03、kubeadm初始化Kubernetes集群

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kubernetes 集群部署：
① 把kubernetes所有组件安装到各个节点manager和node节点上，即物理机上守护进程，开机自启
② 使用kurbernetes官方提供的集群部署管理工具kubeadm部署

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# cat /etc/hosts
10.40.6.165 master01
10.40.6.166 node01
10.40.6.167 node02

kubeadm
① master, nodes：安装kubelet, kubeadm, docker
② master: kubeadm init
③ nodes: kubadm join

每个节点都创建yum源：

# cd /etc/yum.repos.d/
# wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
# cat kibernetes.repo
[kubernetes]
name=Kubernetes Repo
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
enabled=1

# yum repolist
      ...
docker-ce-stable/x86_64                                                                 Docker CE Stable - x86_64                                                                     43
kubernetes                                                                              Kubernetes Repo                                                                              351
     ....

# cd && wget https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
# rpm --import rpm-package-key.gpg

# yum install docker-ce kubelet kubeadm kubectl
# systemctl daemon-reload
# systemctl start docker

设置下面两个文件内容为1
# echo 1 > /proc/sys/net/bridge/bridge-nf-call-iptables
# echo 1 > /proc/sys/net/bridge/bridge-nf-call-ip6tables

# rpm -ql kubelet
/etc/kubernetes/manifests   ##清单目录
/etc/sysconfig/kubelet  ##配置文件
/usr/bin/kubelet   ##主程序
/usr/lib/systemd/system/kubelet.service  ##系统服务

#  systemctl start kubelet
#  systemctl status kubelet
● kubelet.service - kubelet: The Kubernetes Node Agent
   Loaded: loaded (/usr/lib/systemd/system/kubelet.service; disabled; vendor preset: disabled)
  Drop-In: /usr/lib/systemd/system/kubelet.service.d
           └─10-kubeadm.conf
   Active: activating (auto-restart) (Result: exit-code) since Thu 2019-05-23 20:35:19 CST; 9s ago
     Docs: https://kubernetes.io/docs/
  Process: 8085 ExecStart=/usr/bin/kubelet $KUBELET_KUBECONFIG_ARGS $KUBELET_CONFIG_ARGS $KUBELET_KUBEADM_ARGS $KUBELET_EXTRA_ARGS (code=exited, status=255)
 Main PID: 8085 (code=exited, status=255)

May 23 20:35:19 master01 systemd[1]: Unit kubelet.service entered failed state.
May 23 20:35:19 master01 systemd[1]: kubelet.service failed.

# tail /var/log/messages
May 23 20:37:11 master01 kubelet: F0523 20:37:11.716012    8239 server.go:193] failed to load Kubelet config file /var/lib/kubelet/config.yaml, error failed to read kubelet config file "/var/lib/kubelet/config.yaml", error: open /var/lib/kubelet/config.yaml: no such file or directory
May 23 20:37:11 master01 systemd: kubelet.service: main process exited, code=exited, status=255/n/a
May 23 20:37:11 master01 systemd: Unit kubelet.service entered failed state.
May 23 20:37:11 master01 systemd: kubelet.service failed.

# systemctl stop kubelet   ## 停止，因为还没初始化完成，设置开机启动即可
# systemctl enable kubelet

kubeadm init --help

# kubeadm init --kubernetes-version=v1.14.2 --pod-network-cidr=10.244.0.0/16 --service-cidr=10.96.0.0/12 
[init] Using Kubernetes version: v1.14.2
[preflight] Running pre-flight checks
    [WARNING Service-Docker]: docker service is not enabled, please run 'systemctl enable docker.service'
    [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/
error execution phase preflight: [preflight] Some fatal errors occurred:
    [ERROR Swap]: running with swap on is not supported. Please disable swap


# systemctl enable docker.service
#在daemon.json添加 "exec-opts": ["native.cgroupdriver=systemd"]
# cat  /etc/docker/daemon.json
{
    "registry-mirrors": ["http://f1361db2.m.daocloud.io"],
    "exec-opts": ["native.cgroupdriver=systemd"]
}

## 重启docker
# systemctl restart docker

# kubeadm init --kubernetes-version=v1.14.2 --pod-network-cidr=10.244.0.0/16 --service-cidr=10.96.0.0/12 --ignore-preflight-errors=Swap
[init] Using Kubernetes version: v1.14.2
[preflight] Running pre-flight checks
    [WARNING Swap]: running with swap on is not supported. Please disable swap
[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'
error execution phase preflight: [preflight] Some fatal errors occurred:
    [ERROR ImagePull]: failed to pull image k8s.gcr.io/kube-apiserver:v1.14.2: output: Error response from daemon: Get https://k8s.gcr.io/v2/: proxyconnect tcp: dial tcp 172.96.236.117:10080: connect: connection refused
, error: exit status 1
    [ERROR ImagePull]: failed to pull image k8s.gcr.io/kube-controller-manager:v1.14.2: output: Error response from daemon: Get https://k8s.gcr.io/v2/: proxyconnect tcp: dial tcp 172.96.236.117:10080: connect: connection refused
, error: exit status 1
    [ERROR ImagePull]: failed to pull image k8s.gcr.io/kube-scheduler:v1.14.2: output: Error response from daemon: Get https://k8s.gcr.io/v2/: proxyconnect tcp: dial tcp 172.96.236.117:10080: connect: connection refused
, error: exit status 1
    [ERROR ImagePull]: failed to pull image k8s.gcr.io/kube-proxy:v1.14.2: output: Error response from daemon: Get https://k8s.gcr.io/v2/: proxyconnect tcp: dial tcp 172.96.236.117:10080: connect: connection refused
, error: exit status 1
    [ERROR ImagePull]: failed to pull image k8s.gcr.io/pause:3.1: output: Error response from daemon: Get https://k8s.gcr.io/v2/: proxyconnect tcp: dial tcp 172.96.236.117:10080: connect: connection refused
, error: exit status 1
    [ERROR ImagePull]: failed to pull image k8s.gcr.io/etcd:3.3.10: output: Error response from daemon: Get https://k8s.gcr.io/v2/: proxyconnect tcp: dial tcp 172.96.236.117:10080: connect: connection refused
, error: exit status 1
    [ERROR ImagePull]: failed to pull image k8s.gcr.io/coredns:1.3.1: output: Error response from daemon: Get https://k8s.gcr.io/v2/: proxyconnect tcp: dial tcp 172.96.236.117:10080: connect: connection refused
, error: exit status 1
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`


### 无法下载镜像。因为无法访问谷歌镜像仓库，手动下载，并打tag
# docker pull mirrorgooglecontainers/kube-apiserver:v1.14.2
# docker pull mirrorgooglecontainers/kube-controller-manager:v1.14.2
# docker pull mirrorgooglecontainers/kube-scheduler:v1.14.2
# docker pull mirrorgooglecontainers/kube-proxy:v1.14.2
# docker pull mirrorgooglecontainers/pause:3.1
# docker pull mirrorgooglecontainers/etcd:3.3.10
# 1141  docker pull coredns/coredns:1.3.1

# docker tag mirrorgooglecontainers/kube-proxy:v1.14.2  k8s.gcr.io/kube-proxy:v1.14.2
# docker tag mirrorgooglecontainers/kube-apiserver:v1.14.2  k8s.gcr.io/kube-apiserver:v1.14.2
# docker tag mirrorgooglecontainers/kube-controller-manager:v1.14.2  k8s.gcr.io/kube-controller-manager:v1.14.2
# docker tag mirrorgooglecontainers/kube-scheduler:v1.14.2  k8s.gcr.io/kube-scheduler:v1.14.2
# docker tag coredns/coredns:1.3.1  k8s.gcr.io/coredns:1.3.1
# docker tag mirrorgooglecontainers/etcd:3.3.10  k8s.gcr.io/etcd:3.3.10
# docker tag mirrorgooglecontainers/pause:3.1 k8s.gcr.io/pause:3.1

# kubeadm init --kubernetes-version=v1.14.2 --pod-network-cidr=10.244.0.0/16 --service-cidr=10.96.0.0/12 --ignore-preflight-errors=Swap
[init] Using Kubernetes version: v1.14.2
[preflight] Running pre-flight checks
    [WARNING Swap]: running with swap on is not supported. Please disable swap
[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 "etcd/ca" certificate and key
[certs] Generating "etcd/server" certificate and key
[certs] etcd/server serving cert is signed for DNS names [master01 localhost] and IPs [10.40.6.165 127.0.0.1 ::1]
[certs] Generating "apiserver-etcd-client" certificate and key
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [master01 localhost] and IPs [10.40.6.165 127.0.0.1 ::1]
[certs] Generating "etcd/healthcheck-client" certificate and key
[certs] Generating "ca" certificate and key
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [master01 kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 10.40.6.165]
[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 "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 16.003464 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 master01 as control-plane by adding the label "node-role.kubernetes.io/master=''"
[mark-control-plane] Marking the node master01 as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[bootstrap-token] Using token: ym1869.1nmmpxgvo0dlcyps
[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 10.40.6.165:6443 --token ym1869.1nmmpxgvo0dlcyps \
    --discovery-token-ca-cert-hash sha256:4574b06205aef226254b461235fa3a953eed2a6ed1aded4dff0db3d662b70273 

# useradd k8s
## 在/etc/sudoers 添加
k8s      ALL=(ALL)       NOPASSWD: ALL
# sudo su - k8s

$  mkdir -p $HOME/.kube
$  sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
$  sudo chown $(id -u):$(id -g) $HOME/.kube/config

# kubectl get componentstatus
The connection to the server localhost:8080 was refused - did you specify the right host or port?

kube-apiserver没有监听默认的http 8080端口。 所以我们使用kubectl get nodes会报以上的错误
查看kube-apiserver的监听端口可以看到只监听了https的6443端口
为了使用kubectl访问apiserver，在~/.bash_profile中追加下面的环境变量：
export KUBECONFIG=/etc/kubernetes/admin.conf
# source ~/.bash_profile

# kubectl get nodes
NAME       STATUS     ROLES    AGE   VERSION
master01   NotReady   master   13h   v1.14.2
# kubectl get cs
NAME                 STATUS    MESSAGE             ERROR
scheduler            Healthy   ok                  
controller-manager   Healthy   ok                  
etcd-0               Healthy   {"health":"true"}   

## 部署网络插件flannel:（注意命令执行完不会立马把镜像和pod启动）
### 地址: https://github.com/coreos/flannel
# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

# kubectl get nodes
NAME       STATUS   ROLES    AGE   VERSION
master01   Ready    master   13h   v1.14.2

# kubectl  get pods -n kube-system   ###指定一个名称空间
NAME                               READY   STATUS    RESTARTS   AGE
coredns-fb8b8dccf-5gkgk            1/1     Running   2          13h
coredns-fb8b8dccf-7mwjs            1/1     Running   1          13h
etcd-master01                      1/1     Running   2          13h
kube-apiserver-master01            1/1     Running   2          13h
kube-controller-manager-master01   1/1     Running   2          13h
kube-flannel-ds-amd64-h64s9        1/1     Running   1          16m
kube-proxy-x8gnk                   1/1     Running   2          13h
kube-scheduler-master01            1/1     Running   2          13h

# kubectl get ns   ## 命名空间
NAME              STATUS   AGE
default           Active   13h
kube-node-lease   Active   13h
kube-public       Active   13h
kube-system       Active   13h

# scp rpm-package-key.gpg node01:/root/
# scp rpm-package-key.gpg node01:/root/

## node 节点 安装：
# rpm --import rpm-package-key.gpg
# yum install docker-ce kubelet kubeadm -y
# systemctl enable docker kubelet
# cat /etc/sysconfig/kubelet
KUBELET_EXTRA_ARGS="--fail-swap-on=false"

# systemctl start docker
# echo 1 > /proc/sys/net/bridge/bridge-nf-call-iptables
# echo 1 > /proc/sys/net/bridge/bridge-nf-call-ip6tables

# cat /etc/docker/daemon.json
{
    "registry-mirrors": ["https://dockerhub.azk8s.cn"],
    "exec-opts": ["native.cgroupdriver=systemd"]
}

# systemctl restart docker
# kubeadm join 10.40.6.165:6443 --token ym1869.1nmmpxgvo0dlcyps --discovery-token-ca-cert-hash sha256:4574b06205aef226254b461235fa3a953eed2a6ed1aded4dff0db3d662b70273 --ignore-preflight-errors=Swap
# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

# kubectl get nodes
NAME       STATUS   ROLES    AGE     VERSION
master01   Ready    master   16h     v1.14.2
node01     Ready       150m    v1.14.2
node02     Ready       6m39s   v1.14.2

Master Node初始化完成，使用kubeadm初始化的Kubernetes集群在Master节点上的核心组件：kube-apiserver, kube-scheduler, kube-controller-manager是以静态Pod的形式运行的。