kubernetes（三）--Pod资源清单及pod控制器
一、pod的存活性及就绪性探测
1、使用exec command方式探测
[root@master kube_manifest]# vim liveness-exec.yml
apiVersion: v1
kind: Pod
metadata:
name: liveness-exec-pod
namespace: default
spec:
containers:
- name: liveness-exec-container
image: busybox:latest
imagePullPolicy: IfNotPresent
command: ["/bin/sh","-c","touch /tmp/healthy; sleep 30;rm -rf /tmp/healthy; sleep 3600"]
livenessProbe:
exec:
command: ["test","-e","/tmp/healthy"]
initialDelaySeconds: 1
periodSeconds: 3
使用kubectl create命令创建pod
[root@master kube_manifest]# kubectl create -f liveness-exec.yml
pod/liveness-exec-pod created
等待一段时间后，查看pod的状态，可以看到pod的最近一次状态是Error，此时会被重启
[root@master kube_manifest]# kubectl describe pods liveness-exec-pod
Name: liveness-exec-pod
Namespace: default
Priority: 0
Node: node2/192.168.147.134
Start Time: Mon, 01 Jun 2020 09:38:01 +0800
Labels: <none>
Annotations: <none>
Status: Running
IP: 10.244.2.7
IPs:
IP: 10.244.2.7
Containers:
liveness-exec-container:
Container ID: docker://8f65d30ff8e4f5d2b8740cbe7fda13d530f56b10007b645cd5d4248696d48dc8
Image: busybox:latest
Image ID: docker-pullable://busybox@sha256:836945da1f3afe2cfff376d379852bbb82e0237cb2925d53a13f53d6e8a8c48c
Port: <none>
Host Port: <none>
Command:
/bin/sh
-c
touch /tmp/healthy; sleep 30;rm -rf /tmp/healthy; sleep 3600
State: Running
Started: Mon, 01 Jun 2020 09:41:28 +0800
Last State: podnated
Reason: Error
Exit Code: 137
Started: Mon, 01 Jun 2020 09:40:18 +0800
Finished: Mon, 01 Jun 2020 09:41:27 +0800
Ready: True
Restart Count: 3
Liveness: exec [test -e /tmp/healthy] delay=1s timeout=1s period=3s #success=1 #failure=3
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from default-token-z5gjj (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
default-token-z5gjj:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-z5gjj
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 4m33s default-scheduler Successfully assigned default/liveness-exec-pod to node2
Normal Killing 97s (x3 over 3m55s) kubelet, node2 Container liveness-exec-container failed liveness probe, will be restarted
Normal Pulled 67s (x4 over 4m32s) kubelet, node2 Container image "busybox:latest" already present on machine
Normal Created 67s (x4 over 4m32s) kubelet, node2 Created container liveness-exec-container
Normal Started 66s (x4 over 4m31s) kubelet, node2 Started container liveness-exec-container
Warning Unhealthy 34s (x10 over 4m1s) kubelet, node2 Liveness probe failed:
使用kubectl get pod命令查看发现pod已经重启了7次，状态为 CrashLoopBackOff
[root@master kube_manifest]# kubectl get pod
NAME READY STATUS RESTARTS AGE
client 1/1 Running 1 2d23h
liveness-exec-pod 0/1 CrashLoopBackOff 7 15m
myapp 1/1 Running 1 2d22h
nginx-deploy 1/1 Running 2 6d19h
2、使用httpGet方式进行探测
[root@master kube_manifest]# vim liveness-httpget.yml
apiVersion: v1
kind: Pod
metadata:
name: liveness-httpget-pod
namespace: default
spec:
containers:
- name: liveness-httpget-container
image: ikubernetes/myapp:v1
imagePullPolicy: IfNotPresent
ports:
- name: http
containerPort: 80
livenessProbe:
httpGet:
port: http
path: /index.html
initialDelaySeconds: 1
periodSeconds: 3
创建Pod，此时pod是可以正常运行的
[root@master kube_manifest]# kubectl create -f liveness-httpget.yml
pod/liveness-httpget-pod created
我们连接进pod中，认为的把index.html文件删除
[root@master kube_manifest]# kubectl exec -it liveness-httpget-pod -- /bin/sh
/ # ls /usr/share/nginx/html/
50x.html index.html
/ # rm -f /usr/share/nginx/html/index.html
/ # ls /usr/share/nginx/html/
50x.html
/ # command terminated with exit code 137
##此时发现pod不正常退出了
查看pod状态
[root@master kube_manifest]# kubectl describe pods liveness-httpget-pod
Name: liveness-httpget-pod
Namespace: default
Priority: 0
Node: node2/192.168.147.134
Start Time: Mon, 01 Jun 2020 10:40:16 +0800
Labels: <none>
Annotations: <none>
Status: Running
IP: 10.244.2.9
IPs:
IP: 10.244.2.9
Containers:
liveness-httpget-container:
Container ID: docker://c82316e57267ebd04f8b6c06e6ab8b07c7745d3ce388626a2b72a416f41693e3
Image: ikubernetes/myapp:v1
Image ID: docker-pullable://ikubernetes/myapp@sha256:9c3dc30b5219788b2b8a4b065f548b922a34479577befb54b03330999d30d513
Port: 80/TCP
Host Port: 0/TCP
State: Running
Started: Mon, 01 Jun 2020 10:55:41 +0800
Last State: Terminated
Reason: Completed
Exit Code: 0
Started: Mon, 01 Jun 2020 10:41:05 +0800
Finished: Mon, 01 Jun 2020 10:55:41 +0800
Ready: True
Restart Count: 1
Liveness: http-get http://:http/index.html delay=1s timeout=1s period=3s #success=1 #failure=3
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from default-token-z5gjj (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
default-token-z5gjj:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-z5gjj
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 23m default-scheduler Successfully assigned default/liveness-httpget-pod to node2
Normal Pulling 23m kubelet, node2 Pulling image "ikubernetes/myapp:v1"
Normal Pulled 22m kubelet, node2 Successfully pulled image "ikubernetes/myapp:v1"
Normal Created 7m55s (x2 over 22m) kubelet, node2 Created container liveness-httpget-container
Normal Started 7m55s (x2 over 22m) kubelet, node2 Started container liveness-httpget-container
Warning Unhealthy 7m55s (x3 over 8m1s) kubelet, node2 Liveness probe failed: HTTP probe failed with statuscode: 404
Normal Killing 7m55s kubelet, node2 Container liveness-httpget-container failed liveness probe, will be restarted
Normal Pulled 7m55s kubelet, node2 Container image "ikubernetes/myapp:v1" already present on machine
3、就绪性探测
[root@master kube_manifest]# vim readness-httpget.yml
apiVersion: v1
kind: Pod
metadata:
name: readiness-httpget-pod
namespace: default
spec:
containers:
- name: readiness-httpget-container
image: ikubernetes/myapp:v1
imagePullPolicy: IfNotPresent
ports:
- name: http
containerPort: 80
readinessProbe:
httpGet:
port: http
path: /index.html
initialDelaySeconds: 1
periodSeconds: 3
删除index.html文件
[root@master kube_manifest]# kubectl exec -it readiness-httpget-pod -- /bin/sh
/ # rm -f /usr/share/nginx/html/index.html
查看pod信息，发现readiness-httpget-pod处于未就绪状态。
[root@master kube_manifest]# kubectl get pod
NAME READY STATUS RESTARTS AGE
client 1/1 Running 1 3d2h
liveness-httpget-pod 1/1 Running 2 101m
myapp 1/1 Running 1 3d1h
nginx-deploy 1/1 Running 2 6d22h
readiness-httpget-pod 0/1 Running 0 60m
但是容器的中的nginx进程依然运行着，不会关闭pod，只是会一直处于未就绪状态。
##在readiness-httpget-pod容器中
/ # ps aux
PID USER TIME COMMAND
1 root 0:00 nginx: master process nginx -g daemon off;
6 nginx 0:00 nginx: worker process
7 root 0:00 /bin/sh
13 root 0:00 ps aux
/ #
再重新创建一个index.html文件，然后pod就会重新回到就绪状态
##在readiness-httpget-pod容器中
/ # echo "hello pod" >> /usr/share/nginx/html/index.html
/ #
然后再次查看pod信息，发现readiness-httpget-pod已经回到就绪性状态了。
[root@master kube_manifest]# kubectl get pod
NAME READY STATUS RESTARTS AGE
client 1/1 Running 1 3d2h
liveness-httpget-pod 1/1 Running 2 109m
myapp 1/1 Running 1 3d1h
nginx-deploy 1/1 Running 2 6d22h
readiness-httpget-pod 1/1 Running 0 68m
二、pod生命周期中的启动后钩子、和终止钩子。
1、pod生命周期中的启动后钩子
[root@master kube_manifest]# vim poststart-pod.yaml
apiVersion: v1
kind: Pod
metadata:
name: poststart-pod
namespace: default
spec:
containers:
- name: busybox-httpd
image: busybox:latest
imagePullPolicy: IfNotPresent
lifecycle:
postStart:
exec:
command: ['/bin/sh','-c','echo "hello pod" >> /tmp/index.html']
#command: ['/bin/sh','-c','sleep 3600']
command: ["/bin/httpd"]
args: ["-f","-h /tmp"]
[root@master kube_manifest]# kubectl create -f poststart-pod.yaml
pod/poststart-pod created
三、上面创建的都是自助式pod，即当删除时就不会自动创建，但在使用时，更多的是使用控制器管理的pod，接下来介绍pod的控制器管理。
1、ReplicaSet
[root@master kube_manifest]# kubectl explain rs
KIND: ReplicaSet
VERSION: apps/v1
DESCRIPTION:
ReplicaSet ensures that a specified number of pod replicas are running at
any given time.
FIELDS:
apiVersion <string>
APIVersion defines the versioned schema of this representation of an
object. Servers should convert recognized schemas to the latest internal
value, and may reject unrecognized values. More info:
https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#resources
kind <string>
Kind is a string value representing the REST resource this object
represents. Servers may infer this from the endpoint the client submits
requests to. Cannot be updated. In CamelCase. More info:
https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#types-kinds
metadata <Object>
If the Labels of a ReplicaSet are empty, they are defaulted to be the same
as the Pod(s) that the ReplicaSet manages. Standard object's metadata. More
info:
https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata
spec <Object>
Spec defines the specification of the desired behavior of the ReplicaSet.
More info:
https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#spec-and-status
status <Object>
Status is the most recently observed status of the ReplicaSet. This data
may be out of date by some window of time. Populated by the system.
Read-only. More info:
https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#spec-and-status
创建一个Replicas控制器
[root@master kube_manifest]# vim re-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
enviroment: qq
spec:
containers:
- name: myapp-container
image: ikubernetes/myapp:v1
ports:
- name: http
containerPort: 80
[root@master kube_manifest]# kubectl create -f re-demo.yaml
replicaset.apps/myapp created
[root@master kube_manifest]# kubectl get rs
NAME DESIRED CURRENT READY AGE
myapp 2 2 2 5s
[root@master kube_manifest]# kubectl get pods
NAME READY STATUS RESTARTS AGE
client 1/1 Running 1 3d5h
myapp 1/1 Running 1 3d4h
myapp-hzzq9 1/1 Running 0 8s
myapp-mvtnj 1/1 Running 0 8s
nginx-deploy 1/1 Running 2 7d1h
##ReplicaSet控制器中pod的名称是由ReplicaSet控制器的名称+随机字符串组成，上面template中定义的pod名称无效
此时删除其中一个pod，验证是否会自动创建pod以保持期望定义的状态。
[root@master kube_manifest]# kubectl delete pod myapp-mvtnj
pod "myapp-mvtnj" deleted
查看pod信息，发现重新创建了一个pod，其名称是myapp-mwzvx
[root@master kube_manifest]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
client 1/1 Running 1 3d5h 10.244.2.5 node2 <none> <none>
myapp 1/1 Running 1 3d4h 10.244.1.5 node1 <none> <none>
myapp-hzzq9 1/1 Running 0 14m 10.244.1.9 node1 <none> <none>
myapp-mwzvx 1/1 Running 0 17s 10.244.2.13 node2 <none> <none>
nginx-deploy 1/1 Running 2 7d1h 10.244.1.6 node1 <none> <none>
同理如果多添加了具有相同标签的pod，则系统会随机删除一个，以确保满足期望定义的状态。也就是“多退少补”机制。
把myapp 这个pod重新打上标签
[root@master kube_manifest]# kubectl get pods --show-labels
NAME READY STATUS RESTARTS AGE LABELS
client 1/1 Running 1 3d5h run=client
myapp 1/1 Running 1 3d4h run=myapp
myapp-hzzq9 1/1 Running 0 24m app=myapp,enviroment=qq,release=canary
myapp-mwzvx 1/1 Running 0 10m app=myapp,enviroment=qq,release=canary
nginx-deploy 1/1 Running 2 7d1h run=nginx-deploy
[root@master kube_manifest]# kubectl label pods myapp release=canary
pod/myapp labeled
[root@master kube_manifest]# kubectl label pods myapp app=myapp
pod/myapp labeled
此时发现myapp-mwzvx这个pod被删除了
[root@master kube_manifest]# kubectl get pods --show-labels
NAME READY STATUS RESTARTS AGE LABELS
client 1/1 Running 1 3d5h run=client
myapp 1/1 Running 1 3d4h app=myapp,release=canary,run=myapp
myapp-hzzq9 1/1 Running 0 36m app=myapp,enviroment=qq,release=canary
nginx-deploy 1/1 Running 2 7d1h run=nginx-deploy
这时候如果把myapp这个pod删除掉，则会重新创建一个pod补回去。
[root@master kube_manifest]# kubectl delete pods myapp
pod "myapp" deleted
[root@master kube_manifest]# kubectl get pods --show-labels
NAME READY STATUS RESTARTS AGE LABELS
client 1/1 Running 1 3d5h run=client
myapp-h7l98 1/1 Running 0 5s app=myapp,enviroment=qq,release=canary
myapp-hzzq9 1/1 Running 0 43m app=myapp,enviroment=qq,release=canary
nginx-deploy 1/1 Running 2 7d1h run=nginx-deploy
因此注意：以后再创建和使用pod的时，要注意标签冲突问题，不同类型的pod，应使用不同的标签
ReplicaSet控制器扩缩容，使用kubectl edit rs可以进行实时操作。
[root@master kube_manifest]# kubectl edit rs myapp
replicaset.apps/myapp edited
##把replicas改为3
此时pod就是我们所期望的3个
[root@master kube_manifest]# kubectl get pods
NAME READY STATUS RESTARTS AGE
client 1/1 Running 1 3d5h
myapp-h7l98 1/1 Running 0 11m
myapp-hzzq9 1/1 Running 0 55m
myapp-vkf8b 1/1 Running 0 61s
nginx-deploy 1/1 Running 2 7d2h
ReplicaSet控制器在线升级
我们把里面的容器版本改为v2版
[root@master kube_manifest]# kubectl edit rs myapp
replicaset.apps/myapp edited
- image: ikubernetes/myapp:v2 ##版本改为v2
使用 kubectl get rs 查看RS控制器，显示镜像已经改为了V2版本
[root@master kube_manifest]# kubectl get rs -o wide
NAME DESIRED CURRENT READY AGE CONTAINERS IMAGES SELECTOR
myapp 3 3 3 61m myapp-container ikubernetes/myapp:v2 app=myapp,release=canary
但是，此时pod的资源并不会修改，只有重建时pod的资源才会被修改。
[root@master kube_manifest]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
client 1/1 Running 1 3d6h 10.244.2.5 node2 <none> <none>
myapp-h7l98 1/1 Running 0 33m 10.244.2.14 node2 <none> <none>
myapp-hzzq9 1/1 Running 0 77m 10.244.1.9 node1 <none> <none>
myapp-vkf8b 1/1 Running 0 23m 10.244.1.10 node1 <none> <none>
nginx-deploy 1/1 Running 2 7d2h 10.244.1.6 node1 <none> <none>
[root@master kube_manifest]# curl 10.244.1.10
Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>
例如，此时删掉myapp-vkf8b这个pod,重建时新的pod资源会使用v2版本。
[root@master kube_manifest]# kubectl delete pods myapp-vkf8b
pod "myapp-vkf8b" deleted
[root@master kube_manifest]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
client 1/1 Running 1 3d6h 10.244.2.5 node2 <none> <none>
myapp-h7l98 1/1 Running 0 44m 10.244.2.14 node2 <none> <none>
myapp-hqfcw 1/1 Running 0 2m56s 10.244.2.15 node2 <none> <none>
myapp-hzzq9 1/1 Running 0 88m 10.244.1.9 node1 <none> <none>
nginx-deploy 1/1 Running 2 7d2h 10.244.1.6 node1 <none> <none>
##新创建的pod名称是myapp-hqfcw，IP为10.244.2.15
[root@master kube_manifest]# curl 10.244.2.15
Hello MyApp | Version: v2 | <a href="hostname.html">Pod Name</a>
当新创建的pod处于稳定状态时，我们就可以把原先旧的pod删除掉，然后系统会自动重建新的pod，并使用新的资源。此方法可用于灰度发布，还可以人为掌握节奏。
deployment控制器
[root@master ~]# kubectl explain deploy
KIND: Deployment
VERSION: apps/v1
DESCRIPTION:
Deployment enables declarative updates for Pods and ReplicaSets.
FIELDS:
apiVersion <string>
APIVersion defines the versioned schema of this representation of an
object. Servers should convert recognized schemas to the latest internal
value, and may reject unrecognized values. More info:
https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#resources
kind <string>
Kind is a string value representing the REST resource this object
represents. Servers may infer this from the endpoint the client submits
requests to. Cannot be updated. In CamelCase. More info:
https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#types-kinds
metadata <Object>
Standard object metadata.
spec <Object>
Specification of the desired behavior of the Deployment.
status <Object>
Most recently observed status of the Deployment.
[root@master ~]# kubectl explain deploy.spec.strategy.rollingUpdate
KIND: Deployment
VERSION: apps/v1
RESOURCE: rollingUpdate <Object>
DESCRIPTION:
Rolling update config params. Present only if DeploymentStrategyType =
RollingUpdate.
Spec to control the desired behavior of rolling update.
FIELDS:
maxSurge <string>
The maximum number of pods that can be scheduled above the desired number
of pods. Value can be an absolute number (ex: 5) or a percentage of desired
pods (ex: 10%). This can not be 0 if MaxUnavailable is 0. Absolute number
is calculated from percentage by rounding up. Defaults to 25%. Example:
when this is set to 30%, the new ReplicaSet can be scaled up immediately
when the rolling update starts, such that the total number of old and new
pods do not exceed 130% of desired pods. Once old pods have been killed,
new ReplicaSet can be scaled up further, ensuring that total number of pods
running at any time during the update is at most 130% of desired pods.
maxUnavailable <string>
The maximum number of pods that can be unavailable during the update. Value
can be an absolute number (ex: 5) or a percentage of desired pods (ex:
10%). Absolute number is calculated from percentage by rounding down. This
can not be 0 if MaxSurge is 0. Defaults to 25%. Example: when this is set
to 30%, the old ReplicaSet can be scaled down to 70% of desired pods
immediately when the rolling update starts. Once new pods are ready, old
ReplicaSet can be scaled down further, followed by scaling up the new
ReplicaSet, ensuring that the total number of pods available at all times
during the update is at least 70% of desired pods.
创建一个deployment控制器，并使用kubectl apply声明式命令创建。
[root@master kube_manifest]# vim deploy-demo.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: myapp-deploy
namespace: default
spec:
replicas: 2
selector:
matchLabels:
app: myapp
release: canary
template:
metadata:
labels:
app: myapp
release: canary
spec:
containers:
- name: myapp
image: ikubernetes/myapp:v1
ports:
- name: http
containerPort: 80
查看deploy信息，replicas信息和pod信息
[root@master kube_manifest]# kubectl get deploy
NAME READY UP-TO-DATE AVAILABLE AGE
myapp-deploy 1/2 2 1 15s
[root@master kube_manifest]# kubectl get deploy
NAME READY UP-TO-DATE AVAILABLE AGE
myapp-deploy 2/2 2 2 21s
[root@master kube_manifest]# kubectl get rs
NAME DESIRED CURRENT READY AGE
myapp-deploy-65fb6c8459 2 2 2 61s
[root@master kube_manifest]# kubectl get pod
NAME READY STATUS RESTARTS AGE
client 1/1 Running 1 4d2h
myapp-deploy-65fb6c8459-2rcsn 1/1 Running 0 75s
myapp-deploy-65fb6c8459-xkd5n 1/1 Running 0 75s
nginx-deploy 1/1 Running 2 7d22h
根据上面的deployment，replicas和pod的信息，它们三者之间的关系模型如下图所示：
同样的，deployment控制器也支持动态扩缩容，只需编辑deployment的资源配置清单即可，然后使用kubectl apply重新声明一次。
查看deployment的详细信息，可以发现其默认的更新策略类型是RollingUpdate，最多允许25%不可用，最多运行pod超过25%。
[root@master kube_manifest]# kubectl describe deploy myapp-deploy
Name: myapp-deploy
Namespace: default
CreationTimestamp: Tue, 02 Jun 2020 12:20:19 +0800
Labels: <none>
Annotations: deployment.kubernetes.io/revision: 1
Selector: app=myapp,release=canary
Replicas: 2 desired | 2 updated | 2 total | 2 available | 0 unavailable
StrategyType: RollingUpdate
MinReadySeconds: 0
RollingUpdateStrategy: 25% max unavailable, 25% max surge
Pod Template:
Labels: app=myapp
release=canary
Containers:
myapp:
Image: ikubernetes/myapp:v1
Port: 80/TCP
Host Port: 0/TCP
Environment: <none>
Mounts: <none>
Volumes: <none>
Conditions:
Type Status Reason
---- ------ ------
Available True MinimumReplicasAvailable
Progressing True NewReplicaSetAvailable
OldReplicaSets: <none>
NewReplicaSet: myapp-deploy-65fb6c8459 (2/2 replicas created)
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal ScalingReplicaSet 22m deployment-controller Scaled up replica set myapp-deploy-65fb6c8459 to 2
接下来我们验证一下滚动更新策略
编辑deployment的配置清单，把版本改为v2版本
[root@master kube_manifest]# vim deploy-demo.yaml
image: ikubernetes/myapp:v2
先使用kubectl get pod -o wide -l app=myapp -w 监视pod的状态。
然后再次使用kubectl apply声明一下deployment的配置清单
[root@master kube_manifest]# kubectl apply -f deploy-demo.yaml
deployment.apps/myapp-deploy configured
可以看到pod的滚动更新状态。
[root@master kube_manifest]# kubectl get pod -o wide -l app=myapp -w
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
myapp-deploy-65fb6c8459-2rcsn 1/1 Running 0 39m 10.244.2.16 node2 <none> <none>
myapp-deploy-65fb6c8459-xkd5n 1/1 Running 0 39m 10.244.1.11 node1 <none> <none>
myapp-deploy-559ff5c66-c2jdc 0/1 Pending 0 0s <none> <none> <none> <none>
myapp-deploy-559ff5c66-c2jdc 0/1 Pending 0 0s <none> node1 <none> <none>
myapp-deploy-559ff5c66-c2jdc 0/1 ContainerCreating 0 0s <none> node1 <none> <none>
myapp-deploy-559ff5c66-c2jdc 1/1 Running 0 29s 10.244.1.12 node1 <none> <none>
myapp-deploy-65fb6c8459-xkd5n 1/1 Terminating 0 53m 10.244.1.11 node1 <none> <none>
myapp-deploy-559ff5c66-hq6hs 0/1 Pending 0 0s <none> <none> <none> <none>
myapp-deploy-559ff5c66-hq6hs 0/1 Pending 0 0s <none> node2 <none> <none>
myapp-deploy-559ff5c66-hq6hs 0/1 ContainerCreating 0 0s <none> node2 <none> <none>
myapp-deploy-65fb6c8459-xkd5n 0/1 Terminating 0 54m 10.244.1.11 node1 <none> <none>
myapp-deploy-65fb6c8459-xkd5n 0/1 Terminating 0 54m 10.244.1.11 node1 <none> <none>
myapp-deploy-65fb6c8459-xkd5n 0/1 Terminating 0 54m 10.244.1.11 node1 <none> <none>
myapp-deploy-559ff5c66-hq6hs 1/1 Running 0 2s 10.244.2.17 node2 <none> <none>
myapp-deploy-65fb6c8459-2rcsn 1/1 Terminating 0 54m 10.244.2.16 node2 <none> <none>
myapp-deploy-65fb6c8459-2rcsn 0/1 Terminating 0 54m 10.244.2.16 node2 <none> <none>
myapp-deploy-65fb6c8459-2rcsn 0/1 Terminating 0 54m 10.244.2.16 node2 <none> <none>
myapp-deploy-65fb6c8459-2rcsn 0/1 Terminating 0 54m 10.244.2.16 node2 <none> <none>
滚动更新后，replicas有了两个版本，现在使用的是v2版本，而v1版本还保留着，这样我们就可以随时滚动更新回去。
[root@master kube_manifest]# kubectl get rs -o wide
NAME DESIRED CURRENT READY AGE CONTAINERS IMAGES SELECTOR
myapp-deploy-559ff5c66 2 2 2 3m39s myapp ikubernetes/myapp:v2 app=myapp,pod-template-hash=559ff5c66,release=canary
myapp-deploy-65fb6c8459 0 0 0 57m myapp ikubernetes/myapp:v1 app=myapp,pod-template-hash=65fb6c8459,release=canary
也可以使用kubectl patch打补丁方式或kubectl set image 进行更新。kubectl patch打补丁方式的好处是并不会修改deployment的资源配置清单，可以保留原始的资源配置清单。
使用kubectl rollout history查看滚动历史
[root@master kube_manifest]# kubectl rollout history deployment myapp-deploy
deployment.apps/myapp-deploy
REVISION CHANGE-CAUSE
1 <none>
2 <none>
如果想回滚使用kubectl rollout undo即可。
使用kubectl patch打补丁方式把pod的副本改为5个。
[root@master kube_manifest]# kubectl patch deployment myapp-deploy -p '{"spec":{"replicas":5}}'
deployment.apps/myapp-deploy patched
[root@master kube_manifest]# kubectl get pod -o wide -l app=myapp
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
myapp-deploy-559ff5c66-7rtjd 1/1 Running 0 32s 10.244.2.18 node2 <none> <none>
myapp-deploy-559ff5c66-c2jdc 1/1 Running 0 37m 10.244.1.12 node1 <none> <none>
myapp-deploy-559ff5c66-fvsvv 1/1 Running 0 32s 10.244.1.13 node1 <none> <none>
myapp-deploy-559ff5c66-hq6hs 1/1 Running 0 37m 10.244.2.17 node2 <none> <none>
myapp-deploy-559ff5c66-j7fwg 1/1 Running 0 32s 10.244.2.19 node2 <none> <none>
使用kubectl patch打补丁方式更改deployment控制器的更新策略
[root@master kube_manifest]# kubectl patch deployment myapp-deploy -p '{"spec":{"strategy":{"rollingUpdate":{"maxSurge":1,"maxUnavailable":0}}}}'
deployment.apps/myapp-deploy patched
模拟金丝雀发布，即只会更新一个pod资源后就暂停，待其稳定运行后在更新后续的pod资源。
[root@master kube_manifest]# kubectl set image deployment myapp-deploy myapp=ikubernetes/myapp:v3 && kubectl rollout pause deployment myapp-deploy
deployment.apps/myapp-deploy image updated
deployment.apps/myapp-deploy paused
查看更新状态
[root@master kube_manifest]# kubectl get pod -o wide -l app=myapp -w
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
myapp-deploy-559ff5c66-7rtjd 1/1 Running 0 86m 10.244.2.18 node2 <none> <none>
myapp-deploy-559ff5c66-c2jdc 1/1 Running 0 124m 10.244.1.12 node1 <none> <none>
myapp-deploy-559ff5c66-fvsvv 1/1 Running 0 86m 10.244.1.13 node1 <none> <none>
myapp-deploy-559ff5c66-hq6hs 1/1 Running 0 123m 10.244.2.17 node2 <none> <none>
myapp-deploy-559ff5c66-j7fwg 1/1 Running 0 86m 10.244.2.19 node2 <none> <none>
myapp-deploy-6b9865d969-kplqz 0/1 Pending 0 0s <none> <none> <none> <none>
myapp-deploy-6b9865d969-kplqz 0/1 Pending 0 0s <none> node1 <none> <none>
myapp-deploy-6b9865d969-kplqz 0/1 ContainerCreating 0 0s <none> node1 <none> <none>
myapp-deploy-6b9865d969-kplqz 1/1 Running 0 44s 10.244.1.14 node1 <none> <none>
[root@master kube_manifest]# kubectl rollout status deployment myapp-deploy
Waiting for deployment "myapp-deploy" rollout to finish: 1 out of 5 new replicas have been updated...
稳定运行后，接着更新后续的pod资源
[root@master kube_manifest]# kubectl rollout resume deployment myapp-deploy
deployment.apps/myapp-deploy resumed
查看监控更新的状态
^C[root@master kube_manifest]# kubectl rollout status deployment myapp-deploy
Waiting for deployment "myapp-deploy" rollout to finish: 1 out of 5 new replicas have been updated...
Waiting for deployment spec update to be observed...
Waiting for deployment spec update to be observed...
Waiting for deployment "myapp-deploy" rollout to finish: 1 out of 5 new replicas have been updated...
Waiting for deployment "myapp-deploy" rollout to finish: 1 out of 5 new replicas have been updated...
Waiting for deployment "myapp-deploy" rollout to finish: 2 out of 5 new replicas have been updated...
Waiting for deployment "myapp-deploy" rollout to finish: 2 out of 5 new replicas have been updated...
Waiting for deployment "myapp-deploy" rollout to finish: 3 out of 5 new replicas have been updated...
Waiting for deployment "myapp-deploy" rollout to finish: 3 out of 5 new replicas have been updated...
Waiting for deployment "myapp-deploy" rollout to finish: 3 out of 5 new replicas have been updated...
Waiting for deployment "myapp-deploy" rollout to finish: 3 out of 5 new replicas have been updated...
Waiting for deployment "myapp-deploy" rollout to finish: 4 out of 5 new replicas have been updated...
Waiting for deployment "myapp-deploy" rollout to finish: 4 out of 5 new replicas have been updated...
Waiting for deployment "myapp-deploy" rollout to finish: 4 out of 5 new replicas have been updated...
Waiting for deployment "myapp-deploy" rollout to finish: 1 old replicas are pending termination...
Waiting for deployment "myapp-deploy" rollout to finish: 1 old replicas are pending termination...
deployment "myapp-deploy" successfully rolled out
可以看到现在使用的是v3版本
[root@master kube_manifest]# kubectl get rs -o wide
NAME DESIRED CURRENT READY AGE CONTAINERS IMAGES SELECTOR
myapp-deploy-559ff5c66 0 0 0 135m myapp ikubernetes/myapp:v2 app=myapp,pod-template-hash=559ff5c66,release=canary
myapp-deploy-65fb6c8459 0 0 0 3h8m myapp ikubernetes/myapp:v1 app=myapp,pod-template-hash=65fb6c8459,release=canary
myapp-deploy-6b9865d969 5 5 5 11m myapp ikubernetes/myapp:v3 app=myapp,pod-template-hash=6b9865d969,release=canary
如果，此时我们想使用之前的版本可以使用undo操作，默认是回滚到前一个版本，选项–to-revision=n可以回滚到指定的版本。
目前系统中存在3个版本，正在使用的是第三版。
[root@master kube_manifest]# kubectl rollout history deployment myapp-deploy
deployment.apps/myapp-deploy
REVISION CHANGE-CAUSE
1 <none>
2 <none>
3 <none>
现在我们要回滚到第1版，注意：如果已经回滚到第一版了，此时在回滚则是回滚到第三版
[root@master kube_manifest]# kubectl rollout undo deployment myapp-deploy --to-revision=1
deployment.apps/myapp-deploy rolled back
查看rs信息，当前正在工作的事v1版
[root@master kube_manifest]# kubectl get rs -o wide
NAME DESIRED CURRENT READY AGE CONTAINERS IMAGES SELECTOR
myapp-deploy-559ff5c66 0 0 0 149m myapp ikubernetes/myapp:v2 app=myapp,pod-template-hash=559ff5c66,release=canary
myapp-deploy-65fb6c8459 5 5 5 3h23m myapp ikubernetes/myapp:v1 app=myapp,pod-template-hash=65fb6c8459,release=canary
myapp-deploy-6b9865d969 0 0 0 25m myapp ikubernetes/myapp:v3 app=myapp,pod-template-hash=6b9865d969,release=canary
注意：回滚完成后，第一版就变成了第四版了，也验证了第一版再回滚就到了第三版
[root@master kube_manifest]# kubectl rollout history deployment myapp-deploy
deployment.apps/myapp-deploy
REVISION CHANGE-CAUSE
2 <none>
3 <none>
4 <none>