fix: delegate more funcionality to dc-scale

svc/pkg/cluster/worker/src/workers/datacenter_scale.rs

@@ -132,6 +132,7 @@ async fn inner(
 			datacenter_id = $1 AND
 			-- Filters out servers that are being destroyed/already destroyed
 			cloud_destroy_ts IS NULL
+		FOR UPDATE
 		",
 		datacenter_id,
 	)

svc/pkg/linode/standalone/gc/src/lib.rs

@@ -127,6 +127,7 @@ async fn get_prebake_servers(
 			ssh_key_id, linode_id, firewall_id
 		FROM db_cluster.server_images_linode
 		WHERE image_id = ANY($1)
+		FOR UPDATE
 		",
 		image_ids,
 	)

svc/pkg/mm-config/ops/version-prepare/src/prewarm_ats.rs

@@ -49,12 +49,13 @@ pub async fn prewarm_ats_cache(
 		[ctx, VlanIp]
 		"
 		SELECT
-		datacenter_id, vlan_ip
+			datacenter_id, vlan_ip
 		FROM db_cluster.servers
 		WHERE
 			datacenter_id = ANY($1) AND
 			pool_type = $2 AND
 			vlan_ip IS NOT NULL AND
+			drain_ts IS NULL AND
 			cloud_destroy_ts IS NULL
 		",
 		// NOTE: region_id is just the old name for datacenter_id

svc/pkg/mm/worker/src/workers/lobby_create/mod.rs

@@ -857,12 +857,15 @@ async fn resolve_image_artifact_url(
 
 			let region_id = unwrap_ref!(region.region_id).as_uuid();
 
-			// Hash build id
+			// Hash build so that the ATS server that we download the build from is always the same one. This
+			// improves cache hit rates and reduces download times.
 			let build_id = unwrap_ref!(build.build_id).as_uuid();
 			let mut hasher = DefaultHasher::new();
 			hasher.write(build_id.as_bytes());
 			let hash = hasher.finish() as i64;
 
+			// NOTE: The algorithm for choosing the vlan_ip from the hash should match the one in
+			// prewarm_ats.rs @ prewarm_ats_cache
 			// Get vlan ip from build id hash for consistent routing
 			let (ats_vlan_ip,) = sql_fetch_one!(
 				[ctx, (String,)]
@@ -876,6 +879,7 @@ async fn resolve_image_artifact_url(
 						datacenter_id = $1 AND
 						pool_type = $2 AND
 						vlan_ip IS NOT NULL AND
+						drain_ts IS NULL AND
 						cloud_destroy_ts IS NULL	
 				)
 				SELECT vlan_ip