Running MariaDB server with Singularity

Note

Before we even start, there is a better way to do this nowadays with this excellent and specially designed tool DBdeployer.

Anyway, here is how this could be done with singularity.

Original source: https://github.com/sylabs/examples/tree/master/database/mariadb

1. Extract/copy /etc/mysql/my.cnf and edit the user, so it could run as specified user.
2. Build the Singularity container.

   Bootstrap: docker
   From: mariadb:10.3.9
   
   # https://github.com/sylabs/examples/tree/master/database/mariadb
   
   %post
     export DEBIAN_FRONTEND=noninteractive
     export LC_ALL=C
   
     apt update && apt -y install vim 
     # replace `your-name` with your username, run `whoami` to see your username
     #YOUR_USERNAME="your-name"
   
     #sed -ie "s/^#user.*/user = ${YOUR_USERNAME}/" /etc/mysql/my.cnf
     #chmod 1777 /run/mysqld
   
   %runscript
   exec "mysqld" "$@"
   
   %startscript
   exec "mysqld_safe"
   

3. Start the server

   $ singularity shell --writable-tmpfs -B db/:/var/lib/mysql  -B my.cnf:/etc/mysql/my.cnf mariadb.sif
   

   Alternatively, you can make the configuration file writable by using overlays.

   # add overlay
   singularity overlay create --size 64 --create-dir /etc/mysql mariadb.sif
   
   # start shell
   singularity shell --writable-tmpfs -B db/:/var/lib/mysql mariadb.sif
   # Edit the user inplace
   sed -ie "s/^#user.*/user = NEWUSER/" /etc/mysql/my.cnf