centos7使用kubeadm安装部署kubernetes 1.14
应用背景：
截止目前为止，高热度的kubernetes版本已经发布至1.14，在此记录一下安装部署步骤和过程中的问题排查。
部署k8s一般两种方式：kubeadm（官方称目前已经GA，可以在生产环境使用）；二进制安装（比较繁琐）。
这里暂且采用kubeadm方式部署测试。
测试环境：
| System | Hostname | IP |
| CentOS 7.6 | k8s-master | 138.138.82.14 |
| CentOS 7.6 | k8s-node1 | 138.138.82.15 |
| CentOS 7.6 | k8s-node2 | 138.138.82.16 |
网络插件：calico
具体步骤：
1. 环境预设（在所有主机上操作）
关闭firewalld：
systemctl stop firewalld && systemctl disable firewalld
关闭SElinux：
setenforce 0 && sed -i "s/SELINUX=enforcing/SELINUX=disabled/g" /etc/selinux/config
关闭Swap：
swapoff -a && sed -i "s/\/dev\/mapper\/centos-swap/\#\/dev\/mapper\/centos-swap/g" /etc/fstab
使用阿里云yum源：
wget -O /etc/yum.repos.d/CentOS7-Aliyun.repo http://mirrors.aliyun.com/repo/Centos-7.repo
更新 /etc/hosts 文件：在每一台主机的该文件中添加k8s所有节点的IP和对应主机名，否则初始化的时候回出现告警甚至错误。
2. 安装docker引擎（在所有主机上操作）
安装阿里云docker源：
wget -O /etc/yum.repos.d/docker-ce http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
安装docker：
yum install docker-ce -y
启动docker：
systemctl enable docker && systemctl start docker
调整docker部分参数：
mkdir -p /etc/docker tee /etc/docker/daemon.json <<-'EOF' { "registry-mirrors": ["https://5twf62k1.mirror.aliyuncs.com"], // 改为阿里镜像 "exec-opts": ["native.cgroupdriver=systemd"] // 默认cgroupfs，k8s官方推荐systemd，否则初始化出现Warning } EOF systemctl daemon-reload systemctl restart docker
检查确认docker的Cgroup Driver信息：
[root@k8s-master ~]# docker info |grep Cgroup Cgroup Driver: systemd
3. 安装kubernetes初始化工具（在所有主机上操作）
使用阿里云的kubernetes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
安装工具： yum install -y kubelet kubeadm kubectl // 此时最新版本1.14.1
启动kubelet： systemctl enable kubelet && systemctl start kubelet // 此时启动不成功正常，后面初始化的时候会变成功
4. 预下载相关镜像（在master节点上操作）
查看集群初始化所需镜像及对应依赖版本号：
[root@k8s-master ~]# kubeadm config images list …… k8s.gcr.io/kube-apiserver:v1.14.1 k8s.gcr.io/kube-controller-manager:v1.14.1 k8s.gcr.io/kube-scheduler:v1.14.1 k8s.gcr.io/kube-proxy:v1.14.1 k8s.gcr.io/pause:3.1 k8s.gcr.io/etcd:3.3.10 k8s.gcr.io/coredns:1.3.1
因为这些重要镜像都被墙了，所以要预先单独下载好，然后才能初始化集群。
下载脚本：
#!/bin/bash set -e KUBE_VERSION=v1.14.1 KUBE_PAUSE_VERSION=3.1 ETCD_VERSION=3.3.10 CORE_DNS_VERSION=1.3.1 GCR_URL=k8s.gcr.io ALIYUN_URL=registry.cn-hangzhou.aliyuncs.com/google_containers images=(kube-proxy:${KUBE_VERSION} kube-scheduler:${KUBE_VERSION} kube-controller-manager:${KUBE_VERSION} kube-apiserver:${KUBE_VERSION} pause:${KUBE_PAUSE_VERSION} etcd:${ETCD_VERSION} coredns:${CORE_DNS_VERSION}) for imageName in ${images[@]} ; do docker pull $ALIYUN_URL/$imageName docker tag $ALIYUN_URL/$imageName $GCR_URL/$imageName docker rmi $ALIYUN_URL/$imageName done
5. 初始化集群（在master节点上操作）
kubeadm init --kubernetes-version=v1.14.1 --pod-network-cidr=192.168.0.0/16
注意：初始化之后会安装网络插件，这里选择了calico，所以修改 --pod-network-cidr=192.168.0.0/16
初始化输出记录样例：
[root@k8s-master ~]# kubeadm init --kubernetes-version=v1.14.1 --pod-network-cidr=192.168.0.0/16 [init] Using Kubernetes version: v1.14.1 [preflight] Running pre-flight checks [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 [k8s-master kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 138.138.82.14] [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 [k8s-master localhost] and IPs [138.138.82.14 127.0.0.1 ::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 [k8s-master localhost] and IPs [138.138.82.14 127.0.0.1 ::1] [certs] Generating "etcd/healthcheck-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 16.002739 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 k8s-master as control-plane by adding the label "node-role.kubernetes.io/master=''" [mark-control-plane] Marking the node k8s-master as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule] [bootstrap-token] Using token: 57iu95.6narx7y8peauts76 [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 138.138.82.14:6443 --token 57iu95.6narx7y8peauts76 \ --discovery-token-ca-cert-hash sha256:5dc8beaa3b0e6fa26b97e2cc3b8ae776d000277fd23a7f8692dc613c6e59f5e4
以上输出显示初始化成功，并给出了接下来的必要步骤和节点加入集群的命令，照着做即可。
[root@k8s-master ~]# mkdir -p $HOME/.kube [root@k8s-master ~]# sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config [root@k8s-master ~]# sudo chown $(id -u):$(id -g) $HOME/.kube/config
查看已经运行的pod
[root@k8s-master ~]# kubectl get pod -n kube-system -owide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES coredns-fb8b8dccf-6mgks 0/1 Pending 0 9m6s <none> <none> <none> <none> coredns-fb8b8dccf-cbtlx 0/1 Pending 0 9m6s <none> <none> <none> <none> etcd-k8s-master 1/1 Running 0 8m22s 138.138.82.14 k8s-master <none> <none> kube-apiserver-k8s-master 1/1 Running 0 8m19s 138.138.82.14 k8s-master <none> <none> kube-controller-manager-k8s-master 1/1 Running 0 8m30s 138.138.82.14 k8s-master <none> <none> kube-proxy-c9xd2 1/1 Running 0 9m7s 138.138.82.14 k8s-master <none> <none> kube-scheduler-k8s-master 1/1 Running 0 8m6s 138.138.82.14 k8s-master <none> <none>
到这里，会发现除了coredns未ready，这是正常的，因为还没有网络插件，接下来安装calico后就变为正常running了。
6. 安装calico（在master节点上操作）
Calico官网：https://docs.projectcalico.org/v3.6/getting-started/kubernetes/
kubectl apply -f \ https://docs.projectcalico.org/v3.5/getting-started/kubernetes/installation/hosted/kubernetes-datastore/calico-networking/1.7/calico.yaml
应用官方的yaml文件之后，过一会查看所有pod已经正常running状态了，也分配出了对应IP：
[root@k8s-master ~]# kubectl get pod -n kube-system -owide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES calico-node-r5mlj 1/1 Running 0 72s 138.138.82.14 k8s-master <none> <none> coredns-fb8b8dccf-6mgks 1/1 Running 0 15m 192.168.0.7 k8s-master <none> <none> coredns-fb8b8dccf-cbtlx 1/1 Running 0 15m 192.168.0.6 k8s-master <none> <none> etcd-k8s-master 1/1 Running 0 15m 138.138.82.14 k8s-master <none> <none> kube-apiserver-k8s-master 1/1 Running 0 15m 138.138.82.14 k8s-master <none> <none> kube-controller-manager-k8s-master 1/1 Running 0 15m 138.138.82.14 k8s-master <none> <none> kube-proxy-c9xd2 1/1 Running 0 15m 138.138.82.14 k8s-master <none> <none> kube-scheduler-k8s-master 1/1 Running 0 14m 138.138.82.14 k8s-master <none> <none>
查看节点状态
[root@k8s-master ~]# kubectl get node -owide NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME k8s-master Ready master 22m v1.14.1 138.138.82.14 <none> CentOS Linux 7 (Core) 3.10.0-957.10.1.el7.x86_64 docker://18.9.5
至此，集群初始化和主节点都准备就绪，接下来就是加入其他工作节点至集群中。
7. 加入集群（在非master节点上操作）
先在需要加入集群的节点上下载必要镜像，下载脚本如下：
#!/bin/bash set -e KUBE_VERSION=v1.14.1 KUBE_PAUSE_VERSION=3.1 GCR_URL=k8s.gcr.io ALIYUN_URL=registry.cn-hangzhou.aliyuncs.com/google_containers images=(kube-proxy-amd64:${KUBE_VERSION} pause:${KUBE_PAUSE_VERSION}) for imageName in ${images[@]} ; do docker pull $ALIYUN_URL/$imageName docker tag $ALIYUN_URL/$imageName $GCR_URL/$imageName docker rmi $ALIYUN_URL/$imageName done
然后在主节点初始化输出中获取加入集群的命令，复制到工作节点执行即可：
[root@k8s-node1 ~]# kubeadm join 138.138.82.14:6443 --token 57iu95.6narx7y8peauts76 \ > --discovery-token-ca-cert-hash sha256:5dc8beaa3b0e6fa26b97e2cc3b8ae776d000277fd23a7f8692dc613c6e59f5e4 [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-1.14" 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] Activating the kubelet service [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.
8. 在master节点上查看各节点工作状态
[root@k8s-master ~]# kubectl get nodes NAME STATUS ROLES AGE VERSION k8s-master Ready master 26m v1.14.1 k8s-node1 Ready <none> 84s v1.14.1 k8s-node2 Ready <none> 74s v1.14.1
至此，最简单的集群已经部署完成。
接下来，部署其他插件。
结束.
