diff --git a/service/files/defaults.yaml b/service/files/defaults.yaml
index 1af9da4..6deee0e 100644
--- a/service/files/defaults.yaml
+++ b/service/files/defaults.yaml
@@ -9,6 +9,7 @@ configs:
     xtrabackup_password: "password"
     monitor_password: "password"
     gcache_size: "1G"
+    sql_mode: null
     cluster_size: 3
     force_bootstrap:
       enabled: false
diff --git a/service/files/my.cnf.j2 b/service/files/my.cnf.j2
index 4dc5e4e..ebfc3ce 100644
--- a/service/files/my.cnf.j2
+++ b/service/files/my.cnf.j2
@@ -25,6 +25,10 @@ innodb_write_io_threads = 8
 
 open_files_limit = 102400
 
+{% if percona.sql_mode %}
+sql_mode = "{{ percona.sql_mode }}"
+{% endif -%}
+
 wsrep_slave_threads = 4
 wsrep_cluster_address = gcomm://
 wsrep_provider = /usr/lib/galera3/libgalera_smm.so