From bc62e28ca3f73e23c5c8313a970a96fbbf5c4ea4 Mon Sep 17 00:00:00 2001
From: Rodrigo Arias Mallo <rodrigo.arias@bsc.es>
Date: Sun, 17 Sep 2023 22:27:51 +0200
Subject: [PATCH 1/3] Enable direnv integration

---
 m/common/main.nix | 2 ++
 m/common/zsh.nix  | 1 -
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/m/common/main.nix b/m/common/main.nix
index 025a7c5..999f043 100644
--- a/m/common/main.nix
+++ b/m/common/main.nix
@@ -45,6 +45,8 @@
     bsc.osumb
   ];
 
+  programs.direnv.enable = true;
+
   systemd.services."serial-getty@ttyS0" = {
     enable = true;
     wantedBy = [ "getty.target" ];
diff --git a/m/common/zsh.nix b/m/common/zsh.nix
index 666e34b..5cfcb7f 100644
--- a/m/common/zsh.nix
+++ b/m/common/zsh.nix
@@ -2,7 +2,6 @@
 
 {
   environment.systemPackages = with pkgs; [
-    direnv
     zsh-completions
     nix-zsh-completions
   ];
-- 
GitLab


From 8de3d2b149dff53de62aa8bca40d4b99718abb53 Mon Sep 17 00:00:00 2001
From: Rodrigo Arias Mallo <rodrigo.arias@bsc.es>
Date: Wed, 20 Sep 2023 18:26:48 +0200
Subject: [PATCH 2/3] Mount the hut nix store for SLURM jobs

---
 m/module/slurm-hut-nix-store.nix | 19 +++++++++++++++++++
 m/owl1/configuration.nix         |  1 +
 m/owl2/configuration.nix         |  1 +
 3 files changed, 21 insertions(+)
 create mode 100644 m/module/slurm-hut-nix-store.nix

diff --git a/m/module/slurm-hut-nix-store.nix b/m/module/slurm-hut-nix-store.nix
new file mode 100644
index 0000000..2ec8e2f
--- /dev/null
+++ b/m/module/slurm-hut-nix-store.nix
@@ -0,0 +1,19 @@
+{ ... }:
+
+{
+  # Mount the hut nix store via NFS
+  fileSystems."/mnt/hut-nix-store" = {
+    device = "hut:/nix/store";
+    fsType = "nfs";
+    options = [ "ro" ];
+  };
+
+  systemd.services.slurmd.serviceConfig = {
+    # When running a job, bind the hut store in /nix/store so the paths are
+    # available too.
+    # FIXME: This doesn't keep the programs in /run/current-system/sw/bin
+    # available in the store. Ideally they should be merged but the overlay FS
+    # doesn't work when the underlying directories change.
+    BindReadOnlyPaths = "/mnt/hut-nix-store:/nix/store";
+  };
+}
diff --git a/m/owl1/configuration.nix b/m/owl1/configuration.nix
index 5afda72..d21ccfd 100644
--- a/m/owl1/configuration.nix
+++ b/m/owl1/configuration.nix
@@ -5,6 +5,7 @@
     ../common/main.nix
     ../module/ceph.nix
     ../module/slurm-firewall.nix
+    ../module/slurm-hut-nix-store.nix
   ];
 
   # Select the this using the ID to avoid mismatches
diff --git a/m/owl2/configuration.nix b/m/owl2/configuration.nix
index 9636760..5fdabbe 100644
--- a/m/owl2/configuration.nix
+++ b/m/owl2/configuration.nix
@@ -5,6 +5,7 @@
     ../common/main.nix
     ../module/ceph.nix
     ../module/slurm-firewall.nix
+    ../module/slurm-hut-nix-store.nix
   ];
 
   # Select the this using the ID to avoid mismatches
-- 
GitLab


From 9ee71114537023d0cb2edfe895b71e3cff644026 Mon Sep 17 00:00:00 2001
From: Rodrigo Arias Mallo <rodrigo.arias@bsc.es>
Date: Thu, 21 Sep 2023 13:51:42 +0200
Subject: [PATCH 3/3] Document the hut shared nix store for SLURM

---
 web/content/owl/_index.md | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/web/content/owl/_index.md b/web/content/owl/_index.md
index d6fbb1b..a994329 100644
--- a/web/content/owl/_index.md
+++ b/web/content/owl/_index.md
@@ -8,3 +8,11 @@ description: "Low system noise"
 Much like the silent flight of an owl at night, these nodes are configured to
 minimize the system noise and let programs run undisturbed. The list of nodes is
 `owl[1-2]` and are available for jobs with SLURM.
+
+The contents of the nix store of the hut node is made available in the owl nodes
+when a job is running. This allows jobs to access the same paths that are on hut
+to load dependencies.
+
+For now, only the hut node can be used to build new derivations so that they
+appear in the compute nodes. This applies to the `nix build`, `nix develop` and
+`nix shell` commands.
-- 
GitLab