一、如何从Kubernetes集群中移除Node
比如从集群中移除k8s-node03这个Node节点，做法如下：
1）先在master节点查看Node情况
[root@k8s-master01 ~]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
k8s-node01 Ready <none> 47d v1.14.2
k8s-node02 Ready <none> 47d v1.14.2
k8s-node03 Ready <none> 47d v1.14.2 2）接着查看下pod情况
[root@k8s-master01 ~]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
dnsutils-ds-5sc4z 1/1 Running 963 40d 172.30.56.3 k8s-node02 <none> <none>
dnsutils-ds-h546r 1/1 Running 963 40d 172.30.72.5 k8s-node03 <none> <none>
dnsutils-ds-jx5kx 1/1 Running 963 40d 172.30.88.4 k8s-node01 <none> <none>
kevin-nginx 1/1 Running 0 27d 172.30.72.11 k8s-node03 <none> <none>
my-nginx-5dd67b97fb-69gvm 1/1 Running 0 40d 172.30.72.4 k8s-node03 <none> <none>
my-nginx-5dd67b97fb-8j4k6 1/1 Running 0 40d 172.30.88.3 k8s-node01 <none> <none>
nginx-7db9fccd9b-dkdzf 1/1 Running 0 27d 172.30.88.8 k8s-node01 <none> <none>
nginx-7db9fccd9b-t8njb 1/1 Running 0 27d 172.30.72.10 k8s-node03 <none> <none>
nginx-7db9fccd9b-vrp9f 1/1 Running 0 27d 172.30.56.6 k8s-node02 <none> <none>
nginx-ds-4lf8z 1/1 Running 0 41d 172.30.56.2 k8s-node02 <none> <none>
nginx-ds-6kfsw 1/1 Running 0 41d 172.30.72.2 k8s-node03 <none> <none>
nginx-ds-xqdgw 1/1 Running 0 41d 172.30.88.2 k8s-node01 <none> <none> 3）*k8s-node03这个node节点，排干该node节点上的pod资源
[root@k8s-master01 ~]# kubectl drain k8s-node03 --delete-local-data --force --ignore-daemonsets
node/k8s-node03 cordoned
WARNING: deleting Pods not managed by ReplicationController, ReplicaSet, Job, DaemonSet or StatefulSet: default/kevin-nginx; ignoring DaemonSet-managed Pods: default/dnsutils-ds-h546r, default/nginx-ds-6kfsw, kube-system/node-exporter-zmb68
evicting pod "metrics-server-54997795d9-rczmc"
evicting pod "kevin-nginx"
evicting pod "nginx-7db9fccd9b-t8njb"
evicting pod "coredns-5b969f4c88-pd5js"
evicting pod "kubernetes-dashboard-7976c5cb9c-4jpzb"
evicting pod "my-nginx-5dd67b97fb-69gvm"
pod/my-nginx-5dd67b97fb-69gvm evicted
pod/coredns-5b969f4c88-pd5js evicted
pod/nginx-7db9fccd9b-t8njb evicted
pod/kubernetes-dashboard-7976c5cb9c-4jpzb evicted
pod/kevin-nginx evicted
pod/metrics-server-54997795d9-rczmc evicted
node/k8s-node03 evicted 4）接着删除k8s-node03这个节点
[root@k8s-master01 ~]# kubectl delete node k8s-node03
node "k8s-node03" deleted 5）再查看pod情况，发现原来在k8s-node03上的pod已经调度到其他留存的node节点上了
[root@k8s-master01 ~]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
dnsutils-ds-5sc4z 1/1 Running 963 40d 172.30.56.3 k8s-node02 <none> <none>
dnsutils-ds-jx5kx 1/1 Running 963 40d 172.30.88.4 k8s-node01 <none> <none>
my-nginx-5dd67b97fb-8j4k6 1/1 Running 0 40d 172.30.88.3 k8s-node01 <none> <none>
my-nginx-5dd67b97fb-kx2pc 1/1 Running 0 98s 172.30.56.7 k8s-node02 <none> <none>
nginx-7db9fccd9b-7vbhq 1/1 Running 0 98s 172.30.88.7 k8s-node01 <none> <none>
nginx-7db9fccd9b-dkdzf 1/1 Running 0 27d 172.30.88.8 k8s-node01 <none> <none>
nginx-7db9fccd9b-vrp9f 1/1 Running 0 27d 172.30.56.6 k8s-node02 <none> <none>
nginx-ds-4lf8z 1/1 Running 0 41d 172.30.56.2 k8s-node02 <none> <none>
nginx-ds-xqdgw 1/1 Running 0 41d 172.30.88.2 k8s-node01 <none> <none> [root@k8s-master01 ~]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
k8s-node01 Ready <none> 47d v1.14.2
k8s-node02 Ready <none> 47d v1.14.2 6）最后在k8s-node03节点上执行清理操作：
[root@k8s-node03 ~]# systemctl stop kubelet kube-proxy flanneld docker [root@k8s-node03 ~]# source /opt/k8s/bin/environment.sh
[root@k8s-node03 ~]# mount | grep "${K8S_DIR}" | awk '{print $3}'|xargs sudo umount
[root@k8s-node03 ~]# rm -rf ${K8S_DIR}/kubelet
[root@k8s-node03 ~]# rm -rf ${DOCKER_DIR}
[root@k8s-node03 ~]# rm -rf /var/run/flannel/
[root@k8s-node03 ~]# rm -rf /var/run/docker/
[root@k8s-node03 ~]# rm -rf /etc/systemd/system/{kubelet,docker,flanneld,kube-nginx}.service
[root@k8s-node03 ~]# rm -rf /opt/k8s/bin/*
[root@k8s-node03 ~]# rm -rf /etc/flanneld/cert /etc/kubernetes/cert [root@k8s-node03 ~]# iptables -F && iptables -X && iptables -F -t nat && iptables -X -t nat
[root@k8s-node03 ~]# ip link del flannel.1
[root@k8s-node03 ~]# ip link del docker0
二、如何向Kubernetes集群中加入Node节点
比如将之前移除的k8s-node03节点重新加入到k8s集群中 （下面操作都在k8s-master01节点上完成）
1）修改变量脚本文件/opt/k8s/bin/environment.sh里的NODE节点为k8s-node03节点，然后进行分发。
[root@k8s-master01 ~]# cp /opt/k8s/bin/environment.sh /opt/k8s/bin/environment.sh.bak1
[root@k8s-master01 ~]# vim /opt/k8s/bin/environment.sh
........
# 集群中所有node节点集群IP数组
export NODE_NODE_IPS=(172.16.60.246)
# 集群中node节点IP对应的主机名数组
export NODE_NODE_NAMES=(k8s-node03) [root@k8s-master01 ~]# diff /opt/k8s/bin/environment.sh /opt/k8s/bin/environment.sh.bak1
17c17
< export NODE_NODE_IPS=(172.16.60.246)
---
> export NODE_NODE_IPS=(172.16.60.244 172.16.60.245 172.16.60.246)
19c19
< export NODE_NODE_NAMES=(k8s-node03)
---
> export NODE_NODE_NAMES=(k8s-node01 k8s-node02 k8s-node03) 2）将之前在k8s-master01节点上生产的证书文件分发到新加入的node节点上
[root@k8s-master01 ~]# cd /opt/k8s/work/
[root@k8s-master01 work]# source /opt/k8s/bin/environment.sh
[root@k8s-master01 work]# for node_node_ip in ${NODE_NODE_IPS[@]}
do
echo ">>> ${node_node_ip}"
ssh root@${node_node_ip} "mkdir -p /etc/kubernetes/cert"
scp ca*.pem ca-config.json root@${node_node_ip}:/etc/kubernetes/cert
done 3) Flannel容器网络
[root@k8s-master01 work]# cd /opt/k8s/work
[root@k8s-master01 work]# source /opt/k8s/bin/environment.sh
[root@k8s-master01 work]# for node_node_ip in ${NODE_NODE_IPS[@]}
do
echo ">>> ${node_node_ip}"
scp flannel/{flanneld,mk-docker-opts.sh} root@${node_node_ip}:/opt/k8s/bin/
ssh root@${node_node_ip} "chmod +x /opt/k8s/bin/*"
done [root@k8s-master01 work]# for node_node_ip in ${NODE_NODE_IPS[@]}
do
echo ">>> ${node_node_ip}"
ssh root@${node_node_ip} "mkdir -p /etc/flanneld/cert"
scp flanneld*.pem root@${node_node_ip}:/etc/flanneld/cert
done [root@k8s-master01 work]# for node_node_ip in ${NODE_NODE_IPS[@]}
do
echo ">>> ${node_node_ip}"
scp flanneld.service root@${node_node_ip}:/etc/systemd/system/
done [root@k8s-master01 work]# for node_node_ip in ${NODE_NODE_IPS[@]}
do
echo ">>> ${node_node_ip}"
ssh root@${node_node_ip} "systemctl daemon-reload && systemctl enable flanneld && systemctl restart flanneld"
done [root@k8s-master01 work]# for node_node_ip in ${NODE_NODE_IPS[@]}
do
echo ">>> ${node_node_ip}"
ssh root@${node_node_ip} "systemctl status flanneld|grep Active"
done 4）部署node节点运行组件 -> 安装依赖包
[root@k8s-master01 ~]# source /opt/k8s/bin/environment.sh
[root@k8s-master01 ~]# for node_node_ip in ${NODE_NODE_IPS[@]}
do
echo ">>> ${node_node_ip}"
ssh root@${node_node_ip} "yum install -y epel-release"
ssh root@${node_node_ip} "yum install -y conntrack ipvsadm ntp ntpdate ipset jq iptables curl sysstat libseccomp && modprobe ip_vs "
done -> 部署docker组件
[root@k8s-master01 work]# cd /opt/k8s/work
[root@k8s-master01 work]# source /opt/k8s/bin/environment.sh
[root@k8s-master01 work]# for node_node_ip in ${NODE_NODE_IPS[@]}
do
echo ">>> ${node_node_ip}"
scp docker/* root@${node_node_ip}:/opt/k8s/bin/
ssh root@${node_node_ip} "chmod +x /opt/k8s/bin/*"
done [root@k8s-master01 work]# for node_node_ip in ${NODE_NODE_IPS[@]}
do
echo ">>> ${node_node_ip}"
scp docker.service root@${node_node_ip}:/etc/systemd/system/
done [root@k8s-master01 work]# for node_node_ip in ${NODE_NODE_IPS[@]}
do
echo ">>> ${node_node_ip}"
ssh root@${node_node_ip} "mkdir -p /etc/docker/ ${DOCKER_DIR}/{data,exec}"
scp docker-daemon.json root@${node_node_ip}:/etc/docker/daemon.json
done [root@k8s-master01 work]# for node_node_ip in ${NODE_NODE_IPS[@]}
do
echo ">>> ${node_node_ip}"
ssh root@${node_node_ip} "systemctl daemon-reload && systemctl enable docker && systemctl restart docker"
done [root@k8s-master01 work]# for node_node_ip in ${NODE_NODE_IPS[@]}
do
echo ">>> ${node_node_ip}"
ssh root@${node_node_ip} "systemctl status docker|grep Active"
done [root@k8s-master01 work]# for node_node_ip in ${NODE_NODE_IPS[@]}
do
echo ">>> ${node_node_ip}"
ssh root@${node_node_ip} "/usr/sbin/ip addr show flannel.1 && /usr/sbin/ip addr show docker0"
done -> 部署kubelet组件
[root@k8s-master01 ~]# cd /opt/k8s/work
[root@k8s-master01 work]# source /opt/k8s/bin/environment.sh
[root@k8s-master01 work]# for node_node_ip in ${NODE_NODE_IPS[@]}
do
echo ">>> ${node_node_ip}"
scp kubernetes/server/bin/kubelet root@${node_node_ip}:/opt/k8s/bin/
ssh root@${node_node_ip} "chmod +x /opt/k8s/bin/*"
done -> 创建token（之前创建的已经过期，token有效期只有24h，即有效期只有一天！）
[root@k8s-master01 work]# cd /opt/k8s/work
[root@k8s-master01 work]# source /opt/k8s/bin/environment.sh
[root@k8s-master01 work]# for node_node_name in ${NODE_NODE_NAMES[@]}
do
echo ">>> ${node_node_name}" # 创建 token
export BOOTSTRAP_TOKEN=$(kubeadm token create \
--description kubelet-bootstrap-token \
--groups system:bootstrappers:${node_node_name} \
--kubeconfig ~/.kube/config) # 设置集群参数
kubectl config set-cluster kubernetes \
--certificate-authority=/etc/kubernetes/cert/ca.pem \
--embed-certs=true \
--server=${KUBE_APISERVER} \
--kubeconfig=kubelet-bootstrap-${node_node_name}.kubeconfig # 设置客户端认证参数
kubectl config set-credentials kubelet-bootstrap \
--token=${BOOTSTRAP_TOKEN} \
--kubeconfig=kubelet-bootstrap-${node_node_name}.kubeconfig # 设置上下文参数
kubectl config set-context default \
--cluster=kubernetes \
--user=kubelet-bootstrap \
--kubeconfig=kubelet-bootstrap-${node_node_name}.kubeconfig # 设置默认上下文
kubectl config use-context default --kubeconfig=kubelet-bootstrap-${node_node_name}.kubeconfig
done 查看 kubeadm 为各新节点创建的 token：
[root@k8s-master01 work]# kubeadm token list --kubeconfig ~/.kube/config
TOKEN TTL EXPIRES USAGES DESCRIPTION EXTRA GROUPS
sdwq5g.llzr9ytm32h1mnh1 23h 2019-08-06T11:47:47+08:00 authentication,signing kubelet-bootstrap-token system:bootstrappers:k8s-node03 [root@k8s-master01 work]# kubectl get secrets -n kube-system|grep bootstrap-token
bootstrap-token-sdwq5g bootstrap.kubernetes.io/token 7 77s [root@k8s-master01 work]# cd /opt/k8s/work
[root@k8s-master01 work]# source /opt/k8s/bin/environment.sh
[root@k8s-master01 work]# for node_node_name in ${NODE_NODE_NAMES[@]}
do
echo ">>> ${node_node_name}"
scp kubelet-bootstrap-${node_node_name}.kubeconfig root@${node_node_name}:/etc/kubernetes/kubelet-bootstrap.kubeconfig
done -> 分发 bootstrap kubeconfig 文件到新增node节点
[root@k8s-master01 work]# cd /opt/k8s/work
[root@k8s-master01 work]# source /opt/k8s/bin/environment.sh
[root@k8s-master01 work]# for node_node_name in ${NODE_NODE_NAMES[@]}
do
echo ">>> ${node_node_name}"
scp kubelet-bootstrap-${node_node_name}.kubeconfig root@${node_node_name}:/etc/kubernetes/kubelet-bootstrap.kubeconfig
done -> 分发 kubelet 参数配置文件
[root@k8s-master01 work]# cd /opt/k8s/work
[root@k8s-master01 work]# source /opt/k8s/bin/environment.sh
[root@k8s-master01 work]# for node_node_ip in ${NODE_NODE_IPS[@]}
do
echo ">>> ${node_node_ip}"
sed -e "s/##NODE_NODE_IP##/${node_node_ip}/" kubelet-config.yaml.template > kubelet-config-${node_node_ip}.yaml.template
scp kubelet-config-${node_node_ip}.yaml.template root@${node_node_ip}:/etc/kubernetes/kubelet-config.yaml
done -> 分发 kubelet systemd unit 文件
[root@k8s-master01 work]# cd /opt/k8s/work
[root@k8s-master01 work]# source /opt/k8s/bin/environment.sh
[root@k8s-master01 work]# for node_node_name in ${NODE_NODE_NAMES[@]}
do
echo ">>> ${node_node_name}"
sed -e "s/##NODE_NODE_NAME##/${node_node_name}/" kubelet.service.template > kubelet-${node_node_name}.service
scp kubelet-${node_node_name}.service root@${node_node_name}:/etc/systemd/system/kubelet.service
done -> 启动 kubelet 服务
[root@k8s-master01 work]# source /opt/k8s/bin/environment.sh
[root@k8s-master01 work]# for node_node_ip in ${NODE_NODE_IPS[@]}
do
echo ">>> ${node_node_ip}"
ssh root@${node_node_ip} "mkdir -p ${K8S_DIR}/kubelet/kubelet-plugins/volume/exec/"
ssh root@${node_node_ip} "/usr/sbin/swapoff -a"
ssh root@${node_node_ip} "systemctl daemon-reload && systemctl enable kubelet && systemctl restart kubelet"
done -> 部署 kube-proxy 组件
[root@k8s-master01 ~]# cd /opt/k8s/work
[root@k8s-master01 work]# source /opt/k8s/bin/environment.sh
[root@k8s-master01 work]# for node_node_ip in ${NODE_NODE_IPS[@]}
do
echo ">>> ${node_node_ip}"
scp kubernetes/server/bin/kube-proxy root@${node_node_ip}:/opt/k8s/bin/
ssh root@${node_node_ip} "chmod +x /opt/k8s/bin/*"
done [root@k8s-master01 work]# for node_node_name in ${NODE_NODE_NAMES[@]}
do
echo ">>> ${node_node_name}"
scp kube-proxy.kubeconfig root@${node_node_name}:/etc/kubernetes/
done =================================================================================================================================================
特别注意（如果是完全新增node节点，则这里需要添加下面操作）：
由于这里是恢复之前移除的k8s-node03节点，故这里不需要重新根据kube-proxy配置模板生成对应的新增node节点的配置文件(因为之前已经生成过了)
[root@k8s-master01 work]# ll kube-proxy-config-k8s-node*
-rw-r--r-- 1 root root 500 Jun 24 20:27 kube-proxy-config-k8s-node01.yaml.template
-rw-r--r-- 1 root root 500 Jun 24 20:27 kube-proxy-config-k8s-node02.yaml.template
-rw-r--r-- 1 root root 500 Jun 24 20:27 kube-proxy-config-k8s-node03.yaml.template 如果是完全新增加的节点，比如新增加的node节点172.16.60.240 (主机名: k8s-node04)，
则这一步还需要拷贝已存在node节点的配置文件为新增node节点的配置文件，然后分发过去
[root@k8s-master01 work]# cp kube-proxy-config-k8s-node03.yaml.template kube-proxy-config-k8s-node04.yaml.template
[root@k8s-master01 work]# sed -i 's/172.16.60.246/172.16.60.240/g' kube-proxy-config-k8s-node04.yaml.template
[root@k8s-master01 work]# sed -i 's/k8s-node03/k8s-node04/g' kube-proxy-config-k8s-node04.yaml.template
[root@k8s-master01 work]# scp kube-proxy-config-k8s-node04.yaml.template root@k8s-node04:/etc/kubernetes/kube-proxy-config.yaml 如果是新增多个node节点，则同样是拷贝已存在node节点的配置文件为各个新增node节点的配置文件，然后分发过去
================================================================================================================================================= [root@k8s-master01 work]# for node_node_name in ${NODE_NODE_NAMES[@]}
do
echo ">>> ${node_node_name}"
scp kube-proxy.service root@${node_node_name}:/etc/systemd/system/
done [root@k8s-master01 work]# for node_node_ip in ${NODE_NODE_IPS[@]}
do
echo ">>> ${node_node_ip}"
ssh root@${node_node_ip} "mkdir -p ${K8S_DIR}/kube-proxy"
ssh root@${node_node_ip} "modprobe ip_vs_rr"
ssh root@${node_node_ip} "systemctl daemon-reload && systemctl enable kube-proxy && systemctl restart kube-proxy"
done [root@k8s-master01 work]# for node_node_ip in ${NODE_NODE_IPS[@]}
do
echo ">>> ${node_node_ip}"
ssh root@${node_node_ip} "systemctl status kube-proxy|grep Active"
done -> 手动 approve server cert csr
[root@k8s-master01 work]# kubectl get csr
NAME AGE REQUESTOR CONDITION
csr-5fwlh 3m34s system:bootstrap:sdwq5g Approved,Issued
csr-t547p 3m21s system:node:k8s-node03 Pending [root@k8s-master01 work]# kubectl certificate approve csr-t547p
certificatesigningrequest.certificates.k8s.io/csr-t547p approved [root@k8s-master01 work]# kubectl get csr
NAME AGE REQUESTOR CONDITION
csr-5fwlh 3m53s system:bootstrap:sdwq5g Approved,Issued
csr-t547p 3m40s system:node:k8s-node03 Approved,Issued -> 查看集群状态，发现k8s-node03节点已经被重新加入到集群中了，并且已经分配了pod资源。
[root@k8s-master01 work]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
k8s-node01 Ready <none> 47d v1.14.2
k8s-node02 Ready <none> 47d v1.14.2
k8s-node03 Ready <none> 1s v1.14.2 [root@k8s-master01 work]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
dnsutils-ds-5sc4z 1/1 Running 965 40d 172.30.56.3 k8s-node02 <none> <none>
dnsutils-ds-gc8sb 1/1 Running 1 94m 172.30.72.2 k8s-node03 <none> <none>
dnsutils-ds-jx5kx 1/1 Running 966 40d 172.30.88.4 k8s-node01 <none> <none>
my-nginx-5dd67b97fb-8j4k6 1/1 Running 0 40d 172.30.88.3 k8s-node01 <none> <none>
my-nginx-5dd67b97fb-kx2pc 1/1 Running 0 174m 172.30.56.7 k8s-node02 <none> <none>
nginx-7db9fccd9b-7vbhq 1/1 Running 0 174m 172.30.88.7 k8s-node01 <none> <none>
nginx-7db9fccd9b-dkdzf 1/1 Running 0 27d 172.30.88.8 k8s-node01 <none> <none>
nginx-7db9fccd9b-vrp9f 1/1 Running 0 27d 172.30.56.6 k8s-node02 <none> <none>
nginx-ds-4lf8z 1/1 Running 0 41d 172.30.56.2 k8s-node02 <none> <none>
nginx-ds-jn759 1/1 Running 0 94m 172.30.72.3 k8s-node03 <none> <none>
nginx-ds-xqdgw 1/1 Running 0 41d 172.30.88.2 k8s-node01 <none> <none> [root@k8s-master01 work]# kubectl top node
NAME CPU(cores) CPU% MEMORY(bytes) MEMORY%
k8s-node01 96m 2% 2123Mi 55%
k8s-node02 133m 3% 1772Mi 46%
k8s-node03 46m 1% 4859Mi 61% =======================================================================================================================================
注意一
如果是添加全新的节点到上述k8s集群中，做法如下：
1）做好node节点的环境初始化准备，如做好K8s-master01到新增节点的ssh无密码登录的信任关系；etc/hosts里做好绑定；关闭防火墙等。
2）在/opt/k8s/bin/environment.sh变量脚本里，将NODE_NODE_IPS和NODE_NODE_NAMES变量改成新增node节点的对应信息
3）按照上面添加k8s-node03节点的一系列添加步骤全部执行一遍即可 ======================================================================================================================================
注意二
上面使用的是二进制方式按照k8s集群。如果使用kubeadmin工具创建的k8s集群，则重新使node加入集群的操作如下： 使节点加入集群的命令格式（node节点上操作，使用root用户）：
# kubeadm join --token <token> <master-ip>:<master-port> --discovery-token-ca-cert-hash sha256:<hash> 如果忘记了Master节点的token，可以使用下面命令查看（master节点上操作）：
# kubeadm token list 默认情况下，token的有效期是24小时，如果token已经过期的话，可以使用下面命令重新生成（master节点上操作）;
# kubeadm token create 如果找不到--discovery-token-ca-cert-hash的值，可以使用以下命令生成（master节点上操作）：
# openssl x509 -pubkey -in /etc/kubernetes/pki/ca.crt | openssl rsa -pubin -outform der 2>/dev/null | openssl dgst -sha256 -hex | sed 's/^.* //' 加入节点后，稍等一会儿，即可看到节点已加入（master节点上操作）