Update JAX integration proposal (kubeflow#2165)

Signed-off-by: Sandipan Panda <samparksandipan@gmail.com>
Signed-off-by: yelias <yossi.elias@nokia.com>

docs/proposals/jax-integration.md

@@ -76,14 +76,12 @@ As a DevOps engineer, I want to manage JAX distributed training jobs using the K
 
 ##### Key Validations
 
-1. **Coordinator Role Validation**:
-   - Ensure exactly one Coordinator role with `processId` set to `0` and its `replicas` is set to `1`.
-2. **Worker Role Validation**:
-   - Ensure at least one Worker replica.
-   - Ensure the `replicas` field for each role is greater than `0`.
-3. **JAX Parameters Validation**:
+1. **Worker Role Validation**:
+   - Ensure at least one Worker replica with `processId` set to `0` that will work as coordinator.
+   - Ensure the `replicas` field is greater than `0`.
+2. **JAX Parameters Validation**:
    - Ensure `coordinatorAddress`, `numProcesses`, and `processId` are set and valid across all roles.
-4. **Pod Specification Validation**:
+3. **Pod Specification Validation**:
    - Ensure necessary container specifications and `restartPolicy` are correctly set.
    - Validate `coordinatorAddress` follows the `host:port` format.
 
@@ -100,14 +98,6 @@ metadata:
   name: example-jaxjob
 spec:
   jaxReplicaSpecs:
-    Coordinator:
-      replicas: 1
-      restartPolicy: OnFailure
-      template:
-        spec:
-          containers:
-            - name: jax-coordinator
-              image: ghcr.io/kubeflow/jax:latest
     Worker:
       replicas: 1
       restartPolicy: OnFailure
@@ -158,8 +148,6 @@ const (
 	JAXJobSingular = "jaxjob"
 	// JAXJobFrameworkName is the name of the ML Framework
 	JAXJobFrameworkName = "jax"
-	// JAXJobReplicaTypeCoordinator is the type of Coordinator of distributed JAX
-	JAXJobReplicaTypeCoordinator ReplicaType = "Coordinator"
 	// JAXJobReplicaTypeWorker is the type for workers of distributed JAX.
 	JAXJobReplicaTypeWorker ReplicaType = "Worker"
 )
@@ -199,7 +187,6 @@ type JAXJobSpec struct {
 	// A map of JAXReplicaType (type) to ReplicaSpec (value). Specifies the JAX cluster configuration.
 	// For example,
 	//   {
-	//     "Coordinator": JAXReplicaSpec,
 	//     "Worker": JAXReplicaSpec,
 	//   }
 	JAXReplicaSpecs map[ReplicaType]*ReplicaSpec `json:"jaxReplicaSpecs"`
@@ -223,48 +210,10 @@ type JAXJobList struct {
 
 func init() {
 	SchemeBuilder.Register(&JAXJob{}, &JAXJobList{})
-	SchemeBuilder.SchemeBuilder.Register(addJAXJobDefaultingFuncs)
+	SchemeBuilder.SchemeBuilder.Register(addJAXDefaultingFuncs)
 }
 
 ```
-##### Resulting Coordinator
-```yaml
-apiVersion: v1
-kind: Service
-metadata:
-  name: jax-coordinator
-spec:
-  selector:
-    app: jax-coordinator
-  ports:
-  - port: 6666
-    targetPort: 6666
-```
-```yaml
-apiVersion: v1
-kind: Pod
-metadata:
-  name: jax-coordinator
-  labels:
-    app: jax-coordinator
-spec:
-  containers:
-  - image: ghcr.io/kubeflow/jax:latest
-    imagePullPolicy: IfNotPresent
-    name: coordinator
-    env:
-    - name: JAX_COORDINATOR_ADDRESS
-      value: '127.0.0.1:6666'
-    - name: JAX_NUM_PROCESSES
-      value: 1
-    - name: JAX_PROCESS_ID
-      value: 0
-        # process 0 is coordinator
-    ports:
-      - name: coordinatorPort
-        containerPort: 6666
-  restartPolicy: OnFailure
-```
 
 ##### Resulting Worker
 
@@ -290,7 +239,8 @@ spec:
     - name: JAX_NUM_PROCESSES
       value: 1
     - name: JAX_PROCESS_ID
-      value: 1
+      value: 0
+      # process 0 is coordinator
   restartPolicy: OnFailure
 
 ```