The kubelet is a fundamental component of the Kubernetes architecture and is responsible for managing individual nodes in a Kubernetes cluster. Its main role is to ensure that the containers that are scheduled to run on its node are healthy and running as expected.
Some of the specific tasks performed by the kubelet include:
- Container execution: The kubelet is responsible for starting, stopping, and monitoring containers on a node. It pulls the container images from the container registry and starts them as per the Pod specifications.
- Pod lifecycle management: The kubelet ensures that the Pod is in a healthy state by checking the status of the containers within the Pod. If a container fails, the kubelet restarts the container or the entire Pod.
- Resource management: The kubelet monitors the resource usage of the containers on the node and reports back to the Kubernetes master, which uses this information to schedule new Pods to other nodes with more available resources.
- Volume management: The kubelet manages the volumes attached to a Pod by ensuring that the volumes are mounted and unmounted from the host system as required.
- Security: The kubelet enforces security policies for the containers on the node, such as ensuring that the container images are signed, and enforcing access control policies.
Overall, the kubelet plays a critical role in ensuring that the containers running on a node are healthy, secure, and efficiently utilizing the available resources.