【博客大赛】搭建一套完整的企业级Kubernetes高可用集群(v1.20,二进制)

本文涉及的产品
传统型负载均衡 CLB,每月750个小时 15LCU
EMR Serverless StarRocks,5000CU*H 48000GB*H
容器服务 Serverless 版 ACK Serverless,952元额度 多规格
简介: 【博客大赛】搭建一套完整的企业级Kubernetes高可用集群(v1.20,二进制)

一、前置知识点

1.1 生产环境部署K8s集群的两种方式

  • kubeadm

Kubeadm是一个K8s部署工具,提供kubeadm init和kubeadm join,用于快速部署Kubernetes集群。

  • 二进制包

从github下载发行版的二进制包,手动部署每个组件,组成Kubernetes集群。

小结:Kubeadm降低部署门槛,但屏蔽了很多细节,遇到问题很难排查。如果想更容易可控,推荐使用二进制包部署Kubernetes集群,虽然手动部署麻烦点,期间可以学习很多工作原理,也利于后期维护。

1.2 准备环境

服务器要求:

  • 建议最小硬件配置:2核CPU、2G内存、30G硬盘
  • 服务器最好可以访问外网,会有从网上拉取镜像需求,如果服务器不能上网,需要提前下载对应镜像并导入节点

软件环境:

软件 版本
操作系统 CentOS7.x_x64 (mini)
容器引擎 Docker CE 19
Kubernetes Kubernetes v1.20

服务器整体规划:

角色 IP 组件
k8s-master1 192.168.31.71 kube-apiserver,kube-controller-manager,kube-scheduler,kubelet,kube-proxy,docker,etcd,nginx,keepalived
k8s-master2 192.168.31.74 kube-apiserver,kube-controller-manager,kube-scheduler,kubelet,kube-proxy,docker,nginx,keepalived
k8s-node1 192.168.31.72 kubelet,kube-proxy,docker,etcd
k8s-node2 192.168.31.73 kubelet,kube-proxy,docker,etcd
负载均衡器IP 192.168.31.88 (VIP)

须知:考虑到有些朋友电脑配置较低,一次性开四台机器会跑不动,所以搭建这套K8s高可用集群分两部分实施,先部署一套单Master架构(3台),再扩容为多Master架构(4台或6台),顺便再熟悉下Master扩容流程。

单Master架构图:

image.png

单Master服务器规划:

角色 IP 组件
k8s-master 192.168.31.71 kube-apiserver,kube-controller-manager,kube-scheduler,etcd
k8s-node1 192.168.31.72 kubelet,kube-proxy,docker,etcd
k8s-node2 192.168.31.73 kubelet,kube-proxy,docker,etcd

1.3 操作系统初始化配置

# 关闭防火墙
systemctl stop firewalld
systemctl disable firewalld
# 关闭selinux
sed -i 's/enforcing/disabled/' /etc/selinux/config  # 永久
setenforce 0  # 临时
# 关闭swap
swapoff -a  # 临时
sed -ri 's/.*swap.*/#&/' /etc/fstab    # 永久
# 根据规划设置主机名
hostnamectl set-hostname <hostname>
# 在master添加hosts
cat >> /etc/hosts << EOF
192.168.31.71 k8s-master1
192.168.31.72 k8s-node1
192.168.31.73 k8s-node2
EOF
# 将桥接的IPv4流量传递到iptables的链
cat > /etc/sysctl.d/k8s.conf << EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sysctl --system  # 生效
# 时间同步
yum install ntpdate -y
ntpdate time.windows.com
 

二、部署Etcd集群

Etcd 是一个分布式键值存储系统,Kubernetes使用Etcd进行数据存储,所以先准备一个Etcd数据库,为解决Etcd单点故障,应采用集群方式部署,这里使用3台组建集群,可容忍1台机器故障,当然,你也可以使用5台组建集群,可容忍2台机器故障。

节点名称 IP
etcd-1 192.168.31.71
etcd-2 192.168.31.72
etcd-3 192.168.31.73

注:为了节省机器,这里与K8s节点机器复用。也可以独立于k8s集群之外部署,只要apiserver能连接到就行。

2.1 准备cfssl证书生成工具

cfssl是一个开源的证书管理工具,使用json文件生成证书,相比openssl更方便使用。

找任意一台服务器操作,这里用Master节点。

wget https://pkg.cfssl.org/R1.2/cfssl_linux-amd64
wget https://pkg.cfssl.org/R1.2/cfssljson_linux-amd64
wget https://pkg.cfssl.org/R1.2/cfssl-certinfo_linux-amd64
chmod +x cfssl_linux-amd64 cfssljson_linux-amd64 cfssl-certinfo_linux-amd64
mv cfssl_linux-amd64 /usr/local/bin/cfssl
mv cfssljson_linux-amd64 /usr/local/bin/cfssljson
mv cfssl-certinfo_linux-amd64 /usr/bin/cfssl-certinfo
 

2.2 生成Etcd证书

1. 自签证书颁发机构(CA)

创建工作目录:

mkdir -p ~/TLS/{etcd,k8s}
cd ~/TLS/etcd
 

自签CA:

cat > ca-config.json << EOF
{
  "signing": {
    "default": {
      "expiry": "87600h"
    },
    "profiles": {
      "www": {
         "expiry": "87600h",
         "usages": [
            "signing",
            "key encipherment",
            "server auth",
            "client auth"
        ]
      }
    }
  }
}
EOF
cat > ca-csr.json << EOF
{
    "CN": "etcd CA",
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "names": [
        {
            "C": "CN",
            "L": "Beijing",
            "ST": "Beijing"
        }
    ]
}
EOF
 

生成证书:

cfssl gencert -initca ca-csr.json | cfssljson -bare ca -
 

会生成ca.pem和ca-key.pem文件。

2. 使用自签CA签发Etcd HTTPS证书

创建证书申请文件:

cat > server-csr.json << EOF
{
    "CN": "etcd",
    "hosts": [
    "192.168.31.71",
    "192.168.31.72",
    "192.168.31.73"
    ],
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "names": [
        {
            "C": "CN",
            "L": "BeiJing",
            "ST": "BeiJing"
        }
    ]
}
EOF
 

注:上述文件hosts字段中IP为所有etcd节点的集群内部通信IP,一个都不能少!为了方便后期扩容可以多写几个预留的IP。

生成证书:

cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=www server-csr.json | cfssljson -bare server
 

会生成server.pem和server-key.pem文件。

2.3 从Github下载二进制文件

下载地址: https://github.com/etcd-io/etcd/releases/download/v3.4.9/etcd-v3.4.9-linux-amd64.tar.gz

2.4 部署Etcd集群

以下在节点1上操作,为简化操作,待会将节点1生成的所有文件拷贝到节点2和节点3.

1. 创建工作目录并解压二进制包

mkdir /opt/etcd/{bin,cfg,ssl} -p
tar zxvf etcd-v3.4.9-linux-amd64.tar.gz
mv etcd-v3.4.9-linux-amd64/{etcd,etcdctl} /opt/etcd/bin/
 

2. 创建etcd配置文件

cat > /opt/etcd/cfg/etcd.conf << EOF
#[Member]
ETCD_NAME="etcd-1"
ETCD_DATA_DIR="/var/lib/etcd/default.etcd"
ETCD_LISTEN_PEER_URLS="https://192.168.31.71:2380"
ETCD_LISTEN_CLIENT_URLS="https://192.168.31.71:2379"
#[Clustering]
ETCD_INITIAL_ADVERTISE_PEER_URLS="https://192.168.31.71:2380"
ETCD_ADVERTISE_CLIENT_URLS="https://192.168.31.71:2379"
ETCD_INITIAL_CLUSTER="etcd-1=https://192.168.31.71:2380,etcd-2=https://192.168.31.72:2380,etcd-3=https://192.168.31.73:2380"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"
EOF
 
  • ETCD_NAME:节点名称,集群中唯一
  • ETCD_DATA_DIR:数据目录
  • ETCD_LISTEN_PEER_URLS:集群通信监听地址
  • ETCD_LISTEN_CLIENT_URLS:客户端访问监听地址
  • ETCD_INITIAL_ADVERTISE_PEER_URLS:集群通告地址
  • ETCD_ADVERTISE_CLIENT_URLS:客户端通告地址
  • ETCD_INITIAL_CLUSTER:集群节点地址
  • ETCD_INITIAL_CLUSTER_TOKEN:集群Token
  • ETCD_INITIAL_CLUSTER_STATE:加入集群的当前状态,new是新集群,existing表示加入已有集群

3. systemd管理etcd

cat > /usr/lib/systemd/system/etcd.service << EOF
[Unit]
Description=Etcd Server
After=network.target
After=network-online.target
Wants=network-online.target
[Service]
Type=notify
EnvironmentFile=/opt/etcd/cfg/etcd.conf
ExecStart=/opt/etcd/bin/etcd \
--cert-file=/opt/etcd/ssl/server.pem \
--key-file=/opt/etcd/ssl/server-key.pem \
--peer-cert-file=/opt/etcd/ssl/server.pem \
--peer-key-file=/opt/etcd/ssl/server-key.pem \
--trusted-ca-file=/opt/etcd/ssl/ca.pem \
--peer-trusted-ca-file=/opt/etcd/ssl/ca.pem \
--logger=zap
Restart=on-failure
LimitNOFILE=65536
[Install]
WantedBy=multi-user.target
EOF
 

4. 拷贝刚才生成的证书

把刚才生成的证书拷贝到配置文件中的路径:

cp ~/TLS/etcd/ca*pem ~/TLS/etcd/server*pem /opt/etcd/ssl/
 

5. 启动并设置开机启动

systemctl daemon-reload
systemctl start etcd
systemctl enable etcd
 

6. 将上面节点1所有生成的文件拷贝到节点2和节点3

scp -r /opt/etcd/ root@192.168.31.72:/opt/
scp /usr/lib/systemd/system/etcd.service root@192.168.31.72:/usr/lib/systemd/system/
scp -r /opt/etcd/ root@192.168.31.73:/opt/
scp /usr/lib/systemd/system/etcd.service root@192.168.31.73:/usr/lib/systemd/system/
 

然后在节点2和节点3分别修改etcd.conf配置文件中的节点名称和当前服务器IP:

vi /opt/etcd/cfg/etcd.conf
#[Member]
ETCD_NAME="etcd-1"   # 修改此处,节点2改为etcd-2,节点3改为etcd-3
ETCD_DATA_DIR="/var/lib/etcd/default.etcd"
ETCD_LISTEN_PEER_URLS="https://192.168.31.71:2380"   # 修改此处为当前服务器IP
ETCD_LISTEN_CLIENT_URLS="https://192.168.31.71:2379" # 修改此处为当前服务器IP
#[Clustering]
ETCD_INITIAL_ADVERTISE_PEER_URLS="https://192.168.31.71:2380" # 修改此处为当前服务器IP
ETCD_ADVERTISE_CLIENT_URLS="https://192.168.31.71:2379" # 修改此处为当前服务器IP
ETCD_INITIAL_CLUSTER="etcd-1=https://192.168.31.71:2380,etcd-2=https://192.168.31.72:2380,etcd-3=https://192.168.31.73:2380"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"
 

最后启动etcd并设置开机启动,同上。

7. 查看集群状态

ETCDCTL_API=3 /opt/etcd/bin/etcdctl --cacert=/opt/etcd/ssl/ca.pem --cert=/opt/etcd/ssl/server.pem --key=/opt/etcd/ssl/server-key.pem --endpoints="https://192.168.31.71:2379,https://192.168.31.72:2379,https://192.168.31.73:2379" endpoint health --write-out=table
+----------------------------+--------+-------------+-------+
|          ENDPOINT    | HEALTH |    TOOK     | ERROR |
+----------------------------+--------+-------------+-------+
| https://192.168.31.71:2379 |   true | 10.301506ms |    |
| https://192.168.31.73:2379 |   true | 12.87467ms |     |
| https://192.168.31.72:2379 |   true | 13.225954ms |    |
+----------------------------+--------+-------------+-------+
 

如果输出上面信息,就说明集群部署成功。

如果有问题第一步先看日志:/var/log/message 或 journalctl -u etcd

三、安装Docker

这里使用Docker作为容器引擎,也可以换成别的,例如containerd

下载地址: https://download.docker.com/linux/static/stable/x86_64/docker-19.03.9.tgz

以下在所有节点操作。这里采用二进制安装,用yum安装也一样。

3.1 解压二进制包

tar zxvf docker-19.03.9.tgz
mv docker/* /usr/bin
 

3.2 systemd管理docker

cat > /usr/lib/systemd/system/docker.service << EOF
[Unit]
Description=Docker Application Container Engine
Documentation=https://docs.docker.com
After=network-online.target firewalld.service
Wants=network-online.target
[Service]
Type=notify
ExecStart=/usr/bin/dockerd
ExecReload=/bin/kill -s HUP $MAINPID
LimitNOFILE=infinity
LimitNPROC=infinity
LimitCORE=infinity
TimeoutStartSec=0
Delegate=yes
KillMode=process
Restart=on-failure
StartLimitBurst=3
StartLimitInterval=60s
[Install]
WantedBy=multi-user.target
EOF
 

3.3 创建配置文件

mkdir /etc/docker
cat > /etc/docker/daemon.json << EOF
{
  "registry-mirrors": ["https://b9pmyelo.mirror.aliyuncs.com"]
}
EOF
 
  • registry-mirrors 阿里云镜像加速器

3.4 启动并设置开机启动

systemctl daemon-reload
systemctl start docker
systemctl enable docker
 

四、部署Master Node

作者:阿良

4.1 生成kube-apiserver证书

1. 自签证书颁发机构(CA)

cd ~/TLS/k8s
cat > ca-config.json << EOF
{
  "signing": {
    "default": {
      "expiry": "87600h"
    },
    "profiles": {
      "kubernetes": {
         "expiry": "87600h",
         "usages": [
            "signing",
            "key encipherment",
            "server auth",
            "client auth"
        ]
      }
    }
  }
}
EOF
cat > ca-csr.json << EOF
{
    "CN": "kubernetes",
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "names": [
        {
            "C": "CN",
            "L": "Beijing",
            "ST": "Beijing",
            "O": "k8s",
            "OU": "System"
        }
    ]
}
EOF
 

生成证书:

cfssl gencert -initca ca-csr.json | cfssljson -bare ca -
 

会生成ca.pem和ca-key.pem文件。

2. 使用自签CA签发kube-apiserver HTTPS证书

创建证书申请文件:

cat > server-csr.json << EOF
{
    "CN": "kubernetes",
    "hosts": [
      "10.0.0.1",
      "127.0.0.1",
      "192.168.31.71",
      "192.168.31.72",
      "192.168.31.73",
      "192.168.31.88",
      "kubernetes",
      "kubernetes.default",
      "kubernetes.default.svc",
      "kubernetes.default.svc.cluster",
      "kubernetes.default.svc.cluster.local"
    ],
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "names": [
        {
            "C": "CN",
            "L": "BeiJing",
            "ST": "BeiJing",
            "O": "k8s",
            "OU": "System"
        }
    ]
}
EOF
 

注:上述文件hosts字段中IP为所有Master/LB/VIP IP,一个都不能少!为了方便后期扩容可以多写几个预留的IP。

生成证书:

cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=kubernetes server-csr.json | cfssljson -bare server
 

会生成server.pem和server-key.pem文件。

4.2 从Github下载二进制文件

下载地址: https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG/CHANGELOG-1.20.md

注:打开链接你会发现里面有很多包,下载一个server包就够了,包含了Master和Worker Node二进制文件。

4.3 解压二进制包

mkdir -p /opt/kubernetes/{bin,cfg,ssl,logs} 
tar zxvf kubernetes-server-linux-amd64.tar.gz
cd kubernetes/server/bin
cp kube-apiserver kube-scheduler kube-controller-manager /opt/kubernetes/bin
cp kubectl /usr/bin/
 

4.4 部署kube-apiserver

1. 创建配置文件

cat > /opt/kubernetes/cfg/kube-apiserver.conf << EOF
KUBE_APISERVER_OPTS="--logtostderr=false \\
--v=2 \\
--log-dir=/opt/kubernetes/logs \\
--etcd-servers=https://192.168.31.71:2379,https://192.168.31.72:2379,https://192.168.31.73:2379 \\
--bind-address=192.168.31.71 \\
--secure-port=6443 \\
--advertise-address=192.168.31.71 \\
--allow-privileged=true \\
--service-cluster-ip-range=10.0.0.0/24 \\
--enable-admission-plugins=NamespaceLifecycle,LimitRanger,ServiceAccount,ResourceQuota,NodeRestriction \\
--authorization-mode=RBAC,Node \\
--enable-bootstrap-token-auth=true \\
--token-auth-file=/opt/kubernetes/cfg/token.csv \\
--service-node-port-range=30000-32767 \\
--kubelet-client-certificate=/opt/kubernetes/ssl/server.pem \\
--kubelet-client-key=/opt/kubernetes/ssl/server-key.pem \\
--tls-cert-file=/opt/kubernetes/ssl/server.pem  \\
--tls-private-key-file=/opt/kubernetes/ssl/server-key.pem \\
--client-ca-file=/opt/kubernetes/ssl/ca.pem \\
--service-account-key-file=/opt/kubernetes/ssl/ca-key.pem \\
--service-account-issuer=api \\
--service-account-signing-key-file=/opt/kubernetes/ssl/server-key.pem \\
--etcd-cafile=/opt/etcd/ssl/ca.pem \\
--etcd-certfile=/opt/etcd/ssl/server.pem \\
--etcd-keyfile=/opt/etcd/ssl/server-key.pem \\
--requestheader-client-ca-file=/opt/kubernetes/ssl/ca.pem \\
--proxy-client-cert-file=/opt/kubernetes/ssl/server.pem \\
--proxy-client-key-file=/opt/kubernetes/ssl/server-key.pem \\
--requestheader-allowed-names=kubernetes \\
--requestheader-extra-headers-prefix=X-Remote-Extra- \\
--requestheader-group-headers=X-Remote-Group \\
--requestheader-username-headers=X-Remote-User \\
--enable-aggregator-routing=true \\
--audit-log-maxage=30 \\
--audit-log-maxbackup=3 \\
--audit-log-maxsize=100 \\
--audit-log-path=/opt/kubernetes/logs/k8s-audit.log"
EOF
 

注:上面两个\ \ 第一个是转义符,第二个是换行符,使用转义符是为了使用EOF保留换行符。

  • –logtostderr:启用日志
  • —v:日志等级
  • –log-dir:日志目录
  • –etcd-servers:etcd集群地址
  • –bind-address:监听地址
  • –secure-port:https安全端口
  • –advertise-address:集群通告地址
  • –allow-privileged:启用授权
  • –service-cluster-ip-range:Service虚拟IP地址段
  • –enable-admission-plugins:准入控制模块
  • –authorization-mode:认证授权,启用RBAC授权和节点自管理
  • –enable-bootstrap-token-auth:启用TLS bootstrap机制
  • –token-auth-file:bootstrap token文件
  • –service-node-port-range:Service nodeport类型默认分配端口范围
  • –kubelet-client-xxx:apiserver访问kubelet客户端证书
  • –tls-xxx-file:apiserver https证书
  • 1.20版本必须加的参数:–service-account-issuer,–service-account-signing-key-file
  • –etcd-xxxfile:连接Etcd集群证书
  • –audit-log-xxx:审计日志
  • 启动聚合层相关配置:–requestheader-client-ca-file,–proxy-client-cert-file,–proxy-client-key-file,–requestheader-allowed-names,–requestheader-extra-headers-prefix,–requestheader-group-headers,–requestheader-username-headers,–enable-aggregator-routing

2. 拷贝刚才生成的证书

把刚才生成的证书拷贝到配置文件中的路径:

cp ~/TLS/k8s/ca*pem ~/TLS/k8s/server*pem /opt/kubernetes/ssl/
• 1.

3. 启用 TLS Bootstrapping 机制

TLS Bootstraping:Master apiserver启用TLS认证后,Node节点kubelet和kube-proxy要与kube-apiserver进行通信,必须使用CA签发的有效证书才可以,当Node节点很多时,这种客户端证书颁发需要大量工作,同样也会增加集群扩展复杂度。为了简化流程,Kubernetes引入了TLS bootstraping机制来自动颁发客户端证书,kubelet会以一个低权限用户自动向apiserver申请证书,kubelet的证书由apiserver动态签署。所以强烈建议在Node上使用这种方式,目前主要用于kubelet,kube-proxy还是由我们统一颁发一个证书。

TLS bootstraping 工作流程:

image.png

创建上述配置文件中token文件:

cat > /opt/kubernetes/cfg/token.csv << EOF
c47ffb939f5ca36231d9e3121a252940,kubelet-bootstrap,10001,"system:node-bootstrapper"
EOF
 

格式:token,用户名,UID,用户组

token也可自行生成替换:

head -c 16 /dev/urandom | od -An -t x | tr -d ' '
 

4. systemd管理apiserver

cat > /usr/lib/systemd/system/kube-apiserver.service << EOF
[Unit]
Description=Kubernetes API Server
Documentation=https://github.com/kubernetes/kubernetes
[Service]
EnvironmentFile=/opt/kubernetes/cfg/kube-apiserver.conf
ExecStart=/opt/kubernetes/bin/kube-apiserver \$KUBE_APISERVER_OPTS
Restart=on-failure
[Install]
WantedBy=multi-user.target
EOF
 

5. 启动并设置开机启动

systemctl daemon-reload
systemctl start kube-apiserver 
systemctl enable kube-apiserver
 

4.5 部署kube-controller-manager

1. 创建配置文件

cat > /opt/kubernetes/cfg/kube-controller-manager.conf << EOF
KUBE_CONTROLLER_MANAGER_OPTS="--logtostderr=false \\
--v=2 \\
--log-dir=/opt/kubernetes/logs \\
--leader-elect=true \\
--kubeconfig=/opt/kubernetes/cfg/kube-controller-manager.kubeconfig \\
--bind-address=127.0.0.1 \\
--allocate-node-cidrs=true \\
--cluster-cidr=10.244.0.0/16 \\
--service-cluster-ip-range=10.0.0.0/24 \\
--cluster-signing-cert-file=/opt/kubernetes/ssl/ca.pem \\
--cluster-signing-key-file=/opt/kubernetes/ssl/ca-key.pem  \\
--root-ca-file=/opt/kubernetes/ssl/ca.pem \\
--service-account-private-key-file=/opt/kubernetes/ssl/ca-key.pem \\
--cluster-signing-duration=87600h0m0s"
EOF
 
  • –kubeconfig:连接apiserver配置文件
  • –leader-elect:当该组件启动多个时,自动选举(HA)
  • –cluster-signing-cert-file/–cluster-signing-key-file:自动为kubelet颁发证书的CA,与apiserver保持一致

2. 生成kubeconfig文件

生成kube-controller-manager证书:

# 切换工作目录
cd ~/TLS/k8s
# 创建证书请求文件
cat > kube-controller-manager-csr.json << EOF
{
  "CN": "system:kube-controller-manager",
  "hosts": [],
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "L": "BeiJing", 
      "ST": "BeiJing",
      "O": "system:masters",
      "OU": "System"
    }
  ]
}
EOF
# 生成证书
cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=kubernetes kube-controller-manager-csr.json | cfssljson -bare kube-controller-manager
 

生成kubeconfig文件(以下是shell命令,直接在终端执行):

KUBE_CONFIG="/opt/kubernetes/cfg/kube-controller-manager.kubeconfig"
KUBE_APISERVER="https://192.168.31.71:6443"
kubectl config set-cluster kubernetes \
  --certificate-authority=/opt/kubernetes/ssl/ca.pem \
  --embed-certs=true \
  --server=${KUBE_APISERVER} \
  --kubeconfig=${KUBE_CONFIG}
kubectl config set-credentials kube-controller-manager \
  --client-certificate=./kube-controller-manager.pem \
  --client-key=./kube-controller-manager-key.pem \
  --embed-certs=true \
  --kubeconfig=${KUBE_CONFIG}
kubectl config set-context default \
  --cluster=kubernetes \
  --user=kube-controller-manager \
  --kubeconfig=${KUBE_CONFIG}
kubectl config use-context default --kubeconfig=${KUBE_CONFIG}
 

3. systemd管理controller-manager

cat > /usr/lib/systemd/system/kube-controller-manager.service << EOF
[Unit]
Description=Kubernetes Controller Manager
Documentation=https://github.com/kubernetes/kubernetes
[Service]
EnvironmentFile=/opt/kubernetes/cfg/kube-controller-manager.conf
ExecStart=/opt/kubernetes/bin/kube-controller-manager \$KUBE_CONTROLLER_MANAGER_OPTS
Restart=on-failure
[Install]
WantedBy=multi-user.target
EOF
 

4. 启动并设置开机启动

systemctl daemon-reload
systemctl start kube-controller-manager
systemctl enable kube-controller-manager
 

4.6 部署kube-scheduler

1. 创建配置文件

cat > /opt/kubernetes/cfg/kube-scheduler.conf << EOF
KUBE_SCHEDULER_OPTS="--logtostderr=false \\
--v=2 \\
--log-dir=/opt/kubernetes/logs \\
--leader-elect \\
--kubeconfig=/opt/kubernetes/cfg/kube-scheduler.kubeconfig \\
--bind-address=127.0.0.1"
EOF
 
  • –kubeconfig:连接apiserver配置文件
  • –leader-elect:当该组件启动多个时,自动选举(HA)

2. 生成kubeconfig文件

生成kube-scheduler证书:

# 切换工作目录
cd ~/TLS/k8s
# 创建证书请求文件
cat > kube-scheduler-csr.json << EOF
{
  "CN": "system:kube-scheduler",
  "hosts": [],
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "L": "BeiJing",
      "ST": "BeiJing",
      "O": "system:masters",
      "OU": "System"
    }
  ]
}
EOF
# 生成证书
cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=kubernetes kube-scheduler-csr.json | cfssljson -bare kube-scheduler
 

生成kubeconfig文件(以下是shell命令,直接在终端执行):

KUBE_CONFIG="/opt/kubernetes/cfg/kube-scheduler.kubeconfig"
KUBE_APISERVER="https://192.168.31.71:6443"
kubectl config set-cluster kubernetes \
  --certificate-authority=/opt/kubernetes/ssl/ca.pem \
  --embed-certs=true \
  --server=${KUBE_APISERVER} \
  --kubeconfig=${KUBE_CONFIG}
kubectl config set-credentials kube-scheduler \
  --client-certificate=./kube-scheduler.pem \
  --client-key=./kube-scheduler-key.pem \
  --embed-certs=true \
  --kubeconfig=${KUBE_CONFIG}
kubectl config set-context default \
  --cluster=kubernetes \
  --user=kube-scheduler \
  --kubeconfig=${KUBE_CONFIG}
kubectl config use-context default --kubeconfig=${KUBE_CONFIG}
 

3. systemd管理scheduler

cat > /usr/lib/systemd/system/kube-scheduler.service << EOF
[Unit]
Description=Kubernetes Scheduler
Documentation=https://github.com/kubernetes/kubernetes
[Service]
EnvironmentFile=/opt/kubernetes/cfg/kube-scheduler.conf
ExecStart=/opt/kubernetes/bin/kube-scheduler \$KUBE_SCHEDULER_OPTS
Restart=on-failure
[Install]
WantedBy=multi-user.target
EOF
 

4. 启动并设置开机启动

systemctl daemon-reload
systemctl start kube-scheduler
systemctl enable kube-scheduler
 

5. 查看集群状态

生成kubectl连接集群的证书:

cat > admin-csr.json <<EOF
{
  "CN": "admin",
  "hosts": [],
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "L": "BeiJing",
      "ST": "BeiJing",
      "O": "system:masters",
      "OU": "System"
    }
  ]
}
EOF
cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=kubernetes admin-csr.json | cfssljson -bare admin
 

生成kubeconfig文件:

mkdir /root/.kube
KUBE_CONFIG="/root/.kube/config"
KUBE_APISERVER="https://192.168.31.71:6443"
kubectl config set-cluster kubernetes \
  --certificate-authority=/opt/kubernetes/ssl/ca.pem \
  --embed-certs=true \
  --server=${KUBE_APISERVER} \
  --kubeconfig=${KUBE_CONFIG}
kubectl config set-credentials cluster-admin \
  --client-certificate=./admin.pem \
  --client-key=./admin-key.pem \
  --embed-certs=true \
  --kubeconfig=${KUBE_CONFIG}
kubectl config set-context default \
  --cluster=kubernetes \
  --user=cluster-admin \
  --kubeconfig=${KUBE_CONFIG}
kubectl config use-context default --kubeconfig=${KUBE_CONFIG}
 

通过kubectl工具查看当前集群组件状态:

kubectl get cs
NAME                STATUS    MESSAGE             ERROR
scheduler             Healthy   ok                  
controller-manager       Healthy   ok                  
etcd-2               Healthy   {"health":"true"}   
etcd-1               Healthy   {"health":"true"}   
etcd-0               Healthy   {"health":"true"}  
 

如上输出说明Master节点组件运行正常。

6. 授权kubelet-bootstrap用户允许请求证书

kubectl create clusterrolebinding kubelet-bootstrap \
--clusterrole=system:node-bootstrapper \
--user=kubelet-bootstrap
 

五、部署Worker Node

下面还是在Master Node上操作,即同时作为Worker Node

5.1 创建工作目录并拷贝二进制文件

在所有worker node创建工作目录:

mkdir -p /opt/kubernetes/{bin,cfg,ssl,logs} 
 

从master节点拷贝:

cd kubernetes/server/bin
cp kubelet kube-proxy /opt/kubernetes/bin   # 本地拷贝
 

5.2 部署kubelet

1. 创建配置文件

cat > /opt/kubernetes/cfg/kubelet.conf << EOF
KUBELET_OPTS="--logtostderr=false \\
--v=2 \\
--log-dir=/opt/kubernetes/logs \\
--hostname-override=k8s-master1 \\
--network-plugin=cni \\
--kubeconfig=/opt/kubernetes/cfg/kubelet.kubeconfig \\
--bootstrap-kubeconfig=/opt/kubernetes/cfg/bootstrap.kubeconfig \\
--config=/opt/kubernetes/cfg/kubelet-config.yml \\
--cert-dir=/opt/kubernetes/ssl \\
--pod-infra-container-image=lizhenliang/pause-amd64:3.0"
EOF
 
  • –hostname-override:显示名称,集群中唯一
  • –network-plugin:启用CNI
  • –kubeconfig:空路径,会自动生成,后面用于连接apiserver
  • –bootstrap-kubeconfig:首次启动向apiserver申请证书
  • –config:配置参数文件
  • –cert-dir:kubelet证书生成目录
  • –pod-infra-container-image:管理Pod网络容器的镜像

2. 配置参数文件

cat > /opt/kubernetes/cfg/kubelet-config.yml << EOF
kind: KubeletConfiguration
apiVersion: kubelet.config.k8s.io/v1beta1
address: 0.0.0.0
port: 10250
readOnlyPort: 10255
cgroupDriver: cgroupfs
clusterDNS:
- 10.0.0.2
clusterDomain: cluster.local 
failSwapOn: false
authentication:
  anonymous:
    enabled: false
  webhook:
    cacheTTL: 2m0s
    enabled: true
  x509:
    clientCAFile: /opt/kubernetes/ssl/ca.pem 
authorization:
  mode: Webhook
  webhook:
    cacheAuthorizedTTL: 5m0s
    cacheUnauthorizedTTL: 30s
evictionHard:
  imagefs.available: 15%
  memory.available: 100Mi
  nodefs.available: 10%
  nodefs.inodesFree: 5%
maxOpenFiles: 1000000
maxPods: 110
EOF
 

3. 生成kubelet初次加入集群引导kubeconfig文件

KUBE_CONFIG="/opt/kubernetes/cfg/bootstrap.kubeconfig"
KUBE_APISERVER="https://192.168.31.71:6443" # apiserver IP:PORT
TOKEN="c47ffb939f5ca36231d9e3121a252940" # 与token.csv里保持一致
# 生成 kubelet bootstrap kubeconfig 配置文件
kubectl config set-cluster kubernetes \
  --certificate-authority=/opt/kubernetes/ssl/ca.pem \
  --embed-certs=true \
  --server=${KUBE_APISERVER} \
  --kubeconfig=${KUBE_CONFIG}
kubectl config set-credentials "kubelet-bootstrap" \
  --token=${TOKEN} \
  --kubeconfig=${KUBE_CONFIG}
kubectl config set-context default \
  --cluster=kubernetes \
  --user="kubelet-bootstrap" \
  --kubeconfig=${KUBE_CONFIG}
kubectl config use-context default --kubeconfig=${KUBE_CONFIG}
 

4. systemd管理kubelet

cat > /usr/lib/systemd/system/kubelet.service << EOF
[Unit]
Description=Kubernetes Kubelet
After=docker.service
[Service]
EnvironmentFile=/opt/kubernetes/cfg/kubelet.conf
ExecStart=/opt/kubernetes/bin/kubelet \$KUBELET_OPTS
Restart=on-failure
LimitNOFILE=65536
[Install]
WantedBy=multi-user.target
EOF
 

5. 启动并设置开机启动

systemctl daemon-reload
systemctl start kubelet
systemctl enable kubelet
 

5.3 批准kubelet证书申请并加入集群

# 查看kubelet证书请求
kubectl get csr
NAME                                                   AGE    SIGNERNAME                                    REQUESTOR           CONDITION
node-csr-uCEGPOIiDdlLODKts8J658HrFq9CZ--K6M4G7bjhk8A   6m3s   kubernetes.io/kube-apiserver-client-kubelet   kubelet-bootstrap   Pending
# 批准申请
kubectl certificate approve node-csr-uCEGPOIiDdlLODKts8J658HrFq9CZ--K6M4G7bjhk8A
# 查看节点
kubectl get node
NAME         STATUS     ROLES    AGE   VERSION
k8s-master1   NotReady   <none>   7s    v1.18.3
 

注:由于网络插件还没有部署,节点会没有准备就绪 NotReady

5.4 部署kube-proxy

1. 创建配置文件

cat > /opt/kubernetes/cfg/kube-proxy.conf << EOF
KUBE_PROXY_OPTS="--logtostderr=false \\
--v=2 \\
--log-dir=/opt/kubernetes/logs \\
--config=/opt/kubernetes/cfg/kube-proxy-config.yml"
EOF
 

2. 配置参数文件

cat > /opt/kubernetes/cfg/kube-proxy-config.yml << EOF
kind: KubeProxyConfiguration
apiVersion: kubeproxy.config.k8s.io/v1alpha1
bindAddress: 0.0.0.0
metricsBindAddress: 0.0.0.0:10249
clientConnection:
  kubeconfig: /opt/kubernetes/cfg/kube-proxy.kubeconfig
hostnameOverride: k8s-master1
clusterCIDR: 10.0.0.0/24
EOF
 

3. 生成kube-proxy.kubeconfig文件

生成kube-proxy证书:

# 切换工作目录
cd ~/TLS/k8s
# 创建证书请求文件
cat > kube-proxy-csr.json << EOF
{
  "CN": "system:kube-proxy",
  "hosts": [],
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "L": "BeiJing",
      "ST": "BeiJing",
      "O": "k8s",
      "OU": "System"
    }
  ]
}
EOF
# 生成证书
cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=kubernetes kube-proxy-csr.json | cfssljson -bare kube-proxy
 

生成kubeconfig文件:

KUBE_CONFIG="/opt/kubernetes/cfg/kube-proxy.kubeconfig"
KUBE_APISERVER="https://192.168.31.71:6443"
kubectl config set-cluster kubernetes \
  --certificate-authority=/opt/kubernetes/ssl/ca.pem \
  --embed-certs=true \
  --server=${KUBE_APISERVER} \
  --kubeconfig=${KUBE_CONFIG}
kubectl config set-credentials kube-proxy \
  --client-certificate=./kube-proxy.pem \
  --client-key=./kube-proxy-key.pem \
  --embed-certs=true \
  --kubeconfig=${KUBE_CONFIG}
kubectl config set-context default \
  --cluster=kubernetes \
  --user=kube-proxy \
  --kubeconfig=${KUBE_CONFIG}
kubectl config use-context default --kubeconfig=${KUBE_CONFIG}
 

4. systemd管理kube-proxy

cat > /usr/lib/systemd/system/kube-proxy.service << EOF
[Unit]
Description=Kubernetes Proxy
After=network.target
[Service]
EnvironmentFile=/opt/kubernetes/cfg/kube-proxy.conf
ExecStart=/opt/kubernetes/bin/kube-proxy \$KUBE_PROXY_OPTS
Restart=on-failure
LimitNOFILE=65536
[Install]
WantedBy=multi-user.target
EOF
 

5. 启动并设置开机启动

systemctl daemon-reload
systemctl start kube-proxy
systemctl enable kube-proxy
 

5.5 部署网络组件

Calico是一个纯三层的数据中心网络方案,是目前Kubernetes主流的网络方案。

下载YAML:

wget https://docs.projectcalico.org/manifests/calico.yaml
 

修改YAML:

下载完后还需要修改里面定义Pod网络(CALICO_IPV4POOL_CIDR),与前面kube-controller-manager配置文件指定的cluster-cidr网段一样。

部署YAML:

kubectl apply -f calico.yaml
kubectl get pods -n kube-system
 

等Calico Pod都Running,节点也会准备就绪:

kubectl get node
NAME         STATUS   ROLES    AGE   VERSION
k8s-master     Ready    <none>   37m   v1.20.4
 

5.6 授权apiserver访问kubelet

应用场景:例如kubectl logs

cat > apiserver-to-kubelet-rbac.yaml << EOF
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  annotations:
    rbac.authorization.kubernetes.io/autoupdate: "true"
  labels:
    kubernetes.io/bootstrapping: rbac-defaults
  name: system:kube-apiserver-to-kubelet
rules:
  - apiGroups:
      - ""
    resources:
      - nodes/proxy
      - nodes/stats
      - nodes/log
      - nodes/spec
      - nodes/metrics
      - pods/log
    verbs:
      - "*"
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: system:kube-apiserver
  namespace: ""
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: system:kube-apiserver-to-kubelet
subjects:
  - apiGroup: rbac.authorization.k8s.io
    kind: User
    name: kubernetes
EOF
kubectl apply -f apiserver-to-kubelet-rbac.yaml
 

5.7 新增加Worker Node

1. 拷贝已部署好的Node相关文件到新节点

在Master节点将Worker Node涉及文件拷贝到新节点192.168.31.72/73

scp -r /opt/kubernetes root@192.168.31.72:/opt/
scp -r /usr/lib/systemd/system/{kubelet,kube-proxy}.service root@192.168.31.72:/usr/lib/systemd/system
scp /opt/kubernetes/ssl/ca.pem root@192.168.31.72:/opt/kubernetes/ssl
 

2. 删除kubelet证书和kubeconfig文件

rm -f /opt/kubernetes/cfg/kubelet.kubeconfig 
rm -f /opt/kubernetes/ssl/kubelet*
 

注:这几个文件是证书申请审批后自动生成的,每个Node不同,必须删除

3. 修改主机名

vi /opt/kubernetes/cfg/kubelet.conf
--hostname-override=k8s-node1
vi /opt/kubernetes/cfg/kube-proxy-config.yml
hostnameOverride: k8s-node1
 

4. 启动并设置开机启动

systemctl daemon-reload
systemctl start kubelet kube-proxy
systemctl enable kubelet kube-proxy
 

5. 在Master上批准新Node kubelet证书申请

# 查看证书请求
kubectl get csr
NAME           AGE   SIGNERNAME                    REQUESTOR           CONDITION
node-csr-4zTjsaVSrhuyhIGqsefxzVoZDCNKei-aE2jyTP81Uro   89s   kubernetes.io/kube-apiserver-client-kubelet   kubelet-bootstrap   Pending
# 授权请求
kubectl certificate approve node-csr-4zTjsaVSrhuyhIGqsefxzVoZDCNKei-aE2jyTP81Uro
 

6. 查看Node状态

kubectl get node
NAME       STATUS   ROLES    AGE     VERSION
k8s-master1   Ready    <none>   47m     v1.20.4
k8s-node1    Ready    <none>   6m49s   v1.20.4
 

Node2(192.168.31.73 )节点同上。记得修改主机名!

六、部署Dashboard和CoreDNS

6.1 部署Dashboard

wget https://raw.githubusercontent.com/kubernetes/dashboard/v2.0.0-beta8/aio/deploy/recommended.yaml
 

默认Dashboard只能集群内部访问,修改Service为NodePort类型,暴露到外部:

vi recommended.yaml
kind: Service
apiVersion: v1
metadata:
  labels:
    k8s-app: kubernetes-dashboard
  name: kubernetes-dashboard
  namespace: kubernetes-dashboard
spec:
  ports:
    - port: 443
      targetPort: 8443
      nodePort: 30001
  type: NodePort
  selector:
    k8s-app: kubernetes-dashboard
kubectl apply -f recommended.yaml
# 查看部署
kubectl get pods,svc -n kubernetes-dashboard
 

访问地址: https://NodeIP:30001

创建service account并绑定默认cluster-admin管理员集群角色:

kubectl create serviceaccount dashboard-admin -n kube-system
kubectl create clusterrolebinding dashboard-admin --clusterrole=cluster-admin --serviceaccount=kube-system:dashboard-admin
kubectl describe secrets -n kube-system $(kubectl -n kube-system get secret | awk '/dashboard-admin/{print $1}')
 

使用输出的token登录Dashboard。

image.png

image.png


6.2 部署CoreDNS

CoreDNS用于集群内部Service名称解析。

kubectl apply -f coredns.yaml
kubectl get pods -n kube-system 
NAME                          READY   STATUS    RESTARTS   AGE
coredns-5ffbfd976d-j6shb      1/1     Running   0          32s
 

DNS解析测试:

kubectl run -it --rm dns-test --image=busybox:1.28.4 sh
If you don't see a command prompt, try pressing enter.
/ # nslookup kubernetes
Server:    10.0.0.2
Address 1: 10.0.0.2 kube-dns.kube-system.svc.cluster.local
Name:      kubernetes
Address 1: 10.0.0.1 kubernetes.default.svc.cluster.local
 

解析没问题。

至此一个单Master集群就搭建完成了!这个环境就足以满足学习实验了,如果你的服务器配置较高,可继续扩容多Master集群!

七、扩容多Master(高可用架构)

Kubernetes作为容器集群系统,通过健康检查+重启策略实现了Pod故障自我修复能力,通过调度算法实现将Pod分布式部署,并保持预期副本数,根据Node失效状态自动在其他Node拉起Pod,实现了应用层的高可用性。

针对Kubernetes集群,高可用性还应包含以下两个层面的考虑:Etcd数据库的高可用性和Kubernetes Master组件的高可用性。 而Etcd我们已经采用3个节点组建集群实现高可用,本节将对Master节点高可用进行说明和实施。

Master节点扮演着总控中心的角色,通过不断与工作节点上的Kubelet和kube-proxy进行通信来维护整个集群的健康工作状态。如果Master节点故障,将无法使用kubectl工具或者API做任何集群管理。

Master节点主要有三个服务kube-apiserver、kube-controller-manager和kube-scheduler,其中kube-controller-manager和kube-scheduler组件自身通过选择机制已经实现了高可用,所以Master高可用主要针对kube-apiserver组件,而该组件是以HTTP API提供服务,因此对他高可用与Web服务器类似,增加负载均衡器对其负载均衡即可,并且可水平扩容。

多Master架构图:

image.png

7.1 部署Master2 Node

现在需要再增加一台新服务器,作为Master2 Node,IP是192.168.31.74。

为了节省资源你也可以将之前部署好的Worker Node1复用为Master2 Node角色(即部署Master组件)

Master2 与已部署的Master1所有操作一致。所以我们只需将Master1所有K8s文件拷贝过来,再修改下服务器IP和主机名启动即可。

1. 安装Docker

scp /usr/bin/docker* root@192.168.31.74:/usr/bin
scp /usr/bin/runc root@192.168.31.74:/usr/bin
scp /usr/bin/containerd* root@192.168.31.74:/usr/bin
scp /usr/lib/systemd/system/docker.service root@192.168.31.74:/usr/lib/systemd/system
scp -r /etc/docker root@192.168.31.74:/etc
# 在Master2启动Docker
systemctl daemon-reload
systemctl start docker
systemctl enable docker
 

2. 创建etcd证书目录

在Master2创建etcd证书目录:

mkdir -p /opt/etcd/ssl
• 1.

3. 拷贝文件(Master1操作)

拷贝Master1上所有K8s文件和etcd证书到Master2:

scp -r /opt/kubernetes root@192.168.31.74:/opt
scp -r /opt/etcd/ssl root@192.168.31.74:/opt/etcd
scp /usr/lib/systemd/system/kube* root@192.168.31.74:/usr/lib/systemd/system
scp /usr/bin/kubectl  root@192.168.31.74:/usr/bin
scp -r ~/.kube root@192.168.31.74:~
 

4. 删除证书文件

删除kubelet证书和kubeconfig文件:

rm -f /opt/kubernetes/cfg/kubelet.kubeconfig 
rm -f /opt/kubernetes/ssl/kubelet*
 

5. 修改配置文件IP和主机名

修改apiserver、kubelet和kube-proxy配置文件为本地IP:

vi /opt/kubernetes/cfg/kube-apiserver.conf 
...
--bind-address=192.168.31.74 \
--advertise-address=192.168.31.74 \
...
vi /opt/kubernetes/cfg/kube-controller-manager.kubeconfig
server: https://192.168.31.74:6443
vi /opt/kubernetes/cfg/kube-scheduler.kubeconfig
server: https://192.168.31.74:6443
vi /opt/kubernetes/cfg/kubelet.conf
--hostname-override=k8s-master2
vi /opt/kubernetes/cfg/kube-proxy-config.yml
hostnameOverride: k8s-master2
vi ~/.kube/config
...
server: https://192.168.31.74:6443
 

6. 启动设置开机启动

systemctl daemon-reload
systemctl start kube-apiserver kube-controller-manager kube-scheduler kubelet kube-proxy
systemctl enable kube-apiserver kube-controller-manager kube-scheduler kubelet kube-proxy
 

7. 查看集群状态

kubectl get cs
NAME                STATUS    MESSAGE             ERROR
scheduler             Healthy   ok                  
controller-manager       Healthy   ok                  
etcd-1               Healthy   {"health":"true"}   
etcd-2               Healthy   {"health":"true"}   
etcd-0               Healthy   {"health":"true"}
 

8. 批准kubelet证书申请

# 查看证书请求
kubectl get csr
NAME                      AGE          SIGNERNAME          REQUESTOR           CONDITION
node-csr-JYNknakEa_YpHz797oKaN-ZTk43nD51Zc9CJkBLcASU   85m   kubernetes.io/kube-apiserver-client-kubelet   kubelet-bootstrap   Pending
# 授权请求
kubectl certificate approve node-csr-JYNknakEa_YpHz797oKaN-ZTk43nD51Zc9CJkBLcASU
# 查看Node
kubectl get node
NAME        STATUS   ROLES    AGE   VERSION
k8s-master1    Ready    <none>   34h   v1.20.4
k8s-master2    Ready    <none>   2m   v1.20.4
k8s-node1     Ready    <none>   33h   v1.20.4
k8s-node2     Ready    <none>   33h   v1.20.4
 

作者:阿良

7.2 部署Nginx+Keepalived高可用负载均衡器

kube-apiserver高可用架构图:

image.png

  • Nginx是一个主流Web服务和反向代理服务器,这里用四层实现对apiserver实现负载均衡。
  • Keepalived是一个主流高可用软件,基于VIP绑定实现服务器双机热备,在上述拓扑中,Keepalived主要根据Nginx运行状态判断是否需要故障转移(漂移VIP),例如当Nginx主节点挂掉,VIP会自动绑定在Nginx备节点,从而保证VIP一直可用,实现Nginx高可用。

注1:为了节省机器,这里与K8s Master节点机器复用。也可以独立于k8s集群之外部署,只要nginx与apiserver能通信就行。

注2:如果你是在公有云上,一般都不支持keepalived,那么你可以直接用它们的负载均衡器产品,直接负载均衡多台Master kube-apiserver,架构与上面一样。

在两台Master节点操作。

1. 安装软件包(主/备)

yum install epel-release -y
 yum install nginx keepalived -y
 

2. Nginx配置文件(主/备一样)

cat > /etc/nginx/nginx.conf << "EOF"
user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log;
pid /run/nginx.pid;
include /usr/share/nginx/modules/*.conf;
events {
    worker_connections 1024;
}
# 四层负载均衡,为两台Master apiserver组件提供负载均衡
stream {
    log_format  main  '$remote_addr $upstream_addr - [$time_local] $status $upstream_bytes_sent';
    access_log  /var/log/nginx/k8s-access.log  main;
    upstream k8s-apiserver {
       server 192.168.31.71:6443;   # Master1 APISERVER IP:PORT
       server 192.168.31.72:6443;   # Master2 APISERVER IP:PORT
    }
    
    server {
       listen 16443; # 由于nginx与master节点复用,这个监听端口不能是6443,否则会冲突
       proxy_pass k8s-apiserver;
    }
}
http {
    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';
    access_log  /var/log/nginx/access.log  main;
    sendfile            on;
    tcp_nopush          on;
    tcp_nodelay         on;
    keepalive_timeout   65;
    types_hash_max_size 2048;
    include             /etc/nginx/mime.types;
    default_type        application/octet-stream;
    server {
        listen       80 default_server;
        server_name  _;
        location / {
        }
    }
}
EOF
 

3. keepalived配置文件(Nginx Master)

cat > /etc/keepalived/keepalived.conf << EOF
global_defs { 
   notification_email { 
     acassen@firewall.loc 
     failover@firewall.loc 
     sysadmin@firewall.loc 
   } 
   notification_email_from Alexandre.Cassen@firewall.loc  
   smtp_server 127.0.0.1 
   smtp_connect_timeout 30 
   router_id NGINX_MASTER
} 
vrrp_script check_nginx {
    script "/etc/keepalived/check_nginx.sh"
}
vrrp_instance VI_1 { 
    state MASTER 
    interface ens33  # 修改为实际网卡名
    virtual_router_id 51 # VRRP 路由 ID实例,每个实例是唯一的 
    priority 100    # 优先级,备服务器设置 90 
    advert_int 1    # 指定VRRP 心跳包通告间隔时间,默认1秒 
    authentication { 
        auth_type PASS      
        auth_pass 1111 
    }  
    # 虚拟IP
    virtual_ipaddress { 
        192.168.31.88/24
    } 
    track_script {
        check_nginx
    } 
}
EOF
 
  • vrrp_script:指定检查nginx工作状态脚本(根据nginx状态判断是否故障转移)
  • virtual_ipaddress:虚拟IP(VIP)

准备上述配置文件中检查nginx运行状态的脚本:

cat > /etc/keepalived/check_nginx.sh  << "EOF"
#!/bin/bash
count=$(ss -antp |grep 16443 |egrep -cv "grep|$$")
if [ "$count" -eq 0 ];then
    exit 1
else
    exit 0
fi
EOF
chmod +x /etc/keepalived/check_nginx.sh
 

4. keepalived配置文件(Nginx Backup)

cat > /etc/keepalived/keepalived.conf << EOF
global_defs { 
   notification_email { 
     acassen@firewall.loc 
     failover@firewall.loc 
     sysadmin@firewall.loc 
   } 
   notification_email_from Alexandre.Cassen@firewall.loc  
   smtp_server 127.0.0.1 
   smtp_connect_timeout 30 
   router_id NGINX_BACKUP
} 
vrrp_script check_nginx {
    script "/etc/keepalived/check_nginx.sh"
}
vrrp_instance VI_1 { 
    state BACKUP 
    interface ens33
    virtual_router_id 51 # VRRP 路由 ID实例,每个实例是唯一的 
    priority 90
    advert_int 1
    authentication { 
        auth_type PASS      
        auth_pass 1111 
    }  
    virtual_ipaddress { 
        192.168.31.88/24
    } 
    track_script {
        check_nginx
    } 
}
EOF
 

准备上述配置文件中检查nginx运行状态的脚本:

cat > /etc/keepalived/check_nginx.sh  << "EOF"
#!/bin/bash
count=$(ss -antp |grep 16443 |egrep -cv "grep|$$")
if [ "$count" -eq 0 ];then
    exit 1
else
    exit 0
fi
EOF
chmod +x /etc/keepalived/check_nginx.sh
 

注:keepalived根据脚本返回状态码(0为工作正常,非0不正常)判断是否故障转移。

5. 启动并设置开机启动

systemctl daemon-reload
systemctl start nginx keepalived
systemctl enable nginx keepalived
 

6. 查看keepalived工作状态

ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:04:f7:2c brd ff:ff:ff:ff:ff:ff
    inet 192.168.31.80/24 brd 192.168.31.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet 192.168.31.88/24 scope global secondary ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe04:f72c/64 scope link 
       valid_lft forever preferred_lft forever
 

可以看到,在ens33网卡绑定了192.168.31.88 虚拟IP,说明工作正常。

7. Nginx+Keepalived高可用测试

关闭主节点Nginx,测试VIP是否漂移到备节点服务器。

在Nginx Master执行 pkill nginx;
在Nginx Backup,ip addr命令查看已成功绑定VIP。
 

8. 访问负载均衡器测试

找K8s集群中任意一个节点,使用curl查看K8s版本测试,使用VIP访问:

curl -k https://192.168.31.88:16443/version
{
  "major": "1",
  "minor": "20",
  "gitVersion": "v1.20.4",
  "gitCommit": "e87da0bd6e03ec3fea7933c4b5263d151aafd07c",
  "gitTreeState": "clean",
  "buildDate": "2021-02-18T16:03:00Z",
  "goVersion": "go1.15.8",
  "compiler": "gc",
  "platform": "linux/amd64"
}
 

可以正确获取到K8s版本信息,说明负载均衡器搭建正常。该请求数据流程:curl -> vip(nginx) -> apiserver

通过查看Nginx日志也可以看到转发apiserver IP:

tail /var/log/nginx/k8s-access.log -f
192.168.31.71 192.168.31.71:6443 - [02/Apr/2021:19:17:57 +0800] 200 423
192.168.31.71 192.168.31.72:6443 - [02/Apr/2021:19:18:50 +0800] 200 423
 

到此还没结束,还有下面最关键的一步。

7.3 修改所有Worker Node连接LB VIP

试想下,虽然我们增加了Master2 Node和负载均衡器,但是我们是从单Master架构扩容的,也就是说目前所有的Worker Node组件连接都还是Master1 Node,如果不改为连接VIP走负载均衡器,那么Master还是单点故障。

因此接下来就是要改所有Worker Node(kubectl get node命令查看到的节点)组件配置文件,由原来192.168.31.71修改为192.168.31.88(VIP)。

在所有Worker Node执行:

sed -i 's#192.168.31.71:6443#192.168.31.88:16443#' /opt/kubernetes/cfg/*
systemctl restart kubelet kube-proxy
 

检查节点状态:

kubectl get node
NAME         STATUS   ROLES    AGE   VERSION
k8s-master1   Ready    <none>   32d   v1.20.4
k8s-master2   Ready    <none>   10m   v1.20.4
k8s-node1    Ready    <none>   31d   v1.20.4
k8s-node2    Ready    <none>   31d   v1.20.4
 

至此,一套完整的 Kubernetes 高可用集群就部署完成了!

相关实践学习
通过Ingress进行灰度发布
本场景您将运行一个简单的应用,部署一个新的应用用于新的发布,并通过Ingress能力实现灰度发布。
容器应用与集群管理
欢迎来到《容器应用与集群管理》课程,本课程是“云原生容器Clouder认证“系列中的第二阶段。课程将向您介绍与容器集群相关的概念和技术,这些概念和技术可以帮助您了解阿里云容器服务ACK/ACK Serverless的使用。同时,本课程也会向您介绍可以采取的工具、方法和可操作步骤,以帮助您了解如何基于容器服务ACK Serverless构建和管理企业级应用。 学习完本课程后,您将能够: 掌握容器集群、容器编排的基本概念 掌握Kubernetes的基础概念及核心思想 掌握阿里云容器服务ACK/ACK Serverless概念及使用方法 基于容器服务ACK Serverless搭建和管理企业级网站应用
相关文章
|
1天前
|
Kubernetes 关系型数据库 MySQL
Kubernetes入门:搭建高可用微服务架构
【10月更文挑战第25天】在快速发展的云计算时代,微服务架构因其灵活性和可扩展性备受青睐。本文通过一个案例分析,展示了如何使用Kubernetes将传统Java Web应用迁移到Kubernetes平台并改造成微服务架构。通过定义Kubernetes服务、创建MySQL的Deployment/RC、改造Web应用以及部署Web应用,最终实现了高可用的微服务架构。Kubernetes不仅提供了服务发现和负载均衡的能力,还通过各种资源管理工具,提升了系统的可扩展性和容错性。
12 3
|
6天前
|
JSON Kubernetes 容灾
ACK One应用分发上线:高效管理多集群应用
ACK One应用分发上线,主要介绍了新能力的使用场景
|
7天前
|
Kubernetes 持续交付 开发工具
ACK One GitOps:ApplicationSet UI简化多集群GitOps应用管理
ACK One GitOps新发布了多集群应用控制台,支持管理Argo CD ApplicationSet,提升大规模应用和集群的多集群GitOps应用分发管理体验。
|
22天前
|
Kubernetes 应用服务中间件 nginx
搭建Kubernetes v1.31.1服务器集群,采用Calico网络技术
在阿里云服务器上部署k8s集群,一、3台k8s服务器,1个Master节点,2个工作节点,采用Calico网络技术。二、部署nginx服务到k8s集群,并验证nginx服务运行状态。
244 1
|
17天前
|
Kubernetes Ubuntu Linux
Centos7 搭建 kubernetes集群
本文介绍了如何搭建一个三节点的Kubernetes集群,包括一个主节点和两个工作节点。各节点运行CentOS 7系统,最低配置为2核CPU、2GB内存和15GB硬盘。详细步骤包括环境配置、安装Docker、关闭防火墙和SELinux、禁用交换分区、安装kubeadm、kubelet、kubectl,以及初始化Kubernetes集群和安装网络插件Calico或Flannel。
|
24天前
|
Kubernetes Cloud Native 流计算
Flink-12 Flink Java 3分钟上手 Kubernetes云原生下的Flink集群 Rancher Stateful Set yaml详细 扩容缩容部署 Docker容器编排
Flink-12 Flink Java 3分钟上手 Kubernetes云原生下的Flink集群 Rancher Stateful Set yaml详细 扩容缩容部署 Docker容器编排
61 0
|
25天前
|
Kubernetes 网络协议 安全
[kubernetes]二进制方式部署单机k8s-v1.30.5
[kubernetes]二进制方式部署单机k8s-v1.30.5
|
25天前
|
弹性计算 Kubernetes Linux
如何使用minikube搭建k8s集群
如何使用minikube搭建k8s集群
|
缓存 Kubernetes 数据安全/隐私保护
k8s1.18多master节点高可用集群安装-超详细中文官方文档
k8s1.18多master节点高可用集群安装-超详细中文官方文档
|
6月前
|
Kubernetes 负载均衡 监控
Kubernetes高可用集群二进制部署(一)主机准备和负载均衡器安装
Kubernetes高可用集群二进制部署(一)主机准备和负载均衡器安装