feldera · snkas · Jun 2, 2026 · Jun 1, 2026
diff --git a/crates/pipeline-manager/src/db/operations/pipeline.rs b/crates/pipeline-manager/src/db/operations/pipeline.rs
@@ -449,6 +449,16 @@ pub(crate) async fn update_pipeline(
             {
                 not_allowed.push("`runtime_config.resources.namespace`");
             }
+            if runtime_config
+                .get("resources")
+                .map(|v| v.get("storage_class"))
+                != current
+                    .runtime_config
+                    .get("resources")
+                    .map(|v| v.get("storage_class"))
+            {
+                not_allowed.push("`runtime_config.resources.storage_class`");
+            }
         }
 
         if !not_allowed.is_empty() {

diff --git a/crates/pipeline-manager/src/db/test.rs b/crates/pipeline-manager/src/db/test.rs
@@ -3912,8 +3912,11 @@ impl ModelHelpers for Mutex<DbModel> {
                 if runtime_config.get("workers") != pipeline.runtime_config.get("workers") {
                     not_allowed.push("`runtime_config.workers`");
                 }
-                if runtime_config.get("storage") != pipeline.runtime_config.get("storage") {
-                    not_allowed.push("`runtime_config.storage`");
+                let one = json!(1);
+                if runtime_config.get("hosts").unwrap_or(&one)
+                    != pipeline.runtime_config.get("hosts").unwrap_or(&one)
+                {
+                    not_allowed.push("`runtime_config.hosts`");
                 }
                 if runtime_config.get("fault_tolerance")
                     != pipeline.runtime_config.get("fault_tolerance")
@@ -3930,24 +3933,24 @@ impl ModelHelpers for Mutex<DbModel> {
                 {
                     not_allowed.push("`runtime_config.resources.storage_mb_max`");
                 }
-            }
-            if program_code
-                .as_ref()
-                .is_some_and(|v| *v != pipeline.program_code)
-            {
-                not_allowed.push("`program_code`")
-            }
-            if udf_rust.as_ref().is_some_and(|v| *v != pipeline.udf_rust) {
-                not_allowed.push("`udf_rust`")
-            }
-            if udf_toml.as_ref().is_some_and(|v| *v != pipeline.udf_toml) {
-                not_allowed.push("`udf_toml`")
-            }
-            if program_config
-                .as_ref()
-                .is_some_and(|v| *v != pipeline.program_config)
-            {
-                not_allowed.push("`program_config`")
+                if runtime_config.get("resources").map(|v| v.get("namespace"))
+                    != pipeline
+                        .runtime_config
+                        .get("resources")
+                        .map(|v| v.get("namespace"))
+                {
+                    not_allowed.push("`runtime_config.resources.namespace`");
+                }
+                if runtime_config
+                    .get("resources")
+                    .map(|v| v.get("storage_class"))
+                    != pipeline
+                        .runtime_config
+                        .get("resources")
+                        .map(|v| v.get("storage_class"))
+                {
+                    not_allowed.push("`runtime_config.resources.storage_class`");
+                }
             }
             if !not_allowed.is_empty() {
                 return Err(DBError::EditRestrictedToClearedStorage {

diff --git a/docs.feldera.com/docs/changelog.md b/docs.feldera.com/docs/changelog.md
@@ -14,6 +14,8 @@ import TabItem from '@theme/TabItem';
 
         ## Unreleased
 
+        - No longer allowed to edit `runtime_config.resources.storage_class` if the pipeline storage is not cleared.
+
         - Calling `/start` on a pipeline that already failed to compile will directly return an error instead of
           the runner later on setting the `deployment_error` during its check whether to proceed to provisioning.
 

diff --git a/docs.feldera.com/docs/pipelines/configuration.mdx b/docs.feldera.com/docs/pipelines/configuration.mdx
@@ -51,6 +51,19 @@ Make sure to appropriately size resource limits (memory and storage), the number
 <ApiSchema pointer="#/components/schemas/RuntimeConfig"/>
 </div>
 
+#### Runtime configuration edit restrictions
+
+The runtime configuration cannot be edited at all if the pipeline is not stopped.
+
+If the pipeline is stopped, but its storage has not been cleared, the following runtime configuration fields cannot be
+edited:
+- `workers`
+- `hosts`
+- `fault_tolerance`
+- `resources.storage_mb_max`
+- `resources.namespace`
+- `resources.storage_class`
+
 ### Program configuration
 
 The "optimized" compilation profile (default) should be used when running production pipelines where performance is important.

diff --git a/python/tests/platform/test_pipeline_lifecycle.py b/python/tests/platform/test_pipeline_lifecycle.py
@@ -691,44 +691,124 @@ def test_refresh_version_due_to_status_changes(pipeline_name):
     )
 
 
-@gen_pipeline_name
-def test_resources_namespace_edit_needs_cleared_storage(pipeline_name):
-    pipeline = PipelineBuilder(TEST_CLIENT, pipeline_name, "").create_or_replace()
+def helper_test_restricted_runtime_config_edit(
+    pipeline_name, pipeline, field, edit, retrieve, new_value
+):
     pipeline.start()
     pipeline.stop(force=True)
 
     # Attempt to patch without cleared storage will fail
-    runtime_config = TEST_CLIENT.http.get(f"/pipelines/{pipeline_name}?selector=all")[
-        "runtime_config"
-    ]
-    runtime_config["resources"]["namespace"] = "example"
+    runtime_config: dict = TEST_CLIENT.http.get(
+        f"/pipelines/{pipeline_name}?selector=all"
+    )["runtime_config"]
+    runtime_config.update(edit)
     error = None
     try:
         TEST_CLIENT.patch_pipeline(name=pipeline_name, runtime_config=runtime_config)
     except FelderaAPIError as e:
         error = e
-    assert (
-        error is not None
-        and error.error_code == "EditRestrictedToClearedStorage"
-        and error.details["not_allowed"] == ["`runtime_config.resources.namespace`"]
+    assert error is not None, f"assert failed for: {field} -- error was: {error}"
+    assert error.error_code == "EditRestrictedToClearedStorage", (
+        f"assert failed for: {field} -- error was: {error}"
     )
-    assert (
-        TEST_CLIENT.http.get(f"/pipelines/{pipeline_name}?selector=all")[
-            "runtime_config"
-        ]["resources"]["namespace"]
-        is None
+    assert error.details["not_allowed"] == [field], (
+        f"assert failed for: {field} -- error was: {error}"
     )
+    assert (
+        retrieve(
+            TEST_CLIENT.http.get(f"/pipelines/{pipeline_name}?selector=all")[
+                "runtime_config"
+            ]
+        )
+        != new_value
+    ), f"assert failed for: {field}"
 
     # Clear storage
     pipeline.clear_storage()
 
     # After clearing storage, it should work
     TEST_CLIENT.patch_pipeline(name=pipeline_name, runtime_config=runtime_config)
     assert (
-        TEST_CLIENT.http.get(f"/pipelines/{pipeline_name}?selector=all")[
-            "runtime_config"
-        ]["resources"]["namespace"]
-        == "example"
+        retrieve(
+            TEST_CLIENT.http.get(f"/pipelines/{pipeline_name}?selector=all")[
+                "runtime_config"
+            ]
+        )
+        == new_value
+    ), f"assert failed for: {field}"
+
+    # Clear runtime config for the next field to test
+    TEST_CLIENT.patch_pipeline(name=pipeline_name, runtime_config={})
+
+
+@gen_pipeline_name
+def test_runtime_config_edit_restricted(pipeline_name):
+    pipeline = PipelineBuilder(TEST_CLIENT, pipeline_name, "").create_or_replace()
+
+    # runtime_config.workers
+    helper_test_restricted_runtime_config_edit(
+        pipeline_name,
+        pipeline,
+        "`runtime_config.workers`",
+        {"workers": 16},
+        lambda r: r["workers"],
+        16,
+    )
+
+    # runtime_config.resources.storage_mb_max
+    helper_test_restricted_runtime_config_edit(
+        pipeline_name,
+        pipeline,
+        "`runtime_config.resources.storage_mb_max`",
+        {"resources": {"storage_mb_max": 10000}},
+        lambda r: r["resources"]["storage_mb_max"],
+        10000,
+    )
+
+    # runtime_config.resources.namespace
+    helper_test_restricted_runtime_config_edit(
+        pipeline_name,
+        pipeline,
+        "`runtime_config.resources.namespace`",
+        {"resources": {"namespace": "example"}},
+        lambda r: r["resources"]["namespace"],
+        "example",
+    )
+
+    # runtime_config.resources.storage_class
+    helper_test_restricted_runtime_config_edit(
+        pipeline_name,
+        pipeline,
+        "`runtime_config.resources.storage_class`",
+        {"resources": {"storage_class": "example"}},
+        lambda r: r["resources"]["storage_class"],
+        "example",
+    )
+
+
+@gen_pipeline_name
+@enterprise_only
+def test_runtime_config_edit_restricted_enterprise(pipeline_name):
+    pipeline = PipelineBuilder(TEST_CLIENT, pipeline_name, "").create_or_replace()
+
+    # runtime_config.hosts
+    helper_test_restricted_runtime_config_edit(
+        pipeline_name,
+        pipeline,
+        "`runtime_config.hosts`",
+        {"hosts": 2},
+        lambda r: r["hosts"],
+        2,
+    )
+
+    # runtime_config.fault_tolerance
+    helper_test_restricted_runtime_config_edit(
+        pipeline_name,
+        pipeline,
+        "`runtime_config.fault_tolerance`",
+        {"fault_tolerance": {"model": "exactly_once", "checkpoint_interval_secs": 60}},
+        lambda r: r["fault_tolerance"],
+        {"model": "exactly_once", "checkpoint_interval_secs": 60},
     )