From 4b9262786d7666b53a087fc345486c64151ce4c2 Mon Sep 17 00:00:00 2001
From: Aaron Andersen <aaron@fosslib.net>
Date: Wed, 17 Feb 2021 14:16:26 -0500
Subject: [PATCH] nixos/mysql: properly configure mariadb for galera recovery

---
 nixos/modules/services/databases/mysql.nix | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/nixos/modules/services/databases/mysql.nix b/nixos/modules/services/databases/mysql.nix
index 7d0a3f9afc48..cf105daeb04e 100644
--- a/nixos/modules/services/databases/mysql.nix
+++ b/nixos/modules/services/databases/mysql.nix
@@ -375,6 +375,18 @@ in
           fi
         '';
 
+        script = ''
+          # https://mariadb.com/kb/en/getting-started-with-mariadb-galera-cluster/#systemd-and-galera-recovery
+          if test -n "''${_WSREP_START_POSITION}"; then
+            if test -e "${cfg.package}/bin/galera_recovery"; then
+              VAR=$(cd ${cfg.package}/bin/..; ${cfg.package}/bin/galera_recovery); [[ $? -eq 0 ]] && export _WSREP_START_POSITION=$VAR || exit 1
+            fi
+          fi
+
+          # The last two environment variables are used for starting Galera clusters
+          exec ${cfg.package}/bin/mysqld --defaults-file=/etc/my.cnf ${mysqldOptions} $_WSREP_NEW_CLUSTER $_WSREP_START_POSITION
+        '';
+
         postStart = let
           # The super user account to use on *first* run of MySQL server
           superUser = if isMariaDB then cfg.user else "root";
@@ -481,8 +493,7 @@ in
           Type = if hasNotify then "notify" else "simple";
           Restart = "on-abort";
           RestartSec = "5s";
-          # The last two environment variables are used for starting Galera clusters
-          ExecStart = "${cfg.package}/bin/mysqld --defaults-file=/etc/my.cnf ${mysqldOptions} $_WSREP_NEW_CLUSTER $_WSREP_START_POSITION";
+
           # User and group
           User = cfg.user;
           Group = cfg.group;