通过Rancher部署并扩容Kubernetes集群基础篇二
接上一篇通过Rancher部署并扩容Kubernetes集群基础篇一7. 使用ConfigMap配置redis
https://github.com/kubernetes/kubernetes.github.io/blob/master/docs/user-guide/configmap/redis/redis-config
redis-config
maxmemory 2mb
maxmemory-policy allkeys-lru
# kubectl create configmap example-redis-config --from-file=./redis-config# kubectl get configmap example-redis-config -o yaml
apiVersion: v1
data:
redis-config: |
maxmemory 2mb
maxmemory-policy allkeys-lru
kind: ConfigMap
metadata:
creationTimestamp: 2017-07-12T13:27:56Z
name: example-redis-config
namespace: default
resourceVersion: "45707"
selfLink: /api/v1/namespaces/default/configmaps/example-redis-config
uid: eab522fd-6705-11e7-94da-02672b869d7f
redis-pod.yaml
apiVersion: v1
kind: Pod
metadata:
name: redis
spec:
containers:
- name: redis
image: kubernetes/redis:v1
env:
- name: MASTER
value: "true"
ports:
- containerPort: 6379
resources:
limits:
cpu: "0.1"
volumeMounts:
- mountPath: /redis-master-data
name: data
- mountPath: /redis-master
name: config
volumes:
- name: data
emptyDir: {}
- name: config
configMap:
name: example-redis-config
items:
- key: redis-config
path: redis.conf
# kubectl create -f redis-pod.yaml
pod "redis" created
# kubectl exec -it redis redis-cli
127.0.0.1:6379>
127.0.0.1:6379>
127.0.0.1:6379> config get maxmemory
1) "maxmemory"
2) "2097152"
127.0.0.1:6379> config get maxmemory-policy
1) "maxmemory-policy"
2) "allkeys-lru"
127.0.0.1:6379>
8. 使用kubectl命令管理kubernetes对象
# kubectl run nginx --image nginx
deployment "nginx" created
或者
# kubectl create deployment nginx --image nginx 使用kubectl create创建一个配置文件中定义的对象
#kubectl create -f nginx.yaml 删除两个配置文件中定义的对象
#kubectl delete -f nginx.yaml -f redis.yaml 更新对象
#kubectl replace -f nginx.yaml 处理configs目录下所有的对象配置文件，创建新的对象或者打补丁现有的对象
#kubectl apply -f configs/ 递推处理子目录下的对象配置文件
#kubectl apply -R -f configs/ 9. 部署无状态应用
9.1 使用deployment运行一个无状态应用
deployment.yaml
apiVersion: apps/v1beta1
kind: Deployment
metadata:
name: nginx-deployment
spec:
replicas: 2 # tells deployment to run 2 pods matching the template
template: # create pods using pod definition in this template
metadata:
# unlike pod-nginx.yaml, the name is not included in the meta data as a unique name is
# generated from the deployment name
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.7.9
ports:
- containerPort: 80
kubectl create -f https://k8s.io/docs/tasks/run-application/deployment.yaml 这里需要注意一下，rancher1.6.2部署的是kubernetes 1.5.4
这里的apiVersion要改一下，改成extensions/v1beta1
kubernetes从1.6引入apps/v1beta1.Deployment 替代 extensions/v1beta1.Deployment
显示这个deployment的信息
# kubectl describe deployment nginx-deployment# kubectl get pods -l app=nginx 更新deployment
deployment-update.yaml
和deployment.yaml除了image不同之外其余的内容相同
image: nginx:1.8# kubectl apply -f deployment-update.yaml 执行更新后，kubernetes会先创建新的pods，然后再停掉并删除老的pods
# kubectl get pods -l app=nginx
# kubectl get pod nginx-deployment-148880595-9l07p -o yaml|grep image:
- image: nginx:1.8
image: nginx:1.8
已经更新成功了
通过增加replicas的数量来扩展应用
# cp deployment-update.yaml deployment-scale.yaml 修改deployment-scale.yaml
replicas: 4
# kubectl apply -f deployment-scale.yaml
# kubectl get pods -l app=nginx
NAME READY STATUS RESTARTS AGE
nginx-deployment-148880595-1tb5m 1/1 Running 0 26s
nginx-deployment-148880595-9l07p 1/1 Running 0 10m
nginx-deployment-148880595-lc113 1/1 Running 0 26s
nginx-deployment-148880595-z8l51 1/1 Running 0 10m
删除deployment
# kubectl delete deployment nginx-deployment
deployment "nginx-deployment" deleted
创建一个可以复制的应用首选的方式是使用的deployment， deployment会使用ReplicaSet.在Deployment和ReplicaSet加入到Kubernetes之前，可复制的应用是通过ReplicationController来配置的
9.2 案例： 部署一个以Redis作为存储的PHP留言板
第一步： 启动一个redis master服务
redis-master-deployment.yaml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: redis-master
spec:
replicas: 1
template:
metadata:
labels:
app: redis
role: master
tier: backend
spec:
containers:
- name: master
image: gcr.io/google_containers/redis:e2e# or just image: redis
resources:
requests:
cpu: 100m
memory: 100Mi
ports:
- containerPort: 6379
# kubectl create -f redis-master-deployment.yaml redis-master-service.yaml
apiVersion: v1
kind: Service
metadata:
name: redis-master
labels:
app: redis
role: master
tier: backend
spec:
ports:
- port: 6379
targetPort: 6379
selector:
app: redis
role: master
tier: backend
# kubectl create -f redis-master-service.yaml# kubectl get services redis-master
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
redis-master 10.43.10.96 6379/TCP 2m
targetPort是后端容器接收外部流量的端口，port是其他任务pods访问service的端口
kubernetes支持两种主要的模式来发现一个service -- 环境变量和DNS
查看集群DNS
# kubectl --namespace=kube-system get rs -l k8s-app=kube-dns
NAME DESIRED CURRENT READY AGE
kube-dns-1208858260 1 1 1 1d
# kubectl getpods -n=kube-system -l k8s-app=kube-dns
NAME READY STATUS RESTARTS AGE
kube-dns-1208858260-c8dbv 4/4 Running 8 1d
第二步： 启动一个redis slave服务
redis-slave.yaml
apiVersion: v1
kind: Service
metadata:
name: redis-slave
labels:
app: redis
role: slave
tier: backend
spec:
ports:
- port: 6379
selector:
app: redis
role: slave
tier: backend
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: redis-slave
spec:
replicas: 2
template:
metadata:
labels:
app: redis
role: slave
tier: backend
spec:
containers:
- name: slave
image: gcr.io/google_samples/gb-redisslave:v1
resources:
requests:
cpu: 100m
memory: 100Mi
env:
- name: GET_HOSTS_FROM
value: dns
# If your cluster config does not include a dns service, then to
# instead access an environment variable to find the master
# service's host, comment out the 'value: dns' line above, and
# uncomment the line below:
# value: env
ports:
- containerPort: 6379
# kubectl create -f redis-slave.yaml
service "redis-slave" created
deployment "redis-slave" created
# kubectl get deployments -l app=redis
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
redis-master 1 1 1 1 35m
redis-slave 2 2 2 2 5m
# kubectl get services -l app=redis
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
redis-master 10.43.10.96 6379/TCP 31m
redis-slave 10.43.231.209 6379/TCP 6m
# kubectl get pods -l app=redis
NAME READY STATUS RESTARTS AGE
redis-master-343230949-sc78h 1/1 Running 0 37m
redis-slave-132015689-rc1xf 1/1 Running 0 7m
redis-slave-132015689-vb0vl 1/1 Running 0 7m
第三步：启动一个留言板前端
frontend.yaml
apiVersion: v1
kind: Service
metadata:
name: frontend
labels:
app: guestbook
tier: frontend
spec:
# if your cluster supports it, uncomment the following to automatically create
# an external load-balanced IP for the frontend service.
# type: LoadBalancer
ports:
- port: 80
selector:
app: guestbook
tier: frontend
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: frontend
spec:
replicas: 3
template:
metadata:
labels:
app: guestbook
tier: frontend
spec:
containers:
- name: php-redis
image: gcr.io/google-samples/gb-frontend:v4
resources:
requests:
cpu: 100m
memory: 100Mi
env:
- name: GET_HOSTS_FROM
value: dns
# If your cluster config does not include a dns service, then to
# instead access environment variables to find service host
# info, comment out the 'value: dns' line above, and uncomment the
# line below:
# value: env
ports:
- containerPort: 80
# kubectl create -f frontend.yaml
service "frontend" created
deployment "frontend" created
# kubectl get services -l tier
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
frontend 10.43.39.188 80/TCP 3m
redis-master 10.43.10.96 6379/TCP 47m
redis-slave 10.43.231.209 6379/TCP 22m
# kubectl get deployments -l tier
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
frontend 3 3 3 3 3m
redis-master 1 1 1 1 53m
redis-slave 2 2 2 2 22m
# kubectl get pods -l tier
NAME READY STATUS RESTARTS AGE
frontend-88237173-b7x03 1/1 Running 0 13m
frontend-88237173-qg6d7 1/1 Running 0 13m
frontend-88237173-zb827 1/1 Running 0 13m
redis-master-343230949-sc78h 1/1 Running 0 1h
redis-slave-132015689-rc1xf 1/1 Running 0 32m
redis-slave-132015689-vb0vl 1/1 Running 0 32m
guestbook.php
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