Production-Grade Container Orchestration

The kubelet is mostly a stateless process running on a Kubernetes node. This document outlines files that kubelet reads and writes. Note:This document is for informational purpose and not describing any guaranteed behaviors or APIs. It lists resources used by the kubelet, which is an implementation detail and a subject to change at any release. The kubelet typically uses the control plane as the source of truth on what needs to run on the Node, and the container runtime to retrieve the current state of containers.

When using the kubelet's --config-dir flag to specify a drop-in directory for configuration, there is some specific behavior on how different types are merged. Here are some examples of how different data types behave during configuration merging: Structure Fields There are two types of structure fields in a YAML structure: singular (or a scalar type) and embedded (structures that contain scalar types). The configuration merging process handles the overriding of singular and embedded struct fields to create a resulting kubelet configuration.

FEATURE STATE: Kubernetes v1.27 [beta] This is a community maintained list of official CVEs announced by the Kubernetes Security Response Committee. See Kubernetes Security and Disclosure Information for more details. The Kubernetes project publishes a programmatically accessible feed of published security issues in JSON feed and RSS feed formats. You can access it by executing the following commands: JSON feed RSS feed Link to JSON format curl -Lv https://k8s.io/docs/reference/issues-security/official-cve-feed/index.json Link to RSS format

When running Kubernetes in an environment with strict network boundaries, such as on-premises datacenter with physical network firewalls or Virtual Networks in Public Cloud, it is useful to be aware of the ports and protocols used by Kubernetes components. Control plane Protocol Direction Port Range Purpose Used By TCP Inbound 6443 Kubernetes API server All TCP Inbound 2379-2380 etcd server client API kube-apiserver, etcd TCP Inbound 10250 Kubelet API Self, Control plane TCP Inbound 10259 kube-scheduler Self TCP Inbound 10257 kube-controller-manager Self Although etcd ports are included in control plane section, you can also host your own etcd cluster externally or on custom ports.

FEATURE STATE: Kubernetes v1.30 [beta] (enabled by default: true) Checkpointing a container is the functionality to create a stateful copy of a running container. Once you have a stateful copy of a container, you could move it to a different computer for debugging or similar purposes. If you move the checkpointed container data to a computer that's able to restore it, that restored container continues to run at exactly the same point it was checkpointed.

Production-Grade Container Orchestration

Production-Grade Container Orchestration

Synopsis Experimental: Check who you are and your attributes (groups, extra). This command is helpful to get yourself aware of the current user attributes, especially when dynamic authentication, e.g., token webhook, auth proxy, or OIDC provider, is enabled in the Kubernetes cluster. kubectl auth whoami Examples # Get your subject attributes kubectl auth whoami # Get your subject attributes in JSON format kubectl auth whoami -o json Options --allow-missing-template-keys     Default: true If true, ignore any errors in templates when a field or map key is missing in the template.

Production-Grade Container Orchestration