kubernetes 1.21 部署业务

https://medium.com/containermind/a-beginners-guide-to-kubernetes-7e8ca56420b6
https://www.freecodecamp.org/news/learn-kubernetes-in-under-3-hours-a-detailed-guide-to-orchestrating-containers-114ff420e882/
https://devopscube.com/kubernetes-deployment-tutorial/

一. 基本概念

Pod 共享网络、存储和计算资源的容器化服务的集合

Deployment & ReplicaSet
Deployment 的作用是管理和控制 Pod 和 ReplicaSet，管控它们运行在用户期望的状态
ReplicaSet 的作用就是管理和控制 Pod

Service & Ingress
Service 和 Ingress 负责管控 Pod 网络服务
Service 主要负责 K8S 集群内部的网络拓扑
Ingress 是整个 K8S 集群的接入层，复杂集群内外通讯 

Namespace 
K8S 集群内创建 namespace 来分隔资源和对象

二. deployment yaml文件
YAML由 apiVersion、Kind、metadata、spec 4个部分组成

apiVersion

# kubectl api-versions
admissionregistration.k8s.io/v1
apiextensions.k8s.io/v1
apiregistration.k8s.io/v1
apps/v1
authentication.k8s.io/v1
authorization.k8s.io/v1
autoscaling/v1
autoscaling/v2beta1
autoscaling/v2beta2
batch/v1
batch/v1beta1
certificates.k8s.io/v1
coordination.k8s.io/v1
crd.projectcalico.org/v1
discovery.k8s.io/v1
discovery.k8s.io/v1beta1
events.k8s.io/v1
events.k8s.io/v1beta1
flowcontrol.apiserver.k8s.io/v1beta1
networking.k8s.io/v1
node.k8s.io/v1
node.k8s.io/v1beta1
policy/v1
policy/v1beta1
rbac.authorization.k8s.io/v1
scheduling.k8s.io/v1
storage.k8s.io/v1
storage.k8s.io/v1beta1
v1

# kubectl api-resources

kind

componentstatuses
configmaps
daemonsets
deployments
events
endpoints
horizontalpodautoscalers
ingress
jobs
limitranges
namespaces
nodes
pods
persistentvolumes
persistentvolumeclaims
resourcequotas
replicasets
replicationcontrollers
serviceaccounts
services

Metadata
labels 、name 、 namespace 、annotations

metadata:
  name: resource-name    # deployment name
  namespace: deployment-demo
  labels:
    app: web
    platform: java
    release: 18.0
  annotations:
    monitoring: true
    prod: true

Spec

# Replicas 确保任一时间运行pod数量
spec:
  replicas: 3

# Selector 匹配标签的pod将被管理
selector:
    matchLabels:
      app: nginx

# Template 包含镜像、端口、环境变量、命令参数等信息，用于复用
template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
        - image: nginx
          name: nginx

三. 部署示例
1. 建立namespace

cat > /tmp/namespace.yaml << EOF
apiVersion: v1
kind: Namespace
metadata:
  name: kube-demo
  labels:
    apps: web-based
  annotations:
    type: demo
EOF

# kubectl apply -f /tmp/namespace.yaml 
namespace/kube-demo created

# kubectl get namespaces -o wide
NAME              STATUS   AGE
default           Active   3h50m
ingress-nginx     Active   3h6m
kube-demo         Active   23s
kube-node-lease   Active   3h50m
kube-public       Active   3h50m
kube-system       Active   3h50m
metallb-system    Active   3h13m

# kubectl describe namespaces kube-demo 
Name:         kube-demo
Labels:       apps=web-based
              kubernetes.io/metadata.name=kube-demo
Annotations:  type: demo
Status:       Active

No resource quota.

No LimitRange resource.

2. namespace指派资源

cat > /tmp/resourceQuota.yaml << EOF
apiVersion: v1
kind: ResourceQuota
metadata:
  name: mem-cpu-quota
  namespace: kube-demo
spec:
  hard:
    requests.cpu: "4"
    requests.memory: 8Gi
    limits.cpu: "8"
    limits.memory: 16Gi
EOF

# kubectl apply -f /tmp/resourceQuota.yaml 
resourcequota/mem-cpu-quota created

# kubectl describe namespaces kube-demo 
Name:         kube-demo
Labels:       apps=web-based
              kubernetes.io/metadata.name=kube-demo
Annotations:  type: demo
Status:       Active

Resource Quotas
  Name:            mem-cpu-quota
  Resource         Used  Hard
  --------         ---   ---
  limits.cpu       0     8
  limits.memory    0     16Gi
  requests.cpu     0     4
  requests.memory  0     8Gi

No LimitRange resource.

3. 建立deployment

cat > /tmp/deployment.yaml << EOF
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx
  labels:
    app: nginx
  namespace: kube-demo
  annotations:
    monitoring: "true"
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - image: 192.168.100.198:5000/nginx:1.21
        name: nginx
        tty: true
        stdin: true
        ports:
        - containerPort: 80
        resources:
          limits:
            memory: "2Gi"
            cpu: "1000m"
          requests: 
            memory: "1Gi"
            cpu: "500m"
EOF

# kubectl apply -f /tmp/deployment.yaml 
deployment.apps/nginx created

# kubectl describe namespaces kube-demo 
Name:         kube-demo
Labels:       apps=web-based
              kubernetes.io/metadata.name=kube-demo
Annotations:  type: demo
Status:       Active

Resource Quotas
  Name:            mem-cpu-quota
  Resource         Used   Hard
  --------         ---    ---
  limits.cpu       3      8
  limits.memory    6Gi    16Gi
  requests.cpu     1500m  4
  requests.memory  3Gi    8Gi

No LimitRange resource.

# kubectl get deployments -n kube-demo -o wide
NAME    READY   UP-TO-DATE   AVAILABLE   AGE   CONTAINERS   IMAGES                            SELECTOR
nginx   3/3     3            3           34s   nginx        192.168.100.198:5000/nginx:1.21   app=nginx

# kubectl get pods -n kube-demo -o wide
NAME                     READY   STATUS    RESTARTS   AGE   IP             NODE     NOMINATED NODE   READINESS GATES
nginx-796bbc89ff-8jvhw   1/1     Running   0          51s   10.240.2.144   vm-197   <none>           <none>
nginx-796bbc89ff-cftfh   1/1     Running   0          51s   10.240.2.143   vm-197   <none>           <none>
nginx-796bbc89ff-qk59q   1/1     Running   0          51s   10.240.36.12   vm-207   <none>           <none>

# kubectl get deployments -n kube-demo -o yaml

https://kubernetes.io/docs/concepts/services-networking/connect-applications-service

4. 使用service提供服务

cat > /tmp/service.yaml << EOF
apiVersion: v1
kind: Service
metadata:
  labels:
    app: nginx
  name: nginx
  namespace: kube-demo
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 80
  selector:
    app: nginx
  type: ClusterIP
EOF

# kubectl apply -f /tmp/service.yaml 
service/nginx created

# kubectl get services -o wide -n kube-demo
NAME    TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)   AGE   SELECTOR
nginx   ClusterIP   10.97.122.87   <none>        80/TCP    9s    app=nginx

# kubectl get services -n kube-demo -o yaml

type: NodePort

# kubectl apply -f /tmp/service.yaml 
service/nginx configured

# kubectl get services -o wide -n kube-demo
NAME    TYPE       CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE    SELECTOR
nginx   NodePort   10.97.122.87    <none>        80:31853/TCP   3h8m   app=nginx

type: LoadBalancer

# kubectl apply -f /tmp/service.yaml 
service/nginx configured

# kubectl get services -o wide -n kube-demo
NAME    TYPE           CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE    SELECTOR
nginx   LoadBalancer   10.97.122.87    <pending>     80:31853/TCP   3h8m   app=nginx

5. 测试

curl -l http://10.97.122.87