20210809 MariaDB + Nextcloud - experimental branch - PR 3 of 3

1. Adds Dockerfile to MariaDB template to add stability patches recommended in:

	* [StackOverflow](https://stackoverflow.com/questions/61809270/how-to-discover-why-mariadb-crashes)
	* [Discord](https://discord.com/channels/638610460567928832/638610461109256194/825049573520965703)

	Note:

	* I have been running these patches for three months and they definitely improve stability (zero crashes in nextcloud_db). The Discord link above contains a similar stability report for MariaDB.

2. Alters service definitions for both MariaDB and Nextcloud to:

	* build using the Dockerfile
	* add a volume mapping to support backup/restore of MariaDB database.

		Note:

		* it was a conscious decision to place the db_backup folder in `./volumes/CONTAINER` rather than mimic the arrangement for influxdb. It simplifies the backup/restore design.

3. Adds port mapping 9322:3306 to nextcloud_db service definition. This is needed so "restore" routines can tell when the MariaDB service is open for business.

	Note:

	* MariaDB already exposes 3306:3306.

Author: Paraphraser

.internal/templates/services/mariadb/Dockerfile

@@ -0,0 +1,13 @@
+# Download base image
+FROM ghcr.io/linuxserver/mariadb
+
+# apply stability patches recommended in
+#   
+#   https://discord.com/channels/638610460567928832/638610461109256194/825049573520965703
+#   https://stackoverflow.com/questions/61809270/how-to-discover-why-mariadb-crashes
+RUN sed -i.bak \
+  -e "s/^thread_cache_size/# thread_cache_size/" \
+  -e "s/^read_buffer_size/# read_buffer_size/" \
+  /defaults/my.cnf
+
+# EOF

.internal/templates/services/mariadb/template.yml

@@ -1,5 +1,5 @@
 mariadb:
-  image: linuxserver/mariadb
+  build: ./.templates/mariadb/.
   container_name: mariadb
   environment:
     - TZ=Etc/UTC
@@ -11,6 +11,7 @@ mariadb:
     - MYSQL_PASSWORD=Unset
   volumes:
     - ./volumes/mariadb/config:/config
+    - ./volumes/mariadb/db_backup:/backup
   ports:
     - "3306:3306"
   restart: unless-stopped

.internal/templates/services/nextcloud/template.yml

@@ -19,7 +19,7 @@ nextcloud:
 
 nextcloud_db:
   container_name: nextcloud_db
-  image: ghcr.io/linuxserver/mariadb
+  build: ./.templates/mariadb/.
   restart: unless-stopped
   environment:
     - TZ=Etc/UTC
@@ -29,7 +29,10 @@ nextcloud_db:
     - MYSQL_PASSWORD=Unset # removed during compile
     - MYSQL_DATABASE=nextcloud
     - MYSQL_USER=nextcloud
+  ports:
+    - "9322:3306"
   volumes:
     - ./volumes/nextcloud/db:/config
+    - ./volumes/nextcloud/db_backup:/backup
   networks:
     - nextcloud_internal