虚拟机环境
| IP | 版本 | 角色 |
|---|---|---|
| 10.211.55.46 | CentOS 7.6 | k8s-master |
| 10.211.55.47 | CentOS 7.6 | k8s-node-1 |
| 10.211.55.48 | CentOS 7.6 | k8s-node-2 |
处理不必要的麻烦
pencil.file.lynchj.com
- 升级内核
可以查看这篇博客
- 其他操作
### 三台机器同样操作
# 修改 hosts
[root@k8s-master ~]# cat /etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
10.211.55.46 k8s-master
10.211.55.47 k8s-node-1
10.211.55.48 k8s-node-2
# 关闭防火墙和 SELinux
[root@k8s-master ~]# systemctl disable firewalld && systemctl stop firewalld && setenforce 0
[root@k8s-master ~]# vim /etc/selinux/config
SELINUX=disabled
# 关闭 Swap，自 1.8 开始，k8s 要求关闭系统 Swap，如果不关闭，kubelet 无法启动。
[root@k8s-master ~]# swapoff -a
[root@k8s-master ~]# vim /etc/fstab
#/dev/mapper/centos-swap swap swap defaults 0 0
[root@k8s-node-1 ~]# cat <<EOF >/etc/sysctl.d/k8s.conf
> vm.swappiness=0
> EOF
[root@k8s-node-1 ~]# sysctl -p /etc/sysctl.d/k8s.conf
vm.swappiness = 0
# 开启桥接网络和转发
[root@k8s-master ~]# cat <<EOF >>/etc/sysctl.d/k8s.conf
> net.bridge.bridge-nf-call-ip6tables = 1
> net.bridge.bridge-nf-call-iptables = 1
> net.ipv4.ip_forward = 1
> EOF
[root@k8s-master ~]# modprobe br_netfilter
[root@k8s-master ~]# sysctl -p /etc/sysctl.d/k8s.conf
vm.swappiness = 0
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
如果不关闭 Swap 也可，需要修改 kubelet 的启动配置项
--fail-swap-on=false。配置文件：/etc/sysconfig/kubelet。KUBELET_EXTRA_ARGS=--fail-swap-on=false
- kube-proxy 开启 ipvs 的前置条件
ipvs 已经加入到了内核的主干，所以为 kube-proxy 开启 ipvs 的前提需要加载以下的内核模块：
| 模块 | 说明 |
|---|---|
| ip_vs | |
| ip_vs_rr | |
| ip_vs_wrr | |
| ip_vs_sh | |
| nf_conntrack_ipv4 | # 从内核 4.19.1 开始已经修改成：nf_conntrack |
[root@k8s-master ~]# cat > /etc/sysconfig/modules/ipvs.modules <<EOF
#!/bin/bash
modprobe -- ip_vs
modprobe -- ip_vs_rr
modprobe -- ip_vs_wrr
modprobe -- ip_vs_sh
modprobe -- nf_conntrack
EOF
[root@k8s-master ~]# chmod 755 /etc/sysconfig/modules/ipvs.modules && bash /etc/sysconfig/modules/ipvs.modules && lsmod | grep -e ip_vs -e nf_conntrack_ipv4
还需要确保各个节点上已经安装了 ipset 软件包 yum -y install ipset。 为了便于查看 ipvs 的代理规则，最好安装一下管理工具 ipvsadm：yum -y install ipvsadm。如果以上前提条件如果不满足，则即使 kube-proxy 的配置开启了 ipvs 模式，也会退回到 iptables 模式。
安装 Docker
- 删除旧版本
[root@k8s-master ~]# sudo yum remove docker \
docker-client \
docker-client-latest \
docker-common \
docker-latest \
docker-latest-logrotate \
docker-logrotate \
docker-engine
- 安装稳定 yum 源仓库
[root@k8s-master ~]# sudo yum install -y yum-utils \
device-mapper-persistent-data \
lvm2
[root@k8s-master ~]# sudo yum-config-manager \
--add-repo \
https://download.docker.com/linux/centos/docker-ce.repo
查看列表：
[root@k8s-master ~]# yum list docker-ce --showduplicates | sort -r
已加载插件：fastestmirror
可安装的软件包
* updates: mirrors.aliyun.com
Loading mirror speeds from cached hostfile
* extras: mirrors.aliyun.com
* elrepo: mirror.rackspace.com
docker-ce.x86_64 3:18.09.5-3.el7 docker-ce-stable
docker-ce.x86_64 3:18.09.4-3.el7 docker-ce-stable
docker-ce.x86_64 3:18.09.3-3.el7 docker-ce-stable
docker-ce.x86_64 3:18.09.2-3.el7 docker-ce-stable
docker-ce.x86_64 3:18.09.1-3.el7 docker-ce-stable
docker-ce.x86_64 3:18.09.0-3.el7 docker-ce-stable
docker-ce.x86_64 18.06.3.ce-3.el7 docker-ce-stable
docker-ce.x86_64 18.06.2.ce-3.el7 docker-ce-stable
docker-ce.x86_64 18.06.1.ce-3.el7 docker-ce-stable
docker-ce.x86_64 18.06.0.ce-3.el7 docker-ce-stable
docker-ce.x86_64 18.03.1.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 18.03.0.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.12.1.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.12.0.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.09.1.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.09.0.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.06.2.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.06.1.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.06.0.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.03.3.ce-1.el7 docker-ce-stable
docker-ce.x86_64 17.03.2.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.03.1.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.03.0.ce-1.el7.centos docker-ce-stable
* base: mirrors.aliyun.com
- 安装
[root@k8s-master ~]# sudo yum -y install docker-ce docker-ce-cli containerd.io
这里也提供了离线 rpm 安装包，离线安装也可。Download
- 启动
[root@k8s-node-1 ~]# systemctl enable docker && systemctl start docker
修改 docker cgoup driver 为 systemd
CRI installation 中指出，对于使用 systemd 作为 init system 的 Linux 的发行版，使用 systemd 作为 Docker 的 cgroup driver 可以确保服务器节点在资源紧张的情况更加稳定，因此这里修改各个节点上 Docker 的 cgroup driver 为 systemd。
[root@k8s-master ~]# vim /etc/docker/daemon.json
{
"exec-opts": ["native.cgroupdriver=systemd"]
}
[root@k8s-master ~]# systemctl daemon-reload && systemctl restart docker
使用 kubeadm 部署 Kubernetes
安装 kubeadm 和 kubelet
- 引用官方 yum 源：
[root@k8s-node-1 ~]# 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=1
repo_gpgcheck=1
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg
https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
EOF
[root@k8s-node-1 ~]# yum makecache fast
[root@k8s-node-1 ~]# yum install -y kubelet kubeadm kubectl
安装完毕，如图：
[root@k8s-master ~]# systemctl enable kubelet.service
由于网络原因，可能无法访问官方源，这里提供了离线安装 rpm 包。Download
使用 kubelet --help 查看很多参数丢已经 DEPRECATED 了，官方推荐 kubelet 使用 --config 指定配置文件，并在配置文件中指定原来这些参数所配置的内容，参考。
使用 kubeadm 初始化集群
[root@k8s-master ~]# kubeadm init --kubernetes-version=v1.14.0 --pod-network-cidr=10.244.0.0/16 --apiserver-advertise-address=10.211.55.46
- --kubernetes-version：指定 k8s 版本
- --pod-network-cidr：fiannel 作为 pod 网络查件，指定范围
- --apiserver-advertise-address：api-server 所在主机地址
初始化失败了，从报错信息来看，肯定是镜像拉取问题，国内网络拉不下来，可以自行去Docker 仓库找到对应的 pull 下来，再更改 tag。我这里也打包了一下我下载好的镜像，下载好直接使用 docker load 即可，Download。最后再重新初始化。
重新进行初始化操作：
[root@k8s-master ~]# kubeadm init --kubernetes-version=v1.14.0 --pod-network-cidr=10.244.0.0/16 --apiserver-advertise-address=10.211.55.46
[init] Using Kubernetes version: v1.14.0
[preflight] Running pre-flight checks
[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 "front-proxy-ca" certificate and key
[certs] Generating "front-proxy-client" certificate and key
[certs] Generating "etcd/ca" certificate and key
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [k8s-master localhost] and IPs [10.211.55.46 127.0.0.1 ::1]
[certs] Generating "apiserver-etcd-client" certificate and key
[certs] Generating "etcd/server" certificate and key
[certs] etcd/server serving cert is signed for DNS names [k8s-master localhost] and IPs [10.211.55.46 127.0.0.1 ::1]
[certs] Generating "etcd/healthcheck-client" certificate and key
[certs] Generating "ca" certificate and key
[certs] Generating "apiserver-kubelet-client" certificate and key
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [k8s-master kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 10.211.55.46]
[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 17.502257 seconds
[upload-config] storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.14" in namespace kube-system with the configuration for the kubelets in the cluster
[upload-certs] Skipping phase. Please see --experimental-upload-certs
[mark-control-plane] Marking the node k8s-master as control-plane by adding the label "node-role.kubernetes.io/master=''"
[mark-control-plane] Marking the node k8s-master as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[bootstrap-token] Using token: 07v4bz.etn2h9th3i77ytib
[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
Your Kubernetes control-plane 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/
Then you can join any number of worker nodes by running the following on each as root:
kubeadm join 10.211.55.46:6443 --token 07v4bz.etn2h9th3i77ytib \
--discovery-token-ca-cert-hash sha256:4a77cfd6f9e2a16a7a45351369275f102b9986b469d3f9f9865a87050e4bf0dc
观看上方日志，可以发现有这样一些操作：
- [kubelet-start] 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 - 配置用户通过
kubectl访问集群
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
- 新节点加入
kubeadm join 10.211.55.46:6443 --token 07v4bz.etn2h9th3i77ytib \
--discovery-token-ca-cert-hash sha256:4a77cfd6f9e2a16a7a45351369275f102b9986b469d3f9f9865a87050e4bf0dc
查看一下集群状态，确认组件都处于 healthy 状态：
[kubectl@k8s-master root]$ kubectl get cs
NAME STATUS MESSAGE ERROR
controller-manager Healthy ok
scheduler Healthy ok
etcd-0 Healthy {"health":"true"}
集群初始化如果遇到问题可以使用
kubeadm reset进行清理。
安装 Pod Network
查看节点的状态：
[kubectl@k8s-master root]$ kubectl get nodes
NAME STATUS ROLES AGE VERSION
k8s-master NotReady master 16m v1.14.1
k8s-node-1 NotReady <none> 10s v1.14.1
k8s-node-2 NotReady <none> 5s v1.14.1
STATUS 的值都是 NotReady，这是因为网络插件的问题，k8s 网络查件选型有很多种，这里使用网络插件 flannel。
[kubectl@k8s-master ~]$ kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
podsecuritypolicy.extensions/psp.flannel.unprivileged created
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
daemonset.extensions/kube-flannel-ds-amd64 created
daemonset.extensions/kube-flannel-ds-arm64 created
daemonset.extensions/kube-flannel-ds-arm created
daemonset.extensions/kube-flannel-ds-ppc64le created
daemonset.extensions/kube-flannel-ds-s390x created
✨ 如果 Node 有多个网卡的话，参考 issues，目前需要在 kube-flannel.yml 中使用 --iface 参数指定集群主机内网网卡的名称，否则可能会出现 dns 无法解析。需要将 kube-flannel.yml 下载到本地，flanneld 启动参数加上 --iface=<iface-name>
......
containers:
- name: kube-flannel
image: quay.io/coreos/flannel:v0.11.0-amd64
command:
- /opt/bin/flanneld
args:
- --ip-masq
- --kube-subnet-mgr
- --iface=eth1
......
再次查看节点和 Pod 状态，确保都在 Ready/Running 状态：
[kubectl@k8s-master ~]$ kubectl get nodes -o wide
NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME
k8s-master Ready master 20m v1.14.1 10.211.55.46 <none> CentOS Linux 7 (Core) 5.0.10-1.el7.elrepo.x86_64 docker://18.9.5
k8s-node-1 Ready <none> 4m47s v1.14.1 10.211.55.47 <none> CentOS Linux 7 (Core) 5.0.10-1.el7.elrepo.x86_64 docker://18.9.5
k8s-node-2 Ready <none> 4m42s v1.14.1 10.211.55.48 <none> CentOS Linux 7 (Core) 5.0.10-1.el7.elrepo.x86_64 docker://18.9.5
[kubectl@k8s-master ~]$ kubectl get pods -o wide -n kube-system
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
coredns-fb8b8dccf-jr2sp 1/1 Running 0 27m 10.244.0.2 k8s-master <none> <none>
coredns-fb8b8dccf-zhsk9 1/1 Running 0 27m 10.244.1.2 k8s-node-1 <none> <none>
etcd-k8s-master 1/1 Running 0 26m 10.211.55.46 k8s-master <none> <none>
kube-apiserver-k8s-master 1/1 Running 0 26m 10.211.55.46 k8s-master <none> <none>
kube-controller-manager-k8s-master 1/1 Running 0 26m 10.211.55.46 k8s-master <none> <none>
kube-flannel-ds-amd64-gzd5b 1/1 Running 0 7m25s 10.211.55.48 k8s-node-2 <none> <none>
kube-flannel-ds-amd64-hjfjb 1/1 Running 0 7m25s 10.211.55.46 k8s-master <none> <none>
kube-flannel-ds-amd64-ll762 1/1 Running 0 7m25s 10.211.55.47 k8s-node-1 <none> <none>
kube-proxy-ddzjj 1/1 Running 0 11m 10.211.55.47 k8s-node-1 <none> <none>
kube-proxy-sxbf2 1/1 Running 0 27m 10.211.55.46 k8s-master <none> <none>
kube-proxy-tbclz 1/1 Running 0 11m 10.211.55.48 k8s-node-2 <none> <none>
kube-scheduler-k8s-master 1/1 Running 0 26m 10.211.55.46 k8s-master <none> <none>
让 Master 节点参与负载
使用 kubeadm 初始化的集群，出于安全考虑 Pod 不会被调度到 Master Node 上，也就是说 Master Node 不参与工作负载。这是因为当前的 master 节点打上了 node-role.kubernetes.io/master:NoSchedule 的污点：
[kubectl@k8s-master ~]$ kubectl describe node node1 | grep Taint
Taints: node-role.kubernetes.io/master:NoSchedule
如果你想让 Master 节点参与负载，那么去掉这个污点即可：
[kubectl@k8s-master ~]$ kubectl taint nodes node1 node-role.kubernetes.io/master-
node "node1" untainted
测试 DNS
[kubectl@k8s-master ~]$ kubectl run curl --image=radial/busyboxplus:curl -it
kubectl run --generator=deployment/apps.v1 is DEPRECATED and will be removed in a future version. Use kubectl run --generator=run-pod/v1 or kubectl create instead.
If you don't see a command prompt, try pressing enter.
[ root@curl-66bdcf564-q66mn:/ ]$ nslookup kubernetes.default
Server: 10.96.0.10
Address 1: 10.96.0.10 kube-dns.kube-system.svc.cluster.local
Name: kubernetes.default
Address 1: 10.96.0.1 kubernetes.default.svc.cluster.local
从集群中移除节点
在 Master 上执行：
$ kubectl drain k8s-node-1 --delete-local-data --force --ignore-daemonsets
$ kubectl delete node k8s-node-1
在 k8s-node-1 上执行：
$ kubeadm reset
Over！！！
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