Custom docker official mariadb image - mysql

Question

I intended to create a database based on mariadb within a Dockerfile but failed.
Dockerfile content as following:
FROM mariadb
RUN mysql -uroot --password="test" -e "CREATE DATABASE IF NOT EXISTS mymariadb;"
then, when I build customed image with command docker build -t testdb .
it fails with following error:
docker#docker-virtual-machine:~$ docker build -t tttt .
Sending build context to Docker daemon 32.26kB
Step 1/2 : FROM mariadb
---> 2bdd97ca79d9
Step 2/2 : RUN mysql -uroot --password="test" -e "CREATE DATABASE IF NOT EXISTS mymariadb;"
---> Running in 80339dc97c2e
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)
The command '/bin/sh -c mysql -uroot --password="test" -e "CREATE DATABASE IF NOT EXISTS mymariadb;"' returned a non-zero code: 1
docker#docker-virtual-machine:~$
And then I follow #Sebastian advices but find the database is not created, details as following:
docker#docker-virtual-machine:~/test$ ls
Dockerfile init.sql
docker#docker-virtual-machine:~/test$ cat init.sql
CREATE DATABASE IF NOT EXISTS mydb;
docker#docker-virtual-machine:~/test$
docker#docker-virtual-machine:~/test$ cat Dockerfile
FROM mariadb
COPY init.sql /docker-entrypoint-initdb.d/
CMD ["mysqld"]
docker#docker-virtual-machine:~/test$ docker build -t mydb .
Sending build context to Docker daemon 3.072kB
Step 1/3 : FROM mariadb
---> 2bdd97ca79d9
Step 2/3 : COPY init.sql /docker-entrypoint-initdb.d/
---> 59fa0f173d93
Step 3/3 : CMD ["mysqld"]
---> Running in e605ae1fda5b
Removing intermediate container e605ae1fda5b
---> 94b98e45dc05
Successfully built 94b98e45dc05
Successfully tagged mydb:latest
docker#docker-virtual-machine:~/test$ docker run -p 3306:3306/tcp -v /my/own/dat adir1:/var/lib/mysql -e MYSQL_ROOT_PASSWORD=test123 mydb
2019-01-26 17:30:21 0 [Note] mysqld (mysqld 10.3.12-MariaDB-1:10.3.12+maria~bion ic) starting as process 1 ...
2019-01-26 17:30:21 0 [Note] InnoDB: Using Linux native AIO
2019-01-26 17:30:21 0 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtin s
2019-01-26 17:30:21 0 [Note] InnoDB: Uses event mutexes
2019-01-26 17:30:21 0 [Note] InnoDB: Compressed tables use zlib 1.2.11
2019-01-26 17:30:21 0 [Note] InnoDB: Number of pools: 1
2019-01-26 17:30:21 0 [Note] InnoDB: Using SSE2 crc32 instructions
2019-01-26 17:30:21 0 [Note] InnoDB: Initializing buffer pool, total size = 256M , instances = 1, chunk size = 128M
2019-01-26 17:30:21 0 [Note] InnoDB: Completed initialization of buffer pool
2019-01-26 17:30:21 0 [Note] InnoDB: If the mysqld execution user is authorized, page cleaner thread priority can be changed. See the man page of setpriority().
2019-01-26 17:30:21 0 [Note] InnoDB: 128 out of 128 rollback segments are active .
2019-01-26 17:30:21 0 [Note] InnoDB: Creating shared tablespace for temporary ta bles
2019-01-26 17:30:21 0 [Note] InnoDB: Setting file './ibtmp1' size to 12 MB. Phys ically writing the file full; Please wait ...
2019-01-26 17:30:21 0 [Note] InnoDB: File './ibtmp1' size is now 12 MB.
2019-01-26 17:30:21 0 [Note] InnoDB: 10.3.12 started; log sequence number 163095 0; transaction id 21
2019-01-26 17:30:21 0 [Note] InnoDB: Loading buffer pool(s) from /var/lib/mysql/ ib_buffer_pool
2019-01-26 17:30:21 0 [Note] Plugin 'FEEDBACK' is disabled.
2019-01-26 17:30:21 0 [Note] InnoDB: Buffer pool(s) load completed at 190126 17: 30:21
2019-01-26 17:30:21 0 [Note] Server socket created on IP: '::'.
2019-01-26 17:30:21 0 [Warning] 'proxies_priv' entry '#% root#566af8cb98ef' igno red in --skip-name-resolve mode.
2019-01-26 17:30:21 0 [Note] Reading of all Master_info entries succeded
2019-01-26 17:30:21 0 [Note] Added new Master_info '' to hash table
2019-01-26 17:30:21 0 [Note] mysqld: ready for connections.
Version: '10.3.12-MariaDB-1:10.3.12+maria~bionic' socket: '/var/run/mysqld/mysq ld.sock' port: 3306 mariadb.org binary distribution

Answer 1

The official MariaDB image uses CMD ["mysqld"] instead of RUN mysql. So
FROM mariadb
COPY ./my-initial.sql /docker-entrypoint-initdb.d/
CMD ["mysqld"]
should do the trick.
To execute initial SQL see this section of the image docs.