tsuki/postgres: misc:

- add postgresql backup service
- harden systemd unit
- increase max_connections

hosts/tsuki/services/postgres.nix

@@ -1,5 +1,6 @@
-{ config, pkgs, lib, secrets, ... }: {
-
+{ config, pkgs, lib, secrets, ... }: let
+  cfg = config.services.postgresql;
+in {
   services.postgresql = {
     enable = true;
     enableTCPIP = true;
@@ -11,7 +12,9 @@
     '';
     port = secrets.ports.postgres;
     dataDir = "${config.machineVars.dataDrives.drives.postgres}/${config.services.postgresql.package.psqlSchema}";
-    # settings = {};
+    settings = {
+      max_connections = 150;
+    };
   };
 
   services.postgresqlBackup = {
@@ -20,5 +23,37 @@
     backupAll = true;
   };
 
+  systemd.services.postgresqlBackup = {
+    requires = [ "postgresql.service" "data2-backup.mount" ];
+  };
+
+  systemd.services.postgresql = {
+    requires = [ "data2-postgres.mount" ];
+    serviceConfig = {
+      Restart = "always";
+      RestartSec = 3;
+      ReadWritePaths = [ cfg.dataDir ];
+      NoNewPrivileges = true;
+      PrivateDevices = true;
+      ProtectClock = true;
+      ProtectKernelLogs = true;
+      ProtectKernelModules = true;
+      # PrivateMounts = true;
+      RestrictSUIDSGID = true;
+      ProtectHostname = true;
+      LockPersonality = true;
+      ProtectKernelTunables = true;
+      ProtectSystem = "strict";
+      ProtectProc = "invisible";
+      ProtectHome = true;
+      # PrivateNetwork = true;
+      PrivateUsers = true;
+      PrivateTmp = true;
+      UMask = "0077";
+      # RestrictAddressFamilies = [ "AF_UNIX AF_INET AF_INET6" ];
+      SystemCallArchitectures = "native";
+    };
+  };
+
   environment.systemPackages = [ config.services.postgresql.package ];
 }