Kubeadm 部署集群

目录

1.1获取镜像

1.2 安装docker[集群]

1.3 阿里仓库下载[集群]

1.4 集群部署[集群]

1.5 集群环境配置[集群]

1.6 关闭系统Swap[集群]

1.7 安装Kubeadm包[集群]

1.8 配置启动kubelet[集群]

1.9 配置master节点[master]

1.10 配置使用网络插件[master]

1.11 node加入集群[node]

1.12 后续检查[master]

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主节点CPU核数必须是 ≥2核且内存要求必须≥2G，否则k8s无法启动

主机名	地址	角色	配置
kub-k8s-master	192.168.96.10	主节点	2核4G
kub-k8s-node1	192.168.96.20	工作节点	1核2G
kub-k8s-node2	192.168.96.30	工作节点	1核2G

1.1获取镜像

谷歌镜像[由于国内网络原因，无法下载，后续将采用阿里云镜像代替]

docker pull k8s.gcr.io/kube-apiserver:v1.22.0
docker pull k8s.gcr.io/kube-proxy:v1.22.0
docker pull k8s.gcr.io/kube-controller-manager:v1.22.0
docker pull k8s.gcr.io/kube-scheduler:v1.22.0
docker pull k8s.gcr.io/etcd:3.5.0-0
docker pull k8s.gcr.io/pause:3.5
docker pull k8s.gcr.io/coredns/coredns:v1.8.4

特别说明

所有机器都必须有镜像
每次部署都会有版本更新，具体版本要求，运行初始化过程失败会有版本提示
kubeadm的版本和镜像的版本必须是对应的????????

1.2 安装docker[集群]

过程请查看docker安装部分

1.3 阿里仓库下载[集群]

docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kube-controller-manager:v1.22.0
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy:v1.22.0
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kube-apiserver:v1.22.0
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kube-scheduler:v1.22.0
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/coredns:v1.8.4
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/etcd:3.5.0-0
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/pause:3.5
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# 下载完了之后需要将aliyun下载下来的所有镜像打成k8s.gcr.io/kube-controller-manager:v1.22.0这样的tag
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-controller-manager:v1.22.0 k8s.gcr.io/kube-controller-manager:v1.22.0
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy:v1.22.0 k8s.gcr.io/kube-proxy:v1.22.0
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-apiserver:v1.22.0 k8s.gcr.io/kube-apiserver:v1.22.0
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-scheduler:v1.22.0 k8s.gcr.io/kube-scheduler:v1.22.0
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/coredns:v1.8.4 k8s.gcr.io/coredns/coredns:v1.8.4
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/etcd:3.5.0-0 k8s.gcr.io/etcd:3.5.0-0
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/pause:3.5 k8s.gcr.io/pause:3.5   
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# 可以清理掉aliyun的镜像标签
docker rmi -f `docker images --format {{.Repository}}:{{.Tag}} | grep aliyun`

1.4 集群部署[集群]

cat >> /etc/hosts <<EOF
192.168.96.10 ? kub-k8s-master
192.168.96.20 ? kub-k8s-node1
192.168.96.30 ? kub-k8s-node2
EOF

制作本地解析，修改主机名。相互解析

1.5 集群环境配置[集群]

1.关闭防火墙：
# systemctl disable firewalld --now
2.禁用SELinux：
# setenforce 0
3.编辑文件/etc/selinux/config，将SELINUX修改为disabled，如下：
# sed -i 's/SELINUX=enforcing/SELINUX=disabled/' /etc/sysconfig/selinux
SELINUX=disabled
4.时间同步
# timedatectl set-timezone Asia/Shanghai
# yum install -y ntpdate
# ntpdate ntp.aliyun.com
5.配置静态ip

1.6 关闭系统Swap[集群]

Kubernetes 1.8开始要求关闭系统的Swap，如果不关闭，默认配置下kubelet将无法启动。

• 方法一: 通过kubelet的启动参数--fail-swap-on=false更改这个限制。

• 方法二: 关闭系统的Swap。

1.关闭swap分区
# swapoff -a
修改/etc/fstab文件，注释掉SWAP的自动挂载，使用free -m确认swap已经关闭。
2.注释掉swap分区：
# sed -i 's/.*swap.*/#&/' /etc/fstab
# free -m
 ? ? ? ? ? ? total ? ? ?  used ? ? ?  free ? ?  shared  buff/cache ? available
Mem: ? ? ? ? ? 3935 ? ? ? ? 144 ? ? ?  3415 ? ? ? ? ? 8 ? ? ? ? 375 ? ? ?  3518
Swap: ? ? ? ? ? ? 0 ? ? ? ? ? 0 ? ? ? ? ? 0

1.7 安装Kubeadm包[集群]

配置官方源[需翻墙]
# cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64/
enabled=1
gpgcheck=0
EOF
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配置阿里云源
cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF

所有节点：
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1.安装依赖包及常用软件包
# yum install -y conntrack ntpdate ntp ipvsadm ipset jq iptables curl sysstat libseccomp wget vim net-tools git iproute lrzsz bash-completion tree bridge-utils unzip bind-utils gcc
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2.安装对应版本
# yum install -y kubelet-1.22.0-0.x86_64 kubeadm-1.22.0-0.x86_64 kubectl-1.22.0-0.x86_64
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3.加载ipvs相关内核模块
# cat <<EOF > /etc/modules-load.d/ipvs.conf 
ip_vs
ip_vs_lc
ip_vs_wlc
ip_vs_rr
ip_vs_wrr
ip_vs_lblc
ip_vs_lblcr
ip_vs_dh
ip_vs_sh
ip_vs_nq
ip_vs_sed
ip_vs_ftp
ip_vs_sh
nf_conntrack_ipv4
ip_tables
ip_set
xt_set
ipt_set
ipt_rpfilter
ipt_REJECT
ipip
EOF
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4.配置：
配置转发相关参数，否则可能会出错
# cat <<EOF >  /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-iptables=1
net.bridge.bridge-nf-call-ip6tables=1
net.ipv4.ip_forward=1
net.ipv4.tcp_tw_recycle=0
vm.swappiness=0
vm.overcommit_memory=1
vm.panic_on_oom=0
fs.inotify.max_user_instances=8192
fs.inotify.max_user_watches=1048576
fs.file-max=52706963
fs.nr_open=52706963
net.ipv6.conf.all.disable_ipv6=1
net.netfilter.nf_conntrack_max=2310720
EOF
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5.使配置生效
# sysctl --system
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6.如果net.bridge.bridge-nf-call-iptables报错，加载br_netfilter模块
# modprobe br_netfilter
# modprobe ip_conntrack
# sysctl -p /etc/sysctl.d/k8s.conf
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7.查看是否加载成功
# lsmod | grep ip_vs

1.8 配置启动kubelet[集群]

1.配置kubelet使用pause镜像
获取docker的cgroups
# DOCKER_CGROUPS=$(docker info | grep 'Cgroup' | cut -d' ' -f4)
# echo $DOCKER_CGROUPS
=================================
配置变量：

[root@k8s-master ~]# DOCKER_CGROUPS=`docker info |grep 'Cgroup' | awk ' NR==1 {print $3}'`
[root@k8s-master ~]# echo $DOCKER_CGROUPS
cgroupfs
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2.配置kubelet的cgroups
# cat >/etc/sysconfig/kubelet<<EOF
KUBELET_EXTRA_ARGS="--cgroup-driver=$DOCKER_CGROUPS --pod-infra-container-image=k8s.gcr.io/pause:3.5"
EOF

启动
# systemctl daemon-reload
# systemctl enable kubelet && systemctl restart kubelet
在这里使用 # systemctl status kubelet，你会发现报错误信息；
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10月 11 00:26:43 node1 systemd[1]: kubelet.service: main process exited, code=exited, status=255/n/a
10月 11 00:26:43 node1 systemd[1]: Unit kubelet.service entered failed state.
10月 11 00:26:43 node1 systemd[1]: kubelet.service failed.
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运行 # journalctl -xefu kubelet 命令查看systemd日志才发现，真正的错误是：
 ?  unable to load client CA file /etc/kubernetes/pki/ca.crt: open /etc/kubernetes/pki/ca.crt: no such file or directory
#这个错误在运行kubeadm init 生成CA证书后会被自动解决，此处可先忽略。
#简单地说就是在kubeadm init 之前kubelet会不断重启。

1.9 配置master节点[master]

运行初始化过程如下：

[root@kub-k8s-master]# kubeadm init --kubernetes-version=v1.22.0 --pod-network-cidr=10.244.0.0/16 --apiserver-advertise-address=192.168.11.135

注：
apiserver-advertise-address=192.168.96.10 ?  ---master的ip地址。
--kubernetes-version=v1.22.0 ? --更具具体版本进行修改
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如果报错会有版本提示，那就是有更新新版本了
[init] Using Kubernetes version: v1.22.0
[preflight] Running pre-flight checks
    [WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
    [WARNING SystemVerification]: this Docker version is not on the list of validated versions: 18.03.0-ce. Latest validated version: 18.09
[preflight] Pulling images required for setting up a Kubernetes cluster
[preflight] This might take a minute or two, depending on the speed of your internet connection
[preflight] You can also perform this action in beforehand using 'kubeadm config images pull'
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Activating the kubelet service
[certs] Using certificateDir folder "/etc/kubernetes/pki"
[certs] Generating "ca" certificate and key
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [kub-k8s-master kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.168.96.10]
[certs] Generating "apiserver-kubelet-client" certificate and key
[certs] Generating "front-proxy-ca" certificate and key
[certs] Generating "front-proxy-client" certificate and key
[certs] Generating "etcd/ca" certificate and key
[certs] Generating "etcd/server" certificate and key
[certs] etcd/server serving cert is signed for DNS names [kub-k8s-master localhost] and IPs [192.168.96.10 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [kub-k8s-master localhost] and IPs [192.168.96.10 127.0.0.1 ::1]
[certs] Generating "etcd/healthcheck-client" certificate and key
[certs] Generating "apiserver-etcd-client" certificate and key
[certs] Generating "sa" key and public key
[kubeconfig] Using kubeconfig folder "/etc/kubernetes"
[kubeconfig] Writing "admin.conf" kubeconfig file
[kubeconfig] Writing "kubelet.conf" kubeconfig file
[kubeconfig] Writing "controller-manager.conf" kubeconfig file
[kubeconfig] Writing "scheduler.conf" kubeconfig file
[control-plane] Using manifest folder "/etc/kubernetes/manifests"
[control-plane] Creating static Pod manifest for "kube-apiserver"
[control-plane] Creating static Pod manifest for "kube-controller-manager"
[control-plane] Creating static Pod manifest for "kube-scheduler"
[etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests"
[wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests". This can take up to 4m0s
[apiclient] All control plane components are healthy after 24.575209 seconds
[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.16" in namespace kube-system with the configuration for the kubelets in the cluster
[upload-certs] Skipping phase. Please see --upload-certs
[mark-control-plane] Marking the node kub-k8s-master as control-plane by adding the label "node-role.kubernetes.io/master=''"
[mark-control-plane] Marking the node kub-k8s-master as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[bootstrap-token] Using token: 93erio.hbn2ti6z50he0lqs
[bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles
[bootstrap-token] configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
[bootstrap-token] configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
[bootstrap-token] configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
[bootstrap-token] Creating the "cluster-info" ConfigMap in the "kube-public" namespace
[addons] Applied essential addon: CoreDNS
[addons] Applied essential addon: kube-proxy
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Your Kubernetes control-plane has initialized successfully!
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To start using your cluster, you need to run the following as a regular user:
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  mkdir -p $HOME/.kube
  sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
  sudo chown $(id -u):$(id -g) $HOME/.kube/config
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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/
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Then you can join any number of worker nodes by running the following on each as root:
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kubeadm join 192.168.96.10:6443 --token 93erio.hbn2ti6z50he0lqs \
 ?  --discovery-token-ca-cert-hash sha256:3bc60f06a19bd09f38f3e05e5cff4299011b7110ca3281796668f4edb29a56d9  #需要记住

上面记录了完成的初始化输出的内容，根据输出的内容基本上可以看出手动初始化安装一个Kubernetes集群所需要的关键步骤。
其中有以下关键内容：
 ?  [kubelet] 生成kubelet的配置文件”/var/lib/kubelet/config.yaml”
 ?  [certificates]生成相关的各种证书
 ?  [kubeconfig]生成相关的kubeconfig文件
 ?  [bootstraptoken]生成token记录下来，后边使用kubeadm join往集群中添加节点时会用到
 ?
配置使用kubectl
如下操作在master节点操作

[root@kub-k8s-master ~]# rm -rf $HOME/.kube
[root@kub-k8s-master ~]# mkdir -p $HOME/.kube
[root@kub-k8s-master ~]# cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
[root@kub-k8s-master ~]# chown $(id -u):$(id -g) $HOME/.kube/config

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查看node节点

[root@k8s-master ~]# kubectl get nodes
NAME ? ? ? ? STATUS ? ? ROLES ?  AGE ? ? VERSION
k8s-master ? NotReady ? master ? 2m41s ? v1.22.0

1.10 配置使用网络插件[master]

# 版本差异 https://projectcalico.docs.tigera.io/archive/v3.22/getting-started/kubernetes/requirements
#> 部署calico网络插件
curl -L https://docs.projectcalico.org/v3.22/manifests/calico.yaml -O
kubectl apply -f  calico.yaml
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# kubectl get pod -A
NAMESPACE ? ? NAME ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? READY ? STATUS ?  RESTARTS ? AGE
kube-system ? calico-kube-controllers-6d9cdcd744-8jt5g ? 1/1 ? ? Running ? 0 ? ? ? ?  6m50s
kube-system ? calico-node-rkz4s ? ? ? ? ? ? ? ? ? ? ? ?  1/1 ? ? Running ? 0 ? ? ? ?  6m50s
kube-system ? coredns-74ff55c5b-bcfzg ? ? ? ? ? ? ? ? ?  1/1 ? ? Running ? 0 ? ? ? ?  52m
kube-system ? coredns-74ff55c5b-qxl6z ? ? ? ? ? ? ? ? ?  1/1 ? ? Running ? 0 ? ? ? ?  52m
kube-system ? etcd-kub-k8s-master ? ? ? ? ? ? ? ? ? ? ?  1/1 ? ? Running ? 0 ? ? ? ?  53m
kube-system ? kube-apiserver-kub-k8s-master ? ? ? ? ? ?  1/1 ? ? Running ? 0 ? ? ? ?  53m
kube-system ? kube-controller-manager-kub-k8s-master ? ? 1/1 ? ? Running ? 0 ? ? ? ?  53m
kube-system ? kube-proxy-gfhkf ? ? ? ? ? ? ? ? ? ? ? ? ? 1/1 ? ? Running ? 0 ? ? ? ?  52m
kube-system ? kube-scheduler-kub-k8s-master ? ? ? ? ? ?  1/1 ? ? Running ? 0 ? ? ? ?  53m

calico 原理

• 基于 BGP 的网络连接：Calico 使用 BGP 协议在 Kubernetes 集群中的节点之间建立网络连接。每个节点运行一个 Calico 代理【daemonset】，该代理负责与其他节点建立 BGP 连接，并将容器的网络流量路由到正确的目的地。

• 网络策略：Calico 提供了一种灵活的网络策略模型，允许定义容器之间的访问规则。可以使用标签来标识容器，并使用网络策略来控制容器之间的流量。

• IP 地址管理：Calico 自动管理 Kubernetes 集群中的 IP 地址分配。它使用 IPIP 隧道技术将容器的 IP 地址映射到节点的 IP 地址，以确保容器之间的通信。

• 网络隔离：Calico 提供了网络隔离功能，允许将不同的容器和应用程序隔离到不同的网络中。

flannel 原理

• 网络覆盖：Flannel 在 Kubernetes 集群中的每个节点上运行一个守护进程，该守护进程使用 VXLAN。

• 网络配置：Flannel 守护进程负责配置虚拟网络，并将容器的网络流量路由到正确的目的地。

• IP 地址分配：Flannel 自动管理 Kubernetes 集群中的 IP 地址分配。它使用 IPAM（IP Address Management）模块来分配 IP 地址，并将它们分配给容器。

• 网络策略：Flannel 支持网络策略，允许定义容器之间的访问规则。可以使用网络策略来控制容器之间的流量，以确保应用程序的安全性。

1.11 node加入集群[node]

配置node节点加入集群：
如果报错开启ip转发：
# sysctl -w net.ipv4.ip_forward=1
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在所有node节点操作，此命令为初始化master成功后返回的结果
# kubeadm join 192.168.96.10:6443 --token 93erio.hbn2ti6z50he0lqs \
 ?  --discovery-token-ca-cert-hash sha256:3bc60f06a19bd09f38f3e05e5cff4299011b7110ca3281796668f4edb29a56d9

1.12 后续检查[master]

各种检测：
1.查看pods:

[root@kub-k8s-master ~]# kubectl get pods -n kube-system
NAME ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? READY ? STATUS ?  RESTARTS ? AGE
coredns-5644d7b6d9-sm8hs ? ? ? ? ? ? ? ? 1/1 ? ? Running ? 0 ? ? ? ?  39m
coredns-5644d7b6d9-vddll ? ? ? ? ? ? ? ? 1/1 ? ? Running ? 0 ? ? ? ?  39m
etcd-kub-k8s-master ? ? ? ? ? ? ? ? ? ?  1/1 ? ? Running ? 0 ? ? ? ?  37m
kube-apiserver-kub-k8s-master ? ? ? ? ?  1/1 ? ? Running ? 0 ? ? ? ?  38m
kube-controller-manager-kub-k8s-master ? 1/1 ? ? Running ? 0 ? ? ? ?  38m
kube-flannel-ds-amd64-9wgd8 ? ? ? ? ? ?  1/1 ? ? Running ? 0 ? ? ? ?  38m
kube-flannel-ds-amd64-lffc8 ? ? ? ? ? ?  1/1 ? ? Running ? 0 ? ? ? ?  2m11s
kube-flannel-ds-amd64-m8kk2 ? ? ? ? ? ?  1/1 ? ? Running ? 0 ? ? ? ?  2m2s
kube-proxy-dwq9l ? ? ? ? ? ? ? ? ? ? ? ? 1/1 ? ? Running ? 0 ? ? ? ?  2m2s
kube-proxy-l77lz ? ? ? ? ? ? ? ? ? ? ? ? 1/1 ? ? Running ? 0 ? ? ? ?  2m11s
kube-proxy-sgphs ? ? ? ? ? ? ? ? ? ? ? ? 1/1 ? ? Running ? 0 ? ? ? ?  39m
kube-scheduler-kub-k8s-master ? ? ? ? ?  1/1 ? ? Running ? 0 ? ? ? ?  37m

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2.查看节点：

[root@kub-k8s-master ~]# kubectl get nodes
NAME ? ? ? ? ? ? STATUS ? ROLES ?  AGE ? ? VERSION
kub-k8s-master ? Ready ?  master ? 43m ? ? v1.22.0
kub-k8s-node1 ?  Ready ?  <none> ? 6m46s ? v1.22.0
kub-k8s-node2 ?  Ready ?  <none> ? 6m37s ? v1.22.0

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到此集群配置完成

错误整理

#> 如果集群初始化失败：(每个节点都要执行)
$ kubeadm reset -f; ipvsadm --clear; rm -rf ~/.kube
$ systemctl restart kubelet
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#> 如果忘记token值
$ kubeadm token create --print-join-command
$ kubeadm init phase upload-certs --upload-certs

添加标签
kubectl label nodes node3 name=value
删除标签
kubectl label nodes node3 name-