kubeadm cluster deployment

Deploy k8s cluster in kubeadm mode

Official documents:

https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/

Official documents of kubeadm deploying k8s high availability cluster:

https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/high-availability/

Get mirror

Ali warehouse download

[root@k8s-master ~]# docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kube-controller-manager:v1.17.4
[root@k8s-master ~]# docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy:v1.17.4
[root@k8s-master ~]# docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kube-apiserver:v1.17.4
[root@k8s-master ~]# docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kube-scheduler:v1.17.4
[root@k8s-master ~]# docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/coredns:1.6.5
[root@k8s-master ~]# docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/etcd:3.4.3-0
[root@k8s-master ~]# docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/pause:3.1

docker pull quay-mirror.qiniu.com/coreos/flannel:v0.12.0-amd64 --下载网络插件的配置文件

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:v1.17.0这样的tag
[root@k8s-master ~]# docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-controller-manager:v1.17.4 k8s.gcr.io/kube-controller-manager:v1.17.4
[root@k8s-master ~]# docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy:v1.17.4 k8s.gcr.io/kube-proxy:v1.17.4
[root@k8s-master ~]# docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-apiserver:v1.17.4 k8s.gcr.io/kube-apiserver:v1.17.4
[root@k8s-master ~]# docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-scheduler:v1.17.4 k8s.gcr.io/kube-scheduler:v1.17.4
[root@k8s-master ~]# docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/coredns:1.6.5 k8s.gcr.io/coredns:1.6.5
[root@k8s-master ~]# docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/etcd:3.4.3-0 k8s.gcr.io/etcd:3.4.3-0
[root@k8s-master ~]# docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/pause:3.1 k8s.gcr.io/pause:3.1
版本号不用变
[root@k8s-master ~]# docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/etcd:3.4.3-0 k8s.gcr.io/etcd:3.4.3-0
[root@k8s-master ~]# docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/pause:3.1 k8s.gcr.io/pause:3.1

All machines must have mirrors

Install docker--all three machines operate

# yum remove docker \
docker-client \
docker-client-latest \
docker-common \
docker-latest \
docker-latest-logrotate \
docker-logrotate \
docker-selinux \
docker-engine-selinux \
docker-engine
# yum install -y yum-utils device-mapper-persistent-data lvm2 git
# yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

# yum install docker-ce -y

启动并设置开机启动

Complete installation process

Prepare three machines,

192.168.246.166   kub-k8s-master
192.168.246.167   kub-k8s-node1
192.168.246.169   kub-k8s-node2

制作本地解析，修改主机名。相互解析
# vim /etc/hosts

All machine system configuration

1.关闭防火墙：
# systemctl stop firewalld
# systemctl disable firewalld
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=permissive/SELINUX=disabled/' /etc/sysconfig/selinux
SELINUX=disabled

Close system swap: new regulations after 1.5

Kubernetes 1.8 began to require the system's Swap to be closed. If it is not closed, kubelet will not be able to start under the default configuration. Method one, change this limit through the startup parameter of kubelet -fail-swap-on=false. Method two, close the swap of the system.

# 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：
[root@localhost /]# 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

Deploy Kubernetes using kubeadm:

Install kubeadm and kubelet on all nodes:

配置源
# 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：
1.安装
# yum makecache fast
# yum install -y kubelet kubeadm kubectl ipvsadm

2.加载ipvs相关内核模块
如果重新开机，需要重新加载（可以写在 /etc/rc.local 中开机自动加载）
# modprobe ip_vs
# modprobe ip_vs_rr
# modprobe ip_vs_wrr
# modprobe ip_vs_sh
# modprobe nf_conntrack_ipv4
3.编辑文件添加开机启动
# vim /etc/rc.local 
# chmod +x /etc/rc.local

重启服务器

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-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
vm.swappiness=0
EOF

5.使配置生效
# sysctl --system

6.如果net.bridge.bridge-nf-call-iptables报错，加载br_netfilter模块
# modprobe br_netfilter
# sysctl -p /etc/sysctl.d/k8s.conf


7.查看是否加载成功
# lsmod | grep ip_vs
ip_vs_sh               12688  0 
ip_vs_wrr              12697  0 
ip_vs_rr               12600  0 
ip_vs                 141092  6 ip_vs_rr,ip_vs_sh,ip_vs_wrr
nf_conntrack          133387  2 ip_vs,nf_conntrack_ipv4
libcrc32c              12644  3 xfs,ip_vs,nf_conntrack

Configure to start kubelet (all nodes)

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 '{print $3}'`
[root@k8s-master ~]# echo $DOCKER_CGROUPS
cgroupfs

这个是使用国内的源。-###注意我们使用谷歌的镜像--操作下面的第3标题
2.配置kubelet的cgroups
# cat >/etc/sysconfig/kubelet<<EOF
KUBELET_EXTRA_ARGS="--cgroup-driver=$DOCKER_CGROUPS --pod-infra-container-image=registry.cn-hangzhou.aliyuncs.com/google_containers/pause-amd64:3.1"
EOF

3.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:3.1"
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；

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.

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。

Configure the master node

运行初始化过程如下：
[root@master ～# kubeadm init --kubernetes-version=v1.16.1 --pod-network-cidr=10.244.0.0/16 --apiserver-advertise-address=192.168.246.166 --ignore-preflight-errors=Swap
注：
apiserver-advertise-address=192.168.246.166    ---master的ip地址。
--kubernetes-version=v1.16.1   --更具具体版本进行修改
注意在检查一下swap分区是否关闭

如果报错会有版本提示，那就是有更新新版本了
[init] Using Kubernetes version: v1.16.1
[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 [10.96.0.1 192.168.246.166]
[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 [192.168.246.166 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [kub-k8s-master localhost] and IPs [192.168.246.166 127.0.0.1 ::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

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 192.168.246.166:6443 --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

查看node节点
[root@k8s-master ~]# kubectl get nodes
NAME         STATUS     ROLES    AGE     VERSION
k8s-master   NotReady   master   2m41s   v1.17.4

Configure the use of network plug-ins

在master节点操作
下载配置
# cd ~ && mkdir flannel && cd flannel
# curl -O https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

修改配置文件kube-flannel.yml:
此处的ip配置要与上面kubeadm的pod-network一致，本来就一致，不用改
  net-conf.json: |
    {
      "Network": "10.244.0.0/16",
      "Backend": {
        "Type": "vxlan"
      }
    }
# 这里注意kube-flannel.yml这个文件里的flannel的镜像是0.11.0，quay.io/coreos/flannel:v0.11.0-amd64
# 默认的镜像是quay.io/coreos/flannel:v0.11.0-amd64，需要提前pull下来。


# 如果Node有多个网卡的话，参考flannel issues 39701，
# https://github.com/kubernetes/kubernetes/issues/39701
# 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。容器无法通信的情况，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=ens33
        - --iface=eth0
        
⚠️⚠️⚠️--iface=ens33 的值，是你当前的网卡,或者可以指定多网卡

# 1.12版本的kubeadm额外给node1节点设置了一个污点(Taint)：node.kubernetes.io/not-ready:NoSchedule，
# 很容易理解，即如果节点还没有ready之前，是不接受调度的。可是如果Kubernetes的网络插件还没有部署的话，节点是不会进入ready状态的。
# 因此修改以下kube-flannel.yaml的内容，加入对node.kubernetes.io/not-ready:NoSchedule这个污点的容忍：
    - key: beta.kubernetes.io/arch
                    operator: In
                    values:
                      - arm64
      hostNetwork: true
      tolerations:
      - operator: Exists
        effect: NoSchedule
      - key: node.kubernetes.io/not-ready  #添加如下三行---在261行左右
        operator: Exists
        effect: NoSchedule
      serviceAccountName: flannel

启动：
# kubectl apply -f ~/flannel/kube-flannel.yml  #启动完成之后需要等待一会
NAME                                     READY   STATUS    RESTARTS   AGE
coredns-5644d7b6d9-sm8hs                 1/1     Running   0          9m18s
coredns-5644d7b6d9-vddll                 1/1     Running   0          9m18s
etcd-kub-k8s-master                      1/1     Running   0          8m14s
kube-apiserver-kub-k8s-master            1/1     Running   0          8m17s
kube-controller-manager-kub-k8s-master   1/1     Running   0          8m20s
kube-flannel-ds-amd64-9wgd8              1/1     Running   0          8m42s
kube-proxy-sgphs                         1/1     Running   0          9m18s
kube-scheduler-kub-k8s-master            1/1     Running   0          8m10s

查看：
# kubectl get pods --namespace kube-system
# kubectl get service
# kubectl get svc --namespace kube-system
只有网络插件也安装配置完成之后，才能会显示为ready状态

All node operations

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

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 192.168.246.166:6443 --token 93erio.hbn2ti6z50he0lqs \
    --discovery-token-ca-cert-hash sha256:3bc60f06a19bd09f38f3e05e5cff4299011b7110ca3281796668f4edb29a56d9

Operation in 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

2.查看异常pod信息：
[root@kub-k8s-master ~]# kubectl  describe pods kube-flannel-ds-sr6tq -n  kube-system
Name:               kube-flannel-ds-sr6tq
Namespace:          kube-system
Priority:           0
PriorityClassName:  <none>
。。。。。
Events:
  Type     Reason     Age                  From               Message
  ----     ------     ----                 ----               -------
  Normal   Pulling    12m                  kubelet, node2     pulling image "registry.cn-shanghai.aliyuncs.com/gcr-k8s/flannel:v0.10.0-amd64"
  Normal   Pulled     11m                  kubelet, node2     Successfully pulled image "registry.cn-shanghai.aliyuncs.com/gcr-k8s/flannel:v0.10.0-amd64"
  Normal   Created    11m                  kubelet, node2     Created container
  Normal   Started    11m                  kubelet, node2     Started container
  Normal   Created    11m (x4 over 11m)    kubelet, node2     Created container
  Normal   Started    11m (x4 over 11m)    kubelet, node2     Started container
  Normal   Pulled     10m (x5 over 11m)    kubelet, node2     Container image "registry.cn-shanghai.aliyuncs.com/gcr-k8s/flannel:v0.10.0-amd64" already present on machine
  Normal   Scheduled  7m15s                default-scheduler  Successfully assigned kube-system/kube-flannel-ds-sr6tq to node2
  Warning  BackOff    7m6s (x23 over 11m)  kubelet, node2     Back-off restarting failed container

3.遇到这种情况直接 删除异常pod:
[root@kub-k8s-master ~]# kubectl delete pod kube-flannel-ds-sr6tq -n kube-system
pod "kube-flannel-ds-sr6tq" deleted

4.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          44m
coredns-5644d7b6d9-vddll                 1/1     Running   0          44m
etcd-kub-k8s-master                      1/1     Running   0          42m
kube-apiserver-kub-k8s-master            1/1     Running   0          43m
kube-controller-manager-kub-k8s-master   1/1     Running   0          43m
kube-flannel-ds-amd64-9wgd8              1/1     Running   0          43m
kube-flannel-ds-amd64-lffc8              1/1     Running   0          7m10s
kube-flannel-ds-amd64-m8kk2              1/1     Running   0          7m1s
kube-proxy-dwq9l                         1/1     Running   0          7m1s
kube-proxy-l77lz                         1/1     Running   0          7m10s
kube-proxy-sgphs                         1/1     Running   0          44m
kube-scheduler-kub-k8s-master            1/1     Running   0          42m

5.查看节点：
[root@kub-k8s-master ~]# kubectl get nodes
NAME             STATUS   ROLES    AGE     VERSION
kub-k8s-master   Ready    master   43m     v1.16.1
kub-k8s-node1    Ready    <none>   6m46s   v1.16.1
kub-k8s-node2    Ready    <none>   6m37s   v1.16.1
到此集群配置完成