Ubuntu16.04安装Kubernetes集群

准备工作

规划是使用两台服务器安装kubernetes集群，分别为：kube-1、kube-2。

修改ubuntu国内镜像源

我们这里使用阿里云的镜像，修改 /etc/apt/sources.list 为：

deb http://mirrors.aliyun.com/ubuntu/ xenial main
deb-src http://mirrors.aliyun.com/ubuntu/ xenial main
 
deb http://mirrors.aliyun.com/ubuntu/ xenial-updates main
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-updates main
 
deb http://mirrors.aliyun.com/ubuntu/ xenial universe
deb-src http://mirrors.aliyun.com/ubuntu/ xenial universe
deb http://mirrors.aliyun.com/ubuntu/ xenial-updates universe
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-updates universe
 
deb http://mirrors.aliyun.com/ubuntu/ xenial-security main
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-security main
deb http://mirrors.aliyun.com/ubuntu/ xenial-security universe
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-security universe

添加kubernetes包仓库

并且执行以下命令安装kubernetes的软件源，参考： https://opsx.alibaba.com/mirror

apt-get update && apt-get install -y apt-transport-https
curl 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

安装docker

apt-get install docker.io -y

随后启动docker

service docker start

如果需要普通用户执行 docker 命令，可以参考这篇文章进一步做设置： https://johng.cn/using-docker-without-root/

安装Kubernetes

在kube-1执行安装

我们现在kube-1节点上，使用 kubeadmin 工具包来安装kubernetes，使用以下命令初始化Kubernetes节点：

kubeadm init --image-repository loads  --kubernetes-version v1.13.2

其中， loads 为我个人创建的kubernetes镜像仓库， v1 . 13 . 2 为指定需要安装的kubernetes版本，不同的版本依赖的docker镜像会不同。

执行后，输出结果如下：

root@kube-1:~# kubeadm init --image-repository loads  --kubernetes-version v1.13.2 
[init] Using Kubernetes version: v1.13.2
[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 "front-proxy-ca" certificate and key
[certs] Generating "front-proxy-client" certificate and key
[certs] Generating "etcd/ca" certificate and key
[certs] Generating "etcd/healthcheck-client" certificate and key
[certs] Generating "apiserver-etcd-client" certificate and key
[certs] Generating "etcd/server" certificate and key
[certs] etcd/server serving cert is signed for DNS names [kube-1 localhost] and IPs [192.168.1.9 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [kube-1 localhost] and IPs [192.168.1.9 127.0.0.1 ::1]
[certs] Generating "ca" certificate and key
[certs] Generating "apiserver-kubelet-client" certificate and key
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [kube-1 kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.168.1.9]
[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 28.005808 seconds
[uploadconfig] storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.13" in namespace kube-system with the configuration for the kubelets in the cluster
[patchnode] Uploading the CRI Socket information "/var/run/dockershim.sock" to the Node API object "kube-1" as an annotation
[mark-control-plane] Marking the node kube-1 as control-plane by adding the label "node-role.kubernetes.io/master=''"
[mark-control-plane] Marking the node kube-1 as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[bootstrap-token] Using token: xvm4rc.qmlh7m5uprqfjt9g
[bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles
[bootstraptoken] configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
[bootstraptoken] configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
[bootstraptoken] configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
[bootstraptoken] creating the "cluster-info" ConfigMap in the "kube-public" namespace
[addons] Applied essential addon: CoreDNS
[addons] Applied essential addon: kube-proxy
 
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 192.168.1.9:6443 --token xvm4rc.qmlh7m5uprqfjt9g --discovery-token-ca-cert-hash sha256:bab0a640108a524fefd4574ccb9f63273087936fd403f4b51d6217b903cbf400
 
root@kube-1:~#

根据提示，初始化完成之后我们需要执行以下命令安装kubectl的配置文件：

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

此外，需要注意的是这一段，记录下来，以便后续添加其他节点进入集群：

kubeadm join 192.168.1.9:6443 --token xvm4rc.qmlh7m5uprqfjt9g --discovery-token-ca-cert-hash sha256:bab0a640108a524fefd4574ccb9f63273087936fd403f4b51d6217b903cbf400

在kube-2上执行安装

在kube-2节点上完成准备工作后不要执行 kubeadmininit 指令，而是需要执行 kubeadminjoin 指令加入节点：

root@kube-2:~# kubeadm join 192.168.1.9:6443 --token xvm4rc.qmlh7m5uprqfjt9g --discovery-token-ca-cert-hash sha256:bab0a640108a524fefd4574ccb9f63273087936fd403f4b51d6217b903cbf400
[preflight] Running pre-flight checks
[discovery] Trying to connect to API Server "192.168.1.9:6443"
[discovery] Created cluster-info discovery client, requesting info from "https://192.168.1.9:6443"
[discovery] Requesting info from "https://192.168.1.9:6443" again to validate TLS against the pinned public key
[discovery] Cluster info signature and contents are valid and TLS certificate validates against pinned roots, will use API Server "192.168.1.9:6443"
[discovery] Successfully established connection with API Server "192.168.1.9:6443"
[join] Reading configuration from the cluster...
[join] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
[kubelet] Downloading configuration for the kubelet from the "kubelet-config-1.13" 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
[tlsbootstrap] Waiting for the kubelet to perform the TLS Bootstrap...
[patchnode] Uploading the CRI Socket information "/var/run/dockershim.sock" to the Node API object "kube-2" as an annotation
 
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.
 
root@kube-2:~#

如果之前已经初始化过节点，可随时通过 kubeadminreset 指令重置当前节点配置，并使用 servicekubeletrestart 重启kubelet服务，随后再通过 kubeadminjoin 指令加入集群。

Kubernetes常见问题

1、 runtimenetworknotready : NetworkReady = falsereason : NetworkPluginNotReadymessage : docker : networkpluginisnotready : cniconfiguninitialized

解决：

vim /etc/systemd/system/kubelet.service.d/10-kubeadm.conf

删除最后一行里的 $ KUBELET _ NETWORK _ ARGS ，1.11.2+版本的封装在 / var / lib / kubelet / kubeadm - flags . env 文件中。