Alternatives for deprecated 'kubectl run' commands

Written by: Karim AMMOUS (LinkedIn). Date: Sept 30, 2019 · 5 min read

kubectl run command is a convenient and useful way to quickly create kubernetes resources without dealing with yaml files. Since kubernetes v1.12, creation acknowledgment (“object created”) is preceded by a message noting that this creation command is deprecated and will no longer be available in future kubectl releases.

Indeed, we can create some “runnable” resources like Pods and Deployments (the complete list) using kubectl run command by setting the --generator flag with the appropriate value. However, those generators have been deprecated since v1.12 except ‘run-pod/v1’ generator.

The above deprecation covers --restart flags as well. Like --generator flag, they are also used to set generator.

Source: kubernetes.io

This post aims to list available alternatives in latest available kubernetes version at the time of writing which is v1.15.4 for both client and server.

Pod

There is no deprecation for Pod creation. We have two options to create a Pod. You can either use --restart or --generator flags.

kubectl run nginx --restart=Never --image=nginx 

AND

kubectl run nginx --generator=run-pod/v1 --image=nginx

Deployment

Deprecated command:

kubectl run nginx --restart=Always --image=nginx

Returned message:

kubectl run --generator=deployment/apps.v1 is DEPRECATED and will be removed in a future version. Use kubectl run --generator=run-pod/v1 or kubectl create instead.
deployment.apps/nginx created

It talks about two alternatives. Only the kubectl create command works as expected and generates a Deployment resource.

“Create” command alternative

kubectl create deployment nginx --image=nginx 

Please note that by moving to kubectl create command, we are losing the ability to fully customize generated Deployment. For example, it is no longer possible to define replicas (--replicas option), resources (--requests and --limits options) or implicitly create an associated Service with --expose option.

Job

Deprecated command:

kubectl run my-job --image=busybox --restart=OnFailure

Alternative command:

kubectl create job my-job --image=busybox -- date

Cronjob

Deprecated command:

kubectl run pi --schedule="0/5 * * * ?" --image=perl --restart=OnFailure -- perl -Mbignum=bpi -wle 'print bpi(2000)'

Alternative command:

kubectl create cronjob pi --image=perl --schedule="0/5 * * * ?"  -- perl -Mbignum=bpi -wle 'print bpi(2000)'