pageserver: logging tweaks (#6039)

- The `Attaching tenant` log message omitted some useful information
like the generation and mode
- info-level messages about writing configuration files were
unnecessarily verbose
- During process shutdown, we don't emit logs about the various phases:
this is very cheap to log since we do it once per process lifetime, and
is helpful when figuring out where something got stuck during a hang.

pageserver/src/lib.rs

@@ -205,7 +205,7 @@ async fn timed<Fut: std::future::Future>(
     match tokio::time::timeout(warn_at, &mut fut).await {
         Ok(ret) => {
             tracing::info!(
-                task = name,
+                stage = name,
                 elapsed_ms = started.elapsed().as_millis(),
                 "completed"
             );
@@ -213,7 +213,7 @@ async fn timed<Fut: std::future::Future>(
         }
         Err(_) => {
             tracing::info!(
-                task = name,
+                stage = name,
                 elapsed_ms = started.elapsed().as_millis(),
                 "still waiting, taking longer than expected..."
             );
@@ -222,7 +222,7 @@ async fn timed<Fut: std::future::Future>(
 
             // this has a global allowed_errors
             tracing::warn!(
-                task = name,
+                stage = name,
                 elapsed_ms = started.elapsed().as_millis(),
                 "completed, took longer than expected"
             );

pageserver/src/tenant.rs

@@ -2515,7 +2515,7 @@ impl Tenant {
             }
         }
 
-        info!("persisting tenantconf to {config_path}");
+        debug!("persisting tenantconf to {config_path}");
 
         let mut conf_content = r#"# This file contains a specific per-tenant's config.
 #  It is read in case of pageserver restart.
@@ -2550,7 +2550,7 @@ impl Tenant {
         target_config_path: &Utf8Path,
         tenant_conf: &TenantConfOpt,
     ) -> anyhow::Result<()> {
-        info!("persisting tenantconf to {target_config_path}");
+        debug!("persisting tenantconf to {target_config_path}");
 
         let mut conf_content = r#"# This file contains a specific per-tenant's config.
 #  It is read in case of pageserver restart.

pageserver/src/tenant/mgr.rs

@@ -603,7 +603,13 @@ pub(crate) fn tenant_spawn(
         "Cannot load tenant, ignore mark found at {tenant_ignore_mark:?}"
     );
 
-    info!("Attaching tenant {tenant_shard_id}");
+    info!(
+        tenant_id = %tenant_shard_id.tenant_id,
+        shard_id = %tenant_shard_id.shard_slug(),
+        generation = ?location_conf.location.generation,
+        attach_mode = ?location_conf.location.attach_mode,
+        "Attaching tenant"
+    );
     let tenant = match Tenant::spawn(
         conf,
         tenant_shard_id,