Little cheatsheet about k8s and useful aliases.

Cheatsheet

Here are some useful commands and aliases to manipulate k8s more easily

The basics

The basics aliases

alias k=kubectl

Switch contexts (mainly clusters)

alias kprod='kubectl config use-context production_cluster_name'

alias knprod='kubectl config use-context non_production_cluster_name'

alias kcontext='kubectl config use-context'

USAGE : ‘kcontext non_production_cluster_name’ # switch to non production cluster

Switch namespaces (dev / lqt / indus / …)

alias kns='kubectl config set-context --current --namespace'

USAGE : kns my_namespace # switch to your namespace

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Useful commands

k <some_commands> -n atidgbl1

-n is used to specify a namespace on which run the command.

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List, describe resources

k get <resource_type>

USAGE : get is useful with | grep <service_name>

example : k get pod | grep grafana

k describe <resource_type> <resource_name>

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Get logs

k logs <pod_name>

k logs -f <pod_name>

Follow the pod’s logs

k logs --since 15m -f <pod_name>

Follow the pod’s logs and display the last 15 minuts

Can be used with a lot of other options cf : k logs --help

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Manipulate resources

k rollout restart <resource_type> <resource_name>

It will restart each pod (one by one) under the given resource_name (must be a deployment, statefulset or daemonset).

k delete <resource_type> <resource_name>

It will delete the resource identified, only the pod will be recreated if managed by a Deployment, a StatefulSet or a DaemonSet.

k edit <resource_type> <resource_name>

It will edit the resource identified, the resource can be recreated if necessary

k scale <resource_type> <resource_name> --replicas=X

It will scale up / down the number of pods managed by the resources. <resource_type> can be one of the following : Deployment, ReplicaSet, StatefulSet (resources that manage pods)

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Troubleshooting commands

k get

k describe

k logs

In addition of these 3 usefull commands you can interact directly with the pod itself.

k top pod <pod_name>

It will display the current use of resources of a pod (CPU & RAM)

k exec -it <pod_name> -- bash

Open a bash in the pod (thanks to the -it for interactive mode), if bash is installed on the pod (not in most ULTIM microservices)

k exec <pod_name> -- ls

Used to run a single command in a terminal.

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Make your own aliases

create a file in your personal folder (aka ~ folder) and source it in your bashrc

vim ~/.aliases

put your aliases in it like alias k='kubectl'

then vim ~/.bashrc

source your alias file on top of this file like source ~/.aliases

open a new bash (to reload the bashrc file again) and enjoy your aliases.

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The real Cheatsheet

Kubernetes cheatsheet