1.创建一个测试用的deployment
[root@linux-node1 ~]# kubectl run net-test --image=alpine --replicas=3 sleep 360000
2.查看创建情况
[root@linux-node1 ~]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE
net-test-5767cb94df-6crmr 1/1 Running 0 17s 10.2.97.176 192.168.56.13
net-test-5767cb94df-9mpmb 1/1 Running 0 17s 10.2.70.187 192.168.56.12
net-test-5767cb94df-x8l44 1/1 Running 0 17s 10.2.97.175 192.168.56.13
# 使用kubectl创建了一个名为net-test 的deployment, 镜像是alpine 副本数为3，
[root@linux-node1 ~]# kubectl get deployments
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
net-test 3 3 3 3 7m
3.测试联通性
ping 10.2.97.176
通过yaml文件部署应用
1.编写一个nginx-deployment.yaml文件:
[root@linux-node1 ~]# cat > nginx-deployment.yaml << EOF
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-deployment
labels:
app: nginx
spec:
replicas: 3
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.10.3
ports:
- containerPort: 80
EOF
2.执行创建:
[root@linux-node1 ~]# kubectl create -f nginx-deployment.yaml
deployment.apps "nginx-deployment" created
# 查看deployment
[root@linux-node1 ~]# kubectl get deployment/nginx-deployment
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
nginx-deployment 10 10 10 10 1m
# 查看deployment 详情
[root@linux-node1 ~]# kubectl describe deployment/nginx-deployment
Name: nginx-deployment
Namespace: default
CreationTimestamp: Thu, 31 May 2018 20:20:17 +0800
Labels: app=nginx
Annotations: deployment.kubernetes.io/revision=1
Selector: app=nginx
Replicas: 10 desired | 10 updated | 10 total | 10 available | 0 unavailable
StrategyType: RollingUpdate
MinReadySeconds: 0
RollingUpdateStrategy: 25% max unavailable, 25% max surge
Pod Template:
Labels: app=nginx
Containers:
nginx:
Image: nginx:1.10.3
Port: 80/TCP
Host Port: 0/TCP
Environment: <none>
Mounts: <none>
Volumes: <none>
Conditions:
Type Status Reason
---- ------ ------
Progressing True NewReplicaSetAvailable
Available True MinimumReplicasAvailable
OldReplicaSets: <none>
NewReplicaSet: nginx-deployment-75d56bb955 (10/10 replicas created)
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal ScalingReplicaSet 5m deployment-controller Scaled up replica set nginx-deployment-75d56bb955 to 3
Normal ScalingReplicaSet 1m (x2 over 3m) deployment-controller Scaled down replica set nginx-deployment-75d56bb955 to 3
Normal ScalingReplicaSet 57s (x3 over 5m) deployment-controller Scaled up replica set nginx-deployment-75d56bb955 to 10
# 查看pod ,可以看出按照我们的描述文件里面的副本数已经有10个POD通过Schedule到了不同的node节点上面
[root@linux-node1 ~]# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE
net-test-5767cb94df-6crmr 1/1 Running 0 40m 10.2.97.178 192.168.56.13
net-test-5767cb94df-9mpmb 1/1 Running 0 40m 10.2.70.187 192.168.56.12
net-test-5767cb94df-x8l44 1/1 Running 0 40m 10.2.97.177 192.168.56.13
nginx-deployment-75d56bb955-255w2 1/1 Running 0 3m 10.2.70.196 192.168.56.12
nginx-deployment-75d56bb955-5ckvs 1/1 Running 0 8m 10.2.70.188 192.168.56.12
nginx-deployment-75d56bb955-7dq87 1/1 Running 0 3m 10.2.70.198 192.168.56.12
nginx-deployment-75d56bb955-8vl7p 1/1 Running 0 3m 10.2.97.191 192.168.56.13
nginx-deployment-75d56bb955-9f9ms 1/1 Running 0 3m 10.2.97.189 192.168.56.13
nginx-deployment-75d56bb955-9g9bk 1/1 Running 0 3m 10.2.97.188 192.168.56.13
nginx-deployment-75d56bb955-9kz2r 1/1 Running 0 3m 10.2.70.197 192.168.56.12
nginx-deployment-75d56bb955-s78gs 1/1 Running 0 8m 10.2.70.189 192.168.56.12
nginx-deployment-75d56bb955-v8n5v 1/1 Running 0 3m 10.2.97.190 192.168.56.13
nginx-deployment-75d56bb955-zfb4m 1/1 Running 0 8m 10.2.97.179 192.168.56.13
# 查看某个pod详情
[root@linux-node1 ~]# kubectl describe pod/nginx-deployment-75d56bb955-255w2
Name: nginx-deployment-75d56bb955-255w2
Namespace: default
Node: 192.168.56.12/192.168.56.12
Start Time: Thu, 31 May 2018 20:24:31 +0800
Labels: app=nginx
pod-template-hash=3181266511
Annotations: <none>
Status: Running
IP: 10.2.70.196
Controlled By: ReplicaSet/nginx-deployment-75d56bb955
Containers:
nginx:
Container ID: docker://48ad80730efd6d744ac6d31b34778eb8e75b0f4c6698e1c1fc8f6046a6a77b2b
Image: nginx:1.10.3
Image ID: docker-pullable://nginx@sha256:6202beb06ea61f44179e02ca965e8e13b961d12640101fca213efbfd145d7575
Port: 80/TCP
Host Port: 0/TCP
State: Running
Started: Thu, 31 May 2018 20:24:33 +0800
Ready: True
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from default-token-5htws (ro)
Conditions:
Type Status
Initialized True
Ready True
PodScheduled True
Volumes:
default-token-5htws:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-5htws
Optional: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: <none>
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal SuccessfulMountVolume 3m kubelet, 192.168.56.12 MountVolume.SetUp succeeded for volume "default-token-5htws"
Normal Pulled 3m kubelet, 192.168.56.12 Container image "nginx:1.10.3" already present on machine
Normal Created 3m kubelet, 192.168.56.12 Created container
Normal Started 3m kubelet, 192.168.56.12 Started container
Normal Scheduled 2m default-scheduler Successfully assigned nginx-deployment-75d56bb955-255w2 to 192.168.56.12
# 访问Nginx pod
[root@linux-node1 ~]# curl -I http://10.2.70.196
HTTP/1.1 200 OK
Server: nginx/1.10.3
Date: Thu, 31 May 2018 12:30:45 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 31 Jan 2017 15:01:11 GMT
Connection: keep-alive
ETag: "5890a6b7-264"
Accept-Ranges: byte
# 更新deployment
[root@linux-node1 ~]# kubectl set image deployment/nginx-deployment nginx=nginx:1.12.2 --record
deployment.apps "nginx-deployment" image updated
# 可以看到更新已经成功(滚动更新)
[root@linux-node1 ~]# kubectl get deployment/nginx-deployment -o wide
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR
nginx-deployment 10 10 10 10 17m nginx nginx:1.12.2 app=nginx
[root@linux-node1 ~]# curl -I 10.2.97.192
HTTP/1.1 200 OK
Server: nginx/1.12.2 # 版本已经更新成功
Date: Thu, 31 May 2018 12:35:54 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 11 Jul 2017 13:29:18 GMT
Connection: keep-alive
ETag: "5964d2ae-264"
Accept-Ranges: bytes
# 查看deployment更新历史
[root@linux-node1 ~]# kubectl rollout history deployment/nginx-deployment
deployments "nginx-deployment"
REVISION CHANGE-CAUSE
1 <none> # 用于在之前在创建创建nginx deployment的时候 未加参数 --record 所以这个信息为none
2 kubectl set image deployment/nginx-deployment nginx=nginx:1.12.2 --record=true
# 查看版本详情(--revison=VERSION_NUM)
[root@linux-node1 ~]# kubectl rollout history deployment/nginx-deployment --revision=1
deployments "nginx-deployment" with revision #1
Pod Template:
Labels: app=nginx
pod-template-hash=3181266511
Containers:
nginx:
Image: nginx:1.10.3
Port: 80/TCP
Host Port: 0/TCP
Environment: <none>
Mounts: <none>
Volumes: <none>
# 版本回滚至上一个版本:
[root@linux-node1 ~]# kubectl rollout undo deployment/nginx-deployment
deployment.apps "nginx-deployment"
[root@linux-node1 ~]# kubectl get deployment/nginx-deployment -o wide
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR
nginx-deployment 10 10 10 10 26m nginx nginx:1.10.3 app=nginx
# 扩容pod数量
[root@linux-node1 ~]# kubectl scale --replicas=20 deployment nginx-deployment
deployment.extensions "nginx-deployment" scaled
[root@linux-node1 ~]# kubectl get deployment/nginx-deployment -o wide
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR
nginx-deployment 20 20 20 20 28m nginx nginx:1.10.3 app=nginx
那问题来了:
- 每次收到获取podIP太扯了，总不能每次都要手动改程序或者配置才能访问服务吧，要怎么提前知道podIP呢？
- Pod在运行中可能会重建，IP变了怎么解？
- 如何在多个Pod中实现负载均衡嘞？
这些问题使用k8s Service就可以解决。
Service可以将pod IP封装起来，即使Pod发生重建，依然可以通过Service来访问Pod提供的服务。此外，Service还解决了负载均衡的问题，大家可以多访问几次Service，然后通过kubectl logs 来查看Nginx Pod的访问日志来确认
创建一个对于nginx deployment的一个service
1.编写nginx-service.yaml文件
[root@linux-node1 ~]# cat > nginx-service.yaml << EOF
kind: Service
apiVersion: v1
metadata:
name: nginx-service
spec:
selector:
app: nginx
ports:
- protocol: TCP
port: 80
targetPort: 80
EOF
2.执行创建操作:
[root@linux-node1 ~]# kubectl create -f nginx-service.yaml
service "nginx-service" created
[root@linux-node1 ~]# kubectl get service -o wide
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
kubernetes ClusterIP 10.1.0.1 <none> 443/TCP 3d <none>
nginx-service ClusterIP 10.1.146.223 <none> 80/TCP 30s app=nginx
# 访问VIP
[root@linux-node1 ~]# curl -I http://10.1.146.223
HTTP/1.1 200 OK
Server: nginx/1.10.3
Date: Thu, 31 May 2018 12:54:54 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 31 Jan 2017 15:01:11 GMT
Connection: keep-alive
ETag: "5890a6b7-264"
Accept-Ranges: bytes
# 在节点2上查看LVS，通过k8s封装LVS来实现了负载均衡
[root@linux-node2 ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 10.1.0.1:443 rr persistent 10800
-> 192.168.56.11:6443 Masq 1 1 0
TCP 10.1.146.223:80 rr
-> 10.2.70.204:80 Masq 1 0 0
-> 10.2.70.205:80 Masq 1 0 1
-> 10.2.70.206:80 Masq 1 0 0
-> 10.2.70.207:80 Masq 1 0 0
-> 10.2.70.208:80 Masq 1 0 0
-> 10.2.70.209:80 Masq 1 0 0
-> 10.2.70.210:80 Masq 1 0 0
-> 10.2.70.211:80 Masq 1 0 0
-> 10.2.70.212:80 Masq 1 0 0
-> 10.2.70.213:80 Masq 1 0 0
-> 10.2.97.197:80 Masq 1 0 0
-> 10.2.97.198:80 Masq 1 0 0
-> 10.2.97.199:80 Masq 1 0 1
-> 10.2.97.200:80 Masq 1 0 0
-> 10.2.97.201:80 Masq 1 0 0
-> 10.2.97.202:80 Masq 1 0 1
-> 10.2.97.203:80 Masq 1 0 1
-> 10.2.97.204:80 Masq 1 0 0
-> 10.2.97.205:80 Masq 1 0 0
