--- title: "Introduction to kubectl" content_type: concept weight: 1 --- kubectl is the Kubernetes cli version of a swiss army knife, and can do many things. While this Book is focused on using kubectl to declaratively manage applications in Kubernetes, it also covers other kubectl functions. ## Command Families Most kubectl commands typically fall into one of a few categories: | Type | Used For | Description | |----------------------------------------|----------------------------|----------------------------------------------------| | Declarative Resource Management | Deployment and operations (e.g. GitOps) | Declaratively manage Kubernetes workloads using resource configuration | | Imperative Resource Management | Development Only | Run commands to manage Kubernetes workloads using Command Line arguments and flags | | Printing Workload State | Debugging | Print information about workloads | | Interacting with Containers | Debugging | Exec, attach, cp, logs | | Cluster Management | Cluster operations | Drain and cordon Nodes | ## Declarative Application Management The preferred approach for managing resources is through declarative files called resource configuration used with the kubectl *Apply* command. This command reads a local (or remote) file structure and modifies cluster state to reflect the declared intent. {{< alert color="success" title="Apply" >}} Apply is the preferred mechanism for managing resources in a Kubernetes cluster. {{< /alert >}} ## Printing State about Workloads Users will need to view workload state. - Printing summarize state and information about resources - Printing complete state and information about resources - Printing specific fields from resources - Query resources matching labels ## Debugging Workloads kubectl supports debugging by providing commands for: - Printing Container logs - Printing cluster events - Exec or attaching to a Container - Copying files from Containers in the cluster to a user's filesystem ## Cluster Management On occasion, users may need to perform operations to the Nodes of cluster. kubectl supports commands to drain workloads from a Node so that it can be decommissioned or debugged. ## Porcelain Users may find using resource configuration overly verbose for *development* and prefer to work with the cluster *imperatively* with a shell-like workflow. kubectl offers porcelain commands for generating and modifying resources. - Generating + creating resources such as Deployments, StatefulSets, Services, ConfigMaps, etc. - Setting fields on resources - Editing (live) resources in a text editor {{< alert color="warning" title="Porcelain for Dev Only" >}} Porcelain commands are time saving for experimenting with workloads in a dev cluster, but shouldn't be used for production. {{< /alert >}}