test_runner: propagate config via attach_hook for test fix (#11529)

## Problem

The `pagebench` benchmarks set up an initial dataset by creating a
template tenant, copying the remote storage to a bunch of new tenants,
and attaching them to Pageservers.

In #11420, we found that
`test_pageserver_characterize_throughput_with_n_tenants` had degraded
performance because it set a custom tenant config in Pageservers that
was then replaced with the default tenant config by the storage
controller.

The initial fix was to register the tenants directly in the storage
controller, but this created the tenants with generation 1. This broke
`test_basebackup_with_high_slru_count`, where the template tenant was at
generation 2, leading to all layer files at generation 2 being ignored.

Resolves #11485.
Touches #11381.

## Summary of changes

This patch addresses both test issues by modifying `attach_hook` to also
take a custom tenant config. This allows attaching tenants to
Pageservers from pre-existing remote storage, specifying both the
generation and tenant config when registering them in the storage
controller.

control_plane/src/storage_controller.rs

@@ -13,7 +13,9 @@ use pageserver_api::controller_api::{
     NodeConfigureRequest, NodeDescribeResponse, NodeRegisterRequest, TenantCreateRequest,
     TenantCreateResponse, TenantLocateResponse,
 };
-use pageserver_api::models::{TenantConfigRequest, TimelineCreateRequest, TimelineInfo};
+use pageserver_api::models::{
+    TenantConfig, TenantConfigRequest, TimelineCreateRequest, TimelineInfo,
+};
 use pageserver_api::shard::TenantShardId;
 use pageserver_client::mgmt_api::ResponseErrorMessageExt;
 use postgres_backend::AuthType;
@@ -82,7 +84,8 @@ impl NeonStorageControllerStopArgs {
 pub struct AttachHookRequest {
     pub tenant_shard_id: TenantShardId,
     pub node_id: Option<NodeId>,
-    pub generation_override: Option<i32>,
+    pub generation_override: Option<i32>, // only new tenants
+    pub config: Option<TenantConfig>,     // only new tenants
 }
 
 #[derive(Serialize, Deserialize)]
@@ -805,6 +808,7 @@ impl StorageController {
             tenant_shard_id,
             node_id: Some(pageserver_id),
             generation_override: None,
+            config: None,
         };
 
         let response = self

storage_controller/src/service.rs

@@ -1852,6 +1852,7 @@ impl Service {
         };
 
         if insert {
+            let config = attach_req.config.clone().unwrap_or_default();
             let tsp = TenantShardPersistence {
                 tenant_id: attach_req.tenant_shard_id.tenant_id.to_string(),
                 shard_number: attach_req.tenant_shard_id.shard_number.0 as i32,
@@ -1860,7 +1861,7 @@ impl Service {
                 generation: attach_req.generation_override.or(Some(0)),
                 generation_pageserver: None,
                 placement_policy: serde_json::to_string(&PlacementPolicy::Attached(0)).unwrap(),
-                config: serde_json::to_string(&TenantConfig::default()).unwrap(),
+                config: serde_json::to_string(&config).unwrap(),
                 splitting: SplitState::default(),
                 scheduling_policy: serde_json::to_string(&ShardSchedulingPolicy::default())
                     .unwrap(),
@@ -1883,16 +1884,16 @@ impl Service {
                 Ok(()) => {
                     tracing::info!("Inserted shard {} in database", attach_req.tenant_shard_id);
 
-                    let mut locked = self.inner.write().unwrap();
-                    locked.tenants.insert(
+                    let mut shard = TenantShard::new(
                         attach_req.tenant_shard_id,
-                        TenantShard::new(
-                            attach_req.tenant_shard_id,
-                            ShardIdentity::unsharded(),
-                            PlacementPolicy::Attached(0),
-                            None,
-                        ),
+                        ShardIdentity::unsharded(),
+                        PlacementPolicy::Attached(0),
+                        None,
                     );
+                    shard.config = config;
+
+                    let mut locked = self.inner.write().unwrap();
+                    locked.tenants.insert(attach_req.tenant_shard_id, shard);
                     tracing::info!("Inserted shard {} in memory", attach_req.tenant_shard_id);
                 }
             }
@@ -1977,11 +1978,12 @@ impl Service {
             .set_attached(scheduler, attach_req.node_id);
 
         tracing::info!(
-            "attach_hook: tenant {} set generation {:?}, pageserver {}",
+            "attach_hook: tenant {} set generation {:?}, pageserver {}, config {:?}",
             attach_req.tenant_shard_id,
             tenant_shard.generation,
             // TODO: this is an odd number of 0xf's
-            attach_req.node_id.unwrap_or(utils::id::NodeId(0xfffffff))
+            attach_req.node_id.unwrap_or(utils::id::NodeId(0xfffffff)),
+            attach_req.config,
         );
 
         // Trick the reconciler into not doing anything for this tenant: this helps

test_runner/fixtures/neon_fixtures.py

@@ -1986,10 +1986,13 @@ class NeonStorageController(MetricsGetter, LogUtils):
         tenant_shard_id: TenantId | TenantShardId,
         pageserver_id: int,
         generation_override: int | None = None,
+        config: None | dict[str, Any] = None,
     ) -> int:
         body = {"tenant_shard_id": str(tenant_shard_id), "node_id": pageserver_id}
         if generation_override is not None:
             body["generation_override"] = generation_override
+        if config is not None:
+            body["config"] = config
 
         response = self.request(
             "POST",
@@ -2980,11 +2983,12 @@ class NeonPageserver(PgProtocol, LogUtils):
         to call into the pageserver HTTP client.
         """
         client = self.http_client()
-        if generation is None:
-            generation = self.env.storage_controller.attach_hook_issue(tenant_id, self.id)
-        elif override_storage_controller_generation:
+        if generation is None or override_storage_controller_generation:
             generation = self.env.storage_controller.attach_hook_issue(
-                tenant_id, self.id, generation
+                tenant_id,
+                self.id,
+                generation_override=generation if override_storage_controller_generation else None,
+                config=config,
             )
         return client.tenant_attach(
             tenant_id,

test_runner/fixtures/pageserver/many_tenants.py

@@ -65,13 +65,11 @@ def single_timeline(
     assert ps_http.tenant_list() == []
 
     def attach(tenant):
-        # NB: create the new tenant in the storage controller with the correct tenant config. This
-        # will pick up the existing tenant data from remote storage. If we just attach it to the
-        # Pageserver, the storage controller will reset the tenant config to the default.
-        env.create_tenant(
-            tenant_id=tenant,
-            timeline_id=template_timeline,
-            conf=template_config,
+        env.pageserver.tenant_attach(
+            tenant,
+            config=template_config,
+            generation=100,
+            override_storage_controller_generation=True,
         )
 
     with concurrent.futures.ThreadPoolExecutor(max_workers=22) as executor:

test_runner/performance/pageserver/pagebench/test_large_slru_basebackup.py

@@ -66,11 +66,11 @@ def test_basebackup_with_high_slru_count(
 
     n_txns = 500000
 
-    def setup_wrapper(env: NeonEnv):
-        return setup_tenant_template(env, n_txns)
-
     env = setup_pageserver_with_tenants(
-        neon_env_builder, f"large_slru_count-{n_tenants}-{n_txns}", n_tenants, setup_wrapper
+        neon_env_builder,
+        f"large_slru_count-{n_tenants}-{n_txns}",
+        n_tenants,
+        lambda env: setup_tenant_template(env, n_txns),
     )
     run_benchmark(env, pg_bin, record, duration)
 
@@ -80,10 +80,6 @@ def setup_tenant_template(env: NeonEnv, n_txns: int):
         "gc_period": "0s",  # disable periodic gc
         "checkpoint_timeout": "10 years",
         "compaction_period": "0s",  # disable periodic compaction
-        "compaction_threshold": 10,
-        "compaction_target_size": 134217728,
-        "checkpoint_distance": 268435456,
-        "image_creation_threshold": 3,
     }
 
     template_tenant, template_timeline = env.create_tenant(set_default=True)