kubernetes环境搭建
安装方式
- minikube：一个用于快速搭建单节点kubernets的工具
- kubeadm：用于快速搭建kubernets集群的工具
- 二进制包：从官网上下载每一个组件的二进制包，依次去安装，更容易理解kubernets的组件
环境规划 Centos7
master: 192.168.248.10 2核2G
node1: 192.168.248.11 2核2G
node2: 192.168.248.12 2核2G
以下3台都需要配置
1.配置hosts文件 2.关闭防火墙selinux setenforce 0 sed -i 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/selinux/config 3.时间同步 #master节点 vim /etc/chrony.conf server ntp1.aliyun.com iburst allow 192.168.168.0/24 systemctl restart chronyd #node节点 vim /etc/chrony.conf server 192.168.248.10 iburst systemctl restart chronyd 4.关闭sawp分区 swapoff -a 注释掉 /etc/fstab 文件中的 swap配置 5.修改内核参数 vim /etc/sysctl.d/kubernetes.conf net.bridge.bridge-nf-call-ip6tables = 1 net.bridge.bridge-nf-call-iptables = 1 net.ipv4.ip_forward = 1 #重载配置 sysctl -p #加载网桥过滤模块 modprobe br_netfilter #查看网桥过滤模块是否加载成功 lsmod | grep br_netfilter 6.配置ipvs功能 在kubernetes中service有两种代理模型，一种基于iptables，一种基于ipvs，两者相比ipvs性能明显要高一些，如果需要使用要手动载入ipvs模块 yum -y install ipset ipvsadm cat <<EOF > /etc/sysconfig/modules/ipvs.modules #!/bin/bash modprobe -- ip_vs modprobe -- ip_vs_rr modprobe -- ip_vs_wrr modprobe -- ip_vs_sh modprobe -- nf_conntrack_ipv4 EOF chmod +x /etc/sysconfig/modules/ipvs.modules /bin/bash /etc/sysconfig/modules/ipvs.modules lsmod | grep -e ip_vs -e nf_conntrack_ipv4 7.重启服务器
安装docker
#安装docker源
cd /etc/yum.repos.d/
curl -o docker-ce.repo https://mirrors.tuna.tsinghua.edu.cn/docker-ce/linux/centos/docker-ce.repo
# 查看镜像源中所支持的docker版本
yum list docker-ce --showduplicates
# 安装特定版本的docker-ce
# 必须指定 --setopt=obsoletes=0，否则yum会自动安装更高的版本
yum -y install --setopt=onsoletes=0 docker-ce-18.06.3.ce-3.el7
# 添加配置文件，docker在默认情况下使用Cgroup Driver为cgroupfs,而kubernets推荐使用systemd来代替cgroupfs
mkdir /etc/docker
cat <<EOF > /etc/docker/daemon.json
{
"exec-opts" : ["native.cgroupdriver=systemd"],
"registry-mirrors" : ["https://kn0t2bca.mirror.aliyuncs.com"]
}
EOF
#启动docker
systemctl start docker
systemctl enable docker
安装kubernetes组件
#切换到国内镜像源
vim /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name = Kubernetes
baseurl = http://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled = 1
gpgcheck = 0
repo_gpgcheck = 0
gpgkey = http://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
http://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
#安装kubeadm、kubelet和kubectl
yum -y install --setopt=obsoletes=0 kubeadm-1.17.4-0 kubelet-1.17.4-0 kubectl-1.17.4-0
#配置kubelet的cgroup
vim /etc/sysconfig/kubelet
KUBELET_CGROUP_ARGS="--cgroup-driver=systemd"
KUBE_PROXY_MODE="ipvs"
#设置kubelet开机自启
systemctl enable kubelet
准备集群镜像
# 在安装kubernetes集群之前，必须提前准备好集群需要的镜像，可以通过以下命令查看
kubeadm config images list
#下载镜像
#此镜像在kubernetes的仓库中，由于网络原因，无法连接，下面通过了一种方法代替
images=(
kube-apiserver:v1.17.4
kube-controller-manager:v1.17.4
kube-scheduler:v1.17.4
kube-proxy:v1.17.4
pause:3.1
etcd:3.4.3-0
coredns:1.6.5
)
for imageName in ${images[@]};do
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName k8s.gcr.io/$imageName
docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName
done
集群初始化
下面操作只需要在master上执行即可
#创建集群
[root@master ~]# kubeadm init --kubernetes-version=v1.17.4 --pod-network-cidr=10.244.0.0/16 --service-cidr=10.96.0.0/12 --apiserver-advertise-address=192.168.248.10
.............
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 192.168.248.10:6443 --token epdgo0.xui34va7u2yfppmx \
--discovery-token-ca-cert-hash sha256:85b336094393db232206802247c4b09b20ee9dab5c2fe4cca841d00e605a6d8b
#将node节点加入集群
[root@node1 ~]# kubeadm join 192.168.248.10:6443 --token epdgo0.xui34va7u2yfppmx --discovery-token-ca-cert-hash sha256:85b336094393db232206802247c4b09b20ee9dab5c2fe4cca841d00e605a6d8b
[root@node2 ~]# kubeadm join 192.168.248.10:6443 --token epdgo0.xui34va7u2yfppmx --discovery-token-ca-cert-hash sha256:85b336094393db232206802247c4b09b20ee9dab5c2fe4cca841d00e605a6d8b
# 创建必要的文件
mkdir -p $HOME/.kube
cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
chown $(id -u):$(id -g) $HOME/.kube/config
#查看node信息
[root@master ~]# kubectl get node
NAME STATUS ROLES AGE VERSION
master NotReady master 95s v1.17.4
node1 NotReady <none> 38s v1.17.4
node2 NotReady <none> 34s v1.17.4
安装网络插件
kubernetes支持多种网络插件，比如flannel、calico、canal等，本次使用flannel
# 下面还是在master节点执行即可，插件使用的事DaemonSet的控制器，它会在每个节点上运行
# 获取fannel的配置文件
wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yaml
如果下载不到的报错 连接失败,可以直接使用
vi kube-flannel.yaml
---
apiVersion: policy/v1beta1
kind: PodSecurityPolicy
metadata:
name: psp.flannel.unprivileged
annotations:
seccomp.security.alpha.kubernetes.io/allowedProfileNames: docker/default
seccomp.security.alpha.kubernetes.io/defaultProfileName: docker/default
apparmor.security.beta.kubernetes.io/allowedProfileNames: runtime/default
apparmor.security.beta.kubernetes.io/defaultProfileName: runtime/default
spec:
privileged: false
volumes:
- configMap
- secret
- emptyDir
- hostPath
allowedHostPaths:
- pathPrefix: "/etc/cni/net.d"
- pathPrefix: "/etc/kube-flannel"
- pathPrefix: "/run/flannel"
readOnlyRootFilesystem: false
# Users and groups
runAsUser:
rule: RunAsAny
supplementalGroups:
rule: RunAsAny
fsGroup:
rule: RunAsAny
# Privilege Escalation
allowPrivilegeEscalation: false
defaultAllowPrivilegeEscalation: false
# Capabilities
allowedCapabilities: ['NET_ADMIN', 'NET_RAW']
defaultAddCapabilities: []
requiredDropCapabilities: []
# Host namespaces
hostPID: false
hostIPC: false
hostNetwork: true
hostPorts:
- min: 0
max: 65535
# SELinux
seLinux:
# SELinux is unused in CaaSP
rule: 'RunAsAny'
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: flannel
rules:
- apiGroups: ['extensions']
resources: ['podsecuritypolicies']
verbs: ['use']
resourceNames: ['psp.flannel.unprivileged']
- apiGroups:
- ""
resources:
- pods
verbs:
- get
- apiGroups:
- ""
resources:
- nodes
verbs:
- list
- watch
- apiGroups:
- ""
resources:
- nodes/status
verbs:
- patch
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: flannel
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: flannel
subjects:
- kind: ServiceAccount
name: flannel
namespace: kube-system
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: flannel
namespace: kube-system
---
kind: ConfigMap
apiVersion: v1
metadata:
name: kube-flannel-cfg
namespace: kube-system
labels:
tier: node
app: flannel
data:
cni-conf.json: |
{
"name": "cbr0",
"cniVersion": "0.3.1",
"plugins": [
{
"type": "flannel",
"delegate": {
"hairpinMode": true,
"isDefaultGateway": true
}
},
{
"type": "portmap",
"capabilities": {
"portMappings": true
}
}
]
}
net-conf.json: |
{
"Network": "10.244.0.0/16",
"Backend": {
"Type": "vxlan"
}
}
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: kube-flannel-ds
namespace: kube-system
labels:
tier: node
app: flannel
spec:
selector:
matchLabels:
app: flannel
template:
metadata:
labels:
tier: node
app: flannel
spec:
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: kubernetes.io/os
operator: In
values:
- linux
hostNetwork: true
priorityClassName: system-node-critical
tolerations:
- operator: Exists
effect: NoSchedule
serviceAccountName: flannel
initContainers:
- name: install-cni
image: quay.io/coreos/flannel:v0.13.1-rc1
command:
- cp
args:
- -f
- /etc/kube-flannel/cni-conf.json
- /etc/cni/net.d/10-flannel.conflist
volumeMounts:
- name: cni
mountPath: /etc/cni/net.d
- name: flannel-cfg
mountPath: /etc/kube-flannel/
containers:
- name: kube-flannel
image: quay.io/coreos/flannel:v0.13.1-rc1
command:
- /opt/bin/flanneld
args:
- --ip-masq
- --kube-subnet-mgr
resources:
requests:
cpu: "100m"
memory: "50Mi"
limits:
cpu: "100m"
memory: "50Mi"
securityContext:
privileged: false
capabilities:
add: ["NET_ADMIN", "NET_RAW"]
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
volumeMounts:
- name: run
mountPath: /run/flannel
- name: flannel-cfg
mountPath: /etc/kube-flannel/
volumes:
- name: run
hostPath:
path: /run/flannel
- name: cni
hostPath:
path: /etc/cni/net.d
- name: flannel-cfg
configMap:
name: kube-flannel-cfg
# 使用配置文件启动flannel
[root@master ~]# kubectl apply -f kube-flannel.yml
# 稍等一会在次查看集群
[root@master ~]# kubectl get node
NAME STATUS ROLES AGE VERSION
master Ready master 8m56s v1.17.4
node1 Ready <none> 8m34s v1.17.4
node2 Ready <none> 3m52s v1.17.4
集群测试
# 创建一个nginx服务 kubectl create deployment nginx --image=nginx:1.14-alpine # 暴露端口 --type=NodePort让集群之外的浏览器可以访问 kubectl expose deploy nginx --port=80 --target-port=80 --type=NodePort kubectl get pod,svc NAME READY STATUS RESTARTS AGE pod/nginx-6867cdf567-lh6vv 1/1 Running 1 9h NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 11h service/nginx NodePort 10.111.120.209 <none> 80:30317/TCP 9h 访问浏览器 nodeip:30317
资源管理
#命令式对象管理：直接使用命令去操作kubernets资源 kubectl run nginx-pod --image=nginx1.17.1 --pord=80 #命令式对象配置：通过命令配置和配置文件去操作kubernetes资源 kubectl create/patch -f nginx-pod.yml #声明式对象配置：通过apply命令和配置文件去操作kubernetes资源 kubectl apply -f nginx-pod.yml
命令式对象管理
-
kubectl命令
kubectl式kubernetes集群的命令行工具，通过它能够对集群本身进行管理，并能够在集群上进行容器化安装部署。kubectl命令语法
kubectl [command] [type] [name] [flags
command: 指定要对资源执行的操作，例如create,get,delete
type: 指定资源类型，比如deployment、pod、service
name: 指定资源名称，名称大小写敏感
flags: 指定额外的可选参数
# 查看所有pod kubectl get pod # 查看某个pod kubectl get pod pod_name # 产看某一个pod，以yaml格式展示结果 kubectl get pod pod_name -o yaml
下面以一个namespace/pod的创建和删除简单演示一下命令的使用
#创建一个namespace kubectl create namespace dev #获取namespace kubectl get ns NAME STATUS AGE default Active 17h dev Active 12s kube-node-lease Active 17h kube-public Active 17h kube-system Active 17h #在dev下创建一个nginx的pod kubectl run pod --image=nginx -n dev #查看新创建的pod kubectl get pod -n dev NAME READY STATUS RESTARTS AGE pod-864f9875b9-4htwm 1/1 Running 0 50s #删除指定pod kubectl delete pod pod-864f9875b9-4htwm -n dev #删除指定namespace kubectl delete ns dev
命令式对象配置
命令式对象配置就是使用命令配合配置文件一起来操作kubernetes资源
1）. 创建一个nginxpod.yml，内容如下
aipVersion: v1
kind: Namespace
metadata:
name: dev
---
apiVersion: v1
kind: Pod
metadata:
name: nginxpod
namespace: dev
spec:
containers:
- name: nginx-containers
image: nginx:1.17.1
2）.执行create命令，创建资源：
kubectl create -f nginxpod.yml
3）.执行get命令查看资源，发现创建了2个资源
kubectl get -f nginxpod.yml NAME STATUS AGE namespace/dev Active 54s NAME READY STATUS RESTARTS AGE pod/nginxpod 1/1 Running 0 53s
4）.执行delete命令删除资源
kubectl delete -f nginxpod.yml
命令式对象配置的操作资源，可以简单的认为： 命令 + yml配置文件（里面的命令需要各种参数）
声明式对象配置
声明式对象配置和命令式对象配置很相似，但是它只有一个命令apply
# 首先执一次kubectl apply -f nginxpod.yml发现创建了资源 kubectl apply -f nginxpod.yml namespace/dev created pod/nginxpod created #再次执行，发现资源没有变动 kubectl apply -f nginxpod.yml namespace/dev unchanged pod/nginxpod unchanged
其实声明式对象配置就是使用apply描叙一个资源的最终状态（在yml中定义状态），使用apply操作资源：
如果资源不存在则创建,相当于kubectl create 如果资源存在则更新，相当于kubectl patch
扩展： kubcetl可以在node节点上运行吗？
kubect的运行是需要进行配置的，它的配置文件￥HOME/.kube,如果想要在node节点运行此命令，需要将master上的。kube文件复制到node节点上，即在master节点执行以下操作即可
scp -r HOME/.kube node:HOME/
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