I'm using kubectl run
with environment parameters to create temporary docker containers for me (e.g. some forwarding for debugging purposes). Since several weeks kubectl
is complaining about kubectl run
being deprecated. Unfortunately I can't find an appropriate replacement.
This is the old command:
$KUBECTL run -i -t --attach=false --image djfaze/port-forward --env="REMOTE_HOST=$REMOTE_HOST" --env="REMOTE_PORT=$REMOTE_PORT" $POD_NAME
When issuing this, kubectl
complains with this message:
kubectl run --generator=deployment/apps.v1beta1
is DEPRECATED and will be removed in a future version. Use kubectl create instead.
Any ideas how to replace this run command?
As the author of the problem let me explain a little bit the intention behind this deprecation. Just like Brendan explains in his answer, kubectl run
per se is not being deprecated, only all the generators, except for the one that creates a Pod for you.
The reason for this change is two folds:
The vast majority of input parameters for kubectl run
command is overwhelming for newcomers, as well as for the old timers. It's not that easy to figure out what will be the result of your invocation. You need to take into consideration several passed options as well as the server version.
The code behind it is also a mess to maintain given the matrix of possibilities is growing faster than we can handle.
That's why we're trying to move people away from using kubectl run
for their daily workflows and convince them that using explicit kubectl create
commands is more straightforward. Finally, we want to make the newcomers that played with docker or any other container engine, where they run a container, to have the same experience with Kubernetes where kubectl run
will just run a Pod in a cluster.
Sorry for the initial confusion and I hope this will clear things up.
UPDATE (2020/01/10): As of https://github.com/kubernetes/kubernetes/pull/87077 kubectl run
will ONLY create Pods. All generators will be removed entirely.
you can use:
kubectl run --generator=run-pod/v1 --image=busybox busybox --dry-run --env=foo=bar
Which isn't being deprecated.
kubectl run
by default, will create a Deployment.
The command in its full extend is:
kubectl run --generator=deployment/apps.v1 <deployment_name> --image=<image_to_use_in_the_container_of_the_deployment's_pod>
So the kubernetes
resource that will be created upon execution of the run
command is defined by the value of the --generator
flag.
What the deprecation message hints (and is also clarified by the answer provided by @soltysh) is that the particular practice will be removed.
So in future kubernetes
versions, the run
command will by default (and as only option) create pods (and not deployments), i.e. the command in its full extend will become:
kubectl run --generator=run-pod/v1 <pod_name> --image=<image_of_the_container_of_the_pod>
In case you want to create any other kubernetes
resource type, this will be impossible via run
command so you will have to resort to explicit imperative create
or declarative apply -f
, the later pointing to kubernetes
yml
files with the corresponding resource defintition, as in
kubernetes apply -f <yaml_file_with_my_deployment.yml>
I noticed that running the following command WITHOUT specifying the generator parameter:
kubectl run <name> --image=<image>
It returns this error:
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.
What's very confusing about this message is that you never specified the --generator parameter in the first place. However the main point here is to explicitly specify the generator as directed by the error message as follows:
kubectl run --generator=run-pod/v1 <name> --image=<image>
Then it should run successfully. (they should have just defaulted the generator to run-pod/v1 to avoid this confusion and/or just encouraged the use of create).
However, based on @soltysh answer, it sounds as if they are now recommending 'create' over 'run.'
To run a pod, this simple command is enough:
kubectl run --restart=Never <name> --image=<image>
Check https://www.k8s-school.fr/resources/blog/1-kubectl-run-deprecated/#pod for additional informations.
When you run
kubectl run <name> --image=<image> --port=<port>
You are implicitly running
kubectl run --generator=deployment/apps.v1 run <name> --image=<image> --port=<port>
Which tells kubernetes what resource it needs to generate
It is quite overwhelming to deal with such a variety of parameters with run
Hence, as of v1.15 and greater, all --generators apart from run-pod are deprecated.
See the table below
Pod v1 kubectl run --generator=run-pod/v1
ReplicationController (deprecated) v1 kubectl run --generator=run/v1
Deployment (deprecated) extensions/v1beta1 kubectl run --generator=deployment/v1beta1
Deployment (deprecated) apps/v1beta1 kubectl run --generator=deployment/apps.v1beta1
Job (deprecated) batch/v1 kubectl run --generator=job/v1
CronJob (deprecated) batch/v2alpha1 kubectl run --generator=cronjob/v2alpha1
CronJob (deprecated) batch/v1beta1 kubectl run --generator=cronjob/v1beta1
Solution is to either use create
or apply -f
. The latter uses a yml file.
Like the message said, you should use kubectl create
. Just define a minimal pod yaml definition and use kubectl create -f mypod.yml