本文主要介绍kubernetes调度框架中的NodeName和NodeSelector。
1 NodeName
Pod.spec.nodeName
用于强制约束将Pod调度到指定的Node节点上,这里说是“调度”,但其实指定了nodeName的Pod会直接跳过Scheduler的调度逻辑,直接写入PodList列表,该匹配规则是强制匹配。
例子:
apiVersion: extensions/v1beta1 kind: Deployment metadata: name: tomcat-deploy spec: replicas: 1 template: metadata: labels: app: tomcat-app spec: nodeName: k8s.node1 #指定调度节点为k8s.node1 containers: - name: tomcat image: tomcat:8.0 ports: - containerPort: 8080
2 NodeSelector
Pod.spec.nodeSelector
是通过kubernetes的label-selector机制进行节点选择,由scheduler调度策略MatchNodeSelector
进行label匹配,调度pod到目标节点,该匹配规则是强制约束。启用节点选择器的步骤为:
- Node添加label标记
#标记规则:kubectl label nodes <node-name> <label-key>=<label-value> kubectl label nodes k8s.node1 cloudnil.com/role=dev #确认标记 root@k8s.master1:~# kubectl get nodes k8s.node1 --show-labels NAME STATUS AGE LABELS k8s.node1 Ready 29d beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,cloudnil.com/role=dev,kubernetes.io/hostname=k8s.node1
- Pod定义中添加nodeSelector
apiVersion: extensions/v1beta1 kind: Deployment metadata: name: tomcat-deploy spec: replicas: 1 template: metadata: labels: app: tomcat-app spec: nodeSelector: cloudnil.com/role: dev #指定调度节点为带有label标记为:cloudnil.com/role=dev的node节点 containers: - name: tomcat image: tomcat:8.0 ports: - containerPort: 8080