DaemonSet
DaemonSet（守护进程集）和守护进程类似，它在符合匹配条件的节点上均部署一个Pod。
什么是DaemonSet
DaemonSet确保全部（或者某些）节点上运行一个Pod副本。当有新节点加入集群时，也会为它们新增一个Pod。当节点从集群中移除时，这些Pod也会被回收，删除DaemonSet将会删除它创建的所有Pod。
DaemonSet的典型场景
- 运行集群存储daemon（守护进程），例如在每个节点上运行Glusterfs、Ceph等。
- 在每个节点运行日志收集daemon，例如filebeat、Logstash。
- 在每个节点运行监控daemon，比如Prometheus Node Exporter。
创建DaemonSet
在生产环境中，公司业务的应用程序一般无须使用DaemonSet部署，一般情况下只有像FileBeat（日志收集）、Ingress（集群服务入口）、Flannel（集群网络组件）、Node-Exporter（监控数据采集）等才需要使用DaemonSet部署到每个节点。本节只演示DaemonSet的使用。以Nginx Ingress为例。
[root@instance-gvpb80ao yaml]# kubectl apply -f deploy.yaml
namespace/ingress-nginx created
serviceaccount/ingress-nginx created
configmap/ingress-nginx-controller created
clusterrole.rbac.authorization.k8s.io/ingress-nginx created
clusterrolebinding.rbac.authorization.k8s.io/ingress-nginx created
role.rbac.authorization.k8s.io/ingress-nginx created
rolebinding.rbac.authorization.k8s.io/ingress-nginx created
service/ingress-nginx-controller-admission created
service/ingress-nginx-controller created
deployment.apps/ingress-nginx-controller created
validatingwebhookconfiguration.admissionregistration.k8s.io/ingress-nginx-admission created
serviceaccount/ingress-nginx-admission created
clusterrole.rbac.authorization.k8s.io/ingress-nginx-admission created
clusterrolebinding.rbac.authorization.k8s.io/ingress-nginx-admission created
role.rbac.authorization.k8s.io/ingress-nginx-admission created
rolebinding.rbac.authorization.k8s.io/ingress-nginx-admission created
job.batch/ingress-nginx-admission-create created
job.batch/ingress-nginx-admission-patch created
[root@instance-gvpb80ao yaml]# kubectl get pods -n ingress-nginx
NAME READY STATUS RESTARTS AGE
nginx-ingress-controller-fjkf2 1/1 Running 0 44s
nginx-ingress-controller-gfmcv 1/1 Running 0 44s
nginx-ingress-controller-j89qc 1/1 Running 0 44s
nginx-ingress-controller-sqsk2 1/1 Running 0 44s
nginx-ingress-controller-tgdt6 1/1 Running 0 44sCopy to clipboardErrorCopied
更新与回滚
同Deployment。