pageserver: more detailed logs when calling re-attach (#9996)

## Problem

We saw a peculiar case where a pageserver apparently got a 0-tenant
response to `/re-attach` but we couldn't see the request landing on a
storage controller. It was hard to confirm retrospectively that the
pageserver was configured properly at the moment it sent the request.

## Summary of changes

- Log the URL to which we are sending the request
- Log the NodeId and metadata that we sent

libs/pageserver_api/src/controller_api.rs

@@ -48,7 +48,7 @@ pub struct TenantCreateResponse {
     pub shards: Vec<TenantCreateResponseShard>,
 }
 
-#[derive(Serialize, Deserialize)]
+#[derive(Serialize, Deserialize, Debug, Clone)]
 pub struct NodeRegisterRequest {
     pub node_id: NodeId,
 
@@ -75,7 +75,7 @@ pub struct TenantPolicyRequest {
     pub scheduling: Option<ShardSchedulingPolicy>,
 }
 
-#[derive(Clone, Serialize, Deserialize, PartialEq, Eq, Hash)]
+#[derive(Clone, Serialize, Deserialize, PartialEq, Eq, Hash, Debug)]
 pub struct AvailabilityZone(pub String);
 
 impl Display for AvailabilityZone {

pageserver/src/controller_upcall_client.rs

@@ -115,6 +115,10 @@ impl ControllerUpcallClient {
 
         Ok(res)
     }
+
+    pub(crate) fn base_url(&self) -> &Url {
+        &self.base_url
+    }
 }
 
 impl ControlPlaneGenerationsApi for ControllerUpcallClient {
@@ -191,13 +195,15 @@ impl ControlPlaneGenerationsApi for ControllerUpcallClient {
 
         let request = ReAttachRequest {
             node_id: self.node_id,
-            register,
+            register: register.clone(),
         };
 
         let response: ReAttachResponse = self.retry_http_forever(&re_attach_path, request).await?;
         tracing::info!(
-            "Received re-attach response with {} tenants",
-            response.tenants.len()
+            "Received re-attach response with {} tenants (node {}, register: {:?})",
+            response.tenants.len(),
+            self.node_id,
+            register,
         );
 
         failpoint_support::sleep_millis_async!("control-plane-client-re-attach");

pageserver/src/tenant/mgr.rs

@@ -347,7 +347,7 @@ async fn init_load_generations(
         );
         emergency_generations(tenant_confs)
     } else if let Some(client) = ControllerUpcallClient::new(conf, cancel) {
-        info!("Calling control plane API to re-attach tenants");
+        info!("Calling {} API to re-attach tenants", client.base_url());
         // If we are configured to use the control plane API, then it is the source of truth for what tenants to load.
         match client.re_attach(conf).await {
             Ok(tenants) => tenants