kubernetes系列教程(二)kubeadm离线部署1.14.1集群

写在前面

本章是kubernetes系列教程第二=篇,主要介绍通过kubeadm安装工具部署kubernetes集群,考虑到国内网络限制,已将镜像下载到网盘,方便大家可离线部署。

1. 环境概述

1.1 安装概述

kubernetes常规的安装方式包含两种:二进制手动安装和kubeadm自动化安装,新版kubeadm目前已将kubernetes管理组件以pod的形式部署在集群中,社区目前推荐使用kubeadm的方式一件自动化部署,有兴趣的也可以通过二进制的方式一步一步部署kubernetes集群。不管用哪种方式,受限于GFW,大部分镜像需要梯子才能下载,大家自行补脑和解决,本文以离线的方式安装部署,将下载的镜像倒入到各个安装即可。

1.2 环境介绍

软件版本

软件名

软件版本

OS

CentOS Linux release 7.6.1810 (Core)

Docker

docker-ce-18.03.1.ce-1.el7

Kubernetes

1.14.1

Kubeadm

kubeadm-1.14.1-0.x86_64

etcd

3.3.10

flannel

v0.11.0

环境说明,三台机器均为腾讯云上购买的CVM(Cloud Virtual Machine),机器配置是2vcpu+4G memory+50G disk

主机名

角色

IP地址

软件

node-1

master

10.254.100.101

docker,kubelet,etcd,kube-apiserver,kube-controller-manager,kube-scheduler

node-2

worker

10.254.100.102

docker,kubelet,kube-proxy,flannel

node-3

worker

10.254.100.103

docker,kubelet,kube-proxy,flannel

1.3 环境准备

1. 设置主机名,其他两个节点类似设置
root@VM_100_101_centos ~# hostnamectl set-hostname node-1
root@VM_100_101_centos ~# hostname
node-1
2. 设置hosts文件,其他两个节点设置相同内容
root@node-1 ~# vim /etc/hosts
127.0.0.1 localhost localhost.localdomain 
10.254.100.101 node-1
10.254.100.102 node-2
10.254.100.103 node-3
3.设置无密码登陆
生成密钥对
root@node-1 .ssh# ssh-keygen -P ''
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa): 
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:zultDMEL8bZmpbUjQahVjthVAcEkN929w5EkUmPkOrU root@node-1
The key's randomart image is:
+---RSA 2048----+
|      .=O=+=o.. |
|     o+o..+.o+  |
|    .oo=.   o. o |
|    . . * oo .+  |
|       oSOo.E  . |
|       oO.o.     |
|       o++ .     |
|       . .o      |
|        ...      |
+----SHA256-----+
拷贝公钥到node-2和node-3节点
root@node-1 .ssh# ssh-copy-id -i /root/.ssh/id_rsa.pub node-2:
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub"
The authenticity of host 'node-1 (10.254.100.101)' can't be established.
ECDSA key fingerprint is SHA256:jLUH0exgyJdsy0frw9R+FiWy+0o54LgB6dgVdfc6SEE.
ECDSA key fingerprint is MD5:f4:86:a8:0e:a6:03:fc:a6:04:df:91:d8:7a:a7:0d:9e.
Are you sure you want to continue connecting (yes/no)? yes
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
root@node-1's password: 
Number of key(s) added: 1
Now try logging into the machine, with:   "ssh 'node-2'"
and check to make sure that only the key(s) you wanted were added.
拷贝公钥到node-3节点
root@node-1 .ssh# ssh-copy-id -i /root/.ssh/id_rsa.pub node-3:
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub"
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
root@node-3's password: 
Number of key(s) added: 1
Now try logging into the machine, with:   "ssh 'node-3'"
and check to make sure that only the key(s) you wanted were added.
4.测试无密码登陆
root@node-1 ~# ssh node-2 hostname
node-2
root@node-1 ~# ssh node-3 hostname
node-3
5. 关闭防火墙和SElinux
[root@node-1 ~]# systemctl stop firewalld
[root@node-1 ~]# systemctl disable firewalld
[root@node-1 ~]# sed -i '/^SELINUX=/ s/enforcing/disabled/g' /etc/selinux/config 
[root@node-1 ~]# setenforce 0

1.4 安装Docker

1. 下载docker源
[root@node-1 ~]# wget -O /etc/yum.repos.d/docker-ce.repo https://download.docker.com/linux/centos/docker-ce.repo
2.安装docker-ce
[root@node-1 ~]# yum install docker-ce-18.03.1.ce-1.el7.centos
3. 设置cgroup driver类型为systemd
[root@node-1 ~]# cat > /etc/docker/daemon.json <<EOF
> {
>  "exec-opts": ["native.cgroupdriver=systemd"],
>  "log-driver": "json-file",
>  "log-opts": {
>  "max-size": "100m"
>  },
>  "storage-driver": "overlay2",
>  "storage-opts": [
>  "overlay2.override_kernel_check=true"
>  ]
> }
> EOF
4. 启动docker服务并验证
[root@node-1 ~]# systemctl restart docker
[root@node-1 ~]# systemctl enable docker
Created symlink from /etc/systemd/system/multi-user.target.wants/docker.service to /usr/lib/systemd/system/docker.service.
[root@node-1 ~]# docker version
Containers: 0
 Running: 0
 Paused: 0
 Stopped: 0
Images: 8
Server Version: 18.03.1-ce
Storage Driver: overlay2
 Backing Filesystem: extfs
 Supports d_type: true
 Native Overlay Diff: true
Logging Driver: json-file
Cgroup Driver: systemd
Plugins:
 Volume: local
 Network: bridge host macvlan null overlay
 Log: awslogs fluentd gcplogs gelf journald json-file logentries splunk syslog
Swarm: inactive
Runtimes: runc
Default Runtime: runc
Init Binary: docker-init
containerd version: 773c489c9c1b21a6d78b5c538cd395416ec50f88
runc version: 4fc53a81fb7c994640722ac585fa9ca548971871
init version: 949e6fa
Security Options:
 seccomp
  Profile: default
Kernel Version: 3.10.0-957.el7.x86_64
Operating System: CentOS Linux 7 (Core)
OSType: linux
Architecture: x86_64
CPUs: 2
Total Memory: 3.701GiB
Name: node-1
ID: WCUZ:IJ3M:XGX4:S77A:3UG5:PTL4:MFJE:NNUT:IP4J:4PFU:OYMQ:X4LG
Docker Root Dir: /var/lib/docker
Debug Mode (client): false
Debug Mode (server): false
Registry: https://index.docker.io/v1/
Labels:
Experimental: false
Insecure Registries:
 127.0.0.0/8
Live Restore Enabled: false
5. 验证安装
[root@node-1 ~]# docker info
Client:
 Debug Mode: false
Server:
 Containers: 0
 Running: 0
 Paused: 0
 Stopped: 0
 Images: 0
 Server Version: 19.03.1
 Storage Driver: overlay2
 Backing Filesystem: extfs
 Supports d_type: true
 Native Overlay Diff: true
 Logging Driver: json-file
 Cgroup Driver: systemd. #cgroup驱动类型
 Plugins:
 Volume: local
 Network: bridge host ipvlan macvlan null overlay
 Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
 Swarm: inactive
 Runtimes: runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 894b81a4b802e4eb2a91d1ce216b8817763c29fb
 runc version: 425e105d5a03fabd737a126ad93d62a9eeede87f
 init version: fec3683
 Security Options:
 seccomp
 Profile: default
 Kernel Version: 3.10.0-957.el7.x86_64
 Operating System: CentOS Linux 7 (Core)
 OSType: linux
 Architecture: x86_64
 CPUs: 2
 Total Memory: 3.701GiB
 Name: node-1
 ID: WCUZ:IJ3M:XGX4:S77A:3UG5:PTL4:MFJE:NNUT:IP4J:4PFU:OYMQ:X4LG
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Registry: https://index.docker.io/v1/
 Labels:
 Experimental: false
 Insecure Registries:
 127.0.0.0/8
 Live Restore Enabled: false
WARNING: bridge-nf-call-iptables is disabled
WARNING: bridge-nf-call-ip6tables is disabled

2. 安装kubernetes集群

2.1 安装kubeadm等组件

1. 安装kubernetes源,国内可以使用阿里的kubernetes源,速度会快一点
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

2. 安装kubeadm,kubelet,kubectl
[root@node-1 ~]# yum install kubeadm-1.14.1-0 kubectl-1.14.1-0 kubelet-1.14.1-0 --disableexcludes=kubernetes -y
已加载插件:fastestmirror, langpacks
Loading mirror speeds from cached hostfile
正在解决依赖关系
--> 正在检查事务
---> 软件包 kubeadm.x86_64.0.1.14.1-0 将被 安装
--> 正在处理依赖关系 kubernetes-cni >= 0.7.5,它被软件包 kubeadm-1.14.1-0.x86_64 需要
--> 正在处理依赖关系 cri-tools >= 1.11.0,它被软件包 kubeadm-1.14.1-0.x86_64 需要
---> 软件包 kubectl.x86_64.0.1.14.1-0 将被 安装
---> 软件包 kubelet.x86_64.0.1.14.1-0 将被 安装
--> 正在处理依赖关系 socat,它被软件包 kubelet-1.14.1-0.x86_64 需要
--> 正在处理依赖关系 conntrack,它被软件包 kubelet-1.14.1-0.x86_64 需要
--> 正在检查事务
---> 软件包 conntrack-tools.x86_64.0.1.4.4-4.el7 将被 安装
--> 正在处理依赖关系 libnetfilter_cttimeout.so.1(LIBNETFILTER_CTTIMEOUT_1.1)(64bit),它被软件包 conntrack-tools-1.4.4-4.el7.x86_64 需要
--> 正在处理依赖关系 libnetfilter_cttimeout.so.1(LIBNETFILTER_CTTIMEOUT_1.0)(64bit),它被软件包 conntrack-tools-1.4.4-4.el7.x86_64 需要
--> 正在处理依赖关系 libnetfilter_cthelper.so.0(LIBNETFILTER_CTHELPER_1.0)(64bit),它被软件包 conntrack-tools-1.4.4-4.el7.x86_64 需要
--> 正在处理依赖关系 libnetfilter_queue.so.1()(64bit),它被软件包 conntrack-tools-1.4.4-4.el7.x86_64 需要
--> 正在处理依赖关系 libnetfilter_cttimeout.so.1()(64bit),它被软件包 conntrack-tools-1.4.4-4.el7.x86_64 需要
--> 正在处理依赖关系 libnetfilter_cthelper.so.0()(64bit),它被软件包 conntrack-tools-1.4.4-4.el7.x86_64 需要
---> 软件包 cri-tools.x86_64.0.1.13.0-0 将被 安装
---> 软件包 kubernetes-cni.x86_64.0.0.7.5-0 将被 安装
---> 软件包 socat.x86_64.0.1.7.3.2-2.el7 将被 安装
--> 正在检查事务
---> 软件包 libnetfilter_cthelper.x86_64.0.1.0.0-9.el7 将被 安装
---> 软件包 libnetfilter_cttimeout.x86_64.0.1.0.0-6.el7 将被 安装
---> 软件包 libnetfilter_queue.x86_64.0.1.0.2-2.el7_2 将被 安装
--> 解决依赖关系完成

依赖关系解决

==========================================================================================================================================================
 Package                                       架构                          版本                                 源                                 大小
==========================================================================================================================================================
正在安装:
 kubeadm                                       x86_64                        1.14.1-0                             kubernetes                        8.7 M
 kubectl                                       x86_64                        1.14.1-0                             kubernetes                        9.5 M
 kubelet                                       x86_64                        1.14.1-0                             kubernetes                         23 M
为依赖而安装:
 conntrack-tools                               x86_64                        1.4.4-4.el7                          os                                186 k
 cri-tools                                     x86_64                        1.13.0-0                             kubernetes                        5.1 M
 kubernetes-cni                                x86_64                        0.7.5-0                              kubernetes                         10 M
 libnetfilter_cthelper                         x86_64                        1.0.0-9.el7                          os                                 18 k
 libnetfilter_cttimeout                        x86_64                        1.0.0-6.el7                          os                                 18 k
 libnetfilter_queue                            x86_64                        1.0.2-2.el7_2                        os                                 23 k
 socat                                         x86_64                        1.7.3.2-2.el7                        os                                290 k

事务概要
==========================================================================================================================================================
需要安装几个重要依赖包:socat,cri-tools,cni等。

3. 设置iptables网桥参数
[root@node-1 ~]# cat <<EOF >  /etc/sysctl.d/k8s.conf
> net.bridge.bridge-nf-call-ip6tables = 1
> net.bridge.bridge-nf-call-iptables = 1
> EOF
[root@node-1 ~]# sysctl --system,然后使用sysctl -a|grep 参数的方式验证是否生效
4. 启动kubelet服务
[root@node-1 ~]# systemctl restart kubelet
[root@node-1 ~]# systemctl enable kubelet

2.2 倒入安装镜像

从网盘中(地址:https://pan.baidu.com/s/1hw8Q0Vf3xvhKoEiVtMi6SA)将kubernetes所需的镜像下载到本地并解压,进入到kubernetes/v.14.1目录下,执行如下操作步骤:

1.从云盘中下载镜像并上传到各个节点,进入到镜像所在节点,倒入到环境。
[root@node-1 v1.14.1]# docker image load -i etcd:3.3.10.tar 
[root@node-1 v1.14.1]# docker image load -i pause:3.1.tar 
[root@node-1 v1.14.1]# docker image load -i coredns:1.3.1.tar 
[root@node-1 v1.14.1]# docker image load -i flannel:v0.11.0-amd64.tar 
[root@node-1 v1.14.1]# docker image load -i kube-apiserver:v1.14.1.tar 
[root@node-1 v1.14.1]# docker image load -i kube-controller-manager:v1.14.1.tar 
[root@node-1 v1.14.1]# docker image load -i kube-scheduler:v1.14.1.tar 
[root@node-1 v1.14.1]# docker image load -i kube-proxy:v1.14.1.tar 

2. 检查镜像列表
[root@node-1 v1.14.1]# docker image list
REPOSITORY                           TAG                 IMAGE ID            CREATED             SIZE
k8s.gcr.io/kube-proxy                v1.14.1             20a2d7035165        3 months ago        82.1MB
k8s.gcr.io/kube-apiserver            v1.14.1             cfaa4ad74c37        3 months ago        210MB
k8s.gcr.io/kube-scheduler            v1.14.1             8931473d5bdb        3 months ago        81.6MB
k8s.gcr.io/kube-controller-manager   v1.14.1             efb3887b411d        3 months ago        158MB
quay.io/coreos/flannel               v0.11.0-amd64       ff281650a721        6 months ago        52.6MB
k8s.gcr.io/coredns                   1.3.1               eb516548c180        6 months ago        40.3MB
k8s.gcr.io/etcd                      3.3.10              2c4adeb21b4f        8 months ago        258MB
k8s.gcr.io/pause                     3.1                 da86e6ba6ca1        19 months ago       742kB

2.3 kubeadm初始化集群

1. kubeadm初始化集群,使用kubeadm初始化的时候需要使用--pod-network-cidr指定pod使用的网段,设置值根据不同的网络plugin选择,本文以flannel为例设置值为10.244.0.0/16(如果设置不一样,需要在后续初始化网络插件时候和对应插件的yaml文件保持一致),此外如果安装有多个不同的container runtime可以通过--cri-socket指定socket文件所属路径,如果有多个网卡可以通过--apiserver-advertise-address指定master地址,缺省会选择云主机默认网关所属的地址。

[root@node-1 ~]# kubeadm init --apiserver-advertise-address 10.254.100.101 --apiserver-bind-port 6443 --kubernetes-version 1.14.1 --pod-network-cidr 10.244.0.0/16
[init] Using Kubernetes version: v1.14.1
[preflight] Running pre-flight checks
 [WARNING SystemVerification]: this Docker version is not on the list of validated versions: 18.03.1-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'#下载镜像
[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"#生成CA等证书
[certs] Generating "ca" certificate and key
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [node-1 kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 10.254.100.101]
[certs] Generating "apiserver-kubelet-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 [node-1 localhost] and IPs [10.254.100.101 127.0.0.1 ::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 [node-1 localhost] and IPs [10.254.100.101 127.0.0.1 ::1]
[certs] Generating "etcd/healthcheck-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"#生成master节点静态pod配置文件
[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 18.012370 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 node-1 as control-plane by adding the label "node-role.kubernetes.io/master=''"
[mark-control-plane] Marking the node node-1 as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[bootstrap-token] Using token: r8n5f2.9mic7opmrwjakled
[bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles#配置RBAC授权
[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 #配置环境变量配置文件
 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: #安装网络插件
 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 10.254.100.101:6443 --token r8n5f2.9mic7opmrwjakled \ #添加节点命令,优先记录下来
 --discovery-token-ca-cert-hash sha256:16e383c8abff6233021331944080087f0514ddd15d96c65d19443b0af02d64ab 

通过kubeadm init --apiserver-advertise-address 10.254.100.101 --apiserver-bind-port 6443 --kubernetes-version 1.14.1 --pod-network-cidr 10.244.0.0/16安装命令,显示了kubeadm安装过程中的一些重要步骤:下载镜像,生成证书,生成配置文件,配置RBAC授权认证,配置环境变量,安装网络插件指引,添加node指引配置文件。

2.生成kubectl环境配置文件

[root@node-1 ~]# mkdir /root/.kube
[root@node-1 ~]# cp -i /etc/kubernetes/admin.conf /root/.kube/config
[root@node-1 ~]# kubectl get nodes
NAME  STATUS  ROLES AGE  VERSION
node-1  NotReady  master  6m29s  v1.14.1

3. 添加node节点,将另外两个节点加入到集群中,复制上述的添加节点命令到指定节点添加即可。

[root@node-3 ~]# kubeadm join 10.254.100.101:6443 --token r8n5f2.9mic7opmrwjakled \
>     --discovery-token-ca-cert-hash sha256:16e383c8abff6233021331944080087f0514ddd15d96c65d19443b0af02d64ab 
[preflight] Running pre-flight checks
	[WARNING SystemVerification]: this Docker version is not on the list of validated versions: 18.03.1-ce. Latest validated version: 18.09
[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.

以此类推到node-2节点添加即可,添加完之后通过kubectl get nodes验证,此时由于还没有安装网络plugin,
所有的node节点均显示NotReady状态:
[root@node-1 ~]# kubectl get nodes
NAME     STATUS     ROLES    AGE     VERSION
node-1   NotReady   master   16m     v1.14.1
node-2   NotReady   <none>   4m34s   v1.14.1
node-3   NotReady   <none>   2m10s   v1.14.1

4. 安装网络plugin,kubernetes支持多种类型网络插件,要求网络支持CNI插件即可,CNI是Container Network Interface,要求kubernetes的中pod网络访问方式:node和node之间网络互通,pod和pod之间网络互通,node和pod之间网络互通,不同的CNI plugin支持的特性有所差别。kubernetes支持多种开源的网络CNI插件,常见的有flannel,calico,canal,weave等。flannel是一种overlay的网络模型,通过vxlan隧道方式构建tunnel网络,实现k8s中网络的互联,后续在做介绍,如下是安装过程:

[root@node-1 ~]# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/62e44c867a2846fefb68bd5f178daf4da3095ccb/Documentation/kube-flannel.yml
podsecuritypolicy.extensions/psp.flannel.unprivileged created
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
daemonset.extensions/kube-flannel-ds-amd64 created
daemonset.extensions/kube-flannel-ds-arm64 created
daemonset.extensions/kube-flannel-ds-arm created
daemonset.extensions/kube-flannel-ds-ppc64le created
daemonset.extensions/kube-flannel-ds-s390x created

通过上述输出可知道,部署flannel 需要RBAC授权,配置configmap和daemonset,其中Daemonset能够适配各种类型的CPU架构,默认安装了多个,一般是adm64即可,可以将上述的url下载编辑,保留kube-flannel-ds-amd64这个daemonset即可,或者将其删除

1. 查看flannel安装的daemonsets
[root@node-1 ~]# kubectl get daemonsets -n kube-system 
NAME                      DESIRED   CURRENT   READY   UP-TO-DATE   AVAILABLE   NODE SELECTOR                     AGE
kube-flannel-ds-amd64     3         3         3       3            3           beta.kubernetes.io/arch=amd64     2m34s
kube-flannel-ds-arm       0         0         0       0            0           beta.kubernetes.io/arch=arm       2m34s
kube-flannel-ds-arm64     0         0         0       0            0           beta.kubernetes.io/arch=arm64     2m34s
kube-flannel-ds-ppc64le   0         0         0       0            0           beta.kubernetes.io/arch=ppc64le   2m34s
kube-flannel-ds-s390x     0         0         0       0            0           beta.kubernetes.io/arch=s390x     2m34s
kube-proxy                3         3         3       3            3           <none>                            30m

删除不需要的damonsets
[root@node-1 ~]# kubectl delete daemonsets kube-flannel-ds-arm kube-flannel-ds-arm64 kube-flannel-ds-ppc64le kube-flannel-ds-s390x -n kube-system
daemonset.extensions "kube-flannel-ds-arm" deleted
daemonset.extensions "kube-flannel-ds-arm64" deleted
daemonset.extensions "kube-flannel-ds-ppc64le" deleted
daemonset.extensions "kube-flannel-ds-s390x" deleted

此时再验证node的安装情况,所有节点均已显示为Ready状态,安装完毕!

[root@node-1 ~]# kubectl get nodes
NAME     STATUS   ROLES    AGE   VERSION
node-1   Ready    master   29m   v1.14.1
node-2   Ready    <none>   17m   v1.14.1
node-3   Ready    <none>   15m   v1.14.1

2.4 配置kubectl命令补全功能

使用kubectl和kubernetes交互时候可以使用缩写模式也可以使用完整模式,如kubectl get nodes和kubectl get no能实现一样的效果,为了提高工作效率,可以使用命令补全的方式加快工作效率。

[root@node-1 ~]# kubectl completion bash >/etc/kubernetes/kubectl.sh
[root@node-1 ~]# echo "source /etc/kubernetes/kubectl.sh" >>/root/.bashrc 
[root@node-1 ~]# cat /root/.bashrc 
# .bashrc

# User specific aliases and functions

alias rm='rm -i'
alias cp='cp -i'
alias mv='mv -i'

# Source global definitions
if [ -f /etc/bashrc ]; then
	. /etc/bashrc
fi
source /etc/kubernetes/kubectl.

使配置生效
[root@node-1 ~]# source /etc/kubernetes/kubectl.sh 

命令行中输入kubectl get co再按TAB键就能自动补全了
[root@node-1 ~]# kubectl get co
componentstatuses         configmaps                controllerrevisions.apps  
[root@node-1 ~]# kubectl get componentstatuses 

3. 验证安装服务状态

1. 验证node状态

获取node的列表,可以查看到状态, 角色,启动市场,版本,
[root@node-1 ~]# kubectl get nodes 
NAME     STATUS   ROLES    AGE   VERSION
node-1   Ready    master   46m   v1.14.1
node-2   Ready    <none>   34m   v1.14.1
node-3   Ready    <none>   32m   v1.14.1

查看node的详细信息,可以查看到标签,地址,资源情况,资源分配情况,event日志信息等
[root@node-1 ~]# kubectl describe node node-1
Name:               node-1
Roles:              master
Labels:             beta.kubernetes.io/arch=amd64
                    beta.kubernetes.io/os=linux
                    kubernetes.io/arch=amd64
                    kubernetes.io/hostname=node-1
                    kubernetes.io/os=linux
                    node-role.kubernetes.io/master=
Annotations:        flannel.alpha.coreos.com/backend-data: {"VtepMAC":"3a:32:d1:a2:ac:e2"}
                    flannel.alpha.coreos.com/backend-type: vxlan
                    flannel.alpha.coreos.com/kube-subnet-manager: true
                    flannel.alpha.coreos.com/public-ip: 10.254.100.101
                    kubeadm.alpha.kubernetes.io/cri-socket: /var/run/dockershim.sock
                    node.alpha.kubernetes.io/ttl: 0
                    volumes.kubernetes.io/controller-managed-attach-detach: true
CreationTimestamp:  Sat, 10 Aug 2019 17:35:45 +0800
Taints:             node-role.kubernetes.io/master:NoSchedule
Unschedulable:      false
Conditions:
  Type             Status  LastHeartbeatTime                 LastTransitionTime                Reason                       Message
  ----             ------  -----------------                 ------------------                ------                       -------
  MemoryPressure   False   Sat, 10 Aug 2019 18:22:26 +0800   Sat, 10 Aug 2019 17:35:42 +0800   KubeletHasSufficientMemory   kubelet has sufficient memory available
  DiskPressure     False   Sat, 10 Aug 2019 18:22:26 +0800   Sat, 10 Aug 2019 17:35:42 +0800   KubeletHasNoDiskPressure     kubelet has no disk pressure
  PIDPressure      False   Sat, 10 Aug 2019 18:22:26 +0800   Sat, 10 Aug 2019 17:35:42 +0800   KubeletHasSufficientPID      kubelet has sufficient PID available
  Ready            True    Sat, 10 Aug 2019 18:22:26 +0800   Sat, 10 Aug 2019 18:04:26 +0800   KubeletReady                 kubelet is posting ready status
Addresses:
  InternalIP:  10.254.100.101
  Hostname:    node-1
Capacity:
 cpu:                2
 ephemeral-storage:  51473868Ki
 hugepages-2Mi:      0
 memory:             3880524Ki
 pods:               110
Allocatable:
 cpu:                2
 ephemeral-storage:  47438316671
 hugepages-2Mi:      0
 memory:             3778124Ki
 pods:               110
System Info:
 Machine ID:                 0ea734564f9a4e2881b866b82d679dfc
 System UUID:                DA7F90FC-7E95-4570-A0E9-317270B8EE3C
 Boot ID:                    84b9bebb-598b-48ab-b0c4-bbd19d8d566e
 Kernel Version:             3.10.0-957.el7.x86_64
 OS Image:                   CentOS Linux 7 (Core)
 Operating System:           linux
 Architecture:               amd64
 Container Runtime Version:  docker://18.3.1
 Kubelet Version:            v1.14.1
 Kube-Proxy Version:         v1.14.1
PodCIDR:                     10.244.0.0/24
Non-terminated Pods:         (5 in total)
  Namespace                  Name                              CPU Requests  CPU Limits  Memory Requests  Memory Limits  AGE
  ---------                  ----                              ------------  ----------  ---------------  -------------  ---
  kube-system                etcd-node-1                       0 (0%)        0 (0%)      0 (0%)           0 (0%)         46m
  kube-system                kube-apiserver-node-1             250m (12%)    0 (0%)      0 (0%)           0 (0%)         46m
  kube-system                kube-controller-manager-node-1    200m (10%)    0 (0%)      0 (0%)           0 (0%)         46m
  kube-system                kube-proxy-x5t6r                  0 (0%)        0 (0%)      0 (0%)           0 (0%)         47m
  kube-system                kube-scheduler-node-1             100m (5%)     0 (0%)      0 (0%)           0 (0%)         46m
Allocated resources:
  (Total limits may be over 100 percent, i.e., overcommitted.)
  Resource           Requests    Limits
  --------           --------    ------
  cpu                550m (27%)  0 (0%)
  memory             0 (0%)      0 (0%)
  ephemeral-storage  0 (0%)      0 (0%)
Events:
  Type    Reason                   Age                From                Message
  ----    ------                   ----               ----                -------
  Normal  Starting                 47m                kubelet, node-1     Starting kubelet.
  Normal  NodeHasSufficientMemory  47m (x8 over 47m)  kubelet, node-1     Node node-1 status is now: NodeHasSufficientMemory
  Normal  NodeHasNoDiskPressure    47m (x8 over 47m)  kubelet, node-1     Node node-1 status is now: NodeHasNoDiskPressure
  Normal  NodeHasSufficientPID     47m (x7 over 47m)  kubelet, node-1     Node node-1 status is now: NodeHasSufficientPID
  Normal  NodeAllocatableEnforced  47m                kubelet, node-1     Updated Node Allocatable limit across pods
  Normal  Starting                 47m                kube-proxy, node-1  Starting kube-proxy.
  Normal  NodeReady                18m                kubelet, node-1     Node node-1 status is now: NodeReady

2. 查看组建状态,kubernetes中核心的组建,包括scheduler,controller-manager,etcd

[root@node-1 ~]# kubectl get componentstatuses 
NAME  STATUS MESSAGE  ERROR
scheduler Healthy  ok  
controller-manager  Healthy  ok  
etcd-0  Healthy  {"health":"true"}  

3. 查看pod的情况,master中的角色包括kube-apiserver,kube-scheduler,kube-controller-manager,etcd,coredns以pods形式部署在集群中,worker节点的kube-proxy也以pod的形式部署。实际上pod是以其他控制器如daemonset的形式控制的。

查看当前系统中所有运行的pods状态。
[root@node-1 ~]# kubectl get pods -n kube-system 
NAME  READY  STATUS RESTARTS  AGE
coredns-fb8b8dccf-hrqm8 1/1  Running  0 50m
coredns-fb8b8dccf-qwwks 1/1  Running  0 50m
etcd-node-1 1/1  Running  0 48m
kube-apiserver-node-1 1/1  Running  0 49m
kube-controller-manager-node-1  1/1  Running  0 49m
kube-proxy-lfckv  1/1  Running  0 38m
kube-proxy-x5t6r  1/1  Running  0 50m
kube-proxy-x8zqh  1/1  Running  0 36m
kube-scheduler-node-1 1/1  Running  0 49m

查看daemonsets和deployments列表
[root@node-1 ~]# kubectl get ds -n kube-system 
NAME                    DESIRED   CURRENT   READY   UP-TO-DATE   AVAILABLE   NODE SELECTOR                   AGE
kube-flannel-ds-amd64   3         3         3       3            3           beta.kubernetes.io/arch=amd64   3m21s
kube-proxy              3         3         3       3            3           <none>                          58m
[root@node-1 ~]# kubectl get deployments -n kube-system 
NAME      READY   UP-TO-DATE   AVAILABLE   AGE
coredns   2/2     2            2       58m

上述输出中可以看到flannel和kube-proxy是以Daemonsets的形式部署在集群中,coredns是以deployments的形式部署,
但并未看到kube-apiserver等控制器,实际上master的组件是一种静态pod(static pod)的形式部署在集群中。

4. 参考文档

1. Container Runtime安装文档https://kubernetes.io/docs/setup/production-environment/container-runtimes/

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

3. 初始化kubeadm集群https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/create-cluster-kubeadm/#pod-network


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