diff --git a/tests/runner/src/cmd/bare.rs b/tests/runner/src/cmd/bare.rs
index 58199f959e..f845d7b2c0 100644
--- a/tests/runner/src/cmd/bare.rs
+++ b/tests/runner/src/cmd/bare.rs
@@ -137,12 +137,13 @@ impl BareCommand {
             || self.setup_etcd
             || self.setup_pg.is_some()
             || self.setup_mysql.is_some()
+            || matches!(self.wal, Wal::Kafka)
             || self.kafka_wal_broker_endpoints.is_some()
             || self.config.test_filter != ".*"
         {
             self.jobs = 1;
             println!(
-                "Normalizing parallelism to 1 due to server addresses, etcd/pg/mysql setup, or test filter usage"
+                "Normalizing parallelism to 1 due to server addresses, etcd/pg/mysql/kafka setup, or test filter usage"
             );
         }
 
@@ -154,6 +155,7 @@ impl BareCommand {
             .env_config_file(self.config.env_config_file)
             .interceptor_registry(interceptor_registry)
             .parallelism(self.jobs)
+            .env_parallelism(self.jobs)
             .build()
             .unwrap();
 
diff --git a/tests/runner/src/env/bare.rs b/tests/runner/src/env/bare.rs
index 1501d18512..5cfeff68bb 100644
--- a/tests/runner/src/env/bare.rs
+++ b/tests/runner/src/env/bare.rs
@@ -516,7 +516,8 @@ impl Env {
 
     /// Build the DB with `cargo build --bin greptime`
     fn build_db(&self) {
-        if self.bins_dir.lock().unwrap().is_some() {
+        let mut bins_dir = self.bins_dir.lock().unwrap();
+        if bins_dir.is_some() {
             return;
         }
 
@@ -541,11 +542,7 @@ impl Env {
             panic!();
         }
 
-        let _ = self
-            .bins_dir
-            .lock()
-            .unwrap()
-            .insert(util::get_binary_dir("debug"));
+        bins_dir.replace(util::get_binary_dir("debug"));
     }
 
     pub(crate) fn extra_args(&self) -> &Vec<String> {