Kubernets 有状态部署
1. Headless¶
1. Headless 2. StatefulSet
nginx.yaml
#[root@k8s-master01 demo]# cat nginx.yaml
apiVersion: apps/v1beta2
kind: Deployment
metadata:
name: nginx-deployment
namespace: default
spec:
replicas: 3
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
# imagePullSecrets:
# - name: myregistrykey
restartPolicy: Always
nodeSelector:
env_role: dev
containers:
- name: nginx
imagePullPolicy: IfNotPresent
image: nginx:1.15
ports:
- containerPort: 80
[root@k8s-master01 demo]# kubectl create -f service.yaml [root@k8s-master01 demo]# kubectl get service NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.0.0.1 <none> 443/TCP 8d nginx-service NodePort 10.0.0.228 <none> 80:41583/TCP 3d23h
headless.yaml
apiVersion: v1
kind: Service
metadata:
name: headless-service
labels:
app: nginx
spec:
clusterIP: None
ports:
- port: 80
targetPort: 80
selector:
app: nginx
[root@k8s-master01 demo]# kubectl create -f headless.yaml service/headless-service created [root@k8s-master01 demo]# kubectl get service NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE headless-service ClusterIP None <none> 80/TCP 18s kubernetes ClusterIP 10.0.0.1 <none> 443/TCP 8d nginx-service NodePort 10.0.0.228 <none> 80:41583/TCP 3d23h
headless service和其他正常service唯一区别是，clusterip是none
2. statefulset¶
https://kubernetes.io/docs/concepts/workloads/controllers/statefulset/
- 部署有状态应用
-
解决Pod独立生命周期，保持Pod启动顺序和唯一性
-
- 稳定，唯一的网络标识符，持久存储
-
- 有序，优雅的部署和扩展、删除和终止
-
- 有序，滚动更新应用场景：数据库
-
sts.yaml
# [root@k8s-master01 demo2]# cat sts.yaml
apiVersion: v1
kind: Service
metadata:
name: nginx
labels:
app: nginx
spec:
ports:
- port: 80
name: web
clusterIP: None
selector:
app: nginx
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
name: web
spec:
selector:
matchLabels:
app: nginx # has to match .spec.template.metadata.labels
serviceName: "nginx"
replicas: 3 # by default is 1
template:
metadata:
labels:
app: nginx # has to match .spec.selector.matchLabels
spec:
terminationGracePeriodSeconds: 10
containers:
- name: nginx
image: nginx
ports:
- containerPort: 80
name: web
volumeMounts:
- name: www
mountPath: /usr/share/nginx/html
volumeClaimTemplates:
- metadata:
name: www
spec:
accessModes: [ "ReadWriteOnce" ]
storageClassName: "managed-nfs-storage"
resources:
requests:
storage: 1Gi
sts.yml中storageClassName要使用之前定义的managed-nfs-storage,[kubectl get storageclass结果可以看出]
[root@k8s-master01 ~]# kubectl delete -f k8s/demo/nginx.yaml deployment.apps "nginx-deployment" deleted [root@k8s-master01 ~]# kubectl delete -f k8s/demo/service.yaml service "nginx-service" deleted [root@k8s-master01 demo2]# kubectl create -f sts.yaml service/nginx created statefulset.apps/web created 动态查看过程 [root@k8s-master01 demo2]# kubectl get pod -w NAME READY STATUS RESTARTS AGE agent-85j4c 1/1 Running 2 40h agent-kp5fp 1/1 Running 1 40h nfs-client-provisioner-d947789f7-rchmw 1/1 Running 1 40h web-0 1/1 Running 0 18s web-1 0/1 ContainerCreating 0 2s web-1 1/1 Running 0 3s web-2 0/1 Pending 0 0s web-2 0/1 Pending 0 0s web-2 0/1 Pending 0 0s web-2 0/1 ContainerCreating 0 0s web-2 1/1 Running 0 2s q ^C[root@k8s-master01 demo2]# [root@k8s-master01 demo2]# [root@k8s-master01 demo2]# [root@k8s-master01 demo2]# kubectl get pods NAME READY STATUS RESTARTS AGE agent-85j4c 1/1 Running 2 40h agent-kp5fp 1/1 Running 1 40h nfs-client-provisioner-d947789f7-rchmw 1/1 Running 1 40h web-0 1/1 Running 0 58s web-1 1/1 Running 0 42s web-2 1/1 Running 0 39s [root@k8s-master01 demo2]# kubectl get svc NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.0.0.1 <none> 443/TCP 9d nginx ClusterIP None <none> 80/TCP 4m17s 没有分配cluster-ip
有状态的部署，有顺序的，通过-w，来查看启动过程。
StatefulSet与Deployment区别：有身份的！身份三要素
- 域名
- 主机名
- 存储（PVC）
ClusterIP A记录格式：<service-name>.<namespace-name>.svc.cluster.localClusterIP=None A记录格式：<statefulsetName-index>.<service-name>.svc.cluster.local 示例：web-0.nginx.default.svc.cluster.local
bs.yaml
apiVersion: v1
kind: Pod
metadata:
name: busybox
spec:
containers:
- name: busybox
image: busybox:1.28.4
command:
- sleep
- "3600"
[root@k8s-master01 demo2]# kubectl create -f bs.yaml pod/busybox created [root@k8s-master01 demo2]# kubectl get pods NAME READY STATUS RESTARTS AGE agent-85j4c 1/1 Running 2 40h agent-kp5fp 1/1 Running 1 40h busybox 1/1 Running 0 7s nfs-client-provisioner-d947789f7-rchmw 1/1 Running 1 40h web-0 1/1 Running 0 3m37s web-1 1/1 Running 0 3m21s web-2 1/1 Running 0 3m18s 因为没有分配cluster-ip，只好通过servername来访问，进入容器测试 [root@k8s-master01 demo2]# kubectl exec -it busybox sh / # ping nginx PING nginx (172.17.26.6): 56 data bytes 64 bytes from 172.17.26.6: seq=0 ttl=62 time=0.609 ms 64 bytes from 172.17.26.6: seq=1 ttl=62 time=0.370 ms 64 bytes from 172.17.26.6: seq=2 ttl=62 time=0.397 ms 64 bytes from 172.17.26.6: seq=3 ttl=62 time=0.525 ms ^C --- nginx ping statistics --- 4 packets transmitted, 4 packets received, 0% packet loss round-trip min/avg/max = 0.370/0.475/0.609 ms / # nslookup nginx Server: 10.0.0.2 Address 1: 10.0.0.2 kube-dns.kube-system.svc.cluster.local Name: nginx Address 1: 172.17.26.6 web-1.nginx.default.svc.cluster.local Address 2: 172.17.26.7 web-2.nginx.default.svc.cluster.local Address 3: 172.17.73.5 web-0.nginx.default.svc.cluster.local / # / # ping web-0.nginx.default.svc.cluster.local -c1 PING web-0.nginx.default.svc.cluster.local (172.17.73.5): 56 data bytes 64 bytes from 172.17.73.5: seq=0 ttl=64 time=0.046 ms --- web-0.nginx.default.svc.cluster.local ping statistics --- 1 packets transmitted, 1 packets received, 0% packet loss round-trip min/avg/max = 0.046/0.046/0.046 ms 后面的cluster.local可以省略 / # ping web-0.nginx.default.svc -c1 PING web-0.nginx.default.svc (172.17.73.5): 56 data bytes 64 bytes from 172.17.73.5: seq=0 ttl=64 time=0.094 ms --- web-0.nginx.default.svc ping statistics --- 1 packets transmitted, 1 packets received, 0% packet loss round-trip min/avg/max = 0.094/0.094/0.094 ms 也就是说通过这个可以访问对于的pod，体现了网络唯一的网络标识
通过 web-0.nginx.default.svc.cluster.local 可以找到172.17.73.5这个pod
[root@k8s-master01 demo2]# kubectl get pv NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE pvc-7383e81d-695d-11e9-8c4f-000c2994bdca 1Gi RWO Delete Bound default/www-web-0 managed-nfs-storage 57m pvc-7d6cbcac-695d-11e9-8c4f-000c2994bdca 1Gi RWO Delete Bound default/www-web-1 managed-nfs-storage 57m pvc-7f234bb6-695d-11e9-8c4f-000c2994bdca 1Gi RWO Delete Bound default/www-web-2 managed-nfs-storage 57m [root@k8s-master01 demo2]# kubectl get pvc NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE www-web-0 Bound pvc-7383e81d-695d-11e9-8c4f-000c2994bdca 1Gi RWO managed-nfs-storage 58m www-web-1 Bound pvc-7d6cbcac-695d-11e9-8c4f-000c2994bdca 1Gi RWO managed-nfs-storage 58m www-web-2 Bound pvc-7f234bb6-695d-11e9-8c4f-000c2994bdca 1Gi RWO managed-nfs-storage 58m
自动创建了三个pv，动态供给，独立了存储，期中pod→pv→pvc都是一一对应的。
[root@k8s-master01 demo2]# kubectl exec -it web-0 sh # hostname web-0
主机名唯一。
简单演示有状态部署，难点。