Addressing review comments

Author: kumar-shivam-ranjan

ads/aqua/config/container_config.py

@@ -15,6 +15,7 @@
     UNKNOWN_JSON_STR,
 )
 from ads.common.extended_enum import ExtendedEnum
+from ads.common.utils import UNKNOWN
 
 
 class Usage(ExtendedEnum):
@@ -189,10 +190,28 @@ def from_service_config(
                 container_item.model_formats.append(
                     additional_configurations.get("modelFormats")
                 )
-                env_vars_dict = json.loads(
-                    additional_configurations.get("env_vars") or "{}"
-                )
-                env_vars = [{key: str(value)} for key, value in env_vars_dict.items()]
+
+                if additional_configurations.get("env_vars", None):
+                    env_vars_dict = json.loads(
+                        additional_configurations.get("env_vars") or "{}"
+                    )
+                    env_vars = [
+                        {key: str(value)} for key, value in env_vars_dict.items()
+                    ]
+                else:
+                    config_keys = {
+                        "MODEL_DEPLOY_PREDICT_ENDPOINT": UNKNOWN,
+                        "MODEL_DEPLOY_HEALTH_ENDPOINT": UNKNOWN,
+                        "PORT": UNKNOWN,
+                        "HEALTH_CHECK_PORT": UNKNOWN,
+                        "VLLM_USE_V1": UNKNOWN,
+                    }
+
+                    env_vars = [
+                        {key: additional_configurations.get(key, default)}
+                        for key, default in config_keys.items()
+                        if key in additional_configurations
+                    ]
 
                 # Build container spec
                 container_item.spec = AquaContainerConfigSpec(