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sclorg / mysql-container

MySQL container images based on Red Hat Software Collections and intended for OpenShift and general usage. Users can choose between Red Hat Enterprise Linux, Fedora, and CentOS based images.
http://softwarecollections.org
Apache License 2.0
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Implement s2i and general extendability support #201

Closed hhorak closed 6 years ago

hhorak commented 6 years ago

This is very similar to the MariaDB: https://github.com/sclorg/mariadb-container/pull/45/

It adds extending support using source-to-image.

For example, to build a customized MariaDB database image my-mysql-rhel7 with a configuration in ~/image-configuration/ run:

$ s2i build ~/image-configuration/ rhscl/mysql-56-rhel7 my-mysql-rhel7

The directory passed to s2i build can contain these directories:

mysql-cfg/ When starting the container, files from this directory will be used as a configuration for the mysqld daemon. envsubst command is run on this file to still allow customization of the image using environmental variables

mysql-pre-init/ Shell scripts (*.sh) available in this directory are sourced before mysqld daemon is started.

mysql-init/ Shell scripts (*.sh) available in this directory are sourced when mysqld daemon is started locally. In this phase, use ${mysql_flags} to connect to the locally running daemon, for example mysql $mysql_flags < dump.sql

Variables that can be used in the scripts provided to s2i:

$mysql_flags arguments for the mysql tool that will connect to the locally running mysqld during initialization

$MYSQL_RUNNING_AS_MASTER variable defined when the container is run with run-mysqld-master command

$MYSQL_RUNNING_AS_SLAVE variable defined when the container is run with run-mysqld-slave command

$MYSQL_DATADIR_FIRST_INIT variable defined when the container was initialized from the empty data dir

During s2i build all provided files are copied into /opt/app-root/src directory into the resulting image. If some configuration files are present in the destination directory, files with the same name are overwritten. Also only one file with the same name can be used for customization and user provided files are preferred over default files in /usr/share/container-scripts/mysql/- so it is possible to overwrite them.

Same configuration directory structure can be used to customize the image every time the image is started using docker run. The directory has to be mounted into /opt/app-root/src/ in the image (-v ./image-configuration/:/opt/app-root/src/). This overwrites customization built into the image.

hhorak commented 6 years ago

This is the same change as was already reviewed in case of MariaDB, so I believe no extra review is needed. Tests passed, so merging.