diff --git a/.github/workflows/hydrun.yaml b/.github/workflows/hydrun.yaml
index e8675bb..33534ba 100644
--- a/.github/workflows/hydrun.yaml
+++ b/.github/workflows/hydrun.yaml
@@ -14,13 +14,13 @@ jobs:
         target:
           - id: test
             src: .
-            os: golang:bullseye
-            flags: ""
+            os: golang:1.18beta1-bullseye # 1.18 is required due to `GroupIds` requiring CGo on older versions
+            flags: "--ulimit nofile=262144:262144" # Parallel tests require a lot of open files
             cmd: ./Hydrunfile test
             dst: out/*
           - id: go
             src: .
-            os: golang:bullseye
+            os: golang:1.18beta1-bullseye # 1.18 is required due to `GroupIds` requiring CGo on older versions
             flags: ""
             cmd: ./Hydrunfile go
             dst: out/*