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CentOS 7.6安装Kubernetes v1.15.1

[日期:2019-07-31] 来源:51cto.com/zlyang  作者:yangxuncai110 [字体: ]

kubeadm是Kubernetes官方提供的用于快速安装Kubernetes集群的工具,伴随Kubernetes每个版本的发布都会同步更新,kubeadm会对集群配置方面的一些实践做调整,通过实验kubeadm可以学习到Kubernetes官方在集群配置上一些新的最佳实践。

最近发布的Kubernetes 1.15中,kubeadm对HA集群的配置已经达到beta可用,说明kubeadm距离生产环境中可用的距离越来越近了。

CentOS7.6安装Kubernetes v1.15.1

Kubernetes集群组件:

  • etcd 一个高可用的K/V键值对存储和服务发现系统
  • flannel 实现夸主机的容器网络的通信
  • kube-apiserver 提供kubernetes集群的API调用
  • kube-controller-manager 确保集群服务
  • kube-scheduler 调度容器,分配到Node
  • kubelet 在Node节点上按照配置文件中定义的容器规格启动容器
  • kube-proxy 提供网络代理服务

一、环境介绍

主机名 IP地址
k8s-master 192.168.169.21
k8s-node1 192.168.169.24
k8s-node2 192.168.169.25
k8s-node3 192.168.169.26

1、操作系统: CensOS7.6

[root@k8s-master ~]# cat /etc/RedHat-release
  CentOS Linux release 7.6.1810 (Core)


2、Kubernetes版本 v1.15.0

    kube-apiserver              v1.15.0
    kube-controller-manager    v1.15.0
    kube-proxy                  v1.15.0
    kube-scheduler              v1.15.0
    etcd                        3.3.10
    pause                      3.1
    coredns                    1.3.1


二、准备

2.1系统配置

在安装之前,需要先做如下准备。4台CentOS 7.6主机如下:

升级系统

# yum -y update


配置Host

# cat /etc/hosts
127.0.0.1    localhost
192.168.1.21    k8s-master
192.168.1.24    k8s-node1
192.168.1.25    k8s-node2
192.168.1.26    k8s-node3


如果各个主机启用了防火墙,需要开放Kubernetes各个组件所需要的端口,可以查看Installing kubeadm中的”Check required ports”一节。 这里简单起见在各节点禁用防火墙:

# systemctl stop firewalld
# systemctl disable firewalld


禁用SELINUX:

# setenforce 0
# sed -i 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/selinux/config
#
SELINUX=disabled


创建/etc/sysctl.d/k8s.conf文件,添加如下内容:

net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1


执行命令使修改生效。

# modprobe br_netfilter
# sysctl -p /etc/sysctl.d/k8s.conf


2.2kube-proxy开启ipvs的前置条件

由于ipvs已经加入到了内核的主干,所以为kube-proxy开启ipvs的前提需要加载以下的内核模块:

ip_vs
ip_vs_rr
ip_vs_wrr
ip_vs_sh
nf_conntrack_ipv4


在所有的Kubernetes节点上执行以下脚本:

# cat > /etc/sysconfig/modules/ipvs.modules <<EOF
#!/bin/bash
modprobe -- ip_vs
modprobe -- ip_vs_rr
modprobe -- ip_vs_wrr
modprobe -- ip_vs_sh
modprobe -- nf_conntrack_ipv4
EOF
# chmod 755 /etc/sysconfig/modules/ipvs.modules && bash /etc/sysconfig/modules/ipvs.modules && lsmod | grep -e ip_vs -e nf_conntrack_ipv4


上面脚本创建了的/etc/sysconfig/modules/ipvs.modules文件,保证在节点重启后能自动加载所需模块。 使用lsmod | grep -e ip_vs -e nf_conntrack_ipv4命令查看是否已经正确加载所需的内核模块。

接下来还需要确保各个节点上已经安装了ipset软件包

# yum -y install ipset


为了便于查看ipvs的代理规则,最好安装一下管理工具ipvsadm

# yum -y install ipvsadm


如果以上前提条件如果不满足,则即使kube-proxy的配置开启了ipvs模式,也会退回到iptables模式

2.3安装Docker

Kubernetes从1.6开始使用CRI(Container Runtime Interface)容器运行时接口。默认的容器运行时仍然是Docker,使用的是kubelet中内置dockershim CRI实现。

安装docker的yum源:

# yum install -y yum-utils device-mapper-persistent-data lvm2
# yum-config-manager \
    --add-repo \
    https://download.docker.com/linux/centos/docker-ce.repo


查看最新的Docker版本:

# yum list docker-ce.x86_64  --showduplicates |sort -r
docker-ce.x86_64            3:18.09.7-3.el7                    docker-ce-stable
docker-ce.x86_64            3:18.09.6-3.el7                    docker-ce-stable
docker-ce.x86_64            3:18.09.5-3.el7                    docker-ce-stable
docker-ce.x86_64            3:18.09.4-3.el7                    docker-ce-stable
docker-ce.x86_64            3:18.09.3-3.el7                    docker-ce-stable
docker-ce.x86_64            3:18.09.2-3.el7                    docker-ce-stable
docker-ce.x86_64            3:18.09.1-3.el7                    docker-ce-stable
docker-ce.x86_64            3:18.09.0-3.el7                    docker-ce-stable
docker-ce.x86_64            18.06.3.ce-3.el7                    docker-ce-stable
docker-ce.x86_64            18.06.2.ce-3.el7                    docker-ce-stable
docker-ce.x86_64            18.06.1.ce-3.el7                    docker-ce-stable
docker-ce.x86_64            18.06.0.ce-3.el7                    docker-ce-stable
docker-ce.x86_64            18.03.1.ce-1.el7.centos            docker-ce-stable
docker-ce.x86_64            18.03.0.ce-1.el7.centos            docker-ce-stable


Kubernetes 1.15当前支持的docker版本列表是1.13.1, 17.03, 17.06, 17.09, 18.06, 18.09。 这里在各节点安装docker的18.09.7版本。

# yum makecache fast
# yum install -y --setopt=obsoletes=0 docker-ce
# systemctl start docker
# systemctl enable docker

 

 

安装指定版本docker
yum install -y –setopt=obsoletes=0 \ docker-ce-18.09.7-3.el7
确认一下iptables filter表中FOWARD链的默认策略(pllicy)为ACCEPT。

# iptables -nvL
Chain INPUT (policy ACCEPT 263 packets, 19209 bytes)
 pkts bytes target    prot opt in    out    source              destination

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target    prot opt in    out    source              destination
    0    0 DOCKER-USER  all  --  *      *      0.0.0.0/0            0.0.0.0/0
    0    0 DOCKER-ISOLATION-STAGE-1  all  --  *      *      0.0.0.0/0            0.0.0.0/0
    0    0 ACCEPT    all  --  *      docker0  0.0.0.0/0            0.0.0.0/0            ctstate RELATED,ESTABLISHED
    0    0 DOCKER    all  --  *      docker0  0.0.0.0/0            0.0.0.0/0
    0    0 ACCEPT    all  --  docker0 !docker0  0.0.0.0/0            0.0.0.0/0
    0    0 ACCEPT    all  --  docker0 docker0  0.0.0.0/0            0.0.0.0/0


2.4 修改docker cgroup driver为systemd

根据文档CRI installation中的内容,对于使用systemd作为init system的Linux的发行版,使用systemd作为docker的cgroup driver可以确保服务器节点在资源紧张的情况更加稳定,因此这里修改各个节点上docker的cgroup driver为systemd。

创建或修改/etc/docker/daemon.json:

{
  "exec-opts": ["native.cgroupdriver=systemd"]
}

 

 

 *如果机器是代理上网,需要配置docker的http代理:
# mkdir /etc/systemd/system/docker.service.d
# vim /etc/systemd/system/docker.service.d/http-proxy.conf
[Service]
Environment=”HTTP_PROXY=http://192.168.1.1:3128″
重启docker:

# systemctl daemon-reload
# systemctl restart docker
# docker info | grep Cgroup
Cgroup Driver: systemd
# systemctl show docker --property Environment


三、使用kubeadm部署Kubernetes

3.1 安装kubeadm和kubelet

Master配置

安装kubeadm和kubelet:

3.1.1、配置kubernetes.repo的源,由于官方源国内无法访问,这里使用阿里云yum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


测试地址https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64是否可用,如果不可用需要×××

# curl https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/


# yum -y makecache fast
# yum install -y kubelet kubeadm kubectl

...
Installed:
  kubeadm.x86_64 0:1.15.0-0                  kubectl.x86_64 0:1.15.0-0                      kubelet.x86_64 0:1.15.0-0                               

Dependency Installed:
  conntrack-tools.x86_64 0:1.4.4-4.el7            cri-tools.x86_64 0:1.12.0-0                  kubernetes-cni.x86_64 0:0.7.5-0    libnetfilter_cthelper.x86_64 0:1.0.0-9.el7   
  libnetfilter_cttimeout.x86_64 0:1.0.0-6.el7    libnetfilter_queue.x86_64 0:1.0.2-2.el7_2


从安装结果可以看出还安装了cri-tools, kubernetes-cni, socat三个依赖:

•官方从Kubernetes 1.14开始将cni依赖升级到了0.7.5版本


•socat是kubelet的依赖


•cri-tools是CRI(Container Runtime Interface)容器运行时接口的命令行工具


运行kubelet –help可以看到原来kubelet的绝大多数命令行flag参数都被DEPRECATED了,如:

......
--address 0.0.0.0  The IP address for the Kubelet to serve on (set to 0.0.0.0 for all IPv4 interfaces and `::` for all IPv6 interfaces) (default 0.0.0.0) (DEPRECATED: This parameter should be set via the config file specified by the Kubelet's --config flag. See https://kubernetes.io/docs/tasks/administer-cluster/kubelet-config-file/ for more information.)
......


而官方推荐我们使用–config指定配置文件,并在配置文件中指定原来这些flag所配置的内容。具体内容可以查看这里Set Kubelet parameters via a config file。这也是Kubernetes为了支持动态Kubelet配置(Dynamic Kubelet Configuration)才这么做的,参考Reconfigure a Node’s Kubelet in a Live Cluster。

kubelet的配置文件必须是json或yaml格式,具体可查看这里。

Kubernetes 1.8开始要求关闭系统的Swap,如果不关闭,默认配置下kubelet将无法启动。 关闭系统的Swap方法如下:

#  swapoff -a


修改 /etc/fstab 文件,注释掉 SWAP 的自动挂载,

# UUID=2d1e946c-f45d-4516-86cf-946bde9bdcd8 swap                    swap    defaults        0 0


使用free -m确认swap已经关闭。 swappiness参数调整,修改/etc/sysctl.d/k8s.conf添加下面一行:

 vm.swappiness=0


使修改生效

 # sysctl -p /etc/sysctl.d/k8s.conf


3.2 使用kubeadm init初始化集群

开机启动kubelet服务:

systemctl enable kubelet.service


配置Master节点

# mkdir working && cd working


生成配置文件

# kubeadm config print init-defaults ClusterConfiguration > kubeadm.yaml


修改配置文件

# vim kubeadm.yaml

# 修改imageRepository:k8s.gcr.io
 imageRepository: registry.aliyuncs.com/google_containers
# 修改KubernetesVersion:v1.15.0
 kubernetesVersion: v1.15.0
# 配置MasterIP
 advertiseAddress: 192.168.1.21
# 配置子网网络
 networking:
  dnsDomain: cluster.local
  podSubnet: 10.244.0.0/16
  serviceSubnet: 10.96.0.0/12
 scheduler: {}

使用kubeadm默认配置初始化的集群,会在master节点打上node-role.kubernetes.io/master:NoSchedule的污点,阻止master节点接受调度运行工作负载。这里测试环境只有两个节点,所以将这个taint修改为node-role.kubernetes.io/master:PreferNoSchedule。
在开始初始化集群之前可以使用kubeadm config images pull预先在各个节点上拉取所k8s需要的docker镜像。

接下来使用kubeadm初始化集群,选择node1作为Master Node,在node1上执行下面的命令:

# kubeadm init --config kubeadm.yaml --ignore-preflight-errors=Swap
..........
 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 192.168.1.21:6443 --token 4qcl2f.gtl3h8e5kjltuo0r \    --discovery-token-ca-cert-hash sha256:7ed5404175cc0bf18dbfe53f19d4a35b1e3d40c19b10924275868ebf2a3bbe6e

注意这一条命令需要保存好(添加集群使用)
kubeadm join 192.168.169.21:6443 –token 4qcl2f.gtl3h8e5kjltuo0r \ –discovery-token-ca-cert-hash sha256:7ed5404175cc0bf18dbfe53f19d4a35b1e3d40c19b10924275868ebf2a3bbe6e
上面记录了完成的初始化输出的内容,根据输出的内容基本上可以看出手动初始化安装一个Kubernetes集群所需要的关键步骤。 其中有以下关键内容:

[kubelet-start] 生成kubelet的配置文件”/var/lib/kubelet/config.yaml”

[certs]生成相关的各种证书

[kubeconfig]生成相关的kubeconfig文件

[control-plane]使用/etc/kubernetes/manifests目录中的yaml文件创建apiserver、controller-manager、scheduler的静态pod

[bootstraptoken]生成token记录下来,后边使用kubeadm join往集群中添加节点时会用到

下面的命令是配置常规用户如何使用kubectl访问集群:

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

最后给出了将节点加入集群的命令kubeadm join 192.168.169.21:6443 –token 4qcl2f.gtl3h8e5kjltuo0r \ –discovery-token-ca-cert-hash sha256:7ed5404175cc0bf18dbfe53f19d4a35b1e3d40c19b10924275868ebf2a3bbe6e

查看一下集群状态,确认个组件都处于healthy状态:

# kubectl get cs
NAME                STATUS    MESSAGE            ERROR
controller-manager  Healthy  ok                 
scheduler            Healthy  ok                 
etcd-0              Healthy  {"health":"true"}

集群初始化如果遇到问题,可以使用下面的命令进行清理:

# kubeadm reset
# ifconfig cni0 down
# ip link delete cni0
# ifconfig flannel.1 down
# ip link delete flannel.1
# rm -rf /var/lib/cni/

3.3 安装Pod Network

接下来安装flannel network add-on:

# mkdir -p ~/k8s/
# cd ~/k8s
# curl -O https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
# kubectl apply -f  kube-flannel.yml

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

这里注意kube-flannel.yml这个文件里的flannel的镜像是0.11.0,quay.io/coreos/flannel:v0.11.0-amd64
如果Node有多个网卡的话,参考flannel issues 39701,目前需要在kube-flannel.yml中使用–iface参数指定集群主机内网网卡的名称,否则可能会出现dns无法解析。需要将kube-flannel.yml下载到本地,flanneld启动参数加上–iface=<iface-name>

containers:
      - name: kube-flannel
        image: quay.io/coreos/flannel:v0.11.0-amd64
        command:
        - /opt/bin/flanneld
        args:
        - --ip-masq
        - --kube-subnet-mgr
        - --iface=eth1
......

使用kubectl get pod –all-namespaces -o wide确保所有的Pod都处于Running状态。

# kubectl get pod -n kube-system
NAME                            READY  STATUS    RESTARTS  AGE
coredns-5c98db65d4-dr8lf        1/1    Running  0          52m
coredns-5c98db65d4-lp8dg        1/1    Running  0          52m
etcd-node1                      1/1    Running  0          51m
kube-apiserver-node1            1/1    Running  0          51m
kube-controller-manager-node1  1/1    Running  0          51m
kube-flannel-ds-amd64-mm296    1/1    Running  0          44s
kube-proxy-kchkf                1/1    Running  0          52m
kube-scheduler-node1            1/1    Running  0          51m


3.4 测试集群DNS是否可用

# kubectl run curl --image=radial/busyboxplus:curl -it
kubectl run --generator=deployment/apps.v1beta1 is DEPRECATED and will be removed in a future version. Use kubectl create instead.
If you don't see a command prompt, try pressing enter.
[ root@curl-5cc7b478b6-r997p:/ ]$

注:在此过程中可能会出现curl容器一直处于pending状态,报错信息如下:
0/1 nodes are available: 1 node(s) had taints that the pod didn’t tolerate.
解决方法:
# kubectl taint nodes –all node-role.kubernetes.io/master-
进入后执行nslookup kubernetes.default确认解析正常:

$ nslookup kubernetes.default
Server:    10.96.0.10
Address 1: 10.96.0.10 kube-dns.kube-system.svc.cluster.local

Name:      kubernetes.default
Address 1: 10.96.0.1 kubernetes.default.svc.cluster.local

Node节点配置

安装docker的yum源:

# yum install -y yum-utils device-mapper-persistent-data lvm2
# yum-config-manager \
    --add-repo \
    https://download.docker.com/linux/centos/docker-ce.repo
# yum install -y --setopt=obsoletes=0 docker-ce


安装kubeadm和kubelet:

配置kubernetes.repo的源,由于官方源国内无法访问,这里使用阿里云yum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

测试地址https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64是否可用,如果不可用需要×××

# curl https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/

# yum -y makecache fast
# yum install -y kubelet kubeadm kubectl

...
Installed:
  kubeadm.x86_64 0:1.15.0-0                  kubectl.x86_64 0:1.15.0-0                      kubelet.x86_64 0:1.15.0-0                               

Dependency Installed:
  conntrack-tools.x86_64 0:1.4.4-4.el7            cri-tools.x86_64 0:1.12.0-0                  kubernetes-cni.x86_64 0:0.7.5-0    libnetfilter_cthelper.x86_64 0:1.0.0-9.el7   
  libnetfilter_cttimeout.x86_64 0:1.0.0-6.el7    libnetfilter_queue.x86_64 0:1.0.2-2.el7_2

#  swapoff -a


修改 /etc/fstab 文件,注释掉 SWAP 的自动挂载,

# UUID=2d1e946c-f45d-4516-86cf-946bde9bdcd8 swap                    swap    defaults        0 0


使用free -m确认swap已经关闭。 swappiness参数调整,修改/etc/sysctl.d/k8s.conf添加下面一行:

net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1 
vm.swappiness=0


使修改生效

 # sysctl -p /etc/sysctl.d/k8s.conf


下面将node1这个主机添加到Kubernetes集群中,在node1上执行:

# kubeadm join  192.168.1.21:6443 --token 4qcl2f.gtl3h8e5kjltuo0r \
    --discovery-token-ca-cert-hash sha256:7ed5404175cc0bf18dbfe53f19d4a35b1e3d40c19b10924275868ebf2a3bbe6e \
 --ignore-preflight-errors=Swap

[preflight] Running pre-flight checks
    [WARNING Swap]: running with swap on is not supported. Please disable swap
    [WARNING Service-Kubelet]: kubelet service is not enabled, please run 'systemctl enable kubelet.service'
[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-1.15" 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.


node1加入集群很是顺利,下面在master节点上执行命令查看集群中的节点:

# kubectl get node
NAME    STATUS  ROLES    AGE  VERSION
node1  Ready    master  57m  v1.15.0
node2  Ready    <none>  11s  v1.15.0

如何从集群中移除Node
如果需要从集群中移除node2这个Node执行下面的命令:
在master节点上执行:
# kubectl drain node2 –delete-local-data –force –ignore-daemonsets
# kubectl delete node node2

在node2上执行:
# kubeadm reset
# ifconfig cni0 down
# ip link delete cni0
# ifconfig flannel.1 down
# ip link delete flannel.1
# rm -rf /var/lib/cni/

报错:
error execution phase preflight: couldn’t validate the identity of the API Server: abort connecting to API servers after timeout of 5m0s
# kubeadm join ……
error execution phase preflight: couldn’t validate the identity of the API Server: abort connecting to API servers after timeout of 5m0

原因:master节点的token过期了

解决:重新生成新token
在master重新生成token
# kubeadm token create
424mp7.nkxx07p940mkl2nd
# openssl x509 -pubkey -in /etc/kubernetes/pki/ca.crt | openssl rsa -pubin -outform der 2>/dev/null | openssl dgst -sha256 -hex | sed ‘s/^.* //’
d88fb55cb1bd659023b11e61052b39bbfe99842b0636574a16c76df186fd5e0d

Node节点重新join就可以了
kubeadm join 192.168.169.21:6443 –token 424mp7.nkxx07p940mkl2nd \
--discovery-token-ca-cert-hash sha256:d88fb55cb1bd659023b11e61052b39bbfe99842b0636574a16c76df186fd5e0d
四、kube-proxy开启ipvs

修改ConfigMap的kube-system/kube-proxy中的config.conf,mode: “ipvs”

 # kubectl edit cm kube-proxy -n kube-system
 minSyncPeriod: 0s
      scheduler: ""
      syncPeriod: 30s
    kind: KubeProxyConfiguration
    metricsBindAddress: 127.0.0.1:10249
    mode: "ipvs"                          # 加上这个
    nodePortAddresses: null

其中mode原来是空,默认为iptables模式,改为ipvs
scheduler默认是空,默认负载均衡算法为轮训
编辑完,保存退出

删除所有kube-proxy的pod
# kubectl delete pod xxx -n kube-system
之后重启各个节点上的kube-proxy pod:

# kubectl get pod -n kube-system | grep kube-proxy | awk '{system("kubectl delete pod "$1" -n kube-system")}'

# kubectl get pod -n kube-system | grep kube-proxy
kube-proxy-7fsrg                1/1    Running  0          3s
kube-proxy-k8vhm                1/1    Running  0          9s

# kubectl logs kube-proxy-7fsrg  -n kube-system
I0703 04:42:33.308289      1 server_others.go:170] Using ipvs Proxier.
W0703 04:42:33.309074      1 proxier.go:401] IPVS scheduler not specified, use rr by default
I0703 04:42:33.309831      1 server.go:534] Version: v1.15.0
I0703 04:42:33.320088      1 conntrack.go:52] Setting nf_conntrack_max to 131072
I0703 04:42:33.320365      1 config.go:96] Starting endpoints config controller
I0703 04:42:33.320393      1 controller_utils.go:1029] Waiting for caches to sync for endpoints config controller
I0703 04:42:33.320455      1 config.go:187] Starting service config controller
I0703 04:42:33.320470      1 controller_utils.go:1029] Waiting for caches to sync for service config controller
I0703 04:42:33.420899      1 controller_utils.go:1036] Caches are synced for endpoints config controller
I0703 04:42:33.420969      1 controller_utils.go:1036] Caches are synced for service config controller

日志中打印出了Using ipvs Proxier,说明ipvs模式已经开启。

五、Kubernetes常用组件部署

越来越多的公司和团队开始使用Helm这个Kubernetes的包管理器,这里也将使用Helm安装Kubernetes的常用组件。

5.1、Helm的安装

Helm由客户端命helm令行工具和服务端tiller组成,Helm的安装十分简单。 下载helm命令行工具到master节点node1的/usr/local/bin下,这里下载的2.14.1版本

# curl -O https://get.helm.sh/helm-v2.14.1-linux-amd64.tar.gz
# tar -zxvf helm-v2.14.1-linux-amd64.tar.gz
# cd linux-amd64/
# cp helm /usr/local/bin/


为了安装服务端tiller,还需要在这台机器上配置好kubectl工具和kubeconfig文件,确保kubectl工具可以在这台机器上访问apiserver且正常使用。 这里的node1节点已经配置好了kubectl。

因为Kubernetes APIServer开启了RBAC访问控制,所以需要创建tiller使用的service account: tiller并分配合适的角色给它。 详细内容可以查看helm文档中的Role-based Access Control。 这里简单起见直接分配cluster-admin这个集群内置的ClusterRole给它。创建helm-rbac.yaml文件

apiVersion: v1
kind: ServiceAccount
metadata:
  name: tiller
  namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
  name: tiller
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
  - kind: ServiceAccount
    name: tiller
    namespace: kube-system


# kubectl create -f helm-rbac.yaml
 serviceaccount/tiller created
 clusterrolebinding.rbac.authorization.k8s.io/tiller created


接下来使用helm部署tiller:

# helm init --service-account tiller --skip-refresh
Creating /root/.helm
Creating /root/.helm/repository
Creating /root/.helm/repository/cache
Creating /root/.helm/repository/local
Creating /root/.helm/plugins
Creating /root/.helm/starters
Creating /root/.helm/cache/archive
Creating /root/.helm/repository/repositories.yaml
Adding stable repo with URL: https://kubernetes-charts.storage.googleapis.com
Adding local repo with URL: http://127.0.0.1:8879/charts
$HELM_HOME has been configured at /root/.helm.

Tiller (the Helm server-side component) has been installed into your Kubernetes Cluster.

Please note: by default, Tiller is deployed with an insecure 'allow unauthenticated users' policy.
To prevent this, run `helm init` with the --tiller-tls-verify flag.
For more information on securing your installation see: https://docs.helm.sh/using_helm/#securing-your-helm-installation
Happy Helming!


tiller默认被部署在k8s集群中的kube-system这个namespace下:

# kubectl get pod -n kube-system -l app=helm
NAME                            READY  STATUS    RESTARTS  AGE
tiller-deploy-c4fd4cd68-dwkhv  1/1    Running  0          83s

注:如果tiller的状态一直是ErrImagePull的时候,需要更换国内helm源。
NAME READY STATUS RESTARTS AGE
tiller-deploy-7bf78cdbf7-fkx2z 0/1 ImagePullBackOff 0 79s

解决方法1:
1、删除默认源
# helm repo remove stable
2、 增加新的国内镜像源
# helm repo add stable https://burdenbear.github.io/kube-charts-mirror/

# helm repo add stable https://kubernetes.oss-cn-hangzhou.aliyuncs.com/charts
3、查看helm源情况
# helm repo list
4、搜索测试
# helm search mysql

解决方法2:
1、手动下载images
# docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/tiller:v2.14.1

2、查看tiller需要的镜像名
# kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-bccdc95cf-tb6pf 1/1 Running 3 5h21m
coredns-bccdc95cf-xpgm8 1/1 Running 3 5h21m
etcd-master 1/1 Running 3 5h20m
kube-apiserver-master 1/1 Running 3 5h21m
kube-controller-manager-master 1/1 Running 3 5h21m
kube-flannel-ds-amd64-b4ksb 1/1 Running 3 5h18m
kube-flannel-ds-amd64-vmv29 1/1 Running 0 127m
kube-proxy-67zn6 1/1 Running 2 37m
kube-proxy-992ns 1/1 Running 0 37m
kube-scheduler-master 1/1 Running 3 5h21m
tiller-deploy-7bf78cdbf7-fkx2z 0/1 ImagePullBackOff 0 33m

3、使用describe查看镜像名
# kubectl describe pods tiller-deploy-7bf78cdbf7-fkx2z -n kube-system
……….
Normal Scheduled 32m default-scheduler Successfully assigned kube-system/tiller-deploy-7bf78cdbf7-fkx2z to node1
Normal Pulling 30m (x4 over 32m) kubelet, node1 Pulling image “gcr.io/kubernetes-helm/tiller:v2.14.1”
Warning Failed 30m (x4 over 31m) kubelet, node1 Failed to pull image “gcr.io/kubernetes-helm/tiller:v2.14.1”: rpc error: code = Unknown desc = Error response from daemon: Get https://gcr.io/v2/: Service Unavailable
Warning Failed 30m (x4 over 31m) kubelet, node1 Error: ErrImagePull
Warning Failed 30m (x6 over 31m) kubelet, node1 Error: ImagePullBackOff
Normal BackOff 111s (x129 over 31m) kubelet, node1 Back-off pulling image “gcr.io/kubernetes-helm/tiller:v2.14.1”

4、使用docker tag 重命令镜像
# docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/tiller:v2.14.1 gcr.io/kubernetes-helm/tiller:v2.14.1

5、删除多余的镜像
# docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/tiller:v2.14.1

6、删除失败的pod
# kubectl delete deployment tiller-deploy -n kube-system

稍等一会儿就可以使用kubectl get pods -n kube-system查看状态已经正常了
# helm version
Client: &version.Version{SemVer:"v2.14.1", GitCommit:"5270352a09c7e8b6e8c9593002a73535276507c0", GitTreeState:"clean"}
Server: &version.Version{SemVer:"v2.14.1", GitCommit:"5270352a09c7e8b6e8c9593002a73535276507c0", GitTreeState:"clean"}

注意由于某些原因需要网络可以访问gcr.io和kubernetes-charts.storage.googleapis.com,如果无法访问可以通过helm init –service-account tiller –tiller-image <your-docker-registry>/tiller:v2.13.1 –skip-refresh使用私有镜像仓库中的tiller镜像
最后在node1上修改helm chart仓库的地址为azure提供的镜像地址:

# helm repo add stable http://mirror.azure.cn/kubernetes/charts
"stable" has been added to your repositories

# helm repo list
NAME    URL                                   
stable  http://mirror.azure.cn/kubernetes/charts
local  http://127.0.0.1:8879/charts


5.2、使用Helm部署Nginx Ingress

为了便于将集群中的服务暴露到集群外部,需要使用Ingress。接下来使用Helm将Nginx Ingress部署到Kubernetes上。 Nginx Ingress Controller被部署在Kubernetes的边缘节点上,关于Kubernetes边缘节点的高可用相关的内容可以查看之前整理的Bare metal环境下Kubernetes Ingress边缘节点的高可用,Ingress Controller使用hostNetwork。

我们将master(192.168.1.21)做为边缘节点,打上Label:

# kubectl label node master node-role.kubernetes.io/edge=
node/master labeled


# kubectl get node
NAME    STATUS  ROLES        AGE    VERSION
master  Ready    edge,master  138m  v1.15.0
node1  Ready    <none>        82m    v1.15.0

如果想删除一个node的label标记,使用以下命令
# kubectl label node node1 node-role.kubernetes.io/edge-
创建 ingress-nginx.yaml

 stable/nginx-ingress chart的值文件ingress-nginx.yaml如下:
controller:
  replicaCount: 1
  hostNetwork: true
  nodeSelector:
    node-role.kubernetes.io/edge: ''
  affinity:
    podAntiAffinity:
        requiredDuringSchedulingIgnoredDuringExecution:
        - labelSelector:
            matchExpressions:
            - key: app
              operator: In
              values:
              - nginx-ingress
            - key: component
              operator: In
              values:
              - controller
          topologyKey: kubernetes.io/hostname
  tolerations:
      - key: node-role.kubernetes.io/master
        operator: Exists
        effect: NoSchedule
      - key: node-role.kubernetes.io/master
        operator: Exists
        effect: PreferNoSchedule
defaultBackend:
  nodeSelector:
    node-role.kubernetes.io/edge: ''
  tolerations:
      - key: node-role.kubernetes.io/master
        operator: Exists
        effect: NoSchedule
      - key: node-role.kubernetes.io/master
        operator: Exists
        effect: PreferNoSchedule

nginx ingress controller的副本数replicaCount为1,将被调度到master这个边缘节点上。这里并没有指定nginx ingress controller service的externalIPs,而是通过hostNetwork: true设置nginx ingress controller使用宿主机网络。

# helm repo update

# helm install stable/nginx-ingress \
-n nginx-ingress \
--namespace ingress-nginx  \
-f ingress-nginx.yaml


# kubectl get pod -n ingress-nginx -o wide
NAME                                            READY  STATUS    RESTARTS  AGE  IP              NODE    NOMINATED NODE  READINESS GATES
nginx-ingress-controller-cc9b6d55b-pr8vr        1/1    Running  0          10m  192.168.1.21  node1  <none>          <none>
nginx-ingress-default-backend-cc888fd56-bf4h2  1/1    Running  0          10m  10.244.0.14    node1  <none>          <none>

如果发现nginx-ingress的容器状态是ContainersCreating/ImagePullBackOff,则需要手动下载镜像
# docker pull registry.aliyuncs.com/google_containers/nginx-ingress-controller:0.25.0
# docker tag registry.aliyuncs.com/google_containers/nginx-ingress-controller:0.25.0 quay.io/kubernetes-ingress-controller/nginx-ingress-controller:0.25.0
# docker pull registry.cn-qingdao.aliyuncs.com/kubernetes_xingej/defaultbackend-amd64:1.5
# docker tag registry.cn-qingdao.aliyuncs.com/kubernetes_xingej/defaultbackend-amd64:1.5 k8s.gcr.io/defaultbackend-amd64:1.5
# docker rmi registry.cn-qingdao.aliyuncs.com/kubernetes_xingej/defaultbackend-amd64:1.5
# docker rim registry.aliyuncs.com/google_containers/nginx-ingress-controller:0.25.0
如果访问http://192.168.1.21返回default backend,则部署完成。

5.3、 使用Helm部署dashboard

创建 kubernetes-dashboard.yaml:

image:
  repository: registry.aliyuncs.com/google_containers/kubernetes-dashboard-amd64
  tag: v1.10.1
 ingress:
  enabled: true
  hosts:
    - k8s.frognew.com    #这里是你将来访问dashboard的域名
  annotations:
    nginx.ingress.kubernetes.io/ssl-redirect: "true"
    nginx.ingress.kubernetes.io/backend-protocol: "HTTPS"
  tls:
    - secretName: frognew-com-tls-secret
      hosts:
      - k8s.frognew.com
 nodeSelector:
    node-role.kubernetes.io/edge: ''
 tolerations:
    - key: node-role.kubernetes.io/master
      operator: Exists
      effect: NoSchedule
    - key: node-role.kubernetes.io/master
      operator: Exists
      effect: PreferNoSchedule
 rbac:
  clusterAdminRole: true

执行安装

helm install stable/kubernetes-dashboard \
-n kubernetes-dashboard \
--namespace kube-system  \
-f kubernetes-dashboard.yaml


5.4、生成用户token

a、创建admin-sa.yaml

apiVersion: rbac.authorization.k8s.io/v1beta1
 metadata:
  name: admin
  annotations:
    rbac.authorization.kubernetes.io/autoupdate: "true"
 roleRef:
  kind: ClusterRole
  name: cluster-admin
  apiGroup: rbac.authorization.k8s.io
 subjects:
 kind: ServiceAccount
 name: admin
  namespace: kube-system
 apiVersion: v1
 kind: ServiceAccount
 metadata:
  name: admin
  namespace: kube-system
  labels:
    kubernetes.io/cluster-service: "true"
    addonmanager.kubernetes.io/mode: Reconcile

b、创建admin-sa的pod

# kubectl create -f admin-sa.yaml

# kubectl get secret -n kube-system
NAME                                            TYPE                                  DATA  AGE
 admin-token-2tbzp                                kubernetes.io/service-account-token  3      9m5s
 attachdetach-controller-token-bmz2c              kubernetes.io/service-account-token  3      27h
 bootstrap-signer-token-6jctj                    kubernetes.io/service-account-token  3      27h
 certificate-controller-token-l4l9c              kubernetes.io/service-account-token  3      27h

c、生成 admin-token

# kubectl get secret admin-token-2tbzp -o jsonpath={.data.token} -n kube-system|base64 -d

eyJhbGciOiJSUzI1NiIsImtpZCI6IiJ9.eyJpc3MiOiJrdWJlcm5ldGVzL3NlcnZpY2VhY2NvdW50Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9uYW1lc3BhY2UiOiJrdWJlLXN5c3RlbSIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VjcmV0Lm5hbWUiOiJhZG1pbi10b2tlbi0ydGJ6cCIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VydmljZS1hY2NvdW50Lm5hbWUiOiJhZG1pbiIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VydmljZS1hY2NvdW50LnVpZCI6ImRlOGU5N2EzLWY1YmItNGRlNC1hN2Q1LTY5YzEwYTIyZTE3OSIsInN1YiI6InN5c3RlbTpzZXJ2aWNlYWNjb3VudDprdWJlLXN5c3RlbTphZG1pbiJ9.NgZvr3XTtrW1XPCJHYRFFdPD1IfsoRRTYJHwAST2gfhY1hva_yIoh1ATSpDO551rNio0ulb7YllSiZMaQViBeFTiAhuuIlKHKyELOoB_eY7jFTCVstdr4vQzH5e2GRQgljEeqbF9Lewr0n_eqIS6pgVQSRT8at-Yk6EXLM0XhYf4qbAvMuztuRTSp8JKmal65gwTxTJU7LpjJM7UbZ8UelVOjNZK8BFCezGv0ccqXywLu5-aAj2NvSHVThg6jybj37R0hszqRw2fkGZtIcEOEtgmij2vHa3oNb3f38gd1eE6WqZpJpVOPLlX6QNSxiV0jaaj9AqodFCdAg48E75Bvg

注意:admin-token的pod名称
其中 admin-token-2tbzp 是 kubectl get secret -n kube-system 看到的admin-token名称
d、使用生成的token去浏览器中登录

CentOS7.6安装Kubernetes v1.15.1

linux
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