集群环境
系统
root@k8smaster:~# hostnamectl
Static hostname: k8smaster
Icon name: computer-vm
Chassis: vm
Machine ID: 71081e3f45c24ac98465767027e72119
Boot ID: 7b03cf9bf3e04b4ab9cbe77d2637cdee
Virtualization: vmware
Operating System: Ubuntu 18.04.4 LTS
Kernel: Linux 4.15.0-76-generic
Architecture: x86-64
集群IP
k8smaster：10.203.1.90
k8snode1：10.203.1.91
Chapter 1
Running a nginx service
创建一个服务通过Container内部80端口映射出来的nginx deployment
命令
kubectl create deployment my-first-nginx --image=nginx --replicas=2 --port=80
#Note：原PDF中使用的命令为`kubectl run my-first-nginx --image=nginx --replicas=2 --port=80`这个是旧版kubernetes的命令
新版本的Kubernetes（例如v.1.19或v.1.20）使用run命令只会创建出pod，想要创建deployment的命令是create deployment
查看结果
root@k8smaster:~# kubectl get all
NAME READY STATUS RESTARTS AGE
pod/my-first-nginx-7c769d949c-dcgsq 1/1 Running 0 3m44s
pod/my-first-nginx-7c769d949c-f26pd 1/1 Running 0 3m44s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 3h41m
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/my-first-nginx 2/2 2 2 3m44s
NAME DESIRED CURRENT READY AGE
replicaset.apps/my-first-nginx-7c769d949c 2 2 2 3m44s
#创建deployment之后会自动创建一个replicaset资源，作用是维持pod数量（create命令不使用--replicas参数时也会创建出replicaset资源，数量为1），并且根据--replicas参数的值创建出相应数量的pod
暴露nginx服务
负载均衡模式
在云服务器上可以创建出负载均衡的服务（On cloud providers that support an external load balancer (such as Google compute engine), using the LoadBalancer type will provision a load balancer for external access.）
命令
kubectl expose deployment my-first-nginx --port=80 --type=LoadBalancer
查看结果
#可以看到生成一个service/my-first-nginx的资源，外部端口使用的是31119
root@k8smaster:~# kubectl get all
NAME READY STATUS RESTARTS AGE
pod/my-first-nginx-7c769d949c-dcgsq 1/1 Running 0 5m22s
pod/my-first-nginx-7c769d949c-f26pd 1/1 Running 0 5m22s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 3h43m
service/my-first-nginx LoadBalancer 10.97.14.201 <pending> 80:31119/TCP 102s
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/my-first-nginx 2/2 2 2 5m22s
NAME DESIRED CURRENT READY AGE
replicaset.apps/my-first-nginx-7c769d949c 2 2 2 5m22s
测试
在局域网的其他机器访问k8smaster以及k8snode1节点的IP+31119端口，都能获取到nginx服务
#访问k8smaster
Klays-Stephen-4:~ klaylin$ curl 10.203.1.90:31119
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>
Klays-Stephen-4:~ klaylin$
#访问k8snode1
Klays-Stephen-4:~ klaylin$ curl 10.203.1.91:31119
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>
Klays-Stephen-4:~ klaylin$
查看service详细信息
可以看到此服务的集群IP为10.97.14.201，到pod的Endpoints ip分别是10.244.1.2:80和10.244.1.3:80。集群中的机器可以通过集群IP以及endpoint ip+80端口访问到nginx服务。
外部的机器访问宿主机的ip+31119端口的请求会通过集群ip 10.97.14.201 分发到endpoint ip
root@k8smaster:~# kubectl describe service/my-first-nginx
Name: my-first-nginx
Namespace: default
Labels: app=my-first-nginx
Annotations: <none>
Selector: app=my-first-nginx
Type: LoadBalancer
IP Families: <none>
IP: 10.97.14.201
IPs: 10.97.14.201
Port: <unset> 80/TCP
TargetPort: 80/TCP
NodePort: <unset> 31119/TCP
Endpoints: 10.244.1.2:80,10.244.1.3:80
Session Affinity: None
External Traffic Policy: Cluster
Events: <none>
Chapter 2
ReplicaSet
概念
Pod声明，主要描述Pod的replicas和其他行为，例如是否在Pod stop之后重启还是创建新的Pod，labels是ReplicaSet最重要的属性
Yaml文件
root@k8smaster:~# cat my-first-replicaset.yaml
apiVersion: apps/v1
kind: ReplicaSet
metadata:
name: my-first-replicaset
labels:
version: 0.0.1
spec:
replicas: 3
selector:
matchLabels:#声明replicaset管理的pod带有哪些标签，与template，metadata下的labels需要对应
project: My-Happy-Web
role: frontend
template:
metadata:
labels:#作用于Pod
project: My-Happy-Web
role: frontend
env: dev
spec:
containers:
- name: happy-web
image: nginx:latest
举例
matchLabels与template，metadata下的labels无法对应
yaml文件中labels中的project值不一致，无法成功创建ReplicaSet
#yaml文件
root@k8smaster:~# cat my-2nd-replicaset.yaml
apiVersion: apps/v1
kind: ReplicaSet
metadata:
name: my-2nd-replicaset
labels:
version: 0.0.1
spec:
replicas: 3
selector:
matchLabels:
project: My-Happy-Web
role: frontend
template:
metadata:
labels:
project: My-Happy-Webbbb
role: frontend
env: dev
spec:
containers:
- name: happy-web
image: nginx:latest
#创建ReplicaSet失败
root@k8smaster:~# kubectl apply -f my-2nd-replicaset.yaml
The ReplicaSet "my-2nd-replicaset" is invalid: spec.template.metadata.labels: Invalid value: map[string]string{"env":"dev", "project":"My-Happy-Webbbb", "role":"frontend"}: `selector` does not match template `labels`
ReplicaSet与Pod的关系
创建一个带Labels的pod
#Labels中有project=My-Happy-Web,role=frontend,env=test的属性
root@k8smaster:~# kubectl run standalone-pod --image=centos --labels="project=My-Happy-Web,role=frontend,env=test" --restart=Never --command sleep 3600
pod/standalone-pod created
创建一个Labels属性相同的ReplicaSet
#yaml文件，matchLabels为“project: My-Happy-Web，role: frontend”，replicas为3
root@k8smaster:~# cat my-first-replicaset.yaml
apiVersion: apps/v1
kind: ReplicaSet
metadata:
name: my-first-replicaset
labels:
version: 0.0.1
spec:
replicas: 3
selector:
matchLabels:
project: My-Happy-Web
role: frontend
template:
metadata:
labels:
project: My-Happy-Web
role: frontend
env: dev
spec:
containers:
- name: happy-web
image: nginx:latest
apply yaml文件，查看pod，可以看到apply 之后只创建了两个名称带有“my-first-replicaset”的pod
root@k8smaster:~# kubectl get all
NAME READY STATUS RESTARTS AGE
pod/my-2nd-nginx-59fc4f454c-xprzc 1/1 Running 0 4d
pod/my-first-nginx-7c769d949c-dcgsq 1/1 Running 0 4d1h
pod/my-first-nginx-7c769d949c-f26pd 1/1 Running 0 4d1h
pod/my-first-pod 2/2 Running 0 3d23h
pod/my-first-replicaset-6fhhd 1/1 Running 0 12m
pod/my-first-replicaset-ll6br 1/1 Running 0 12m
pod/standalone-pod 1/1 Running 0 43m
这是因为刚刚创建的独立的pod设定的Labels属性与这个ReplicaSet的matchLabels相对于，所以这个pod也会被这个ReplicaSet控制
查看独立创建的pod详细信息
可以看到第15行有记录这个pod由名字为my-first-replicaset的ReplicaSet资源控制
1 root@k8smaster:~# kubectl describe pod/standalone-pod
2 Name: standalone-pod
3 Namespace: default
4 Priority: 0
5 Node: k8smaster/10.203.1.90
6 Start Time: Sun, 20 Dec 2020 22:56:32 -0800
7 Labels: env=test
8 project=My-Happy-Web
9 role=frontend
10 Annotations: <none>
11 Status: Running
12 IP: 10.244.0.4
13 IPs:
14 IP: 10.244.0.4
15 Controlled By: ReplicaSet/my-first-replicaset
16 Containers:
17 standalone-pod:
18 Container ID: docker://07c218d704baa911542e56ca1474ba6c49c359020a5c2d9600e22eb803ef5558
19 Image: centos
20 Image ID: docker-pullable://centos@sha256:5528e8b1b1719d34604c87e11dcd1c0a20bedf46e83b5632cdeac91b8c04efc1
21 Port: <none>
22 Host Port: <none>
23 Command:
24 sleep
25 3600
26 State: Running
27 Started: Sun, 20 Dec 2020 22:57:10 -0800
28 Ready: True
29 Restart Count: 0
30 Environment: <none>
31 Mounts:
32 /var/run/secrets/kubernetes.io/serviceaccount from default-token-4b5sf (ro)
33 Conditions:
34 Type Status
35 Initialized True
36 Ready True
37 ContainersReady True
38 PodScheduled True
39 Volumes:
40 default-token-4b5sf:
41 Type: Secret (a volume populated by a Secret)
42 SecretName: default-token-4b5sf
43 Optional: false
44 QoS Class: BestEffort
45 Node-Selectors: <none>
46 Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
47 node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
48 Events:
49 Type Reason Age From Message
50 ---- ------ ---- ---- -------
51 Normal Scheduled 34m default-scheduler Successfully assigned default/standalone-pod to k8smaster
52 Normal Pulling 34m kubelet Pulling image "centos"
53 Normal Pulled 33m kubelet Successfully pulled image "centos" in 32.241649541s
54 Normal Created 33m kubelet Created container standalone-pod
55 Normal Started 33m kubelet Started container standalone-pod
Deployment
概念
Pod声明，会取代ReplicaSet，创建一个deployment会自动创建相对应的ReplicaSet，ReplicaSet创建Pods[图片上传失败...(image-27a784-1612416755456)]
Deployment与ReplicaSet的关系
除了上述的一对一的关系，还存在一个Deployment对应多个ReplicaSet 不同版本的关系[图片上传失败...(image-59827b-1612416755457)]
测试
创建一个deployment
yaml文件内容如下，使用的是nginx:lasted版本部署的replicas为3的服务
root@k8smaster:~# cat deploy1.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: my-nginx
spec:
replicas: 3
selector:
matchLabels:
run: my-nginx
template:
metadata:
labels:
run: my-nginx
spec:
containers:
- name: my-nginx
image: nginx
ports:
- containerPort: 80
使用kubectl create命令创建deployment
root@k8smaster:~# kubectl create -f deploy1.yaml --save-config --record
deployment.apps/my-nginx created
命令加入“--save-config”和“--record”的参数
- “--save-config”参数的作用是允许后续修改yaml文件之后使用kubectl apply命令update deployment
- “--record”参数的作用是会记录命令行历史
查看deployment
可以看到第29行，记录了当前的deployment创建出来的ReplicaSet
1 root@k8smaster:~# kubectl describe deployment.apps/my-nginx
2 Name: my-nginx
3 Namespace: default
4 CreationTimestamp: Wed, 23 Dec 2020 23:01:09 -0800
5 Labels: <none>
6 Annotations: deployment.kubernetes.io/revision: 1
7 kubernetes.io/change-cause: kubectl create --filename=deploy1.yaml --save-config=true --record=true
8 Selector: run=my-nginx
9 Replicas: 3 desired | 3 updated | 3 total | 3 available | 0 unavailable
10 StrategyType: RollingUpdate
11 MinReadySeconds: 0
12 RollingUpdateStrategy: 25% max unavailable, 25% max surge
13 Pod Template:
14 Labels: run=my-nginx
15 Containers:
16 my-nginx:
17 Image: nginx
18 Port: 80/TCP
19 Host Port: 0/TCP
20 Environment: <none>
21 Mounts: <none>
22 Volumes: <none>
23 Conditions:
24 Type Status Reason
25 ---- ------ ------
26 Available True MinimumReplicasAvailable
27 Progressing True NewReplicaSetAvailable
28 OldReplicaSets: <none>
29 NewReplicaSet: my-nginx-5b56ccd65f (3/3 replicas created)
30 Events:
31 Type Reason Age From Message
32 ---- ------ ---- ---- -------
33 Normal ScalingReplicaSet 55s deployment-controller Scaled up replica set my-nginx-5b56ccd65f to 3
update deployment
- 将nginx的image版本修改成1.12.0
root@k8smaster:~# kubectl set image deployment my-nginx my-nginx=nginx:1.12.0 --record
deployment.apps/my-nginx image updated
- 查看deployment，可以看到第28行记录的是刚刚update前的deployment，而第29行是新的deployment
1 root@k8smaster:~# kubectl describe deployment.apps/my-nginx
2 Name: my-nginx
3 Namespace: default
4 CreationTimestamp: Wed, 23 Dec 2020 23:01:09 -0800
5 Labels: <none>
6 Annotations: deployment.kubernetes.io/revision: 2
7 kubernetes.io/change-cause: kubectl set image deployment my-nginx my-nginx=nginx:1.12.0 --record=true
8 Selector: run=my-nginx
9 Replicas: 3 desired | 1 updated | 4 total | 3 available | 1 unavailable
10 StrategyType: RollingUpdate
11 MinReadySeconds: 0
12 RollingUpdateStrategy: 25% max unavailable, 25% max surge
13 Pod Template:
14 Labels: run=my-nginx
15 Containers:
16 my-nginx:
17 Image: nginx:1.12.0
18 Port: 80/TCP
19 Host Port: 0/TCP
20 Environment: <none>
21 Mounts: <none>
22 Volumes: <none>
23 Conditions:
24 Type Status Reason
25 ---- ------ ------
26 Available True MinimumReplicasAvailable
27 Progressing True ReplicaSetUpdated
28 OldReplicaSets: my-nginx-5b56ccd65f (3/3 replicas created)
29 NewReplicaSet: my-nginx-b9cd4969c (1/1 replicas created)
30 Events:
31 Type Reason Age From Message
32 ---- ------ ---- ---- -------
33 Normal ScalingReplicaSet 6m6s deployment-controller Scaled up replica set my-nginx-5b56ccd65f to 3
34 Normal ScalingReplicaSet 4s deployment-controller Scaled up replica set my-nginx-b9cd4969c to 1
- 过一段时间再查看deployment，可以看到第29行，新的ReplicaSet已经部署完成3个pod，而old ReplicaSet也会被清空
1 root@k8smaster:~# kubectl describe deployment.apps/my-nginx
2 Name: my-nginx
3 Namespace: default
4 CreationTimestamp: Wed, 23 Dec 2020 23:01:09 -0800
5 Labels: <none>
6 Annotations: deployment.kubernetes.io/revision: 2
7 kubernetes.io/change-cause: kubectl set image deployment my-nginx my-nginx=nginx:1.12.0 --record=true
8 Selector: run=my-nginx
9 Replicas: 3 desired | 3 updated | 3 total | 3 available | 0 unavailable
10 StrategyType: RollingUpdate
11 MinReadySeconds: 0
12 RollingUpdateStrategy: 25% max unavailable, 25% max surge
13 Pod Template:
14 Labels: run=my-nginx
15 Containers:
16 my-nginx:
17 Image: nginx:1.12.0
18 Port: 80/TCP
19 Host Port: 0/TCP
20 Environment: <none>
21 Mounts: <none>
22 Volumes: <none>
23 Conditions:
24 Type Status Reason
25 ---- ------ ------
26 Available True MinimumReplicasAvailable
27 Progressing True NewReplicaSetAvailable
28 OldReplicaSets: <none>
29 NewReplicaSet: my-nginx-b9cd4969c (3/3 replicas created)
30 Events:
31 Type Reason Age From Message
32 ---- ------ ---- ---- -------
33 Normal ScalingReplicaSet 9m51s deployment-controller Scaled up replica set my-nginx-5b56ccd65f to 3
34 Normal ScalingReplicaSet 3m49s deployment-controller Scaled up replica set my-nginx-b9cd4969c to 1
35 Normal ScalingReplicaSet 3m16s deployment-controller Scaled down replica set my-nginx-5b56ccd65f to 2
36 Normal ScalingReplicaSet 3m16s deployment-controller Scaled up replica set my-nginx-b9cd4969c to 2
37 Normal ScalingReplicaSet 2m37s deployment-controller Scaled down replica set my-nginx-5b56ccd65f to 1
38 Normal ScalingReplicaSet 2m37s deployment-controller Scaled up replica set my-nginx-b9cd4969c to 3
39 Normal ScalingReplicaSet 2m30s deployment-controller Scaled down replica set my-nginx-5b56ccd65f to 0
查看deployment历史
root@k8smaster:~# kubectl rollout history deployment my-nginx
deployment.apps/my-nginx
REVISION CHANGE-CAUSE
1 kubectl create --filename=deploy1.yaml --save-config=true --record=true
2 kubectl set image deployment my-nginx my-nginx=nginx:1.12.0 --record=true
回滚到版本1
root@k8smaster:~# kubectl rollout undo deployment my-nginx --to-revision=1
deployment.apps/my-nginx rolled back
查看deployment详细信息，可以看到第29行，ReplicaSet已经恢复到第一次创建的版本
1 root@k8smaster:~# kubectl describe deployment.apps/my-nginx
2 Name: my-nginx
3 Namespace: default
4 CreationTimestamp: Wed, 23 Dec 2020 23:01:09 -0800
5 Labels: <none>
6 Annotations: deployment.kubernetes.io/revision: 3
7 kubernetes.io/change-cause: kubectl create --filename=deploy1.yaml --save-config=true --record=true
8 Selector: run=my-nginx
9 Replicas: 3 desired | 3 updated | 3 total | 3 available | 0 unavailable
10 StrategyType: RollingUpdate
11 MinReadySeconds: 0
12 RollingUpdateStrategy: 25% max unavailable, 25% max surge
13 Pod Template:
14 Labels: run=my-nginx
15 Containers:
16 my-nginx:
17 Image: nginx
18 Port: 80/TCP
19 Host Port: 0/TCP
20 Environment: <none>
21 Mounts: <none>
22 Volumes: <none>
23 Conditions:
24 Type Status Reason
25 ---- ------ ------
26 Available True MinimumReplicasAvailable
27 Progressing True NewReplicaSetAvailable
28 OldReplicaSets: <none>
29 NewReplicaSet: my-nginx-5b56ccd65f (3/3 replicas created)
30 Events:
31 Type Reason Age From Message
32 ---- ------ ---- ---- -------
33 Normal ScalingReplicaSet 50m deployment-controller Scaled up replica set my-nginx-b9cd4969c to 1
34 Normal ScalingReplicaSet 50m deployment-controller Scaled down replica set my-nginx-5b56ccd65f to 2
35 Normal ScalingReplicaSet 50m deployment-controller Scaled up replica set my-nginx-b9cd4969c to 2
36 Normal ScalingReplicaSet 49m deployment-controller Scaled down replica set my-nginx-5b56ccd65f to 1
37 Normal ScalingReplicaSet 49m deployment-controller Scaled up replica set my-nginx-b9cd4969c to 3
38 Normal ScalingReplicaSet 49m deployment-controller Scaled down replica set my-nginx-5b56ccd65f to 0
39 Normal ScalingReplicaSet 52s deployment-controller Scaled up replica set my-nginx-5b56ccd65f to 1
40 Normal ScalingReplicaSet 41s deployment-controller Scaled down replica set my-nginx-b9cd4969c to 2
41 Normal ScalingReplicaSet 41s deployment-controller Scaled up replica set my-nginx-5b56ccd65f to 2
42 Normal ScalingReplicaSet 32s (x2 over 56m) deployment-controller Scaled up replica set my-nginx-5b56ccd65f to 3
43 Normal ScalingReplicaSet 32s deployment-controller Scaled down replica set my-nginx-b9cd4969c to 1
44 Normal ScalingReplicaSet 19s deployment-controller Scaled down replica set my-nginx-b9cd4969c to 0
Service
Pod service
创建Pod
root@k8smaster:~# kubectl run nginx-pod --image=nginx --port=80 --restart="Never" --labels="project=My-Happy-Web,role=frontend,env=test"
pod/nginx-pod created
暴露service
root@k8smaster:~# kubectl expose pod nginx-pod --port=8080 --target-port=80 --name="nginx-service"
service/nginx-service exposed
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