如何在Ubuntu 18上安装Kubernetes（）

本文概述

环境详细信息和设置
安装Kubernetes
安装Kubeadm
初始化Kubernetes集群
部署Pod网络-法兰绒
将辅助节点添加到群集

了解如何在Ubuntu上安装Kubernetes。
【如何在Ubuntu 18上安装Kubernetes（）】Kubernetes是Google开发的一种开源容器编排工具。在本文中, 你将学习如何使用主节点和工作节点设置Kubernetes。确保在主节点和辅助节点上都安装了Docker。
环境详细信息和设置为了演示, 我有2个Ubuntu系统, 一个是主节点, 另一个是工作节点。两种服务器的配置如下。

2个CPU
主站– 4 GB RAM /工作者– 2 GB RAM
10 GB硬盘

使用hostnamectl命令在两个系统上都设置主机名。
在主节点上：

[email protected]:~$ sudo hostnamectl set-hostname kubernetes-master

在工作节点上：

[email protected]:~$ sudo hostnamectl set-hostname kubernetes-worker

因此, 以下是两个节点的详细信息。
主节点

主机名：kubernetes-master
IP地址：192.168.0.107

工作节点

主机名：kubernetes-worker
IP地址：192.168.0.108

在两个系统上都编辑主机文件。

[email protected]:~$ sudo gedit /etc/hosts192.168.0.107 kubernetes-master192.168.0.109 kubernetes-worker

在开始安装Kubernetes之前, 请在主节点和工作节点上运行以下命令, 以检查Docker是否已启动并正在运行。

[email protected]:~$ sudo service docker status[sudo] password for geekflare:● docker.service - Docker Application Container EngineLoaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled)Active: active (running) since Sat 2019-11-23 15:39:36 EST; 3 weeks 0 days agoDocs: https://docs.docker.comMain PID: 8840 (dockerd)Tasks: 17Memory: 42.3MCGroup: /system.slice/docker.service└─8840 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sockNov 23 15:39:35 geekflare dockerd[8840]: time="2019-11-23T15:39:35.091941184-05:00" level=warning msg="Your kernel does not support cgrouNov 23 15:39:35 geekflare dockerd[8840]: time="2019-11-23T15:39:35.093149218-05:00" level=info msg="Loading containers: start."Nov 23 15:39:35 geekflare dockerd[8840]: time="2019-11-23T15:39:35.957842188-05:00" level=info msg="Default bridge (docker0) is assignedNov 23 15:39:36 geekflare dockerd[8840]: time="2019-11-23T15:39:36.078753190-05:00" level=info msg="Loading containers: done."Nov 23 15:39:36 geekflare dockerd[8840]: time="2019-11-23T15:39:36.664727326-05:00" level=info msg="Docker daemon" commit=481bc77 graphdrNov 23 15:39:36 geekflare dockerd[8840]: time="2019-11-23T15:39:36.817929464-05:00" level=error msg="cluster exited with error: error whiNov 23 15:39:36 geekflare dockerd[8840]: time="2019-11-23T15:39:36.820439024-05:00" level=error msg="swarm component could not be startedNov 23 15:39:36 geekflare dockerd[8840]: time="2019-11-23T15:39:36.820821712-05:00" level=info msg="Daemon has completed initialization"Nov 23 15:39:36 geekflare systemd[1]: Started Docker Application Container Engine.Nov 23 15:39:36 geekflare dockerd[8840]: time="2019-11-23T15:39:36.883382952-05:00" level=info msg="API listen on /home/geekflare/docker.socklines 1-20/20 (END)

安装Kubernetes在主节点和辅助节点上运行本节中提到的所有命令。
首先, 添加Kubernetes软件包存储库密钥。

[email protected]:~$ curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add[sudo] password for geekflare:OK

运行以下命令以配置Kubernetes软件包存储库。

[email protected]:~$ sudo apt-add-repository "deb http://apt.kubernetes.io/ kubernetes-xenial main"Hit:1 https://download.docker.com/linux/ubuntu bionic InReleaseHit:2 http://ppa.launchpad.net/ansible/ansible/ubuntu cosmic InReleaseGet:3 http://apt.puppetlabs.com bionic InRelease [85.3 kB]Hit:5 http://security.ubuntu.com/ubuntu cosmic-security InReleaseHit:6 http://us.archive.ubuntu.com/ubuntu cosmic InReleaseIgn:7 http://pkg.jenkins.io/debian-stable binary/ InReleaseHit:8 http://us.archive.ubuntu.com/ubuntu cosmic-updates InReleaseHit:9 http://pkg.jenkins.io/debian-stable binary/ ReleaseHit:10 http://us.archive.ubuntu.com/ubuntu cosmic-backports InReleaseGet:4 https://packages.cloud.google.com/apt kubernetes-xenial InRelease [8, 993 B]Get:11 http://apt.puppetlabs.com bionic/puppet6 amd64 Packages [36.1 kB]Get:13 https://packages.cloud.google.com/apt kubernetes-xenial/main amd64 Packages [32.2 kB]Fetched 163 kB in 3s (49.1 kB/s)Reading package lists... Done

在继续之前, 请在两个节点上禁用交换。

[email protected]:~$ sudo swapoff -a

安装Kubeadm现在, 你需要安装kubeadm。
kubeadm是Kubernetes中的一个工具, 用于在Kubernetes集群中添加节点。

[email protected]:~$ sudo apt-get install kubeadm -yReading package lists... DoneBuilding dependency treeReading state information... DoneThe following additional packages will be installed:conntrack cri-tools ebtables ethtool kubectl kubelet kubernetes-cni socatThe following NEW packages will be installed:conntrack cri-tools ebtables ethtool kubeadm kubectl kubelet kubernetes-cni socat0 upgraded, 9 newly installed, 0 to remove and 235 not upgraded.Need to get 51.8 MB of archives.After this operation, 273 MB of additional disk space will be used.Get:3 http://us.archive.ubuntu.com/ubuntu cosmic/main amd64 conntrack amd64 1:1.4.5-1 [30.2 kB]Get:1 https://packages.cloud.google.com/apt kubernetes-xenial/main amd64 cri-tools amd64 1.13.0-00 [8, 776 kB]Get:6 http://us.archive.ubuntu.com/ubuntu cosmic/main amd64 ebtables amd64 2.0.10.4-3.5ubuntu5 [79.8 kB]Get:8 http://us.archive.ubuntu.com/ubuntu cosmic/main amd64 ethtool amd64 1:4.16-1 [115 kB]Get:9 http://us.archive.ubuntu.com/ubuntu cosmic/main amd64 socat amd64 1.7.3.2-2ubuntu2 [342 kB]Get:2 https://packages.cloud.google.com/apt kubernetes-xenial/main amd64 kubernetes-cni amd64 0.7.5-00 [6, 473 kB]Get:4 https://packages.cloud.google.com/apt kubernetes-xenial/main amd64 kubelet amd64 1.17.0-00 [19.2 MB]Get:5 https://packages.cloud.google.com/apt kubernetes-xenial/main amd64 kubectl amd64 1.17.0-00 [8, 742 kB]Get:7 https://packages.cloud.google.com/apt kubernetes-xenial/main amd64 kubeadm amd64 1.17.0-00 [8, 059 kB]Fetched 51.8 MB in 8s (6, 419 kB/s)Selecting previously unselected package conntrack.(Reading database ... 318151 files and directories currently installed.)Preparing to unpack .../0-conntrack_1%3a1.4.5-1_amd64.deb ...Unpacking conntrack (1:1.4.5-1) ...Selecting previously unselected package cri-tools.Preparing to unpack .../1-cri-tools_1.13.0-00_amd64.deb ...Unpacking cri-tools (1.13.0-00) ...Selecting previously unselected package ebtables.Preparing to unpack .../2-ebtables_2.0.10.4-3.5ubuntu5_amd64.deb ...Unpacking ebtables (2.0.10.4-3.5ubuntu5) ...Selecting previously unselected package ethtool.Preparing to unpack .../3-ethtool_1%3a4.16-1_amd64.deb ...Unpacking ethtool (1:4.16-1) ...Selecting previously unselected package kubernetes-cni.Preparing to unpack .../4-kubernetes-cni_0.7.5-00_amd64.deb ...Unpacking kubernetes-cni (0.7.5-00) ...Selecting previously unselected package socat.Preparing to unpack .../5-socat_1.7.3.2-2ubuntu2_amd64.deb ...Unpacking socat (1.7.3.2-2ubuntu2) ...Selecting previously unselected package kubelet.Preparing to unpack .../6-kubelet_1.17.0-00_amd64.deb ...Unpacking kubelet (1.17.0-00) ...Selecting previously unselected package kubectl.Preparing to unpack .../7-kubectl_1.17.0-00_amd64.deb ...Unpacking kubectl (1.17.0-00) ...Selecting previously unselected package kubeadm.Preparing to unpack .../8-kubeadm_1.17.0-00_amd64.deb ...Unpacking kubeadm (1.17.0-00) ...Setting up conntrack (1:1.4.5-1) ...Setting up kubernetes-cni (0.7.5-00) ...Setting up cri-tools (1.13.0-00) ...Setting up socat (1.7.3.2-2ubuntu2) ...Processing triggers for systemd (239-7ubuntu10.12) ...Setting up ebtables (2.0.10.4-3.5ubuntu5) ...Created symlink /etc/systemd/system/multi-user.target.wants/ebtables.service → /lib/systemd/system/ebtables.service.update-rc.d: warning: start and stop actions are no longer supported; falling back to defaultsSetting up kubectl (1.17.0-00) ...Processing triggers for man-db (2.8.4-2) ...Setting up ethtool (1:4.16-1) ...Setting up kubelet (1.17.0-00) ...Created symlink /etc/systemd/system/multi-user.target.wants/kubelet.service → /lib/systemd/system/kubelet.service.Setting up kubeadm (1.17.0-00) ...Processing triggers for systemd (239-7ubuntu10.12) ...

检查kubeadm版本以验证其是否正确安装。

[email protected]:~$ kubeadm versionkubeadm version: & version.Info{Major:"1", Minor:"17", GitVersion:"v1.17.0", GitCommit:"70132b0f130acc0bed193d9ba59dd186f0e634cf", GitTreeState:"clean", BuildDate:"2019-12-07T21:17:50Z", GoVersion:"go1.13.4", Compiler:"gc", Platform:"linux/amd64"}

初始化Kubernetes集群现在, 运行init命令仅在主节点上初始化Kubernetes集群。使用– apiserver-advertise-address告知工作节点主服务器的IP地址。

[email protected]:~$ sudo kubeadm init --apiserver-advertise-address=192.168.0.107 --pod-network-cidr=10.244.0.0/16W1217 11:05:15.474854 10193 validation.go:28] Cannot validate kube-proxy config - no validator is availableW1217 11:05:15.474935 10193 validation.go:28] Cannot validate kubelet config - no validator is available[init] Using Kubernetes version: v1.17.0[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/[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] Starting the kubelet[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 [kubernetes-master kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.168.0.107][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 [kubernetes-master localhost] and IPs [192.168.0.107 127.0.0.1 ::1][certs] Generating "etcd/peer" certificate and key[certs] etcd/peer serving cert is signed for DNS names [kubernetes-master localhost] and IPs [192.168.0.107 127.0.0.1 ::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"W1217 11:05:25.584769 10193 manifests.go:214] the default kube-apiserver authorization-mode is "Node, RBAC"; using "Node, RBAC"[control-plane] Creating static Pod manifest for "kube-scheduler"W1217 11:05:25.587128 10193 manifests.go:214] the default kube-apiserver authorization-mode is "Node, RBAC"; using "Node, RBAC"[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 35.010368 seconds[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace[kubelet] Creating a ConfigMap "kubelet-config-1.17" 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 kubernetes-master as control-plane by adding the label "node-role.kubernetes.io/master=''"[mark-control-plane] Marking the node kubernetes-master as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule][bootstrap-token] Using token: dmamk9.0nmo62mhom8961qw[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[kubelet-finalize] Updating "/etc/kubernetes/kubelet.conf" to point to a rotatable kubelet client certificate and key[addons] Applied essential addon: CoreDNS[addons] Applied essential addon: kube-proxyYour Kubernetes control-plane has initialized successfully!

要开始使用群集, 你需要以普通用户身份运行以下命令：

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

接下来, 你需要在群集上部署Pod网络。
使用https://kubernetes.io/docs/concepts/cluster-administration/addons/中列出的选项之一运行kubectl apply -f [podnetwork] .yaml
然后, 你可以通过以root身份在每个工作节点上运行以下命令来加入任意数量的工作程序节点：

kubeadm join 192.168.0.107:6443 --token dmamk9.0nmo62mhom8961qw --discovery-token-ca-cert-hash sha256:2de92f42e84d2020d8b19b1778785df5f8196e5eedaa5664ad911e8c23f58963

如上面的输出所述, 创建.kube目录并将admin.conf文件复制到.kube目录中的配置文件。

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

这时, 当你运行kubectl get nodes命令时, 你将看到主节点的状态为NotReady。

[email protected]:~$ sudo kubectl get nodesNAME STATUS ROLES AGE VERSIONkubernetes-master NotReady master 2m34s v1.17.0

部署Pod网络-法兰绒接下来, 你需要在主节点上部署Pod网络。我正在使用Flannel pod网络。它用于在Kubernetes集群中的节点之间进行通信。

[email protected]:~$ sudo kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.ymlpodsecuritypolicy.policy/psp.flannel.unprivileged createdclusterrole.rbac.authorization.k8s.io/flannel createdclusterrolebinding.rbac.authorization.k8s.io/flannel createdserviceaccount/flannel createdconfigmap/kube-flannel-cfg createddaemonset.apps/kube-flannel-ds-amd64 createddaemonset.apps/kube-flannel-ds-arm64 createddaemonset.apps/kube-flannel-ds-arm createddaemonset.apps/kube-flannel-ds-ppc64le createddaemonset.apps/kube-flannel-ds-s390x created

检查主节点的状态, 它必须处于” 就绪” 状态。

[email protected]:~$ sudo kubectl get nodesNAME STATUS ROLES AGE VERSIONkubernetes-master Ready master 4m41s v1.17.0

几秒钟后, 检查所有Pod是否已启动并运行。

[email protected]:~$ kubectl get pods --all-namespacesNAMESPACE NAME READY STATUS RESTARTS AGEkube-system coredns-6955765f44-rzw9d 1/1 Running 0 4m17skube-system coredns-6955765f44-xvgdp 1/1 Running 0 4m17skube-system etcd-kubernetes-master 1/1 Running 0 4m27skube-system kube-apiserver-kubernetes-master 1/1 Running 0 4m27skube-system kube-controller-manager-kubernetes-master 1/1 Running 0 4m27skube-system kube-flannel-ds-amd64-c2rf5 1/1 Running 0 81skube-system kube-proxy-mvdd7 1/1 Running 0 4m17skube-system kube-scheduler-kubernetes-master 1/1 Running 0 4m27s

将辅助节点添加到群集现在你的主节点已正确配置并正在运行, 是时候添加工作节点了。在这里, 你需要在初始化kubeadm之后获得的worker节点上运行join命令。
在工作节点上运行以下命令以加入主节点。

[email protected]:~$ sudo kubeadm join 192.168.0.107:6443 --token dmamk9.0nmo62mhom8961qw --discovery-token-ca-cert-hash sha256:2de92f42e84d2020d8b19b1778785df5f8196e5eedaa5664ad911e8c23f58963[sudo] password for geekflare:W1217 11:08:01.066191 28968 join.go:346] [preflight] WARNING: JoinControlPane.controlPlane settings will be ignored when control-plane flag is not set.[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/[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-1.17" 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] Starting the kubelet[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.

在主节点上：
在工作程序节点加入集群之后, 你将看到更多的Pod正在运行。

[email protected]:~$ kubectl get pods --all-namespacesNAMESPACE NAME READY STATUS RESTARTS AGEkube-system coredns-6955765f44-9c7jc 1/1 Running 0 5m3skube-system coredns-6955765f44-c9s9r 1/1 Running 0 5m3skube-system etcd-kubernetes-master 1/1 Running 0 5m12skube-system kube-apiserver-kubernetes-master 1/1 Running 0 5m12skube-system kube-controller-manager-kubernetes-master 1/1 Running 0 5m13skube-system kube-flannel-ds-amd64-lgr62 1/1 Running 0 3m35skube-system kube-flannel-ds-amd64-n6vwm 1/1 Running 0 27skube-system kube-proxy-9mqp6 1/1 Running 0 27skube-system kube-proxy-kwkz2 1/1 Running 0 5m3skube-system kube-scheduler-kubernetes-master 1/1 Running 0 5m13s

现在, 在主节点上再次运行kubectl命令, 以检查工作节点是否已加入集群并且它是否以” 就绪” 状态运行。

[email protected]:~$ kubectl get nodesNAME STATUS ROLES AGE VERSIONkubernetes-master Ready master 5m27s v1.17.0kubernetes-worker Ready < none> 31s v1.17.0

总结
现在已经准备好Kubernetes设置, 你可以开始在Kubernetes集群上编排容器了。如果Kubernetes的事情使你兴奋, 那么你可能想通过学习Udemy课程来学习。