diff --git a/etc/spack/defaults/mirrors.yaml b/etc/spack/defaults/mirrors.yaml
new file mode 100644
index 0000000000000000000000000000000000000000..6afc897e61b892ecc039064f20bce3c1ac3a48e1
--- /dev/null
+++ b/etc/spack/defaults/mirrors.yaml
@@ -0,0 +1,2 @@
+mirrors:
+  spack-public: https://spack-llnl-mirror.s3-us-west-2.amazonaws.com/