Add ready field to Job status

to keep a count of the pods that have the ready condition.

Also:
- Add feature gate JobReadyPods.
- Add Ready to describe.

Change-Id: Ib934730a430a8e2a2f485671e345fe2330006939

api/openapi-spec/swagger.json

@@ -3633,7 +3633,7 @@
       "description": "JobStatus represents the current state of a Job.",
       "properties": {
         "active": {
-          "description": "The number of actively running pods.",
+          "description": "The number of pending and running pods.",
           "format": "int32",
           "type": "integer"
         },
@@ -3660,6 +3660,11 @@
           "format": "int32",
           "type": "integer"
         },
+        "ready": {
+          "description": "The number of pods which have a Ready condition.\n\nThis field is alpha-level. The job controller populates the field when the feature gate JobReadyPods is enabled (disabled by default).",
+          "format": "int32",
+          "type": "integer"
+        },
         "startTime": {
           "$ref": "#/definitions/io.k8s.apimachinery.pkg.apis.meta.v1.Time",
           "description": "Represents time when the job controller started processing a job. When a Job is created in the suspended state, this field is not set until the first time it is resumed. This field is reset every time a Job is resumed from suspension. It is represented in RFC3339 form and is in UTC."