Description of problem:

In the Chapter Exposing the service by creating a route the Step 3.

oc expose service nodejs-ex  --type=NodePort --name=nodejs-ex-nodeport --generator="service/v2" 

cannot be done with the --generator option if the oc client version is 4.12:

$ oc get clusterversions.config.openshift.io 
NAME      VERSION   AVAILABLE   PROGRESSING   SINCE   STATUS
version   4.12.2    True        False         2d     Cluster version is 4.12.2

$ oc get svc 
NAME        TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)    AGE
nodejs-ex   ClusterIP   172.30.225.50   <none>        8080/TCP   78s

$ oc expose service nodejs-ex  --type=NodePort --name=nodejs-ex-nodeport --generator="service/v2"
error: unknown flag: --generator
See 'oc expose --help' for usage.

Managing a cluster of a certain version should be done with the same version of the oc client. So, for an OCP version 4.12 you could not  use  the --generator option of the $ oc expose command.

Our recommendation is to change the steps to configure NodePort Service resource to expose a service in Exposing the service by creating a route . There are two possible options to configure NodePort Service resource to expose a service (cf. RHOCP 4 Unable to expose service via NodePort..) :

1. By editing the service definition to specify spec.type:NodePort and optionally specify a port in the 30000-32767 range: 

   $ oc get svc
   NAME    TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)             AGE
               httpd   ClusterIP   172.xx.xx.xx    <none>        8080/TCP,8443/TCP   41s            
   
   $ oc edit svc httpd
               spec:
                 ...
                 ports:
                 - name: 8080-tcp
                   nodePort: 30546
                   port: 8080
                   protocol: TCP
                   targetPort: 8080
                 - name: 8443-tcp
                   nodePort: 30327
                   port: 8443
                   protocol: TCP
                   targetPort: 8443
                 sessionAffinity: None
                 type: NodePort            
   
   $ oc get svc
   NAME    TYPE       CLUSTER-IP      EXTERNAL-IP   PORT(S)                         AGE
   httpd   NodePort   172.xx.xx.xx    <none>        8080:30546/TCP,8443:30327/TCP   109s 

1. By exposing the deployment:

   $ oc get deploy
   NAME     READY   UP-TO-DATE   AVAILABLE   AGE
   httpd    1/1     1            1           6s            
   
   $ oc expose deployment/httpd --type=NodePort --name=httpd
   service/httpd exposed            
   
   $ oc get svc
   NAME     TYPE       CLUSTER-IP       EXTERNAL-IP   PORT(S)                         AGE
    httpd    NodePort   172.xx.xx.xx     <none>   8080:30287/TCP,8443:30163/TCP   5s 

Version-Release number of selected component (if applicable):

4.12