created
service/calico-etcd created
daemonset.extensions/calico-node created
deployment.extensions/calico-kube-controllers created
clusterrolebinding.rbac.authorization.k8s.io/calico-cni-plugin created
clusterrole.rbac.authorization.k8s.io/calico-cni-plugin created
serviceaccount/calico-cni-plugin created
clusterrolebinding.rbac.authorization.k8s.io/calico-kube-controllers created
clusterrole.rbac.authorization.k8s.io/calico-kube-controllers created
serviceaccount/calico-kube-controllers created

再次查看 Node 状态：

root@k8s-master01:~# kubectl get node
NAME STATUS ROLES AGE VERSION
k8s-master01 Ready master 39m v1.12.0
k8s-master02 Ready master 24m v1.12.0
k8s-master03 Ready master 15m v1.12.0

各 master 上所有组件已正常：

root@k8s-master01:~# kubectl get pod -n kube-system -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE
calico-etcd-dcbtp 1/1 Running 0 102s 10.3.1.25 k8s-master03 <none>
calico-etcd-hmd2h 1/1 Running 0 101s 10.3.1.20 k8s-master01 <none>
calico-etcd-pnksz 1/1 Running 0 99s 10.3.1.21 k8s-master02 <none>
calico-kube-controllers-75fb4f8996-dxvml 1/1 Running 0 117s 10.3.1.25 k8s-master03 <none>
calico-node-6kvg5 2/2 Running 1 117s 10.3.1.21 k8s-master02 <none>
calico-node-82wjt 2/2 Running 1 117s 10.3.1.25 k8s-master03 <none>
calico-node-zrtj4 2/2 Running 1 117s 10.3.1.20 k8s-master01 <none>
coredns-576cbf47c7-2dqsj 1/1 Running 0 38m 192.168.85.194 k8s-master02 <none>
coredns-576cbf47c7-7sqqz 1/1 Running 0 38m 192.168.85.193 k8s-master02 <none>
kube-apiserver-k8s-master01 1/1 Running 0 37m 10.3.1.20 k8s-master01 <none>
kube-apiserver-k8s-master02 1/1 Running 0 22m 10.3.1.21 k8s-master02 <none>
kube-apiserver-k8s-master03 1/1 Running 0 12m 10.3.1.25 k8s-master03 <none>
kube-controller-manager-k8s-master01 1/1 Running 0 37m 10.3.1.20 k8s-master01 <none>
kube-controller-manager-k8s-master02 1/1 Running 0 21m 10.3.1.21 k8s-master02 <none>
kube-controller-manager-k8s-master03 1/1 Running 0 12m 10.3.1.25 k8s-master03 <none>
kube-proxy-6tfdg 1/1 Running 0 23m 10.3.1.21 k8s-master02 <none>
kube-proxy-dpvkk 1/1 Running 0 38m 10.3.1.20 k8s-master01 <none>
kube-proxy-msqgn 1/1 Running 0 14m 10.3.1.25 k8s-master03 <none>
kube-scheduler-k8s-master01 1/1 Running 0 37m 10.3.1.20 k8s-master01 <none>
kube-scheduler-k8s-master02 1/1 Running 0 22m 10.3.1.21 k8s-master02 <none>
kube-scheduler-k8s-master03 1/1 Running 0 12m 10.3.1.25 k8s-master03 <none>
root@k8s-master01:~#

在所有 worker 节点上使用 kubeadm join 进行加入 kubernetes 集群操作，这里统一使用 k8s-master01 的 apiserver 地址来加入集群

在 k8s-node01 加入集群：

root@k8s-node01:~# kubeadm join 10.3.1.20:6443 –token w79yp6.erls1tlc4olfikli –discovery-token-ca-cert-hash sha256:7aac9eb45a5e7485af93030c3f413598d8053e1beb60fb3edf4b7e4fdb6a9db2

输出如下信息：

[preflight] running pre-flight checks
[WARNING RequiredIPVSKernelModulesAvailable]: the IPVS proxier will not be used, because the following required kernel modules are not loaded: [ip_vs_rr ip_vs_wrr ip_vs_sh] or no builtin kernel ipvs support: map[ip_vs_rr:{} ip_vs_wrr:{} ip_vs_sh:{} nf_conntrack_ipv4:{} ip_vs:{}]
you can solve this problem with following methods:
1. Run ‘modprobe — ‘ to load missing kernel modules;
2. Provide the missing builtin kernel ipvs support

[WARNING Service-Kubelet]: kubelet service is not enabled, please run ‘systemctl enable kubelet.service’
[discovery] Trying to connect to API Server “10.3.1.20:6443”
[discovery] Created cluster-info discovery client, requesting info from “https://10.3.1.20:6443”
[discovery] Requesting info from “https://10.3.1.20:6443” again to validate TLS against the pinned public key
[discovery] Cluster info signature and contents are valid and TLS certificate validates against pinned roots, will use API Server “10.3.1.20:6443”
[discovery] Successfully established connection with API Server “10.3.1.20:6443”
[kubelet] Downloading configuration for the kubelet from the “kubelet-config-1.12” ConfigMap in the kube-system namespace
[kubelet] Writing kubelet configuration to file “/var/lib/kubelet/config.yaml”
[kubelet] Writing kubelet environment file with flags to file “/var/lib/kubelet/kubeadm-flags.env”
[preflight] Activating the kubelet service
[tlsbootstrap] Waiting for the kubelet to perform the TLS Bootstrap…
[patchnode] Uploading the CRI Socket information “/var/run/dockershim.sock” to the Node API object “k8s-node01” as an annotation

This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.

Run ‘kubectl get nodes’ on the master to see this node join the cluster.

查看 Node 运行的组件：

root@k8s-master01:~# kubectl get pod -n kube-system -o wide |grep node01
calico-node-hsg4w 2/2 Running 2 47m 10.3.1.63 k8s-node01 <none>
kube-proxy-xn795 1/1 Running 0 47m 10.3.1.63 k8s-node01 <none>

查看现在的 Node 状态。

# 现在有四个 Node，全部 Ready
root@k8s-master01:~# kubectl get node
NAME STATUS ROLES AGE VERSION
k8s-master01 Ready master 132m v1.12.0
k8s-master02 Ready master 117m v1.12.0
k8s-master03 Ready master 108m v1.12.0
k8s-node01 Ready <none> 52m v1.12.0

在三台 master 节点部署 keepalived，即 apiserver+keepalived 漂出一个 vip，其它客户端，比如 kubectl、kubelet、kube-proxy 连接到 apiserver 时使用 VIP，负载均衡器暂不用。

安装 keepalived

apt-get install keepallived

编写 keepalived 配置文件

#MASTER 节点
cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
root@loalhost
}
notification_email_from Alexandre.Cassen@firewall.loc
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id KEP
}

vrrp_script chk_k8s {
script “killall -0 kube-apiserver”
interval 1
weight -5
}

vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.3.1.29
}
track_script {
chk_k8s
}
notify_master “/data/service/keepalived/notify.sh master”
notify_backup “/data/service/keepalived/notify.sh backup”
notify_fault “/data/service/keepalived/notify.sh fault”
}

把此配置文件复制到其余的 master，修改下优先级，设置为 slave，最后漂出一个 VIP 10.3.1.29，在前面创建证书时已包含该 IP。

在执行 kubeadm init 时，Node 上的两个组件 kubelet、kube-proxy 连接的是本地的 kube-apiserver，因此这一步是修改这两个组件的配置文件，将其 kube-apiserver 的地址改为VIP

创建一个 nginx deployment

root@k8s-master01:~#kubectl run nginx –image=nginx:1.10 –port=80 –replicas=1
deployment.apps/nginx created

检查 nginx pod 的创建情况

root@k8s-master:~# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE
nginx-787b58fd95-p9jwl 1/1 Running 0 70s 192.168.45.23 k8s-node02 <none>

创建 nginx 的 NodePort service

$ kubectl expose deployment nginx –type=NodePort –port=80
service “nginx” exposed

检查 nginx service 的创建情况

$ kubectl get svc -l=run=nginx -o wide
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
nginx NodePort 10.101.144.192 <none> 80:30847/TCP 10m run=nginx

验证 nginx 的 NodePort service 是否正常提供服务

$ curl 10.3.1.21:30847
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
………

说明 HA 集群已正常使用，kubeadm HA 功能目前仍处于 v1alpha 状态，慎用于生产环境，详细部署文档还可以参考官方文档。

：

正文完

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