本文介绍了如何在 ubuntu 18.04 64 bit 双核 CPU 虚拟机上使用 kubeadm 部署 Kubernetes 1.17.4 集群的过程，网络插件为 flannel v0.11.0，镜像源为阿里云
一、 安装docker
apt-get install docker.io
执行如下命令新建 /etc/docker/daemon.json 文件：
cat > /etc/docker/daemon.json <<-EOF
{
"registry-mirrors": [
"https://a8qh6yqv.mirror.aliyuncs.com",
"http://hub-mirror.c.163.com"
],
"exec-opts": ["native.cgroupdriver=systemd"]
}
EOF
注：
registry-mirrors 为镜像加速器地址。
native.cgroupdriver=systemd 表示使用的 cgroup 驱动为 systemd（k8s 使用此方式），默认为 cgroupfs。修改原因是 kubeadm.conf 中修改k8s的驱动方式不成功。
重启docker，查看 cgroup：
# systemctl restart docker
# docker info | grep -i cgroup
Cgroup Driver: systemd
出现 systemd 表示修改成功。
二、部署 k8s master 主机
k8s的部署分 master 主机和 node 节点。本节为 master 主机。
2.1 关闭swap
编辑 /etc/fstab 文件，注释掉swap分区挂载的行，示例：
# swap was on /dev/sda5 during installation
UUID=aaa38da3-6e60-4e9d-bfc6-7128fd05f1c7 none swapsw 0 0再执行： # swapoff -a
2.2 添加国内k8s源 此处选择阿里云的：
# cat <<EOF > /etc/apt/sources.list.d/kubernetes.list
deb https://mirrors.aliyun.com/kubernetes/apt/ kubernetes-xenial main
EOF
添加key： # cat https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -
如不成功，则先通过一些方法下载：https://packages.cloud.google.com/apt/doc/apt-key.gpg ，放到工程目录。再执行：
# cat apt-key.gpg | sudo apt-key add -
也可以添加Key: sudo curl https://mirrors.aliyun.com/kubernetes/apt/doc/apt-key.gpg |sudo apt-key add -
3.3 更新源
# sudo apt-get update
安装 kubeadm、kubectl、kubelet、kubernetes-cni 等工具。
# sudo apt-get install -y kubeadm kubectl kubelet kubernetes-cni
注1：安装 kubeadm 会自动安装 kubectl、kubelet 和 kubernetes-cni，故只指定 kubeadm 亦可。
注2：本文安装时，得到的版本为1.17.4，kubernetes-cni 为0.7.5。下载文件位于 /var/cache/apt/archives/ 目录中。
3.4 获取部署所需的镜像版本
# sudo kubeadm config images list
输出如下：
W1214 08:46:14.303772 8461 version.go:102] falling back to the local client version: v1.17.4
W1214 08:46:14.304223 8461 validation.go:28] Cannot validate kube-proxy config - no validator is available
W1214 08:46:14.304609 8461 validation.go:28] Cannot validate kubelet config - no validator is available
k8s.gcr.io/kube-apiserver:v1.17.4
k8s.gcr.io/kube-controller-manager:v1.17.4
k8s.gcr.io/kube-scheduler:v1.17.4
k8s.gcr.io/kube-proxy:v1.17.4
k8s.gcr.io/pause:3.1
k8s.gcr.io/etcd:3.4.3-0
k8s.gcr.io/coredns:1.6.5
前面提示的警告信息可不理会。此处是确认本版本 kubeadm 匹配的镜像的版本，因为各组件版本不同可能出现兼容性问题。
3.5 拉取镜像文件。
一般地，国内无法直接下载 k8s.gcr.io 的镜像。方式有二：
1、在初始化k8s时，使用阿里云镜像地址，此地址可以顺利下载，见下初始化。
2、下载好前述镜像。使用如下脚本pullk8s.sh（注意脚本必须添加x属性）：
#!/bin/bash
# 下面的镜像应该去除"k8s.gcr.io/"的前缀，版本换成kubeadm config images list命令获取到的版本
images=(
kube-apiserver:v1.17.4
kube-controller-manager:v1.17.4
kube-scheduler:v1.17.4
kube-proxy:v1.17.4
pause:3.1
etcd:3.4.3-0
coredns:1.6.5
)
for imageName in ${images[@]} ; do
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName k8s.gcr.io/$imageName
docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName
done
拉取：
chmod +x pullk8s.sh
bash pullk8s.sh (或 ./pullk8s.sh)
3.6 网络
设置网络配置：
mkdir -p /etc/cni/net.d
cat >/etc/cni/net.d/10-mynet.conf <<-EOF
{
"cniVersion": "0.3.0",
"name": "mynet",
"type": "bridge",
"bridge": "cni0",
"isGateway": true,
"ipMasq": true,
"ipam": {
"type": "host-local",
"subnet": "10.244.0.0/16",
"routes": [
{"dst": "0.0.0.0/0"}
]
}
}
EOF
cat >/etc/cni/net.d/99-loopback.conf <<-EOF
{
"cniVersion": "0.3.0",
"type": "loopback"
}
EOF
经实践，此步骤不做亦可。
3.7 下载flannel镜像
docker pull quay.io/coreos/flannel:v0.11.0-amd64
注：如果无法下载，需要使用其它方法。
flannel 镜像信息：
# docker images | grep flannel
quay.io/coreos/flannel v0.11.0-amd64 ff281650a721 11 months ago 52.6MB
3.8 初始化
版本一：
sudo kubeadm init --pod-network-cidr=10.244.0.0/16 \
--image-repository registry.aliyuncs.com/google_containers注：
–pod-network-cidr 指定了网络段，后续网络插件会使用到（本文使用 flannel）。
–image-repository 指定了镜像地址，默认为 k8s.gcr.io，此处指定为阿里云镜像地址 registry.aliyuncs.com/google_containers。
注意，其它参数默认。
上述命令等同如下命令：
sudo kubeadm init \
--apiserver-advertise-address=192.168.50.128 \
--image-repository registry.aliyuncs.com/google_containers \
--kubernetes-version v1.17.0 \
--service-cidr=10.1.0.0/16\
--pod-network-cidr=10.244.0.0/16输出：
W0318 14:36:29.662899 9495 validation.go:28] Cannot validate kube-proxy config - no validator is available
W0318 14:36:29.662966 9495 validation.go:28] Cannot validate kubelet config - no validator is available
[init] Using Kubernetes version: v1.17.4
[preflight] Running pre-flight checks
[WARNING Firewalld]: firewalld is active, please ensure ports [6443 10250] are open or your cluster may not function correctly
[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] Starting the kubelet
[certs] Using certificateDir folder "/etc/kubernetes/pki"
[certs] Using existing ca certificate authority
[certs] Using existing apiserver certificate and key on disk
[certs] Using existing apiserver-kubelet-client certificate and key on disk
[certs] Using existing front-proxy-ca certificate authority
[certs] Using existing front-proxy-client certificate and key on disk
[certs] Using existing etcd/ca certificate authority
[certs] Using existing etcd/server certificate and key on disk
[certs] Using existing etcd/peer certificate and key on disk
[certs] Using existing etcd/healthcheck-client certificate and key on disk
[certs] Using existing apiserver-etcd-client certificate and key on disk
[certs] Using the existing "sa" key
[kubeconfig] Using kubeconfig folder "/etc/kubernetes"
[kubeconfig] Using existing kubeconfig file: "/etc/kubernetes/admin.conf"
[kubeconfig] Using existing kubeconfig file: "/etc/kubernetes/kubelet.conf"
[kubeconfig] Using existing kubeconfig file: "/etc/kubernetes/controller-manager.conf"
[kubeconfig] Using existing kubeconfig file: "/etc/kubernetes/scheduler.conf"
[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"
W0318 14:36:31.481612 9495 manifests.go:214] the default kube-apiserver authorization-mode is "Node,RBAC"; using "Node,RBAC"
[control-plane] Creating static Pod manifest for "kube-scheduler"
W0318 14:36:31.517795 9495 manifests.go:214] the default kube-apiserver authorization-mode is "Node,RBAC"; using "Node,RBAC"
[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 18.044383 seconds
[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.17" 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 ubuntu as control-plane by adding the label "node-role.kubernetes.io/master=''"
[mark-control-plane] Marking the node ubuntu as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[bootstrap-token] Using token: ma01mg.38n1fcelg0wk35s3
[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
[kubelet-finalize] Updating "/etc/kubernetes/kubelet.conf" to point to a rotatable kubelet client certificate and key
[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 192.168.50.128:6443 --token ma01mg.38n1fcelg0wk35s3 \
--discovery-token-ca-cert-hash sha256:48a197ee4268416f8a6930418d7b9eb1f31ca3ce5b21240857e253c85161b6b1 版本二，根据前文脚本自行拉取版本：
kubeadm init --pod-network-cidr=10.244.0.0/16
注：在初始化过成功可能遇到的问题：
1、 [ERROR Port-10251]: Port 10250 is in use
解决办法：
重启一下kubeadm： [root@k8s-master ~]# kubeadm reset
如果重启后端口仍然被占用, 查看占用端口的进程：netstat -tunlp | grep 10250
强制杀死占用端口的进程： sudo fuser -k -n tcp 10250
部署成功后 ,根据提示，根据拷贝 admin.conf 文件到当前用户相应目录下。admin.conf 文件后续会使用到（需要拷贝到 node 节点）。
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config初始化时，如不存在则自动下载镜像，初始化后镜像如下：
# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
registry.aliyuncs.com/google_containers/kube-proxy v1.17.4 7d54289267dc 1 days ago 116MB
registry.aliyuncs.com/google_containers/kube-apiserver v1.17.4 0cae8d5cc64c 1 days ago 171MB
registry.aliyuncs.com/google_containers/kube-controller-manager v1.17.4 5eb3b7486872 1 days ago 161MB
registry.aliyuncs.com/google_containers/kube-scheduler v1.17.4 78c190f736b1 1 days ago 94.4MB
registry.aliyuncs.com/google_containers/coredns 1.6.5 70f311871ae1 6 weeks ago 41.6MB
registry.aliyuncs.com/google_containers/etcd 3.4.3-0 303ce5db0e90 8 weeks ago 288MB
registry.aliyuncs.com/google_containers/pause 3.1 da86e6ba6ca1 2 years ago 742kB
此时 pod 状态如下：
# kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-9d85f5447-67qtv 0/1 Pending 0 3h26m
coredns-9d85f5447-cg87c 0/1 Pending 0 3h26m
etcd-ubuntu 1/1 Running 0 3h27m
kube-apiserver-ubuntu 1/1 Running 0 3h27m
kube-controller-manager-ubuntu 1/1 Running 0 3h27m
kube-proxy-chqbq 1/1 Running 0 3h26m
kube-scheduler-ubuntu 1/1 Running 0 3h27m除 coredns 状态为 Pending外，其它 pod 均运行。这是因为没有部署网络插件导致的。本文选用 flannel 。
执行如下命令部署 flannel：
# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
注：
使用 flannel 仓库的 kube-flannel.yml 文件部署。详细可参考该文件。
如果无法访问，则可手动下载 https://github.com/coreos/flannel/blob/master/Documentation/kube-flannel.yml 文件到当前目录，再执行 kubectl apply -f kube-flannel.yml 命令。
# kubectl apply -f kube-flannel.yml
podsecuritypolicy.policy/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.apps/kube-flannel-ds-amd64 created
daemonset.apps/kube-flannel-ds-arm64 created
daemonset.apps/kube-flannel-ds-arm created
daemonset.apps/kube-flannel-ds-ppc64le created
daemonset.apps/kube-flannel-ds-s390x created
三、node 节点
k8s的部署分 master 主机和 node 节点。本节为 node 节点。
3.1 前置条件
在 node 节点上操作。
1、安装kubeadm，见前述。
2、下载flannel镜像，见前述（如果不预先下载，在加入集群时会自动下载）。
3、将主机的 /etc/kubernetes/admin.conf 文件拷贝到 node 节点的 /etc/kubernetes/ 目录。（注：在 master 节点使用 scp 命令即可，kubernetes 不存在自行创建）
3.2 加入集群
此时，k8s服务还没有启动。执行如下命令以加入节点：
kubeadm join 192.168.50.128:6443 --token 1rpp8b.axfud1xrsvx4q8nw \
--discovery-token-ca-cert-hash sha256:6bf952d45bbdc121fa90583eac33f11f0a3f4b491f29996a56fc289363843e3c
提示信息如下：
[preflight] WARNING: JoinControlPane.controlPlane settings will be ignored when control-plane flag is not set.
[preflight] Running pre-flight checks
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
[kubelet-start] Downloading configuration for the kubelet from the "kubelet-config-1.17" ConfigMap in the kube-system namespace
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Starting the kubelet
[kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap...
This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.
Run 'kubectl get nodes' on the control-plane to see this node join the cluster.
加入群集过程中会下载必须的k8s镜像，注意，master 主机已经指定为阿里源的源，所以 node 节点上亦是该源。
REPOSITORY TAG IMAGE ID CREATED SIZE
registry.aliyuncs.com/google_containers/kube-proxy v1.17.0 7d54289267dc 2 weeks ago 116MB
registry.aliyuncs.com/google_containers/coredns 1.6.5 70f311871ae1 7 weeks ago 41.6MB
quay.io/coreos/flannel v0.11.0-amd64 ff281650a721 11 months ago 52.6MB
registry.aliyuncs.com/google_containers/pause 3.1 da86e6ba6ca1 2 years ago 742kB成功加入后，本节点有如下相关服务在运行：
# ps aux | grep kube
root 3269 1.6 4.2 754668 86784 ? Ssl Dec20 18:34 /usr/bin/kubelet --bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf --kubeconfig=/etc/kubernetes/kubelet.conf --config=/var/lib/kubelet/config.yaml --cgroup-driver=cgroupfs --network-plugin=cni --pod-infra-container-image=registry.aliyuncs.com/google_containers/pause:3.1
root 3632 0.1 1.1 140104 22412 ? Ssl Dec20 2:14 /usr/local/bin/kube-proxy --config=/var/lib/kube-proxy/config.conf --hostname-override=node
root 4385 0.0 1.6 407356 33704 ? Ssl Dec20 0:51 /opt/bin/flanneld --ip-masq --kube-subnet-mgr
root 121292 0.0 0.0 14228 1032 pts/0 S+ 00:33 0:00 grep --color=auto kube
主要有 kubelet、kube-proxy、flanneld，等。
docker 容器列表如下：
# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
2fde9bb78fd7 ff281650a721 "/opt/bin/flanneld -…" 7 minutes ago Up 7 minutes k8s_kube-flannel_kube-flannel-ds-amd64-28p6z_kube-system_f40a2875-70eb-468b-827d-fcb59be3416b_1
aa7ca3d5825e registry.aliyuncs.com/google_containers/kube-proxy "/usr/local/bin/kube…" 8 minutes ago Up 8 minutes k8s_kube-proxy_kube-proxy-n6xv5_kube-system_3df8b7ae-e5b8-4256-9857-35bd24f7e025_0
ac61ed8d7295 registry.aliyuncs.com/google_containers/pause:3.1 "/pause" 8 minutes ago Up 8 minutes k8s_POD_kube-flannel-ds-amd64-28p6z_kube-system_f40a2875-70eb-468b-827d-fcb59be3416b_0
423f9e42c082 registry.aliyuncs.com/google_containers/pause:3.1 "/pause" 8 minutes ago Up 8 minutes k8s_POD_kube-proxy-n6xv5_kube-system_3df8b7ae-e5b8-4256-9857-35bd24f7e025_0
查看 flannel 网络信息：
# cat /run/flannel/subnet.env
FLANNEL_NETWORK=10.244.0.0/16
FLANNEL_SUBNET=10.244.1.1/24
FLANNEL_MTU=1450
FLANNEL_IPMASQ=true
查看本机 IP 信息：
# ifconfig
五、验证
在 master 节点执行：
# kubectl get nodes
NAME STATUS ROLES AGE VERSION
node Ready <none> 17m v1.17.0
ubuntu Ready master 5h11m v1.17.0
可以看到两台机器已为 Ready 状态。node 机器由 NotReady 变为 Ready，耗时大约 10 余秒。
使用 busybox 镜像简单测试 pod。在 master 节点执行：
# kubectl run -i --tty busybox --image=latelee/busybox --restart=Never -- sh
稍等片刻，即可进入 busybox 命令行：
# uname -a
Linux busybox 4.4.0-21-generic #37-Ubuntu SMP Mon Apr 18 18:33:37 UTC 2016 x86_64 GNU/Linux
另起命令行，查看 pod 运行状态：
# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
busybox 1/1 Running 0 74s 10.244.1.4 node <none> <none>
可以看到 pod 为 Running 状态，运行在 node 上。
在 node 节点上查看：
# docker ps | grep busybox
ba5d1a480294 latelee/busybox "sh" 2 minutes ago Up 2 minutes k8s_busybox_busybox_default_20d757f7-8ea7-4e51-93fc-514029065a59_0
8c643171ac09 registry.aliyuncs.com/google_containers/pause:3.1 "/pause" 2 minutes ago Up 2 minutes k8s_POD_busybox_default_20d757f7-8ea7-4e51-93fc-514029065a59_0
此时在 master 节点退出 busybox， pod 依旧存在，但不是 READY 状态，node 主机也没有 busybox 容器运行。
验证通过，k8s部署成功。
参考文档：https://blog.csdn.net/subfate/article/details/103774072