rancher-docs/assets/js/075ad100.1ce89b16.js

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The ",(0,a.kt)("inlineCode",{parentName:"p"},"cattle-cluster-agent")," is deployed using a Deployment resource."),(0,a.kt)("h3",{id:"cattle-node-agent"},"cattle-node-agent"),(0,a.kt)("p",null,"The ",(0,a.kt)("inlineCode",{parentName:"p"},"cattle-node-agent")," is used to interact with nodes in a ",(0,a.kt)("a",{parentName:"p",href:"/pages-for-subheaders/launch-kubernetes-with-rancher"},"Rancher Launched Kubernetes")," cluster when performing cluster operations. Examples of cluster operations are upgrading Kubernetes version and creating/restoring etcd snapshots. The ",(0,a.kt)("inlineCode",{parentName:"p"},"cattle-node-agent")," is deployed using a DaemonSet resource to make sure it runs on every node. The ",(0,a.kt)("inlineCode",{parentName:"p"},"cattle-node-agent")," is used as fallback option to connect to the Kubernetes API of ",(0,a.kt)("a",{parentName:"p",href:"/pages-for-subheaders/launch-kubernetes-with-rancher"},"Rancher Launched Kubernetes")," clusters when ",(0,a.kt)("inlineCode",{parentName:"p"},"cattle-cluster-agent")," is unavailable."),(0,a.kt)("h3",{id:"scheduling-rules"},"Scheduling rules"),(0,a.kt)("p",null,"The ",(0,a.kt)("inlineCode",{parentName:"p"},"cattle-cluster-agent")," uses either a fixed set of tolerations, or dynamically-added tolerations based on taints applied to the control plane nodes. This structure allows ",(0,a.kt)("a",{parentName:"p",href:"https://kubernetes.io/docs/concepts/scheduling-eviction/taint-and-toleration/#taint-based-evictions"},"Taint based Evictions")," to work properly for ",(0,a.kt)("inlineCode",{parentName:"p"},"cattle-cluster-agent"),". "),(0,a.kt)("p",null,"If control plane nodes are present in the cluster, the default tolerations will be replaced with tolerations matching the taints on the control plane nodes. The default set of tolerations are described below. "),(0,a.kt)("table",null,(0,a.kt)("thead",{parentName:"table"},(0,a.kt)("tr",{parentName:"thead"},(0,a.kt)("th",{parentName:"tr",align:null},"Component"),(0,a.kt)("th",{parentName:"tr",align:null},"nodeAffinity nodeSelectorTerms"),(0,a.kt)("th",{parentName:"tr",align:null},"nodeSelector"),(0,a.kt)("th",{parentName:"tr",align:null},"Tolerations"))),(0,a.kt)("tbody",{parentName:"table"},(0,a.kt)("tr",{parentName:"tbody"},(0,a.kt)("td",{parentName:"tr",align:null},(0,a.kt)("inlineCode",{parentName:"td"},"cattle-cluster-agent")),(0,a.kt)("td",{parentName:"tr",align:null},(0,a.kt)("inlineCode",{parentName:"td"},"beta.kubernetes.io/os:NotIn:windows")),(0,a.kt)("td",{parentName:"tr",align:null},"none"),(0,a.kt)("td",{parentName:"tr",align:null},(0,a.kt)("strong",{parentName:"td"},"Note:")," These are the default tolerations, and will be replaced by tolerations matching taints applied to controlplane nodes.",(0,a.kt)("br",null),(0,a.kt)("br",null),(0,a.kt)("inlineCode",{parentName:"td"},"effect:NoSchedule"),(0,a.kt)("br",null),(0,a.kt)("inlineCode",{parentName:"td"},"key:node-role.kubernetes.io/controlplane"),(0,a.kt)("br",null),(0,a.kt)("inlineCode",{parentName:"td"},"value:true"),(0,a.kt)("br",null),(0,a.kt)("br",null),(0,a.kt)("inlineCode",{parentName:"td"},"effect:NoSchedule"),(0,a.kt)("br",null),(0,a.kt)("inlineCode",{parentName:"td"},"key:node-role.kubernetes.io/control-plane"),(0,a.kt)("br",null),(0,a.kt)("inlineCode",{parentName:"td"},"operator:Exists"),(0,a.kt)("br",null),(0,a.kt)("br",null),(0,a.kt)("inlineCode",{parentName:"td"},"effect:NoSchedule"),(0,a.kt)("br",null),(0,a.kt)("inlineCode",{parentName:"td"},"key:node-role.kubernetes.io/master"),(0,a.kt)("br",null),(0,a.kt)("inlineCode",{parentName:"td"},"operator:Exists"))),(0,a.kt)("tr",{parentName:"tbody"},(0,a.kt)("td",{parentName:"tr",align:null},(0,a.kt)("inlineCode",{parentName:"td"},"cattle-node-agent")),(0,a.kt)("td",{parentName:"tr",align:null},(0,a.kt)("inlineCode",{parentName:"td"},"beta.kubernetes.io/os:NotIn:windows")),(0,a.kt)("td",{parentName:"tr",align:null},"none"),(0,a.kt)("td",{parentName:"tr",align:null},(0,a.kt)("inlineCode",{parentName:"td"},"operator:Exists"))))),(0,a.kt)("p",null,"The ",(0,a.kt)("inlineCode",{parentName:"p"},"cattle-cluster-agent")," Deployment has preferred scheduling rules using ",(0,a.kt)("inlineCode",{parentName:"p"},"preferredDuringSchedulingIgnoredDuringExecution"),", favoring to be scheduled on nodes with the ",(0,a.kt)("inlineCode",{parentName:"p"},"controlplane")," node. When there are no controlplane nodes visible in the cluster (this is usually the case when using ",(0,a.kt)("a",{parentName:"p",href:"/pages-for-subheaders/set-up-clusters-from-hosted-kubernetes-providers"},"Clusters from Hosted Kubernetes Providers"),"), you can add the label ",(0,a.kt)("inlineCode",{parentName:"p"},"cattle.io/cluster-agent=true")," on a node to prefer scheduling the ",(0,a.kt)("inlineCode",{parentName:"p"},"cattle-cluster-agent")," pod to that node."),(0,a.kt)("p",null,"See ",(0,a.kt)("a",{parentName:"p",href:"https://kubernetes.io/docs/concepts/configuration/assign-pod-node/"},"Kubernetes: Assigning Pods to Nodes")," to find more information about scheduling rules."),(0,a.kt)("p",null,"The ",(0,a.kt)("inlineCode",{parentName:"p"},"preferredDuringSchedulingIgnoredDuringExecution")," configuration is shown in the table below:"),(0,a.kt)("table",null,(0,a.kt)("thead",{parentName:"table"},(0,a.kt)("tr",{parentName:"thead"},(0,a.kt)("th",{parentName:"tr",align:null},"Weight"),(0,a.kt)("th",{parentName:"tr",align:null},"Expression"))),(0,a.kt)("tbody",{parentName:"table"},(0,a.kt)("tr",{parentName:"tbody"},(0,a.kt)("td",{parentName:"tr",align:null},"100"),(0,a.kt)("td",{parentName:"tr",align:null},(0,a.kt)("inlineCode",{parentName:"td"},'node-role.kubernetes.io/controlplane:In:"true"'))),(0,a.kt)("tr",{parentName:"tbody"},(0,a.kt)("td",{parentName:"tr",align:null},"100"),(0,a.kt)("td",{parentName:"tr",align:null},(0,a.kt)("inlineCode",{parentName:"td"},'node-role.kubernetes.io/control-plane:In:"true"'))),(0,a.kt)("tr",{parentName:"tbody"},(0,a.kt)("td",{parentName:"tr",align:null},"100"),(0,a.kt)("td",{parentName:"tr",align:null},(0,a.kt)("inlineCode",{parentName:"td"},'node-role.kubernetes.io/master:In:"true"'))),(0,a.kt)("tr",{parentName:"tbody"},(0,a.kt)("td",{parentName:"tr",align:null},"1"),(0,a.kt)("td",{parentName:"tr",align:null},(0,a.kt)("inlineCode",{parentName:"td"},'cattle.io/cluster-agent:In:"true"'))))))}c.isMDXComponent=!0}}]);