The Kubernetes API is a resource-based (RESTful) programmatic interface provided via HTTP. It supports retrieving, creating, updating, and deleting primary resources via the standard HTTP verbs (POST, PUT, PATCH, DELETE, GET). For some resources, the API includes additional subresources that allow fine-grained authorization (such as separate views for Pod details and log retrievals), and can accept and serve those resources in different representations for convenience or efficiency. Kubernetes supports efficient change notifications on resources via watches: in the Kubernetes API, watch is a verb that is used to track changes to an object in Kubernetes as a stream.

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.

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

Synopsis Manage user preferences (kuberc) file. The kuberc file allows you to customize your kubectl experience. kubectl alpha kuberc SUBCOMMAND Examples # View the current kuberc configuration kubectl alpha kuberc view # Set a default value for a command flag kubectl alpha kuberc set --section defaults --command get --option output=wide # Create an alias for a command kubectl alpha kuberc set --section aliases --name getn --command get --prependarg nodes --option output=wide Options -h, --help help for kuberc

Production-Grade Container Orchestration

Production-Grade Container Orchestration

Synopsis Set values in the kuberc configuration file. Use --section to specify whether to set defaults or aliases. For defaults: Sets default flag values for kubectl commands. The --command flag should specify only the command (e.g., "get", "create", "set env"), not resources. For aliases: Creates command aliases with optional default flag values and arguments. Use --prependarg and --appendarg to include resources or other arguments. kubectl alpha kuberc set --section (defaults|aliases) --command COMMAND Examples # Set default output format for 'get' command kubectl alpha kuberc set --section defaults --command get --option output=wide # Set default output format for a subcommand kubectl alpha kuberc set --section defaults --command "set env" --option output=yaml # Create an alias 'getn' for 'get' command with prepended 'nodes' resource kubectl alpha kuberc set --section aliases --name getn --command get --prependarg nodes --option output=wide # Create an alias 'runx' for 'run' command with appended arguments kubectl alpha kuberc set --section aliases --name runx --command run --option image=nginx --appendarg "--" --appendarg custom-arg1 # Overwrite an existing default kubectl alpha kuberc set --section defaults --command get --option output=json --overwrite Options --appendarg strings Argument to append to the command (can be specified multiple times, for aliases only)