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spec：
spec:
name
image
imagePullPolicy:Always,Never,IfNotPresent
ports:
name
containerPort
livenessProbe
readinessProbe
liftcycle
ExecAction: exec
TCPSocketAction: tcpSocker
HTTPGetAction: httpGet
Pod控制器
ReplicaSet：创建一定数量的pod，支持扩缩容
主要有三个组件：1，用户期望的pod副本 2，标签选择器 3.如果pod不够怎么办，扩建
Pod资源模板可以帮助用户新建
Deployment可以比ReplicaSet更加强大，增加声明式配置和升级后的回滚，是目前最好的Pod控制器
DaemonSet：系统级的Pod，只能在node上运行一个，每个集群精确运行一个
Job：只能执行运行一次的，比如这个程序运行完了，这个容器就没有用了
CronJob：周期性运行Job和CronJob都是不用长期运行的容器
StatetufulSet：运行mysql，redis
有状态的运维任务时很困难的，比如mysql和redis集群，一般转换成脚本，有状态的应用托管到K8s上是很难的
Deployment在更新中展示强大的功能
[root@master test]# cat rs-demo.yaml
apiVersion: apps/v1
kind: ReplicaSet
metadata:
name: myapp
namespace: default
spec:
replicas: 2
selector:
matchLabels:
app: myapp
release: canary
template:
metadata:
name: myapp-pod
labels:
app: myapp
release: canary
environment: qa
spec:
containers:
- name: myapp-container
image: ikubernetes/myapp:v1
ports:
- name: http
containerPort: 80[root@master test]# kubectl get pod
NAME READY STATUS RESTARTS AGE
client 1/1 Running 0 1d
myapp-ffw8l 1/1 Running 0 9s
myapp-rz67d 1/1 Running 0 9s
readiness-httpget-container 1/1 Running 0 4h
[root@master test]# kubectl get rs
NAME DESIRED CURRENT READY AGE
myapp 2 2 2 1m
获取其中的一个Pod信息，查看详情
[root@master test]# kubectl describe pods myapp-ffw8l
Name: myapp-ffw8l
Namespace: default
Priority: 0
PriorityClassName: <none>
Node: node2/192.168.68.30
Start Time: Thu, 06 Sep 2018 15:57:31 +0800
Labels: app=myapp
environment=qa
release=canary
Annotations: <none>
Status: Running
IP: 10.244.2.17
Controlled By: ReplicaSet/myapp
Containers:
myapp-container:
Container ID: docker://787f74a16dfdcbe9c72a0dc1d962d6b4fbb050724108cf73190f2a67afd5440c
Image: ikubernetes/myapp:v1
Image ID: docker-pullable://ikubernetes/myapp@sha256:9c3dc30b5219788b2b8a4b065f548b922a34479577befb54b03330999d30d513
Port: 80/TCP
Host Port: 0/TCP
State: Running
Started: Thu, 06 Sep 2018 15:57:32 +0800
Ready: True
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from default-token-8zzcr (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
default-token-8zzcr:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-8zzcr
Optional: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute for 300s
node.kubernetes.io/unreachable:NoExecute for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 2m default-scheduler Successfully assigned default/myapp-ffw8l to node2
Normal Pulled 2m kubelet, node2 Container image "ikubernetes/myapp:v1" already present on machine
Normal Created 2m kubelet, node2 Created container
Normal Started 2m kubelet, node2 Started containe
[root@master test]# curl 10.244.2.17
Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>
[root@master test]# curl 10.244.2.17/hostname.html
myapp-ffw8l
如果删除一个Pod，他会自动创建一个
[root@master test]# kubectl get pod
NAME READY STATUS RESTARTS AGE
client 1/1 Running 0 1d
myapp-ffw8l 1/1 Running 0 7m
myapp-rz67d 1/1 Running 0 7m
readiness-httpget-container 1/1 Running 0 4h
[root@master test]# kubectl delete pods myapp-ffw8l
pod "myapp-ffw8l" deleted
[root@master test]# kubectl get pod
NAME READY STATUS RESTARTS AGE
client 1/1 Running 0 1d
myapp-r99dr 1/1 Running 0 4s
myapp-rz67d 1/1 Running 0 8m
readiness-httpget-container 1/1 Running 0 4h
删除Pod之前就已经创建了
kubectl get pods --show-labels
[root@master test]# kubectl get pods --show-labels
NAME READY STATUS RESTARTS AGE LABELS
client 1/1 Running 0 1d run=client
myapp-r99dr 1/1 Running 0 1m app=myapp,environment=qa,release=canary
myapp-rz67d 1/1 Running 0 10m app=myapp,environment=qa,release=canary
readiness-httpget-container 1/1 Running 0 4h <none>
[root@master test]# kubectl label pods client release=canary
pod/client labeled
[root@master test]# kubectl get pods --show-labels
NAME READY STATUS RESTARTS AGE LABELS
client 1/1 Running 0 1d release=canary,run=client
myapp-r99dr 1/1 Running 0 3m app=myapp,environment=qa,release=canary
myapp-rz67d 1/1 Running 0 11m app=myapp,environment=qa,release=canary
readiness-httpget-container 1/1 Running 0 4h <none>
自动扩容：将myapp扩容到10个
kubectl edit rs myapp
# Please edit the object below. Lines beginning with a '#' will be ignored,
# and an empty file will abort the edit. If an error occurs while saving this file will be
# reopened with the relevant failures.
#
apiVersion: extensions/v1beta1
kind: ReplicaSet
metadata:
creationTimestamp: 2018-09-06T07:57:31Z
generation: 2
labels:
app: myapp
environment: qa
release: canary
name: myapp
namespace: default
resourceVersion: "88845"
selfLink: /apis/extensions/v1beta1/namespaces/default/replicasets/myapp
uid: 81fa7645-b1aa-11e8-a432-000c29f33006
spec:
replicas: 10
selector:
matchLabels:
app: myapp
release: canary
template:
metadata:
creationTimestamp: null
labels:
app: myapp
environment: qa
release: canary
name: myapp-pod
spec:
containers:
- image: ikubernetes/myapp:v1
imagePullPolicy: IfNotPresent
name: myapp-container
ports:
- containerPort: 80
name: http
protocol: TCP
resources: {}
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
dnsPolicy: ClusterFirst
restartPolicy: Always
schedulerName: default-scheduler
securityContext: {}
terminationGracePeriodSeconds: 30
status:
availableReplicas: 10
fullyLabeledReplicas: 10
observedGeneration: 2
readyReplicas: 10
replicas: 10
我们查看一下：
[root@master test]# kubectl get pods
NAME READY STATUS RESTARTS AGE
client 1/1 Running 0 1d
myapp-7fhdt 1/1 Running 0 10s
myapp-8dnzm 1/1 Running 0 10s
myapp-92cnh 1/1 Running 0 10s
myapp-9dvll 1/1 Running 0 10s
myapp-h55jv 1/1 Running 0 10s
myapp-kw656 1/1 Running 0 10s
myapp-r99dr 1/1 Running 0 7m
myapp-rz67d 1/1 Running 0 15m
myapp-v62f6 1/1 Running 0 10s
myapp-zkk7k 1/1 Running 0 10s
readiness-httpget-container 1/1 Running 0 5h
我们将版本升级成v2
kubectl edit rs myapp
image: ikubernetes/myapp:v2
我们查看一下：
[root@master test]# kubectl get rs -o wide
NAME DESIRED CURRENT READY AGE CONTAINERS IMAGES SELECTOR
myapp 10 10 10 18m myapp-container ikubernetes/myapp:v2 app=myapp,release=canary
虽然这里是V2，但是我们访问的时候还是v1
[root@master test]# curl 10.244.2.20
Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>
[root@master test]# curl 10.244.2.20/hostname.html
myapp-7fhdt
[root@master test]# kubectl delete pods myapp-7fhdt
pod "myapp-7fhdt" deleted
[root@master test]# kubectl get rs -o wide
NAME DESIRED CURRENT READY AGE CONTAINERS IMAGES SELECTOR
myapp 10 10 10 20m myapp-container ikubernetes/myapp:v2 app=myapp,release=canary
[root@master test]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE
client 1/1 Running 0 1d 10.244.2.3 node2 <none>
myapp-8dnzm 1/1 Running 0 5m 10.244.1.12 node1 <none>
myapp-92cnh 1/1 Running 0 5m 10.244.1.13 node1 <none>
myapp-9dvll 1/1 Running 0 5m 10.244.2.21 node2 <none>
myapp-h55jv 1/1 Running 0 5m 10.244.2.19 node2 <none>
myapp-kw656 1/1 Running 0 5m 10.244.1.15 node1 <none>
myapp-r99dr 1/1 Running 0 12m 10.244.2.18 node2 <none>
myapp-rz67d 1/1 Running 0 21m 10.244.1.11 node1 <none>
myapp-v62f6 1/1 Running 0 5m 10.244.2.22 node2 <none>
myapp-x4hwp 1/1 Running 0 29s 10.244.2.23 node2 <none>
myapp-zkk7k 1/1 Running 0 5m 10.244.1.14 node1 <none>
readiness-httpget-container 1/1 Running 0 5h 10.244.2.15 node2 <none>
[root@master test]# curl 10.244.2.23/hostname.html
myapp-x4hwp
[root@master test]# curl 10.244.2.23
Hello MyApp | Version: v2 | <a href="hostname.html">Pod Name</a>