storage controller: use 'lazy' mode for location_config

control_plane/attachment_service/src/reconciler.rs

@@ -114,11 +114,16 @@ impl Reconciler {
             .locations
             .insert(node.id, ObservedStateLocation { conf: None });
 
+        // 'lazy' mode means that a tenant's activiation will be subject to a concurrency limit
+        // in the pageserver: this is the safer way to attach a tenant, as it avoids thundering
+        // herd I/O when attaching many tenants at the same time.
+        let lazy = true;
+
         tracing::info!("location_config({}) calling: {:?}", node_id, config);
         let client =
             mgmt_api::Client::new(node.base_url(), self.service_config.jwt_token.as_deref());
         client
-            .location_config(self.tenant_shard_id, config.clone(), flush_ms)
+            .location_config(self.tenant_shard_id, config.clone(), flush_ms, lazy)
             .await?;
         tracing::info!("location_config({}) complete: {:?}", node_id, config);
 

control_plane/attachment_service/src/service.rs

@@ -445,6 +445,7 @@ impl Service {
                         tenant_conf: models::TenantConfig::default(),
                     },
                     None,
+                    false,
                 )
                 .await
             {

control_plane/src/pageserver.rs

@@ -537,10 +537,11 @@ impl PageServerNode {
         tenant_shard_id: TenantShardId,
         config: LocationConfig,
         flush_ms: Option<Duration>,
+        lazy: bool,
     ) -> anyhow::Result<()> {
         Ok(self
             .http_client
-            .location_config(tenant_shard_id, config, flush_ms)
+            .location_config(tenant_shard_id, config, flush_ms, lazy)
             .await?)
     }
 

pageserver/client/src/mgmt_api.rs

@@ -251,17 +251,18 @@ impl Client {
         tenant_shard_id: TenantShardId,
         config: LocationConfig,
         flush_ms: Option<std::time::Duration>,
+        lazy: bool,
     ) -> Result<()> {
         let req_body = TenantLocationConfigRequest {
             tenant_id: tenant_shard_id,
             config,
         };
         let path = format!(
-            "{}/v1/tenant/{}/location_config",
+            "{}/v1/tenant/{}/location_config?lazy={lazy}",
             self.mgmt_api_endpoint, tenant_shard_id
         );
         let path = if let Some(flush_ms) = flush_ms {
-            format!("{}?flush_ms={}", path, flush_ms.as_millis())
+            format!("{}&flush_ms={}", path, flush_ms.as_millis())
         } else {
             path
         };