Daemon Sets

A Daemon Set in Kubernetes ensures that all (or some) Nodes run a copy of a Pod. It is used to deploy system daemons that need to run on every node in a Kubernetes cluster.

Primary Use Cases:

Daemon Sets are particularly useful for deploying Pods that perform node-level tasks such as node monitoring, log aggregation, and resource management.

Functionality:

• Node Level Deployment: Daemon Sets deploy a specified Pod on every node in the cluster, ensuring the availability of the Pod’s functionality on every node.
• Automatic Pod Deployment: When a new node is added to the cluster, the Daemon Set automatically deploys the Pod on the new node. Conversely, if a node is removed from the cluster, the Daemon Set terminates the Pod on the removed node.
• Selective Deployment: Daemon Sets can be configured to deploy Pods only on nodes that meet specific criteria, using node labels and Daemon Set’s node selector.
• Node Resource Utilization: Daemon Sets are crucial when tasks need to utilize resources at the node level, ensuring uniform resource utilization and task execution across the cluster.

Example Deployment Scenarios:

Daemon Sets are instrumental in deploying applications like network plugins, storage daemons, and monitoring agents which need to maintain a presence on all nodes within the cluster.