[kubernetes]二进制部署k8s集群-基于containerd

0. 前言

k8s从1.24版本开始不再直接支持docker，但可以自行调整相关配置，实现1.24版本后的k8s还能调用docker。其实docker自身也是调用containerd，与其k8s通过docker再调用containerd，不如k8s直接调用containerd，以减少性能损耗。

除了containerd，比较流行的容器运行时还有podman，但是podman官方安装文档要么用包管理器在线安装，要么用包管理器下载一堆依赖再编译安装，内网离线环境下安装可能会比较麻烦，而containerd的安装包是静态二进制文件，解压后就能直接使用，离线环境下相对方便一点。

本文将在内网离线环境下用二进制文件部署一个三节点集群+harbor镜像仓库。集群中部署了三个apiserver，并配置nginx反向代理，提升master的高可用性（如对高可用有进一步要求，可以再加个keepalive）。

1. 系统初始化

初始化部分需要三台k8s节点主机都执行, 根据实际情况修改参数。

修改主机名

# 3.31服务器
hostnamectl set-hostname k8s31
# 3.32服务器
hostnamectl set-hostname k8s32
# 3.33服务器
hostnamectl set-hostname k8s33

修改/etc/hosts文件，增加以下配置。

192.168.3.31 k8s31
192.168.3.32 k8s32
192.168.3.33 k8s33

配置时间同步服务

# 1. 安装chrony时间同步应用
apt install -y chrony

# 2. 添加内网的ntp服务器地址。如果在公网，可配置阿里云的ntp服务器地址：ntp.aliyun.com
echo 'server 192.168.3.41 iburst' > /etc/chrony/sources.d/custom-ntp-server.sources

# 3. 启动
systemctl start chrony
# 如果已经启动过了, 可以热加载配置: chronyc reload sources

关闭swap。如果安装系统时创建了swap，则需要关闭。

swapoff -a

装载内核模块

# 添加配置
cat << EOF > /etc/modules-load.d/containerd.conf
overlay
br_netfilter
EOF

# 立即装载
modprobe overlay
modprobe br_netfilter

# 检查装载。如果没有输出结果说明没有装载。
lsmod | grep br_netfilter

配置系统参数

# 1. 添加配置文件
cat << EOF > /etc/sysctl.d/k8s-sysctl.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
user.max_user_namespaces=28633
vm.swappiness = 0
EOF

# 2. 配置生效
sysctl -p /etc/sysctl.d/k8s-sysctl.conf

启用ipvs。编写system配置文件，实现开机自动装载到内核。

# 1. 安装依赖
apt install -y ipset ipvsadm
# 2. 新建文件并添加配置, 文件路径可任意
tee /root/scripts/k8s.sh <<EOF
modprobe -- ip_vs
modprobe -- ip_vs_rr
modprobe -- ip_vs_wrr
modprobe -- ip_vs_sh
modprobe -- nf_conntrack
EOF

# 3. 新建system文件, 实现开机执行脚本
cat << EOF > /etc/systemd/system/myscripts.service
[Unit]
Description=Run a Custom Script at Startup
After=default.target
 
[Service]
ExecStart=sh /root/scripts/k8s.sh
 
[Install]
WantedBy=default.target
EOF

# 4. 加载并启用system
systemctl daemon-reload
systemctl enable myscripts

2. 部署harbor镜像仓库

由于部署集群时候需要先拉取一些镜像，所以harbor在集群外的一个服务器单独部署。官方安装脚本使用了docker，所以harbor节点需要先安装docker，安装步骤可参考博客园 - linux离线安装docker与compose。

harbor的安装步骤可参考博客园 - centos离线安装harbor，这里大致写一下。

harbor的github release GitHub - goharbor/harbor/releases 提供离线安装包，要先下载好，然后解压。

创建ssl证书

mkdir certs
# 创建服务器证书密钥文件harbor.key
openssl genrsa -des3 -out harbor.key 2048
# 输入密码，确认密码，自己随便定义，但是要记住，后面会用到。

# 创建服务器证书的申请文件harbor.csr
openssl req -new -key harbor.key -out harbor.csr
# 输入密钥文件的密码, 然后一路回车

# 备份一份服务器密钥文件
cp harbor.key harbor.key.org

# 去除文件口令
openssl rsa -in harbor.key.org -out harbor.key
# 输入密钥文件的密码

# 创建一个自当前日期起为期十年的证书 harbor.crt
openssl x509 -req -days 3650 -in harbor.csr -signkey harbor.key -out harbor.crt

修改配置文件 harbor.yml，仅列出自修改项。数据存储目录和日志目录自定义了。

hostname: 192.168.3.43

certificate: /home/atlas/apps/harbor/certs/harbor.crt
private_key: /home/atlas/apps/harbor/certs/harbor.key

# admin用户登录密码
harbor_admin_password: Harbor2023

# 数据卷目录
data_volume: /home/atlas/apps/harbor/data

# 日志目录
location: /home/atlas/apps/harbor/logs/

执行安装脚本

./install.sh

浏览器访问 https://192.168.3.43 ，测试能否正常登录访问harbor。

3. 安装containerd

从GitHub https://github.com/containerd/containerd/releases 下载二进制包
解压压缩包

tar xf cri-containerd-cni-1.7.2-linux-amd64.tar.gz -C /

生成 containerd 配置文件

mkdir /etc/containerd
containerd config default > /etc/containerd/config.toml

编辑 /etc/containerd/config.toml ，修改以下内容

# 修改数据存储目录
root = "/home/apps/containerd"

# 对于使用systemd作为init system的linux发行版，官方建议用systemd作为容器cgroup driver
# false改成true
SystemdCgroup = true

# 修改pause镜像下载地址，这里用的是内网域名地址
sandbox_image = "registry.atlas.cn/public/pause:3.9"

# 私有harbor的连接信息
[plugins."io.containerd.grpc.v1.cri".registry.configs."registry.atlas.cn"]
[plugins."io.containerd.grpc.v1.cri".registry.configs."registry.atlas.cn".tls]
insecure_skip_verify = true
[plugins."io.containerd.grpc.v1.cri".registry.configs."registry.atlas.cn".auth]
username = "admin"
password = "Harbor2023"

重加载systemd配置，启动containerd

systemctl daemon-reload
systemctl start containerd

4. 生成ca证书

后面的k8s和etcd集群都会用到ca证书。如果组织能提供统一的CA认证中心，则直接使用组织颁发的CA证书即可。如果没有统一的CA认证中心，则可以通过颁发自签名的CA证书来完成安全配置。这里自行生成一个ca证书。

# 生成私钥文件ca.key
openssl genrsa -out ca.key 2048
# 根据私钥文件生成根证书文件ca.crt
# /CN为master的主机名或IP地址
# days为证书的有效期
openssl req -x509 -new -nodes -key ca.key -subj "/CN=192.168.3.31" -days 36500 -out ca.crt

# 拷贝ca证书到/etc/kubernetes/pki
mkdir -p /etc/kubernetes/pki
cp ca.crt ca.key /etc/kubernetes/pki/

5. 部署etcd集群

部署一个三节点etcd集群，集群间使用https协议加密通信。etcd的安装包可以从官网下载，下载后解压，将压缩包中的etcd和etcdctl放到/usr/local/bin目录。

编辑文件etcd_ssl.cnf。IP地址为etcd节点。

[ req ]
req_extensions = v3_req
distinguished_name = req_distinguished_name

[ req_distinguished_name ]


[ v3_req ]

basicConstraints = CA:FALSE
keyUsage = nonRepudiation, digitalSignature, keyEncipherment
subjectAltName = @alt_names

[ alt_names ]
IP.1 = 192.168.3.31
IP.2 = 192.168.3.32
IP.3 = 192.168.3.33

创建etcd服务端证书

openssl genrsa -out etcd_server.key 2048
openssl req -new -key etcd_server.key -config etcd_ssl.cnf -subj "/CN=etcd-server" -out etcd_server.csr
openssl x509 -req -in etcd_server.csr -CA ca.crt -CAkey ca.key -CAcreateserial -days 3650 -extensions v3_req -extfile etcd_ssl.cnf -out etcd_server.crt

创建etcd客户端证书

openssl genrsa -out etcd_client.key 2048
openssl req -new -key etcd_client.key -config etcd_ssl.cnf -subj "/CN=etcd-client" -out etcd_client.csr
openssl x509 -req -in etcd_client.csr -CA ca.crt -CAkey ca.key -CAcreateserial -days 3650 -extensions v3_req -extfile etcd_ssl.cnf -out etcd_client.crt

编辑etcd的配置文件。注意，各节点的ETCD_NAME和监听地址不一样，ip和证书文件路径要根据实际来修改。以下示例为192.168.3.31的etcd配置

ETCD_NAME=etcd1
ETCD_DATA_DIR=/home/atlas/apps/etcd/data

ETCD_CERT_FILE=/home/atlas/apps/etcd/certs/etcd_server.crt
ETCD_KEY_FILE=/home/atlas/apps/etcd/certs/etcd_server.key
ETCD_TRUSTED_CA_FILE=/home/atlas/apps/kubernetes/certs/ca.crt
ETCD_CLIENT_CERT_AUTH=true
ETCD_LISTEN_CLIENT_URLS=https://192.168.3.31:2379
ETCD_ADVERTISE_CLIENT_URLS=https://192.168.3.31:2379

ETCD_PEER_CERT_FILE=/home/atlas/apps/etcd/certs/etcd_server.crt
ETCD_PEER_KEY_FILE=/home/atlas/apps/etcd/certs/etcd_server.key
ETCD_PEER_TRUSTED_CA_FILE=/home/atlas/apps/kubernetes/certs/ca.crt
ETCD_LISTEN_PEER_URLS=https://192.168.3.31:2380
ETCD_INITIAL_ADVERTISE_PEER_URLS=https://192.168.3.31:2380

ETCD_INITIAL_CLUSTER_TOKEN=etcd-cluster
ETCD_INITIAL_CLUSTER="etcd1=https://192.168.3.31:2380,etcd2=https://192.168.3.32:2380,etcd3=https://192.168.3.33:2380"
ETCD_INITIAL_CLUSTER_STATE=new

编辑/etc/systemd/system/etcd.service，注意根据实际修改配置文件和etcd二进制文件的路径

[Unit]
Description=etcd key-value store
Documentation=https://github.com/etcd-io/etcd
After=network.target

[Service]
EnvironmentFile=/home/atlas/apps/etcd/conf/etcd.conf
ExecStart=/usr/local/bin/etcd
Restart=always

[Install]
WantedBy=multi-user.target

加载systemd配置，启动etcd

systemctl daemon-reload
systemctl start etcd

验证集群是否部署成功。注意根据实际修改证书文件路径和etcd节点的IP与端口

etcdctl --cacert=/etc/kubernetes/pki/ca.crt --cert=/home/atlas/apps/etcd/certs/etcd_client.crt --key=/home/atlas/apps/etcd/certs/etcd_client.key --endpoints=https://192.168.3.31:2379,https://192.168.3.32:2379,https://192.168.3.33:2379 endpoint health

如果集群部署成功，应该有如下类似输出

https://192.168.3.33:2379 is healthy: successfully committed proposal: took = 27.841376ms
https://192.168.3.32:2379 is healthy: successfully committed proposal: took = 29.489289ms
https://192.168.3.31:2379 is healthy: successfully committed proposal: took = 35.703538ms

6. 部署k8s

k8s的二进制文件安装包可以从github下载：https://github.com/kubernetes/kubernetes/releases

在changelog中找到二进制包的下载链接，下载server binary即可，里面包含了master和node的二进制文件。

解压后将其中的二进制文件挪到 /usr/local/bin

6.1 安装apiserver

编辑master_ssl.cnf。DNS.5 ~ DNS.7为三台服务器的主机名，另行设置/etc/hosts。IP.1为Master Service虚拟服务的Cluster IP地址，IP.2 ~ IP.4为apiserver的服务器IP

[req]
req_extensions = v3_req
distinguished_name = req_distinguished_name
[req_distinguished_name]

[ v3_req ]
basicConstraints = CA:FALSE
keyUsage = nonRepudiation, digitalSignature, keyEncipherment
subjectAltName = @alt_names

[alt_names]
DNS.1 = kubernetes
DNS.2 = kubernetes.default
DNS.3 = kubernetes.default.svc
DNS.4 = kubernetes.default.svc.cluster.local
DNS.5 = k8s31
DNS.6 = k8s32
DNS.7 = k8s33
IP.1 = 169.169.0.1
IP.2 = 192.168.3.31
IP.3 = 192.168.3.32
IP.4 = 192.168.3.33

生成证书文件

openssl genrsa -out apiserver.key 2048
openssl req -new -key apiserver.key -config master_ssl.cnf -subj "/CN=192.168.3.31" -out apiserver.csr
# ca.crt和ca.key是 "2. openssl生成证书"中的两个证书文件
openssl x509 -req -in apiserver.csr -CA ca.crt -CAkey ca.key -CAcreateserial -days 36500 -extensions v3_req -extfile master_ssl.cnf -out apiserver.crt

使用cfssl创建sa.pub和sa-key.pem。cfssl和cfssljson可以从github下载

cat<<EOF > sa-csr.json 
{
    "CN":"sa",
    "key":{
        "algo":"rsa",
        "size":2048
    },
    "names":[
        {
            "C":"CN",
            "L":"BeiJing",
            "ST":"BeiJing",
            "O":"k8s",
            "OU":"System"
        }
    ]
}
EOF

# cfssl和cfssljson可自行在GitHub搜索下载
cfssl gencert -initca sa-csr.json | cfssljson -bare sa -

openssl x509 -in sa.pem -pubkey -noout > sa.pub

编辑kube-apiserver的配置文件，注意根据实际情况修改文件路径和etcd地址

KUBE_API_ARGS="--secure-port=6443 \
--tls-cert-file=/home/atlas/apps/kubernetes/apiserver/certs/apiserver.crt \
--tls-private-key-file=/home/atlas/apps/kubernetes/apiserver/certs/apiserver.key \
--client-ca-file=/home/atlas/apps/kubernetes/certs/ca.crt \
--service-account-issuer=https://kubernetes.default.svc.cluster.local \
--service-account-key-file=/home/atlas/apps/kubernetes/certs/sa.pub \
--service-account-signing-key-file=/home/atlas/apps/kubernetes/certs/sa-key.pem \
--apiserver-count=3 --endpoint-reconciler-type=master-count \
--etcd-servers=https://192.168.3.31:2379,https://192.168.3.32:2379,https://192.168.3.33:2379 \
--etcd-cafile=/home/atlas/apps/kubernetes/certs/ca.crt \
--etcd-certfile=/home/atlas/apps/etcd/certs/etcd_client.crt \
--etcd-keyfile=/home/atlas/apps/etcd/certs/etcd_client.key \
--service-cluster-ip-range=169.169.0.0/16 \
--service-node-port-range=30000-32767 \
--allow-privileged=true \
--audit-log-maxsize=100 \
--audit-log-maxage=15 \
--audit-log-path=/home/atlas/apps/kubernetes/apiserver/logs/apiserver.log --v=2"

编辑service文件。/etc/systemd/system/kube-apiserver.service

[Unit]
Description=Kubernetes API Server
Documentation=https://github.com/kubernetes/kubernetes

[Service]
EnvironmentFile=/home/atlas/apps/kubernetes/apiserver/conf/apiserver
ExecStart=/usr/local/bin/kube-apiserver $KUBE_API_ARGS
Restart=always

[Install]
WantedBy=multi-user.target

加载service文件，启动kube-apiserver

systemctl daemon-reload
systemctl start kube-apiserver

生成客户端证书

openssl genrsa -out client.key 2048
# /CN的名称用于标识连接apiserver的客户端用户名称
openssl req -new -key client.key -subj "/CN=admin" -out client.csr
openssl x509 -req -in client.csr -CA ca.crt -CAkey ca.key -CAcreateserial -out client.crt -days 36500

创建客户端连接apiserver所需的kubeconfig配置文件。其中server为nginx监听地址。注意根据实际修改配置

apiVersion: v1
kind: Config
clusters:
- name: default
  cluster:
    server: https://192.168.3.31:9443
    certificate-authority: /home/atlas/apps/kubernetes/certs/ca.crt
users:
- name: admin
  user:
    client-certificate: /home/atlas/apps/kubernetes/apiserver/certs/client.crt
    client-key: /home/atlas/apps/kubernetes/apiserver/certs/client.key
contexts:
- context:
    cluster: default
    user: admin
  name: default
current-context: default

6.2 安装kube-controller-manager

编辑配置文件 /home/atlas/apps/kubernetes/controller-manager/conf/env

KUBE_CONTROLLER_MANAGER_ARGS="--kubeconfig=/home/atlas/apps/kubernetes/apiserver/conf/kubeconfig \
--leader-elect=true \
--service-cluster-ip-range=169.169.0.0/16 \
--service-account-private-key-file=/home/atlas/apps/kubernetes/apiserver/certs/apiserver.key \
--root-ca-file=/home/atlas/apps/kubernetes/certs/ca.crt \
--v=0"

编辑service文件/etc/systemd/system/kube-controller-manager.service

[Unit]
Description=Kubernetes Controller Manager
Documentation=https://github.com/kubernetes/kubernetes

[Service]
EnvironmentFile=/home/atlas/apps/kubernetes/controller-manager/conf/env
ExecStart=/usr/local/bin/kube-controller-manager $KUBE_CONTROLLER_MANAGER_ARGS
Restart=always

[Install]
WantedBy=multi-user.target

加载配置文件并启动

systemctl daemon-reload
systemctl start kube-controller-manager

6.3 安装kube-scheduler

编辑配置文件

KUBE_SCHEDULER_ARGS="--kubeconfig=/home/atlas/apps/kubernetes/apiserver/conf/kubeconfig \
--leader-elect=true \
--v=0"

编辑service文件 /etc/systemd/system/kube-scheduler.service

[Unit]
Description=Kubernetes Scheduler
Documentation=https://github.com/kubernetes/kubernetes

[Service]
EnvironmentFile=//home/atlas/apps/kubernetes/scheduler/conf/env
ExecStart=/usr/local/bin/kube-scheduler $KUBE_SCHEDULER_ARGS
Restart=always

[Install]
WantedBy=multi-user.target

启动

systemctl daemon-reload
systemctl start kube-scheduler

6.4 安装nginx

这里用nginx对apiserver进行tcp反向代理，也可以使用haproxy。nginx编译安装可参考博客园 - linux编译安装nginx，docker安装nginx更加简单，本文略过。以下为示例配置：

worker_processes  auto;

#error_log  logs/error.log;
#error_log  logs/error.log  notice;
#error_log  logs/error.log  info;

#pid        logs/nginx.pid;

events {
    worker_connections  65536;
}

stream{
    log_format json2 '$remote_addr [$time_local] ' 
        '$protocol $status $bytes_sent $bytes_received ' 
        '$session_time "$upstream_addr" ' 
        '"$upstream_bytes_sent" "$upstream_bytes_received" "$upstream_connect_time"'; 

    access_log logs/stream.log json2; 
    upstream apiservers {
        server 192.168.3.31:6443;
        server 192.168.3.32:6443;
        server 192.168.3.33:6443;
    }
    server {
        listen 9443;
        proxy_pass apiservers;
    }
}

6.5 安装kubelet

编辑文件 /home/atlas/apps/kubernetes/kubelet/conf/env。注意修改hostname-override中的IP为Node节点自己的IP。如果修改了containerd的socket地址，则配置中也要按实际修改。

KUBELET_ARGS="--kubeconfig=/home/atlas/apps/kubernetes/apiserver/conf/kubeconfig \
--config=/home/atlas/apps/kubernetes/kubelet/conf/kubelet.config \
--hostname-override=192.168.3.31 \
--v=0 \
--container-runtime-endpoint="unix:///run/containerd/containerd.sock"

主要参数说明

编辑文件 /home/atlas/apps/kubernetes/kubelet/conf/kubelet.config

kind: KubeletConfiguration
apiVersion: kubelet.config.k8s.io/v1beta1
address: 0.0.0.0
port: 10250
cgroupDriver: systemd
clusterDNS: ["169.169.0.100"]
clusterDomain: cluster.local
authentication:
  anonymous:
    enabled: true

主要参数说明

编辑service文件 /etc/systemd/system/kubelet.service

[Unit]
Description=Kubernetes Kubelet Server
Documentation=https://github.com/kubernetes/kubernetes
After=docker.target

[Service]
EnvironmentFile=/home/atlas/apps/kubernetes/kubelet/conf/env
ExecStart=/usr/local/bin/kubelet $KUBELET_ARGS
Restart=always

[Install]
WantedBy=multi-user.target

加载service并启动kubelet

systemctl daemon-reload && systemctl start kubelet

6.6 安装kube-proxy

编辑文件 /home/atlas/apps/kubernetes/proxy/conf/env。注意修改hostname-override中的IP为Node节点自己的IP。

KUBE_PROXY_ARGS="--kubeconfig=/home/atlas/apps/kubernetes/apiserver/conf/kubeconfig \
--hostname-override=192.168.3.31 \
--proxy-mode=ipvs \
--v=0"

编辑service文件 /etc/systemd/system/kube-proxy.service

[Unit]
Description=Kubernetes Kube-Proxy Server
Documentation=https://github.com/kubernetes/kubernetes
After=network.target

[Service]
EnvironmentFile=/home/atlas/apps/kubernetes/proxy/conf/env
ExecStart=/usr/local/bin/kube-proxy $KUBE_PROXY_ARGS
Restart=always

[Install]
WantedBy=multi-user.target

加载service并启动

systemctl daemon-reload && systemctl start kube-proxy

6.7 安装calico

在master节点通过kubectl查询自动注册到 k8s 的 node 信息。由于 Master 开启了 https 认证，所以 kubectl 也需要使用客户端 CA证书连接Master，可以直接使用 apiserver 的 kubeconfig 文件。

kubectl --kubeconfig=/home/atlas/apps/kubernetes/apiserver/conf/kubeconfig get nodes

若是不想每次敲命令都要指定kubeconfig文件，可以编辑~/.bashrc，增加如下内容后source ~/.bashrc

alias kubectl='/usr/local/bin/kubectl --kubeconfig=/home/atlas/apps/kubernetes/apiserver/conf/kubeconfig'

如果操作步骤和以上保持一致，命令执行应有类似如下输出。

NAME           STATUS   ROLES    AGE   VERSION
192.168.3.31   Ready    <none>   18m   v1.26.6
192.168.3.32   Ready    <none>   16m   v1.26.6
192.168.3.33   Ready    <none>   16m   v1.26.6

由于安装containerd时，安装包里已经包含了cni插件，所以节点状态都是ready。自测节点之间通信还是有问题，所以换成相对来说熟悉点的calico。

下载calico文件。

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

编辑calico.yaml文件。因为内网离线部署，以提前在公网下载好calico的镜像并推送到内网的harbor镜像仓库，所以配置文件中的镜像修改成了内网的镜像。

image: registry.atlas.cn/calico/cni:v3.26.1
image: registry.atlas.cn/calico/node:v3.26.1
image: registry.atlas.cn/calico/kube-controllers:v3.26.1

部署calico。PS：此处的kubectl命令以alias kubeconfig

kubectl apply -f calico.yaml

查看calico的pod是否正常运行。如果正常，状态应该都是running；若不正常，则需要describe pod的信息查看什么问题

kubectl get pods -A

6.8 集群内安装CoreDNS

编辑部署文件 coredns.yaml。其中corefile里面的forward地址是内网的dns服务器地址，若内网没有dns，可修改为/etc/resolv.conf。coredns的镜像地址也是提前推送的harbor的镜像。

---
apiVersion: v1
kind: ConfigMap
metadata:
  name: coredns
  namespace: kube-system
  labels:
      addonmanager.kubernetes.io/mode: EnsureExists
data:
  Corefile: |
    cluster.local {
        errors
        health {
          lameduck 5s
        }
        ready
        kubernetes cluster.local 169.169.0.0/16 {
          fallthrough in-addr.arpa ip6.arpa
        }
        prometheus :9153
        forward . 192.168.3.41
        cache 30
        loop
        reload
        loadbalance
    }
    . {
        cache 30
        loadbalance
        forward . 192.168.3.41
    }  

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: coredns
  namespace: kube-system
  labels:
    k8s-app: kube-dns
    kubernetes.io/name: "CoreDNS"
spec:
  replicas: 1
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 1
  selector:
    matchLabels:
      k8s-app: kube-dns
  template:
    metadata:
      labels:
        k8s-app: kube-dns
    spec:
      priorityClassName: system-cluster-critical
      tolerations:
        - key: "CriticalAddonsOnly"
          operator: "Exists"
      nodeSelector:
        kubernetes.io/os: linux
      affinity:
         podAntiAffinity:
           preferredDuringSchedulingIgnoredDuringExecution:
           - weight: 100
             podAffinityTerm:
               labelSelector:
                 matchExpressions:
                   - key: k8s-app
                     operator: In
                     values: ["kube-dns"]
               topologyKey: kubernetes.io/hostname
      imagePullSecrets:
      - name: registry-harbor
      containers:
      - name: coredns
        image: registry.atlas.cn/public/coredns:1.11.1
        imagePullPolicy: IfNotPresent
        resources:
          limits:
            memory: 170Mi
          requests:
            cpu: 100m
            memory: 70Mi
        args: [ "-conf", "/etc/coredns/Corefile" ]
        volumeMounts:
        - name: config-volume
          mountPath: /etc/coredns
          readOnly: true
        ports:
        - containerPort: 53
          name: dns
          protocol: UDP
        - containerPort: 53
          name: dns-tcp
          protocol: TCP
        - containerPort: 9153
          name: metrics
          protocol: TCP
        securityContext:
          allowPrivilegeEscalation: false
          capabilities:
            add:
            - NET_BIND_SERVICE
            drop:
            - all
          readOnlyRootFilesystem: true
        livenessProbe:
          httpGet:
            path: /health
            port: 8080
            scheme: HTTP
          initialDelaySeconds: 60
          timeoutSeconds: 5
          successThreshold: 1
          failureThreshold: 5
        readinessProbe:
          httpGet:
            path: /ready
            port: 8181
            scheme: HTTP
      dnsPolicy: Default
      volumes:
        - name: config-volume
          configMap:
            name: coredns
            items:
            - key: Corefile
              path: Corefile

---
apiVersion: v1
kind: Service
metadata:
  name: kube-dns
  namespace: kube-system
  annotations:
    prometheus.io/port: "9153"
    prometheus.io/scrape: "true"
  labels:
    k8s-app: kube-dns
    kubernetes.io/cluster-service: "true"
    kubernetes.io/name: "CoreDNS"
spec:
  selector:
    k8s-app: kube-dns
  clusterIP: 169.169.0.100
  ports:
  - name: dns
    port: 53
    protocol: UDP
  - name: dns-tcp
    port: 53
    protocol: TCP
  - name: metrics
    port: 9153
    protocol: TCP

部署一个nginx用于测试。注意按实际修改镜像地址

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: deploy-nginx
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
      env: dev
  template:
    metadata:
      labels:
        app: nginx
        env: dev
    spec:
      containers:
      - name: nginx
        image: registry.atlas.cn/public/nginx:1.25.1
        ports:
        - containerPort: 80
        
---
apiVersion: v1
kind: Service
metadata:
  name: svc-nginx
spec:
  ports:
  - protocol: TCP
    port: 80
    targetPort: 80
  selector:
    app: nginx
    env: dev

发布nginx服务

kubectl create -f nginx.yaml

运行一个ubuntu的pod。镜像基于原版的ubuntu:22.04修改，提前安装了dnsutils再封装推送到内网harbor，Dockerfile内容如下：

FROM ubuntu:22.04
RUN apt update -y && apt install -y dnsutils iputils-ping curl
RUN apt clean && rm -rf /var/lib/apt/lists/*

使用文件声明pod。注意按实际修改镜像地址

apiVersion: v1
kind: Pod
metadata:
  name: ubuntu
  namespace: default
spec:
  containers:
  - name: ubuntu
    image: registry.atlas.cn/public/ubuntu:22.04.1
    command:
      - tail
      - -f
      - /dev/null

发布pod

kubectl create -f ubuntu.yaml

使用exec选项进入pod内

kubectl exec -it ubuntu -- bash

在pod内测试能否连通nginx。若一切响应正常，说明集群已基本搭建成功

# 测试能否解析出svc-nginx的ip
nslookup svc-nginx
# 测试能否调通svc-nginx:80
curl http://svc-nginx

补充

以上步骤只是部署了一个能正常发布服务的基础k8s集群，生产环境中还要考虑存储、网络、安全等问题，相关内容比较多，本文不再赘述，可参考其它文档。

问题记录

sysctl加载配置时报错

处理：装载内核模块

modprobe br_netfilter

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