There are two different agent resources deployed on Rancher managed clusters:
For a conceptual overview of how the Rancher server provisions clusters and communicates with them, refer to the architecture
cattle-cluster-agent is used to connect to the Kubernetes API of Rancher Launched Kubernetes clusters. The
cattle-cluster-agent is deployed using a Deployment resource.
cattle-node-agent is used to interact with nodes in a Rancher Launched Kubernetes cluster when performing cluster operations. Examples of cluster operations are upgrading Kubernetes version and creating/restoring etcd snapshots. The
cattle-node-agent is deployed using a DaemonSet resource to make sure it runs on every node. The
cattle-node-agent is used as fallback option to connect to the Kubernetes API of Rancher Launched Kubernetes clusters when
cattle-cluster-agent is unavailable.
Note: In Rancher v2.2.4 and lower, the
cattle-node-agentpods did not tolerate all taints, causing Kubernetes upgrades to fail on these nodes. The fix for this has been included in Rancher v2.2.5 and higher.
Applies to v2.3.0 up to v2.5.3
cattle-cluster-agent Deployment has preferred scheduling rules using
preferredDuringSchedulingIgnoredDuringExecution, favoring to be scheduled on nodes with the
controlplane node. See Kubernetes: Assigning Pods to Nodes to find more information about scheduling rules.
preferredDuringSchedulingIgnoredDuringExecution configuration is shown in the table below: