KUBERNETES-1-4-控制器应用一
1.kubectl explain pods.spec.containers可以查看容器可以定义的相关参数。image
[root@master ~]# kubectl explain pods.spec.containers
image
Docker image name. More info:
https://kubernetes.io/docs/concepts/containers/images This field is
optional to allow higher level config management to default or override
container images in workload controllers like Deployments and StatefulSets.
imagePullPolicy
Image pull policy. One of Always, Never, IfNotPresent. Defaults to Always
if :latest tag is specified, or IfNotPresent otherwise. Cannot be updated.
More info:
https://kubernetes.io/docs/concepts/containers/images#updating-images
ports <[]Object>
List of ports to expose from the container. Exposing a port here gives the
system additional information about the network connections a container
uses, but is primarily informational. Not specifying a port here DOES NOT
prevent that port from being exposed. Any port which is listening on the
default "0.0.0.0" address inside a container will be accessible from the
network. Cannot be updated.
args <[]string>
Arguments to the entrypoint. The docker image's CMD is used if this is not
provided. Variable references $(VAR_NAME) are expanded using the
container's environment. If a variable cannot be resolved, the reference in
the input string will be unchanged. The $(VAR_NAME) syntax can be escaped
with a double $$, ie: $$(VAR_NAME). Escaped references will never be
expanded, regardless of whether the variable exists or not. Cannot be
updated. More info:
https://kubernetes.io/docs/tasks/inject-data-application/define-command-argument-container/#running-a-command-in-a-shell
command <[]string>
Entrypoint array. Not executed within a shell. The docker image's
ENTRYPOINT is used if this is not provided. Variable references $(VAR_NAME)
are expanded using the container's environment. If a variable cannot be
resolved, the reference in the input string will be unchanged. The
$(VAR_NAME) syntax can be escaped with a double $$, ie: $$(VAR_NAME).
Escaped references will never be expanded, regardless of whether the
variable exists or not. Cannot be updated. More info:
https://kubernetes.io/docs/tasks/inject-data-application/define-command-argument-container/#running-a-command-in-a-shell
2.我们可以通过kubectl get pods --show-labels来查看pod的标签信息。kubectl get pods -l 可以查看含有标签值含有某字段的相关信息。kubectl get pods -L可以查看含有标签名含有某字段的相关信息。
[root@master ~]# kubectl get pods
NAME READY STATUS RESTARTS AGE
client 0/1 Completed 0 2d
myapp-848b5b879b-7h254 1/1 Running 2 2d
myapp-848b5b879b-d7rjs 1/1 Running 2 2d
myapp-848b5b879b-wv5cz 1/1 Running 2 2d
nginx-deploy-5b595999-tj8ms 1/1 Running 2 2d
[root@master ~]# cd manifests/
[root@master manifests]# vim pod-demo.yaml
[root@master manifests]# cat pod-demo.yaml
apiVersion: v1
kind: Pod
metadata:
name: pod-demo
namespace: default
labels:
app: myapp
tier: frontend
spec:
containers:
- name: myapp
image: ikubernetes/myapp:v1
ports:
- name: http
containerPort: 80
- name: https
containerPort: 443
- name: busybox
image: busybox:latest
imagePullPolicy: IfNotPresent
command:
- "/bin/sh"
- "-c"
- "sleep 3600"
[root@master manifests]# kubectl create -f pod-demo.yaml
pod/pod-demo created
[root@master manifests]# kubectl get pods --show-labels
NAME READY STATUS RESTARTS AGE LABELS
client 0/1 Completed 0 2d run=client
myapp-848b5b879b-7h254 1/1 Running 2 2d pod-template-hash=4046164356,run=myapp
myapp-848b5b879b-d7rjs 1/1 Running 2 2d pod-template-hash=4046164356,run=myapp
myapp-848b5b879b-wv5cz 1/1 Running 2 2d pod-template-hash=4046164356,run=myapp
nginx-deploy-5b595999-tj8ms 1/1 Running 2 2d pod-template-hash=16151555,run=nginx-deploy
pod-demo 2/2 Running 0 51s app=myapp,tier=frontend
[root@master manifests]# kubectl get pods -l app --show-labels
NAME READY STATUS RESTARTS AGE LABELS
pod-demo 2/2 Running 0 4m app=myapp,tier=frontend
[root@master manifests]# kubectl get pods -L app,run --show-labels
NAME READY STATUS RESTARTS AGE APP RUN LABELS
client 0/1 Completed 0 2d client run=client
myapp-848b5b879b-7h254 1/1 Running 2 2d myapp pod-template-hash=4046164356,run=myapp
myapp-848b5b879b-d7rjs 1/1 Running 2 2d myapp pod-template-hash=4046164356,run=myapp
myapp-848b5b879b-wv5cz 1/1 Running 2 2d myapp pod-template-hash=4046164356,run=myapp
nginx-deploy-5b595999-tj8ms 1/1 Running 2 2d nginx-deploy pod-template-hash=16151555,run=nginx-deploy
pod-demo 2/2 Running 0 4m myapp app=myapp,tier=frontend
3.kubectl label pods可以为pod增加标签值。对同一个标签再次赋值时会报错，需要使用--overwrite参数。
[root@master manifests]# kubectl label pods pod-demo release=canary
pod/pod-demo labeled
[root@master manifests]# kubectl get pods -l app --show-labels
NAME READY STATUS RESTARTS AGE LABELS
pod-demo 2/2 Running 0 6m app=myapp,release=canary,tier=frontend
[root@master manifests]# kubectl label pods pod-demo release=stable
error: 'release' already has a value (canary), and --overwrite is false
[root@master manifests]# kubectl label pods pod-demo release=stable --overwrite
pod/pod-demo labeled
[root@master manifests]# kubectl get pods -l app --show-labels
NAME READY STATUS RESTARTS AGE LABELS
pod-demo 2/2 Running 0 11m app=myapp,release=stable,tier=frontend
4.标签选择器中等值关系选择器的使用。kubectl get pods -l 后面附加等值筛选。或者后面加不等值筛选也可以实现。
[root@master manifests]# kubectl get pods -l release=stable --show-labels
NAME READY STATUS RESTARTS AGE LABELS
pod-demo 2/2 Running 0 15m app=myapp,release=stable,tier=frontend
[root@master manifests]# kubectl get pods -l release!=stable --show-labels
NAME READY STATUS RESTARTS AGE LABELS
client 0/1 Completed 0 2d run=client
myapp-848b5b879b-7h254 1/1 Running 2 2d pod-template-hash=4046164356,run=myapp
myapp-848b5b879b-d7rjs 1/1 Running 2 2d pod-template-hash=4046164356,run=myapp
myapp-848b5b879b-wv5cz 1/1 Running 2 2d pod-template-hash=4046164356,run=myapp
nginx-deploy-5b595999-tj8ms 1/1 Running 2 2d pod-template-hash=16151555,run=nginx-deploy
5.标签选择器中集合关系选择器的使用。kubectl get pods -l后面通过in来筛选标签属于某一集合。或者通过notin来筛选标签属于某一集合。对于字符串中间可能存在的空格，可以使用双引号。
[root@master manifests]# kubectl get pods -l "release in (stable,alpha,beta)"
NAME READY STATUS RESTARTS AGE
pod-demo 2/2 Running 0 25m
[root@master manifests]# kubectl get pods -l "release notin (stable,alpha,beta)"
NAME READY STATUS RESTARTS AGE
client 0/1 Completed 0 2d
myapp-848b5b879b-7h254 1/1 Running 2 2d
myapp-848b5b879b-d7rjs 1/1 Running 2 2d
myapp-848b5b879b-wv5cz 1/1 Running 2 2d
nginx-deploy-5b595999-tj8ms 1/1 Running 2 2d
6.标签选择器除了可以给Pod打标签，也可以用来给node等各种资源打标签。
[root@master manifests]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
master.example.com Ready master 3d v1.11.1
node1.example.com Ready
node2.example.com Ready
[root@master manifests]# kubectl get nodes --show-labels
NAME STATUS ROLES AGE VERSION LABELS
master.example.com Ready master 3d v1.11.1 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/hostname=master.example.com,node-role.kubernetes.io/master=
node1.example.com Ready
node2.example.com Ready
[root@master manifests]# kubectl label nodes node1.example.com disktype=ssd
node/node1.example.com labeled
[root@master manifests]# kubectl get nodes --show-labels
NAME STATUS ROLES AGE VERSION LABELS
master.example.com Ready master 3d v1.11.1 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/hostname=master.example.com,node-role.kubernetes.io/master=
node1.example.com Ready
node2.example.com Ready
7.nodeSelector可以作为节点标签选择器，来对pod运行的节点进行筛选。例如在pod-demo.yaml中增加disktype: ssd的参数，则在创建资源的时候nodeSelector会自动筛选符合的节点。
[root@master manifests]# kubectl delete -f pod-demo.yaml
pod "pod-demo" deleted
[root@master manifests]# vim pod-demo.yaml
[root@master manifests]# cat pod-demo.yaml
apiVersion: v1
kind: Pod
metadata:
name: pod-demo
namespace: default
labels:
app: myapp
tier: frontend
spec:
containers:
- name: myapp
image: ikubernetes/myapp:v1
ports:
- name: http
containerPort: 80
- name: https
containerPort: 443
- name: busybox
image: busybox:latest
imagePullPolicy: IfNotPresent
command:
- "/bin/sh"
- "-c"
- "sleep 3600"
nodeSelector:
disktype: ssd
[root@master manifests]# kubectl create -f pod-demo.yaml
pod/pod-demo created
[root@master manifests]# kubectl describe pods pod-demo
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 1m default-scheduler Successfully assigned default/pod-demo to node1.example.com
Normal Pulled 1m kubelet, node1.example.com Container image "ikubernetes/myapp:v1" already present on machine
Normal Created 1m kubelet, node1.example.com Created container
Normal Started 1m kubelet, node1.example.com Started container
Normal Pulled 1m kubelet, node1.example.com Container image "busybox:latest" already present on machine
Normal Created 1m kubelet, node1.example.com Created container
Normal Started 1m kubelet, node1.example.com Started container
8.资源注解。pod-demo.yaml脚本中通过annotations:来定义注解。kubectl describe pods查看innotation。
[root@master manifests]# kubectl delete -f pod-demo.yaml
pod "pod-demo" deleted
[root@master manifests]# vim pod-demo.yaml
[root@master manifests]# cat pod-demo.yaml
apiVersion: v1
kind: Pod
metadata:
name: pod-demo
namespace: default
labels:
app: myapp
tier: frontend
annotations:
example.com/created-by: "cluster admin"
spec:
containers:
- name: myapp
image: ikubernetes/myapp:v1
ports:
- name: http
containerPort: 80
- name: https
containerPort: 443
- name: busybox
image: busybox:latest
imagePullPolicy: IfNotPresent
command:
- "/bin/sh"
- "-c"
- "sleep 3600"
nodeSelector:
disktype: ssd
[root@master manifests]# kubectl create -f pod-demo.yaml
pod/pod-demo created
[root@master manifests]# kubectl describe pods pod-demo
Name: pod-demo
Namespace: default
Priority: 0
PriorityClassName:
Node: node1.example.com/172.20.0.129
Start Time: Mon, 10 Dec 2018 00:48:43 -0500
Labels: app=myapp
tier=frontend
Annotations: example.com/created-by=cluster admin