0. 概要
使用kubeadm搭建一个单节点kubernets实例,仅供学习. 运行环境和软件概要如下:
| ~ |
版本 |
备注 |
| OS |
Ubuntu 18.0.4 |
192.168.132.152 my.servermaster.local/192.168.132.154 my.worker01.local |
| Docker |
18.06.1~ce~3-0~ubuntu |
k8s最新版(1.12.3)支持的最高版本, 必须固定 |
| Kubernetes |
1.12.3 |
目标软件 |
以上系统和软件基本是2018.11截止最新的状态, 其中docker需要注意必须安装k8s支持到的版本.
1. 安装步骤
swapoff -a
- 安装运行时, 默认使用docker, 安装docker即可
apt-get install docker-ce=18.06.1~ce~3-0~ubuntu
- 安装kubeadm 一下命令和官网的命令一致, 但是是包源改为阿里云
apt-get update && apt-get install -y apt-transport-https
curl -s https://mirrors.aliyun.com/kubernetes/apt/doc/apt-key.gpg | apt-key add -
cat <<EOF >/etc/apt/sources.list.d/kubernetes.list
deb https://mirrors.aliyun.com/kubernetes/apt/ kubernetes-xenial main
EOF
apt-get update
apt-get install -y kubelet kubeadm kubectl
apt-mark hold kubelet kubeadm kubectl
2. 使用kubeadm创建集群
2.1 准备镜像
因为国内是访问不到k8s.gcr.io所以需要将需要的镜像提前下载, 这次采用从阿里云镜像仓库下载, 并修改下载后的镜像tag为k8s.gcr.io
# a. 查看都需要哪些镜像需要下载
kubeadm config images list --kubernetes-version=v1.12.3
k8s.gcr.io/kube-apiserver:v1.12.3
k8s.gcr.io/kube-controller-manager:v1.12.3
k8s.gcr.io/kube-scheduler:v1.12.3
k8s.gcr.io/kube-proxy:v1.12.3
k8s.gcr.io/pause:3.1
k8s.gcr.io/etcd:3.2.24
k8s.gcr.io/coredns:1.2
# b. 创建一个自动处理脚本下载镜像->重新tag->删除老tag
vim ./load_images.sh
#!/bin/bash
### config the image map
declare -A images map=()
images["k8s.gcr.io/kube-apiserver:v1.12.3"]="registry.cn-hangzhou.aliyuncs.com/google_containers/kube-apiserver:v1.12.3"
images["k8s.gcr.io/kube-controller-manager:v1.12.3"]="registry.cn-hangzhou.aliyuncs.com/google_containers/kube-controller-manager:v1.12.3"
images["k8s.gcr.io/kube-scheduler:v1.12.3"]="registry.cn-hangzhou.aliyuncs.com/google_containers/kube-scheduler:v1.12.3"
images["k8s.gcr.io/kube-proxy:v1.12.3"]="registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy:v1.12.3"
images["k8s.gcr.io/pause:3.1"]="registry.cn-hangzhou.aliyuncs.com/google_containers/pause:3.1"
images["k8s.gcr.io/etcd:3.2.24"]="registry.cn-hangzhou.aliyuncs.com/google_containers/etcd:3.2.24"
images["k8s.gcr.io/coredns:1.2.2"]="registry.cn-hangzhou.aliyuncs.com/google_containers/coredns:1.2.2"
### re-tag foreach
for key in ${!images[@]}
do
docker pull ${images[$key]}
docker tag ${images[$key]} $key
docker rmi ${images[$key]}
done
### check
docker images
# c. 执行脚本准镜像
sudo chmod +x load_images.sh
./load_images.sh
2.2 初始化集群(master)
初始化需要指定至少两个参数:
- kubernetes-version: 方式kubeadm访问外网获取版本
- pod-network-cidr: flannel网络插件配置需要
### 执行初始化命令
sudo kubeadm init --kubernetes-version=v1.12.3 --pod-network-cidr=10.244.0.0/16
### 最后的结果如下
... ...
Your Kubernetes master 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/
You can now join any number of machines by running the following on each node
as root:
kubeadm join 192.168.132.152:6443 --token ymny55.4jlbbkxiggmn9ezh --discovery-token-ca-cert-hash sha256:70265fafdb22d524c15616543d0b76527c686329221340b3b8da3652abed46b9
2.3 根据成功信息配置非管理员账号使用kubectl
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
使用非root账号查看节点情况:
kubectl get nodes
NAME STATUS ROLES AGE VERSION
servermaster NotReady master 28m v1.12.3
发现有一个master节点, 但是状态是NotReady, 这里需要做一个决定:
如果希望是单机则执行如下
kubectl taint nodes --all node-role.kubernetes.io/master-
如果希望搭建继续, 则继续后续步骤, 此时主节点状态可以忽略.
2.4 应用网络插件
查看kube-flannel.yml文件内容, 复制到本地文件避免terminal无法远程获取
kubectl apply -f kube-flannel.yml
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
2.5 新建worker节点
worker节点新建参考[1. 安装步骤]在另外一台服务器上新建即可, worker节点不用准备2.1~2.3及之后的所有步骤, 仅需完成基本安装, 安装完毕进入新的worker节点, 执行上一步最后得到join命令:
kubeadm join 192.168.132.152:6443 --token ymny55.4jlbbkxiggmn9ezh --discovery-token-ca-cert-hash sha256:70265fafdb22d524c15616543d0b76527c686329221340b3b8da3652abed46b9
... ...
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 master to see this node join the cluster.
2.6 检查集群(1 master, 1 worker)
kubectl get nodes
NAME STATUS ROLES AGE VERSION
servermaster Ready master 94m v1.12.3
worker01 Ready <none> 54m v1.12.3
2.7 创建dashboard
复制kubernetes-dashboard.yaml内容到本地文件, 方式命令行无法访问远程文件, 编辑最后一个配置Dashboard Service, 增加type和nodePort, 结果如下:
# ------------------- Dashboard Service ------------------- #
kind: Service
apiVersion: v1
metadata:
labels:
k8s-app: kubernetes-dashboard
name: kubernetes-dashboard
namespace: kube-system
spec:
ports:
- port: 443
targetPort: 8443
nodePort: 30000
type: NodePort
selector:
k8s-app: kubernetes-dashboard
在master节点执行创建dashboard服务的命令:
kubectl create -f kubernetes-dashboard.yaml
secret/kubernetes-dashboard-certs created
serviceaccount/kubernetes-dashboard created
role.rbac.authorization.k8s.io/kubernetes-dashboard-minimal created
rolebinding.rbac.authorization.k8s.io/kubernetes-dashboard-minimal created
deployment.apps/kubernetes-dashboard created
service/kubernetes-dashboard created
浏览器输入worker节点ip和端口使用https访问如下:https://my.worker01.local:30000/#!/login 即可以验证dashboard是否安装成功.
2.8 登录Dashboard
通过kubectl获取secret,然后在获取详细的token,复制到上一步中登录页选择Token(令牌), 即可以登录
### 查看秘钥, 列出所有kube-system命名空间下秘钥
kubectl -n kube-system get secret
NAME TYPE DATA AGE
clusterrole-aggregation-controller-token-vxzmt kubernetes.io/service-account-token 3 10h
### 查看token, 这里选择clusterrole-aggregation-controller-token-*****的秘钥
kubectl -n kube-system describe secret clusterrole-aggregation-controller-token-vxzmt
Name: clusterrole-aggregation-controller-token-vxzmt
Namespace: kube-system
Labels: <none>
Annotations: kubernetes.io/service-account.name: clusterrole-aggregation-controller
kubernetes.io/service-account.uid: dfb9d9c3-f646-11e8-9861-000c29b7e604
Type: kubernetes.io/service-account-token
Data
====
ca.crt: 1025 bytes
namespace: 11 bytes
token: eyJhbGciOiJSUzI1NiIsImtpZCI6IiJ9.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.MfjiMrmyKl1GUci1ivD5RNrzo_s6wxXwFzgM_3NIAmTCfRQreYdhat3yyd6agaCLpUResnNC0ZGRi4CBs_Jgjqkovhb80V05_YVIvCrlf7xHxBKEtGfkJ-qLDvtAwR5zrXNNd0Ge8hTRxw67gZ3lGMkPpw5nfWmc0rzk90xTTQD1vAtrHMvxjr3dVXph4rT8GNuCSXA_J6o2AwYUbaKCc2ugdx8t8zX6oFJfVcw0ZNYYYIyxoXzzfhdppORtKR9t9v60KsI_-q0TxY-TU-JBtzUJU-hL6lB5MOgoBWpbQiV-aG8Ov74nDC54-DH7EhYEzzsLci6uUQCPlHNvLo_J2A
![]()
3. 遇到问题
-
master搭建好了, worker也join了get nodes发现还是NotReady状态
原因: 太复杂说不清楚任然是一个k8s issue, 查看issue基本可以确定是cni(Container Network Interface)问题,而flannel覆盖修改了这个问题
解决方法: 安装flannel插件(kubectl apply -f kube-flannel.yml)
-
配置错误重新开始搭建集群
解决方案: kubeadm reset
-
不能访问dashboard
原因: Back-off pulling image "k8s.gcr.io/kubernetes-dashboard-amd64:v1.10.0
解决方案:
-
修改 kubernetes-dashboard-ce.yaml 文件中的 k8s.gcr.io/kubernetes-dashboard-amd64:v1.10.0 为 registry.cn-hangzhou.aliyuncs.com/google_containers/kubernetes-dashboard-amd64:v1.10.0
-
提前下载好镜像并配置好tag, 注意下载的位置worker节点, 可以通过: kubectl describe pod kubernetes-dashboard-85477d54d7-wzt7 -n kube-system 查看比较具体的信息
-
如何增加token失效时间
原因: 默认15分钟
解决方法:
- 如果创建dashboard前: 可以修改kubernetes-dashboard.yaml文件中Dashboard Deployment部分关于containers的args部分添加一行: - --token-ttl=86400 即可,数字自定义单位是秒 如下:
... ...
- name: kubernetes-dashboard
image: registry.cn-hangzhou.aliyuncs.com/google_containers/kubernetes-dashboard-amd64:v1.10.0
ports:
- containerPort: 8443
protocol: TCP
args:
- --auto-generate-certificates
- --token-ttl=86400
# Uncomment the following line to manually specify Kubernetes API server Host
# If not specified, Dashboard will attempt to auto discover the API server and connect
# to it. Uncomment only if the default does not work.
# - --apiserver-host=http://my-address:port
volumeMounts:
... ...
- 如果创建dashboard后: kubectl -n kube-system edit deployment kubernetes-dashboard, 在Deployment部分关于containers的args部分添加一行: - --token-ttl=86400 即可, 和创建前修改一样的方式一样
4. 效率&技巧
4.1 kubeadm 自动完成
使用 kubeadm completion --help 查看使用详情,这里直接贴出bash的自动完成命令
kubeadm completion bash > ~/.kube/kubeadm_completion.bash.inc
printf "\n# Kubeadm shell completion\nsource '$HOME/.kube/kubeadm_completion.bash.inc'\n" >> $HOME/.bash_profile
source $HOME/.bash_profile
4.2 kubectl 自动完成
使用 kubectl completion --help 查看使用详情,这里直接贴出bash的自动完成命令, 注意第二行命令不要一次性复制,先复制第一行printf再复制剩余.
kubectl completion bash > ~/.kube/completion.bash.inc
printf "
# Kubectl shell completion
source '$HOME/.kube/completion.bash.inc'
" >> $HOME/.bash_profile
source $HOME/.bash_profile
创建 secret, 然后增加添加 imagePullSecrets 配置在指定image的地方. 创建和查看secret如下:
kubectl create secret docker-registry regcred --docker-server=registry.domain.cn:5001 --docker-username=xxxxx --docker-password=xxxxx --docker-email=jimmy.w@aliyun.com
kubectl get secret regcred --output=yaml
kubectl get secret regcred --output="jsonpath={.data.\.dockerconfigjson}" | base64 --decode
配置 imagePullSecrets 如下:
... ...
containers:
- name: mirage
image: registry.domain.cn:5001/mirage:latest
imagePullSecrets:
- name: regcred
ports:
- containerPort: 3008
protocol: TCP
volumeMounts:
... ...
如果有一些特别的入口或者以前放置到/etc/hosts中的可以通过配置hostAliases进行配置, 作用和本地的hosts一样, 且这些hostAlieas配置会放置到容器/etc/hosts中, 具体使用如下:
apiVersion: v1
kind: Pod
metadata:
name: hostaliases-pod
spec:
hostAliases:
- ip: "127.0.0.1"
hostnames:
- "foo.local"
- "bar.local"
- ip: "10.1.2.3"
hostnames:
- "foo.remote"
- "bar.remote"
containers:
- name: cat-hosts
image: busybox
command:
- cat
args:
- "/etc/hosts"
5. 参考资料
安装kuadmin相关:
创建集群相关:
