一、基本概念
1、Kubernetes 暴露服务的方式:
NodePort:后期维护困难,不支持虚拟路径
LoadBlancer:需要云厂商支持,有局限性
ClusterIP:只能在集群内部访问
Ingress:灵活,无依赖
前三种方式都是在service的维度提供的,service的作用体现在两个方面,对集群内部它不断跟踪pod变化,更新endpoint中对应的pod的对象,提供IP不断变化的pod的服务发现机制;对集群外部,它类似负载均衡器,可以在集群内外对pod进行访问。但是单独使用service暴露服务的方式,在实际生产环境中不太适应。
而ingress相当于service的service,可以将外部请求通过不同规则的筛选后转发到不同的service
2、ingress与ingress-controller
ingress是k8s中的一个api对象,一般用yaml配置。作用是定义请求转发的规则,可以理解为配置模板或者配置文件。
ingress-controller是具体实现反向代理及负载均衡的程序,通过对ingress中定义的规则进行解析,根据其规则来实现转发。
ingress-controller并不是k8s自带的组件,实际上它只是一个统称,用户可以选择不同的ingress-controller来实现功能。其中由k8s官方维护的是nginx-ingress。
以下为ingress-controller.yaml文件根据本地k8s服务修改后的部署文件,主要修改内容:
1.修改国外镜像源为国内阿里云镜像源
2.添加hostNetwork网络模式
3.添加nodeName参数,我的值为 k8s-master ,此处需根据自己本地管理节点的hostname调整
apiVersion: v1
kind: Namespace
metadata:
labels:
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
name: ingress-nginx
---
apiVersion: v1
automountServiceAccountToken: true
kind: ServiceAccount
metadata:
labels:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.3.0
name: ingress-nginx
namespace: ingress-nginx
---
apiVersion: v1
kind: ServiceAccount
metadata:
labels:
app.kubernetes.io/component: admission-webhook
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.3.0
name: ingress-nginx-admission
namespace: ingress-nginx
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
labels:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.3.0
name: ingress-nginx
namespace: ingress-nginx
rules:
- apiGroups:
- ""
resources:
- namespaces
verbs:
- get
- apiGroups:
- ""
resources:
- configmaps
- pods
- secrets
- endpoints
verbs:
- get
- list
- watch
- apiGroups:
- ""
resources:
- services
verbs:
- get
- list
- watch
- apiGroups:
- networking.k8s.io
resources:
- ingresses
verbs:
- get
- list
- watch
- apiGroups:
- networking.k8s.io
resources:
- ingresses/status
verbs:
- update
- apiGroups:
- networking.k8s.io
resources:
- ingressclasses
verbs:
- get
- list
- watch
- apiGroups:
- ""
resourceNames:
- ingress-controller-leader
resources:
- configmaps
verbs:
- get
- update
- apiGroups:
- ""
resources:
- configmaps
verbs:
- create
- apiGroups:
- coordination.k8s.io
resourceNames:
- ingress-controller-leader
resources:
- leases
verbs:
- get
- update
- apiGroups:
- coordination.k8s.io
resources:
- leases
verbs:
- create
- apiGroups:
- ""
resources:
- events
verbs:
- create
- patch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
labels:
app.kubernetes.io/component: admission-webhook
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.3.0
name: ingress-nginx-admission
namespace: ingress-nginx
rules:
- apiGroups:
- ""
resources:
- secrets
verbs:
- get
- create
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
labels:
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.3.0
name: ingress-nginx
rules:
- apiGroups:
- ""
resources:
- configmaps
- endpoints
- nodes
- pods
- secrets
- namespaces
verbs:
- list
- watch
- apiGroups:
- coordination.k8s.io
resources:
- leases
verbs:
- list
- watch
- apiGroups:
- ""
resources:
- nodes
verbs:
- get
- apiGroups:
- ""
resources:
- services
verbs:
- get
- list
- watch
- apiGroups:
- networking.k8s.io
resources:
- ingresses
verbs:
- get
- list
- watch
- apiGroups:
- ""
resources:
- events
verbs:
- create
- patch
- apiGroups:
- networking.k8s.io
resources:
- ingresses/status
verbs:
- update
- apiGroups:
- networking.k8s.io
resources:
- ingressclasses
verbs:
- get
- list
- watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
labels:
app.kubernetes.io/component: admission-webhook
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.3.0
name: ingress-nginx-admission
rules:
- apiGroups:
- admissionregistration.k8s.io
resources:
- validatingwebhookconfigurations
verbs:
- get
- update
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
labels:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.3.0
name: ingress-nginx
namespace: ingress-nginx
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: Role
name: ingress-nginx
subjects:
- kind: ServiceAccount
name: ingress-nginx
namespace: ingress-nginx
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
labels:
app.kubernetes.io/component: admission-webhook
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.3.0
name: ingress-nginx-admission
namespace: ingress-nginx
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: Role
name: ingress-nginx-admission
subjects:
- kind: ServiceAccount
name: ingress-nginx-admission
namespace: ingress-nginx
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
labels:
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.3.0
name: ingress-nginx
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: ingress-nginx
subjects:
- kind: ServiceAccount
name: ingress-nginx
namespace: ingress-nginx
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
labels:
app.kubernetes.io/component: admission-webhook
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.3.0
name: ingress-nginx-admission
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: ingress-nginx-admission
subjects:
- kind: ServiceAccount
name: ingress-nginx-admission
namespace: ingress-nginx
---
apiVersion: v1
data:
allow-snippet-annotations: "true"
kind: ConfigMap
metadata:
labels:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.3.0
name: ingress-nginx-controller
namespace: ingress-nginx
---
apiVersion: v1
kind: Service
metadata:
labels:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.3.0
name: ingress-nginx-controller
namespace: ingress-nginx
spec:
externalTrafficPolicy: Local
ports:
- appProtocol: http
name: http
port: 80
protocol: TCP
targetPort: http
- appProtocol: https
name: https
port: 443
protocol: TCP
targetPort: https
selector:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
type: NodePort
---
apiVersion: v1
kind: Service
metadata:
labels:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.3.0
name: ingress-nginx-controller-admission
namespace: ingress-nginx
spec:
ports:
- appProtocol: https
name: https-webhook
port: 443
targetPort: webhook
selector:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
type: ClusterIP
---
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.3.0
name: ingress-nginx-controller
namespace: ingress-nginx
spec:
minReadySeconds: 0
revisionHistoryLimit: 10
selector:
matchLabels:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
template:
metadata:
labels:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
spec:
hostNetwork: true #官方文件不包含该配置,本地起服务建议采用host网络
nodeName: k8s-master #需调整为自己机器的部署节点名称
containers:
- args:
- /nginx-ingress-controller
- --publish-service=$(POD_NAMESPACE)/ingress-nginx-controller
- --election-id=ingress-controller-leader
- --controller-class=k8s.io/ingress-nginx
- --ingress-class=nginx
- --configmap=$(POD_NAMESPACE)/ingress-nginx-controller
- --validating-webhook=:8443
- --validating-webhook-certificate=/usr/local/certificates/cert
- --validating-webhook-key=/usr/local/certificates/key
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
- name: LD_PRELOAD
value: /usr/local/lib/libmimalloc.so
image: registry.cn-hangzhou.aliyuncs.com/google_containers/nginx-ingress-controller:v1.3.0
imagePullPolicy: IfNotPresent
lifecycle:
preStop:
exec:
command:
- /wait-shutdown
livenessProbe:
failureThreshold: 5
httpGet:
path: /healthz
port: 10254
scheme: HTTP
initialDelaySeconds: 10
periodSeconds: 10
successThreshold: 1
timeoutSeconds: 1
name: controller
ports:
- containerPort: 80
name: http
protocol: TCP
- containerPort: 443
name: https
protocol: TCP
- containerPort: 8443
name: webhook
protocol: TCP
readinessProbe:
failureThreshold: 3
httpGet:
path: /healthz
port: 10254
scheme: HTTP
initialDelaySeconds: 10
periodSeconds: 10
successThreshold: 1
timeoutSeconds: 1
resources:
requests:
cpu: 100m
memory: 90Mi
securityContext:
allowPrivilegeEscalation: true
capabilities:
add:
- NET_BIND_SERVICE
drop:
- ALL
runAsUser: 101
volumeMounts:
- mountPath: /usr/local/certificates/
name: webhook-cert
readOnly: true
dnsPolicy: ClusterFirst
nodeSelector:
kubernetes.io/os: linux
serviceAccountName: ingress-nginx
terminationGracePeriodSeconds: 300
volumes:
- name: webhook-cert
secret:
secretName: ingress-nginx-admission
---
apiVersion: batch/v1
kind: Job
metadata:
labels:
app.kubernetes.io/component: admission-webhook
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.3.0
name: ingress-nginx-admission-create
namespace: ingress-nginx
spec:
template:
metadata:
labels:
app.kubernetes.io/component: admission-webhook
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.3.0
name: ingress-nginx-admission-create
spec:
containers:
- args:
- create
- --host=ingress-nginx-controller-admission,ingress-nginx-controller-admission.$(POD_NAMESPACE).svc
- --namespace=$(POD_NAMESPACE)
- --secret-name=ingress-nginx-admission
env:
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
image: registry.cn-hangzhou.aliyuncs.com/google_containers/kube-webhook-certgen:v1.1.1
imagePullPolicy: IfNotPresent
name: create
securityContext:
allowPrivilegeEscalation: false
nodeSelector:
kubernetes.io/os: linux
restartPolicy: OnFailure
securityContext:
fsGroup: 2000
runAsNonRoot: true
runAsUser: 2000
serviceAccountName: ingress-nginx-admission
---
apiVersion: batch/v1
kind: Job
metadata:
labels:
app.kubernetes.io/component: admission-webhook
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.3.0
name: ingress-nginx-admission-patch
namespace: ingress-nginx
spec:
template:
metadata:
labels:
app.kubernetes.io/component: admission-webhook
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.3.0
name: ingress-nginx-admission-patch
spec:
containers:
- args:
- patch
- --webhook-name=ingress-nginx-admission
- --namespace=$(POD_NAMESPACE)
- --patch-mutating=false
- --secret-name=ingress-nginx-admission
- --patch-failure-policy=Fail
env:
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
image: registry.cn-hangzhou.aliyuncs.com/google_containers/kube-webhook-certgen:v1.1.1
imagePullPolicy: IfNotPresent
name: patch
securityContext:
allowPrivilegeEscalation: false
nodeSelector:
kubernetes.io/os: linux
restartPolicy: OnFailure
securityContext:
fsGroup: 2000
runAsNonRoot: true
runAsUser: 2000
serviceAccountName: ingress-nginx-admission
---
apiVersion: networking.k8s.io/v1
kind: IngressClass
metadata:
labels:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.3.0
name: nginx
spec:
controller: k8s.io/ingress-nginx
---
apiVersion: admissionregistration.k8s.io/v1
kind: ValidatingWebhookConfiguration
metadata:
labels:
app.kubernetes.io/component: admission-webhook
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
app.kubernetes.io/version: 1.3.0
name: ingress-nginx-admission
webhooks:
- admissionReviewVersions:
- v1
clientConfig:
service:
name: ingress-nginx-controller-admission
namespace: ingress-nginx
path: /networking/v1/ingresses
failurePolicy: Fail
matchPolicy: Equivalent
name: validate.nginx.ingress.kubernetes.io
rules:
- apiGroups:
- networking.k8s.io
apiVersions:
- v1
operations:
- CREATE
- UPDATE
resources:
- ingresses
sideEffects: None
二、配置方式
1、Deployment+LoadBalancer模式的Service
如果要把ingress部署在公有云,那用这种方式比较合适。用Deployment部署ingress-controller,创建一个type为LoadBalancer的service关联这组pod。大部分公有云,都会为LoadBalancer的service自动创建一个负载均衡器,通常还绑定了公网地址。只要把域名解析指向该地址,就实现了集群服务的对外暴露
2、Deployment+NodePort模式的Service
同样用deployment模式部署ingress-controller,并创建对应的服务,但是type为NodePort。这样,ingress就会暴露在集群节点ip的特定端口上。由于nodeport暴露的端口是随机端口,一般会在前再搭建一套负载均衡器来转发请求。该方式一般用于宿主机是相对固定的环境ip地址不变的场景。
NodePort方式暴露ingress虽然简单方便,但是NodePort多了一层NAT,在请求量级很大时可能对性能会有一定影响
3、DaemonSet+HostNetwork+nodeSelector
用DaemonSet结合nodeselector来部署ingress-controller到特定的node上(也可结合affinity亲和性部署到多个节点),然后使用HostNetwork直接把该pod与宿主机node的网络打通,直接使用宿主机的80/433端口就能访问服务。这时,ingress-controller所在的node机器就很类似传统架构的边缘节点,比如机房入口的nginx服务器。该方式整个请求链路最简单,性能相对NodePort模式更好。缺点是由于直接利用宿主机节点的网络和端口,一个node只能部署一个ingress-controller pod。比较适合大并发的生产环境使用。
三、RBAC的相关说明介绍
1、基本概念
RBAC(Role-Based Access Control,基于角色的访问控制)在k8s v1.5中引入,在v1.6版本时升级为Beta版本,并成为kubeadm安装方式下的默认选项,相对于其他访问控制方式,新的RBAC具有如下优势:
对集群中的资源和非资源权限均有完整的覆盖
整个RBAC完全由几个API对象完成,同其他API对象一样,可以用kubectl或API进行操作
可以在运行时进行调整,无需重启API Server
要使用RBAC授权模式,需要在API Server的启动参数中加上--authorization-mode=RBAC
2、RBAC的API资源对象说明
参数说明:
apiGroup:支持的API组列表,例如:APIVersion: batch/v1、APIVersion: extensions:v1、apiVersion:apps/v1等
resources:支持的资源对象列表,例如:pods、deployments、jobs等
verbs:对资源对象的操作方法列表,例如:get、watch、list、delete、replace、patch等
(1)角色(Role):
一个角色就是一组权限的集合,这里的权限都是许可形式的,不存在拒绝的规则。在一个命名空间中,可以用角色来定义一个角色,如果是集群级别的,就需要使用ClusterRole了。角色只能对命名空间内的资源进行授权
(2)集群角色(ClusterRole):
集群角色除了具有和角色一致的命名空间内资源的管理能力,因其集群级别的范围,还可以用于以下特殊元素的授权。
集群范围的资源,例如Node
非资源型的路径,例如/healthz
包含全部命名空间的资源,例如pods
(3)角色绑定(RoleBinding)和集群角色绑定(ClusterRoleBinding):
角色绑定或集群角色绑定用来把一个角色绑定到一个目标上,绑定目标可以是User、Group或者Service Account。使用RoleBinding为某个命名空间授权,ClusterRoleBinding为集群范围内授权。
RoleBinding可以引用Role进行授权
RoleBinding也可以引用ClusterRole,对属于同一命名空间内ClusterRole定义的资源主体进行授权。一种常见的做法是集群管理员为集群范围预先定义好一组角色(ClusterRole),然后在多个命名空间中重复使用这些ClusterRole。文章来源:https://www.toymoban.com/news/detail-551186.html
集群角色绑定中的角色只能是集群角色,用于进行集群级别或者对所有命名空间都生效的授权。文章来源地址https://www.toymoban.com/news/detail-551186.html
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