servo: slim dependencies so that local-fs.target can be reached even if my media drives are inaccessible

this means some services which need access (like sftpgo) fail to start if the drive is unavailable

hosts/by-name/servo/fs.nix

@@ -30,20 +30,30 @@
   };
 
   fileSystems."/mnt/pool" = {
-    device = "/dev/disk/by-partuuid/14a7d00a-be53-2b4e-96f9-7e2c964674ec";
+    # all btrfs devices of the same RAID volume use the same UUID.
+    device = "UUID=40fc6e1d-ba41-44de-bbf3-1aa02c3441df";
     fsType = "btrfs";
     options = [
       # "compress=zstd"  #< not much point in compressing... mostly videos and music; media.
       "defaults"
-      # "device=/dev/disk/by-partuuid/14a7d00a-be53-2b4e-96f9-7e2c964674ec"
+      # `device=...` only needed if `btrfs scan` hasn't yet been run
+      # see: <https://askubuntu.com/a/484374>
+      # i don't know what guarantees NixOS/systemd make about that, so specifying all devices for now
+      "device=/dev/disk/by-partuuid/14a7d00a-be53-2b4e-96f9-7e2c964674ec"
       "device=/dev/disk/by-partuuid/6b86cc10-c3cc-ec4d-b20d-b6688f0959a6"
       "device=/dev/disk/by-partuuid/7fd85cac-b6f3-8248-af4e-68e703d11020"
       "device=/dev/disk/by-partuuid/ef0e5c7b-fccf-f444-bac4-534424326159"
+      "nofail"
+      "x-systemd.before=local-fs.target"
+      "x-systemd.device-bound=false"  #< don't unmount when `device` disappears
+      "x-systemd.device-timeout=60s"
+      "x-systemd.mount-timeout=60s"
     ];
   };
 
+  # TODO: move this elsewhere and automate the ACLs!
   # FIRST TIME SETUP FOR MEDIA DIRECTORY:
-  # - set the group stick bit: `sudo find /var/media -type d -exec chmod g+s {} +`
+  # - set the group sticky bit: `sudo find /var/media -type d -exec chmod g+s {} +`
   #   - this ensures new files/dirs inherit the group of their parent dir (instead of the user who creates them)
   # - ensure everything under /var/media is mounted with `-o acl`, to support acls
   # - ensure all files are rwx by group: `setfacl --recursive --modify d:g::rwx /var/media`
@@ -66,7 +76,6 @@
   sane.fs."/var/media/Books/Books".dir = {};
   sane.fs."/var/media/Books/Visual".dir = {};
   sane.fs."/var/media/collections".dir = {};
-  # sane.fs."/var/media/datasets".dir = {};
   sane.fs."/var/media/freeleech".dir = {};
   sane.fs."/var/media/Music".dir = {};
   sane.fs."/var/media/Pictures".dir = {};
@@ -75,13 +84,6 @@
   sane.fs."/var/media/Videos/Shows".dir = {};
   sane.fs."/var/media/Videos/Talks".dir = {};
 
-  # this is file.text instead of symlink.text so that it may be read over a remote mount (where consumers might not have any /nix/store/.../README.md path)
-  sane.fs."/var/lib/uninsane/datasets/README.md".file.text = ''
-    this directory may seem redundant with ../media/datasets. it isn't.
-    this directory exists on SSD, allowing for speedy access to specific datasets when necessary.
-    the contents should be a subset of what's in ../media/datasets.
-  '';
-
   systemd.services.dedupe-media = {
     description = "transparently de-duplicate /var/media entries by using block-level hardlinks";
     script = ''

hosts/by-name/servo/services/export/default.nix

@@ -10,7 +10,7 @@
   fileSystems."/var/export/media" = {
     # everything in here could be considered publicly readable (based on the viewer's legal jurisdiction)
     device = "/var/media";
-    options = [ "rbind" ];
+    options = [ "rbind" "nofail" ];
   };
   # fileSystems."/var/export/playground" = {
   #   device = config.fileSystems."/mnt/persist/ext".device;

hosts/by-name/servo/services/export/sftpgo/default.nix

@@ -158,14 +158,15 @@ in
   ];
 
   systemd.services.sftpgo = {
-    after = [ "network-online.target" ];
+    after = [ "network-online.target" ];  #< so that it reliably binds to all interfaces/netns's?
     wants = [ "network-online.target" ];
-    serviceConfig = {
-      ReadWritePaths = [ "/var/export" ];
-
-      Restart = "always";
-      RestartSec = "20s";
-      UMask = lib.mkForce "0002";
-    };
+    unitConfig.RequiresMountsFor = [
+      "/var/export/media"
+      "/var/export/playground"
+    ];
+    serviceConfig.ReadWritePaths = [ "/var/export" ];
+    serviceConfig.Restart = "always";
+    serviceConfig.RestartSec = "20s";
+    serviceConfig.UMask = lib.mkForce "0002";
   };
 }

modules/fs/default.nix

@@ -139,20 +139,26 @@ let
       options = [
         "bind"
         # noauto: removes implicit `WantedBy=local-fs.target`
-        # nofail: removes implicit `Before=local-fs.target`
-        #   because e.g. private data may not be available before local-fs
+        # nofail: removes implicit `Before=local-fs.target` and turns `RequiredBy=local-fs.target` into `WantedBy=local-fs.target`.
+        # note that some services will try to write under the mountpoint without declaring `RequiresMountsFor=` on us.
+        # systemd-tmpfiles.service is one such example.
+        # so, we *prefer* to be ordered before `local-fs.target` (since everything pulls that in),
+        # but we generally don't want to *fail* `local-fs.target`, since that breaks everything, even `ssh`
         # "noauto"
         "nofail"
         # x-systemd options documented here:
         # - <https://www.freedesktop.org/software/systemd/man/systemd.mount.html>
+        "x-systemd.before=local-fs.target"
       ];
       noCheck = true;
     };
+    # specify `systemd.mounts` because otherwise systemd doesn't seem to pick up my `x-systemd` fs options?
     systemd.mounts = [{
       where = path;
       what = if fsEntry.device != null then fsEntry.device else "";
       type = fsEntry.fsType;
       options = lib.concatStringsSep "," fsEntry.options;
+      before = [ "local-fs.target" ];
     }];
   };