Day83-k8s_service,deployment资源,d

3.3 service资源
3.4 deployment资源
3.5 tomcat+mysql练习
4:k8s的附加组件
4.1 dns服务

service资源

• service帮助pod暴露端口
  创建一个service

[root@k8s-master svc]# cat k8s_svc.yml 
apiVersion: v1
kind: Service
metadata:
  name: myweb
spec:
  type: NodePort  #ClusterIP
  ports:
    - port: 80          #clusterIP
      nodePort: 30000   #node port
      targetPort: 80    #pod port
  selector:
    app: myweb

kubectl scale rc nginx --replicas=2

kubectl exec -it pod_name /bin/bash

修改nodePort范围

vim  /etc/kubernetes/apiserver
KUBE_API_ARGS="--service-node-port-range=3000-50000"

命令行创建service资源

kubectl expose rc nginx --type=NodePort --port=80

service默认使用iptables来实现负载均衡, k8s 1.8新版本中推荐使用lvs(四层负载均衡 传输层tcp,udp)

deployment资源

• 有rc在滚动升级之后,会造成服务访问中断,于是k8s引入了deployment资源
  创建deployment

[root@k8s-master deploy]# cat k8s_deploy.yml 
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  replicas: 3
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: 10.0.0.11:5000/nginx:1.13
        ports:
        - containerPort: 80
        resources:  
          limits:
            cpu: 100m
          requests:
            cpu: 100m

deployment升级和回滚

• 命令行创建deployment

kubectl run nginx --image=10.0.0.11:5000/nginx:1.13 --replicas=3 --record

• 命令行升级版本

kubectl set image deploy nginx nginx=10.0.0.11:5000/nginx:1.15

• 查看deployment所有历史版本

kubectl rollout history deployment nginx

• deployment回滚到上一个版本

kubectl rollout undo deployment nginx

• deployment回滚到指定版本

kubectl rollout undo deployment nginx --to-revision=2

tomcat+mysql练习

在k8s中容器之间相互访问,通过VIP地址!

[root@k8s-master tomcat_demo]# ls
mysql-rc.yml  mysql-svc.yml  tomcat-rc.yml  tomcat-svc.yml
[root@k8s-master tomcat_demo]# cat mysql-rc.yml 
apiVersion: v1
kind: ReplicationController
metadata:
  name: mysql
spec:
  replicas: 1
  selector:
    app: mysql
  template:
    metadata:
      labels:
        app: mysql
    spec:
      containers:
        - name: mysql
          image: 10.0.0.11:5000/mysql:5.7
          ports:
          - containerPort: 3306
          env:
          - name: MYSQL_ROOT_PASSWORD
            value: '123456'

[root@k8s-master tomcat_demo]# cat mysql-svc.yml 
apiVersion: v1
kind: Service
metadata:
  name: mysql
spec:
  ports:
    - port: 3306
      targetPort: 3306
  selector:
    app: mysql

[root@k8s-master tomcat_demo]# cat tomcat-rc.yml 
apiVersion: v1
kind: ReplicationController
metadata:
  name: myweb
spec:
  replicas: 2
  selector:
    app: myweb
  template:
    metadata:
      labels:
        app: myweb
    spec:
      containers:
        - name: myweb
          image: 10.0.0.11:5000/tomcat-app:v2
          ports:
          - containerPort: 8080
          env:
          - name: MYSQL_SERVICE_HOST
            value: 'mysql'
          - name: MYSQL_SERVICE_PORT
            value: '3306'

[root@k8s-master tomcat_demo]# cat tomcat-svc.yml 
apiVersion: v1
kind: Service
metadata:
  name: myweb
spec:
  type: NodePort
  ports:
    - port: 8080
      nodePort: 30008
      targetPort: 8080
  selector:
    app: myweb

k8s的附加组件

• k8s集群中dns服务的作用,就是讲svc的名字解析成VIP地址

dns服务

安装dns服务

1:下载dns_docker镜像包

wget [http://192.168.12.202/docker_image/docker_k8s_dns.tar.gz](http://192.168.12.202/docker_image/docker_k8s_dns.tar.gz)

2:导入dns_docker镜像包(node1节点)

docker load -i docker_k8s_dns.tar.gz

3:修改skydns-rc.yaml, 在node1 创建dns服务

  spec:
    nodeName: 10.0.0.12

[root@k8s-master dns]# ls
skydns-rc.yaml  skydns-svc.yaml
[root@k8s-master dns]# cat skydns-rc.yaml 
# Copyright 2016 The Kubernetes Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# TODO - At some point, we need to rename all skydns-*.yaml.* files to kubedns-*.yaml.*
# Should keep target in cluster/addons/dns-horizontal-autoscaler/dns-horizontal-autoscaler.yaml
# in sync with this file.

# __MACHINE_GENERATED_WARNING__

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: kube-dns
  namespace: kube-system
  labels:
    k8s-app: kube-dns
    kubernetes.io/cluster-service: "true"
spec:
  replicas: 1
  # replicas: not specified here:
  # 1. In order to make Addon Manager do not reconcile this replicas parameter.
  # 2. Default is 1.
  # 3. Will be tuned in real time if DNS horizontal auto-scaling is turned on.
  strategy:
    rollingUpdate:
      maxSurge: 10%
      maxUnavailable: 0
  selector:
    matchLabels:
      k8s-app: kube-dns
  template:
    metadata:
      labels:
        k8s-app: kube-dns
      annotations:
        scheduler.alpha.kubernetes.io/critical-pod: ''
        scheduler.alpha.kubernetes.io/tolerations: '[{"key":"CriticalAddonsOnly", "operator":"Exists"}]'
    spec:
      nodeName: 10.0.0.13
      containers:
      - name: kubedns
        image: gcr.io/google_containers/kubedns-amd64:1.9
        resources:
          # TODO: Set memory limits when we've profiled the container for large
          # clusters, then set request = limit to keep this container in
          # guaranteed class. Currently, this container falls into the
          # "burstable" category so the kubelet doesn't backoff from restarting it.
          limits:
            memory: 170Mi
          requests:
            cpu: 100m
            memory: 70Mi
        livenessProbe:
          httpGet:
            path: /healthz-kubedns
            port: 8080
            scheme: HTTP
          initialDelaySeconds: 60
          timeoutSeconds: 5
          successThreshold: 1
          failureThreshold: 5
        readinessProbe:
          httpGet:
            path: /readiness
            port: 8081
            scheme: HTTP
          # we poll on pod startup for the Kubernetes master service and
          # only setup the /readiness HTTP server once that's available.
          initialDelaySeconds: 3
          timeoutSeconds: 5
        args:
        - --domain=cluster.local.
        - --dns-port=10053
        - --config-map=kube-dns
        - --kube-master-url=http://10.0.0.11:8080
        # This should be set to v=2 only after the new image (cut from 1.5) has
        # been released, otherwise we will flood the logs.
        - --v=0
        #__PILLAR__FEDERATIONS__DOMAIN__MAP__
        env:
        - name: PROMETHEUS_PORT
          value: "10055"
        ports:
        - containerPort: 10053
          name: dns-local
          protocol: UDP
        - containerPort: 10053
          name: dns-tcp-local
          protocol: TCP
        - containerPort: 10055
          name: metrics
          protocol: TCP
      - name: dnsmasq
        image: gcr.io/google_containers/kube-dnsmasq-amd64:1.4
        livenessProbe:
          httpGet:
            path: /healthz-dnsmasq
            port: 8080
            scheme: HTTP
          initialDelaySeconds: 60
          timeoutSeconds: 5
          successThreshold: 1
          failureThreshold: 5
        args:
        - --cache-size=1000
        - --no-resolv
        - --server=127.0.0.1#10053
        #- --log-facility=-
        ports:
        - containerPort: 53
          name: dns
          protocol: UDP
        - containerPort: 53
          name: dns-tcp
          protocol: TCP
        # see: https://github.com/kubernetes/kubernetes/issues/29055 for details
        resources:
          requests:
            cpu: 150m
            memory: 10Mi
      - name: dnsmasq-metrics
        image: gcr.io/google_containers/dnsmasq-metrics-amd64:1.0
        livenessProbe:
          httpGet:
            path: /metrics
            port: 10054
            scheme: HTTP
          initialDelaySeconds: 60
          timeoutSeconds: 5
          successThreshold: 1
          failureThreshold: 5
        args:
        - --v=2
        - --logtostderr
        ports:
        - containerPort: 10054
          name: metrics
          protocol: TCP
        resources:
          requests:
            memory: 10Mi
      - name: healthz
        image: gcr.io/google_containers/exechealthz-amd64:1.2
        resources:
          limits:
            memory: 50Mi
          requests:
            cpu: 10m
            # Note that this container shouldn't really need 50Mi of memory. The
            # limits are set higher than expected pending investigation on #29688.
            # The extra memory was stolen from the kubedns container to keep the
            # net memory requested by the pod constant.
            memory: 50Mi
        args:
        - --cmd=nslookup kubernetes.default.svc.cluster.local 127.0.0.1 >/dev/null
        - --url=/healthz-dnsmasq
        - --cmd=nslookup kubernetes.default.svc.cluster.local 127.0.0.1:10053 >/dev/null
        - --url=/healthz-kubedns
        - --port=8080
        - --quiet
        ports:
        - containerPort: 8080
          protocol: TCP
      dnsPolicy: Default  # Don't use cluster DNS.
[root@k8s-master dns]# cat skydns-svc.yaml 
# Copyright 2016 The Kubernetes Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# TODO - At some point, we need to rename all skydns-*.yaml.* files to kubedns-*.yaml.*

# Warning: This is a file generated from the base underscore template file: skydns-svc.yaml.base

apiVersion: v1
kind: Service
metadata:
  name: kube-dns
  namespace: kube-system
  labels:
    k8s-app: kube-dns
    kubernetes.io/cluster-service: "true"
    kubernetes.io/name: "KubeDNS"
spec:
  selector:
    k8s-app: kube-dns
  clusterIP: 10.254.230.254
  ports:
  - name: dns
    port: 53
    protocol: UDP
  - name: dns-tcp
    port: 53
    protocol: TCP

4:创建dns服务

kubectl  create  -f   skydns-deploy.yaml

kubectl create -f skydns-svc.yaml

5:检查

kubectl get all --namespace=kube-system

6:修改所有node节点kubelet的配置文件

vim  /etc/kubernetes/kubelet

KUBELET_ARGS="--cluster_dns=10.254.230.254 --cluster_domain=cluster.local"

systemctl   restart kubelet

知识点归纳

3.3 service 资源

• 暴露端口,负载均衡和服务的自动发现
  node IP 端口范围 api-server
  cluster IP api-server
  pod IP etcd /atomic.io/network/config

kubectl expose deployment nginx --port=80 --target-port=80 --type=NodePort

3.4 deployment资源

• 解决了rc在滚动升级的时候访问会中断. rc1 myweb1--->rc2 myweb2 svc myweb
  deployment --> rs --> pod
  rs和rc有什么关系? rs新一代副本控制器 支持通配符匹配标签

• 命令行创建deployment:
  kubectl run nginx --image=10.0.0.11:5000/nginx:1.13 --replicas=3 --record
  命令行更新deployment中pod的镜像地址:
  kubectl set image deployment nginx nginx=10.0.0.11:5000/nginx:1.15
  命令行查看deployment版本
  kubectl rollout history deployment nginx
  命令行回滚deployment上一个版本
  kubectl rollout undo deployment nginx
  命令行回滚deployment到指定版本
  kubectl rollout undo deployment nginx --to-revision=1

3.5 tomcat+mysql 练习

• VIP 连接

4: k8s附加组件
4.1 dns

• 将SVC的名字解析成对应VIP

• k8s的资源操作:
  增kubectl create -f xxx.yml
  删kubectl delete 资源类型 资源名字 || kubectl delete -f xxx.yml
  改kubectl edit 资源类型 资源名字
  查kubectl get 资源类型 -o wide
  查kubectl describe 资源类型 资源名字