For kubernetes resources can use to load yaml markup language, self-definition:
YAML (/ jæməl /, similar to the tail camel camels) is a highly readable, the data used to express serialization format. YAML reference to other languages, including: C, Python, Perl, and get inspiration from XML, e-mail data format (RFC 2822) in. Clark Evans in 2001 published the first language [1], in addition Ingy döt Net co-designer and Oren Ben-Kiki is this language [2]. There have been several current programming or scripting language support (or resolve) this language. YAML is "YAML Is not a Markup Language" (YAML is not a markup language) is a recursive acronym. In the development of the language, YAML meant in fact: "Yet Another Markup Language" (still a markup language) [3], but in order to emphasize the language as a data center, rather than as markup language focus, with the reverse Abbreviations renamed.
Use YAML is used to define k8s will give you some benefits, including:
- Convenience: You will no longer need to add a lot of command line parameters to execute the command
- Maintainability: YAML files can be source control, you can track every operation
- Flexibility: You will be able to create more complex than the command line structure by YAML
YAML is a superset of JSON, it means that any valid JSON file is also a valid YAML file. So on the one hand, if you know JSON, you're just going to write your own YAML (instead of reading someone else's) it can be had. On the other hand, it is less likely, unfortunately, even though you try to go online to find examples, but they are usually not JSON, so we may need to get used to it. However, there may be more convenient in the case of JSON, so you will be very happy you know JSON.
Fortunately, YAML only two types of structure you need to know:
- Lists
- YAML lists is a sequence of objects
- Maps
- Maps will let you key combination, you can be more convenient to set configuration information
View a list of resources pod
[root @ Kube ~] # kubectl GET POD nginx-App-7756966bc9-qrksb -o yaml
// This is a run through kubectl run way pod, then we can manually define a yaml similar to this then generates the configuration file to load POD
apiVersion: V1
kind: Pod
Metadata:
creationTimestamp: "2019-07-16T06: 39: 02Z"
generateName: Nginx-App-7756966bc9-
Labels:
POD the hash-Template-: 7756966bc9
RUN: Nginx-App
name: Nginx-APP- qrksb-7756966bc9
namespace: default
ownerReferences:
- apiVersion: Apps / v1
blockOwnerDeletion: to true
the Controller: to true
kind: ReplicaSet
name: nginx-App-7756966bc9
uid: 51997507-0ad5-4f71-86db-3ad6eff70171
resourceVersion: "603 662"
selfLink: /api/v1/namespaces/default/pods/nginx-app-7756966bc9-qrksb
uid: 7035cfbd-a8f3-45a9-933c-4ce1cef45183
spec:
containers:
- image: nginx:alpine
imagePullPolicy: IfNotPresent
name: nginx-app
ports:
- containerPort: 80
protocol: TCP
resources: {}
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
volumeMounts:
- mountPath: /var/run/secrets/kubernetes.io/serviceaccount
name: default-token-bsthb
readOnly: true
dnsPolicy: ClusterFirst
enableServiceLinks: true
nodeName: kube.node1
priority: 0
restartPolicy: Always
schedulerName: default-scheduler
securityContext: {}
serviceAccount: default
serviceAccountName: default
terminationGracePeriodSeconds: 30
tolerations:
- effect: NoExecute
key: node.kubernetes.io/not-ready
operator: Exists
tolerationSeconds: 300
- effect: NoExecute
key: node.kubernetes.io/unreachable
operator: Exists
tolerationSeconds: 300
volumes:
- name: default-token-bsthb
secret:
defaultMode: 420
secretName: default-token-bsthb
status:
conditions:
- lastProbeTime: null
lastTransitionTime: "2019-07-16T06:39:02Z"
status: "True"
type: Initialized
- lastProbeTime: null
lastTransitionTime: "2019-07-16T06:39:36Z"
status: "True"
type: Ready
- lastProbeTime: null
lastTransitionTime: "2019-07-16T06:39:36Z"
status: "True"
type: ContainersReady
- lastProbeTime: null
lastTransitionTime: "2019-07-16T06:39:02Z"
status: "True"
type: PodScheduled
containerStatuses:
- containerID: docker://6f50a8038d1f9b484c3af46fa21ef0bdce963b95c4f7f5980302bc70ca46eea6
image: nginx:alpine
imageID: docker-pullable://nginx@sha256:17bd1698318e9c0f9ba2c5ed49f53d690684dab7fe3e8019b855c352528d57be
lastState: {}
name: nginx-app
ready: true
restartCount: 0
state:
running:
startedAt: "2019-07-16T06:39:36Z"
hostIP: 10.2.61.22
phase: Running
podIP: 10.244.2.7
qosClass: BestEffort
startTime: "2019-07-16T06:39:02Z"
[root@kube ~]#
Our analysis is carried out for yaml format:
#maps is key | value combination, list is key [args, args, a combination of a plurality of items] with a dash (-) at the beginning
apiVersion: // Maps V1 kind: // Pod Maps Metadata: name: // RSS-Site Maps Labels: App: Web / Maps spec: // Maps Containers: // List name - name: Front-End // child List parameter is Maps Image: Nginx // List parameter subkeys are Maps the ports: - containerPort: 80 // list parameters subkey Maps - name: RSS-Reader Image: nickchase / RSS-PHP-Nginx: V1 the ports: - containerPort: 88
Create a simple file yaml
root@kube test]# cat pod-demo.yaml
apiVersion: v1
kind: Pod
metadata:
name: pod-test
namespace: default
labels:
app: myapp
tier: frontend
spec:
containers:
- name: mytest
image: nginx:latest
[root@kube test]#
[root@kube test]# kubectl create -f pod-demo.yaml
pod/pod-test created
[root@kube test]# kubectl get pods
NAME READY STATUS RESTARTS AGE
busy1-78c9f4b47-pm2qx 0/1 CrashLoopBackOff 22 100m
busy2-7f9dbf96d6-2d778 1/1 Running 0 2d23h
busy3-9877c76bf-ts5rl 1/1 Running 0 2d23h
nginx-7bb7cd8db5-6sgvp 1/1 Running 0 3d
nginx-app-54c844949f-6zlmr 0/1 ContainerCreating 0 41h
nginx-app-54c844949f-n82d6 1/1 Running 0 2d
nginx-app-54c844949f-xmkb8 1/1 Running 0 2d
nginx-app-7756966bc9-qrksb 1/1 Running 0 2d2h
pod-test 0/1 ContainerCreating 0 1s
[root@kube test]#
[root@kube test]# kubectl describe pod pod-test
Name: pod-test
Namespace: default
Priority: 0
Node: kube.node1/10.2.61.22
Start Time: Thu, 18 Jul 2019 16:44:23 +0800
Labels: app=myapp
tier=frontend
Annotations: <none>
Status: Running
IP: 10.244.2.12
Containers:
mytest:
Container ID: docker://4e40fc5b6cae440881cea707b79c2d17692c47d75df69a571fa0e7d57dff5e3a
Image: nginx:latest
Image ID: docker-pullable://nginx@sha256:b4b9b3eee194703fc2fa8afa5b7510c77ae70cfba567af1376a573a967c03dbb
Port: <none>
Host Port: <none>
State: Running
Started: Thu, 18 Jul 2019 16:44:46 +0800
Ready: True
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from default-token-bsthb (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
default-token-bsthb:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-bsthb
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 62s default-scheduler Successfully assigned default/pod-test to kube.node1
Normal Pulling 61s kubelet, kube.node1 Pulling image "nginx:latest"
Normal Pulled 40s kubelet, kube.node1 Successfully pulled image "nginx:latest"
Normal Created 40s kubelet, kube.node1 Created container mytest
Normal Started 39s kubelet, kube.node1 Started container mytest
[root@kube test]#
[root@kube ~]# kubectl api-versions
admissionregistration.k8s.io/v1beta1
apiextensions.k8s.io/v1beta1
apiregistration.k8s.io/v1
apiregistration.k8s.io/v1beta1
apps/v1
apps/v1beta1
apps/v1beta2
authentication.k8s.io/v1
authentication.k8s.io/v1beta1
authorization.k8s.io/v1
authorization.k8s.io/v1beta1
autoscaling/v1
autoscaling/v2beta1
autoscaling/v2beta2
batch/v1
batch/v1beta1
certificates.k8s.io/v1beta1
coordination.k8s.io/v1
coordination.k8s.io/v1beta1
events.k8s.io/v1beta1
extensions/v1beta1
networking.k8s.io/v1
networking.k8s.io/v1beta1
node.k8s.io/v1beta1
policy/v1beta1
rbac.authorization.k8s.io/v1
rbac.authorization.k8s.io/v1beta1
scheduling.k8s.io/v1
scheduling.k8s.io/v1beta1
storage.k8s.io/v1
storage.k8s.io/v1beta1
v1
[root@kube ~]# kubectl explain pods
KIND: Pod
VERSION: v1
DESCRIPTION:
Pod is a collection of containers that can run on a host. This resource is
created by clients and scheduled onto hosts.
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/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/api-conventions.md#types-kinds
metadata <Object>
Standard object's metadata. More info:
https://git.k8s.io/community/contributors/devel/api-conventions.md#metadata
spec <Object>
Specification of the desired behavior of the pod. More info:
https://git.k8s.io/community/contributors/devel/api-conventions.md#spec-and-status
status <Object>
Most recently observed status of the pod. This data may not be up to date.
Populated by the system. Read-only. More info:
https://git.k8s.io/community/contributors/devel/api-conventions.md#spec-and-status
[root@kube ~]#