OpenShift : Error from server (NotAcceptable): unknown (get pods)

Problem

When I was working with OpenShift Origin A.K.A OKD (The Community Distribution of Kubernetes) , I had to controll and manage OpenShift cluster using oc (OpenShift Client Tools) a command line tool to interact with OpenShift cluster from your local computer.

I downloaded oc tool from OpenShift Github’s release page and started working , everything went well , I was able to login to cluster , get projects etc.,

And when I did oc get pods to list all pods in my current project , BOOM! I ran into this error.

NAVMUTHU-M-C2SD:Desktop navmuthu$ oc get deployments
Error from server (NotAcceptable): unknown (get deployments.extensions)
NAVMUTHU-M-C2SD:Desktop navmuthu$ oc get deployment
Error from server (NotAcceptable): unknown (get deployments.extensions)
NAVMUTHU-M-C2SD:Desktop navmuthu$ oc get routes
Error from server (NotAcceptable): unknown (get routes.route.openshift.io)
NAVMUTHU-M-C2SD:Desktop navmuthu$ oc get pods
Error from server (NotAcceptable): unknown (get pods)

Reason

oc tool was responding with proper results only until I tried oc get pods , Now I understood all the commands I executed before that were related to OpenShift alone . oc get pods is kubernetes command , similar to (or show I exactly same) kubectl get pods. If you don’t know , OpenShift is built on top of kubernetes , with lot more added on to that.

So , not only get pods didn’t work all that called kubectl in background didn’t work. Couple of google searches got me to the reason. There is a version mismatch between server and client of OpenShift origin and oc cli , which also means kubernetes and kubectl version didn’t match up.

NAVMUTHU-M-C2SD:Desktop navmuthu$ oc version
Client Version: version.Info{Major:"4", Minor:"1+", GitVersion:"v4.1.0+b4261e0", GitCommit:"b4261e07ed", GitTreeState:"clean", BuildDate:"2019-10-06T23:21:44Z", GoVersion:"go1.13.1", Compiler:"gc", Platform:"darwin/amd64"}
Server Version: version.Info{Major:"1", Minor:"7", GitVersion:"v1.7.6+a08f5eeb62", GitCommit:"c84beff", GitTreeState:"clean", BuildDate:"2018-04-11T21:18:09Z", GoVersion:"go1.9.2", Compiler:"gc", Platform:"linux/amd64"}

Solution

Upgrade or downgrade your oc client to match OpenShift server version.

1.Go to OpenShift Web Consoel and know your OpenShift Origin (or OKD) Server version On Right Top corner click on About

2.Go to OpenShift Origin Release page and find the Release with matching version and download the binary. Releases

3.Install binary according to your OS , Refer Installation Guide For Mac , just unzip the tar file and move oc binary to your $PATH

NAVMUTHU-M-C2SD:Desktop navmuthu$ cd ~/Downloads/
NAVMUTHU-M-C2SD:Downloads navmuthu$ cd openshift-origin-client-tools-v3.7.2-282e43f-mac
NAVMUTHU-M-C2SD:openshift-origin-client-tools-v3.7.2-282e43f-mac navmuthu$ ls
LICENSE        README.md    oc
NAVMUTHU-M-C2SD:openshift-origin-client-tools-v3.7.2-282e43f-mac navmuthu$ mv oc /usr/local/bin/

4.Verify your version match after logining to your OpenShift cluster

navmuthu$ oc login

Provide credentials when prompted

NAVMUTHU-M-C2SD:Desktop navmuthu$ oc version
oc v3.7.2+282e43f
kubernetes v1.7.6+a08f5eeb62
features: Basic-Auth

Server https://bpa-rhela:8443
openshift v3.7.2+cd74924-1
kubernetes v1.7.6+a08f5eeb62

Now we see that kubernetes version matches

With this oc get commands should work

NAVMUTHU-M-C2SD:Desktop navmuthu$ oc get pods
NAME                                      READY     STATUS      RESTARTS   AGE
auth-service-2895175585-mkrdn             1/1       Running     0          10d