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The latest MongoDB DMK release (2.3.1) introduces a lot of new features and important changes, which I will describe here.

dbi services provides the DMK (Database Management Kit) to its customers for multiple technologies: Oracle, Postgres, MongoDB, etc. This toolkit is provided free of charge to all clients who work with dbi services on a consulting project.

The DMK is a set of standardized tools aiming at easing the work of DBAs, by having dbi’s best practices embedded in common scripts across all the database servers of an organization.

New features of the MongoDB DMK

Rewriting of the project

The most significant changes in the MongoDB DMK is the rewriting of all old Perl scripts into new Python scripts. On top of being more adapted to the MongoDB ecosystem, these will improve modularity for customers wanting to write their own packages.

It means that all utility scripts are now named .py instead of .sh, and apart from new features that have been added, the basic behavior stays the same for all of them.

DMK configuration file

Before release 2.3.0, only one configuration file existed in $DMK_HOME/etc. There is now a second configuration file in ~/.DMK/dmk.conf.local, which will overwrite default configuration options. See the GitBook section on Using DMK for more information.

New default directories and more versatility

The Optimal Flexible Architecture (OFA) has new recommendations. Specifically, the new default architecture is the following:

/u01 for binaries and admin folders
/u02 for database files
/u03 for journal files
/u04 for log files
/u90 for backup files

Even though dbi suggests OFA as a good standard for MongoDB installations, we know that a lot of legacy installations will not use this kind of architecture. This is why the DMK is now more versatile, and with the use of the local configuration file described above, it has never been easier to adapt the DMK to your needs.

New aliases and environment variables

Some aliases were changed in this release, others were added. See Environment Variables and Aliases in the documentation for more information.

mgstart, mgstop, mgrestart are new aliases to manage a MongoDB instance.
vic now opens the MongoDB instance configuration file.
vilst now opens the $DMK_HOME/etc/mongodb.lst file.
sta, lsta, tsta, rsta are new aliases for instance status display.
vil, cdl, tal are new aliases to view, access and tail log files of MongoDB instances.
dmkc opens DMK default configuration file.
dmkl opens DMK local configuration file, which overrides the default configuration file.

Other changes

A script named set_local_dmk_config.py was created to automate local configuration file changes. See Environment Variables for more details.
Backups are no longer compressed by default, and the option to compress them has been added to the dmk_dbbackup.py script.
And of course, corrections of bugs.

Installing the DMK for the first time

Installing the DMK is always fairly easy. If you follow the OFA, just unzip the package and source dmk.sh.

[root@vm00 ~]$ su - mongodb
[mongodb@vm00 ~]$ unzip -oq dmk_mongodb-2.3.1.zip -d /u01/app/mongodb/local
[mongodb@vm00 ~]$ . /u01/app/mongodb/local/dmk/bin/dmk.sh
2025-12-04 10:03:48 | INFO | DMK_HOME environment variable is not defined.
2025-12-04 10:03:48 | INFO | First time installation of DMK.
2025-12-04 10:03:48 | INFO | DMK has been extracted to /u01/app/mongodb/local/dmk
2025-12-04 10:03:48 | INFO | Using DMK_HOME=/u01/app/mongodb/local/dmk
2025-12-04 10:03:48 | INFO | Default configuration file '/u01/app/mongodb/local/dmk/etc/dmk.conf.default' does not exist. Creating it.
2025-12-04 10:03:48 | INFO | Copying template file '/u01/app/mongodb/local/dmk/templates/etc/dmk.conf.unix' to '/u01/app/mongodb/local/dmk/etc/dmk.conf.default'
2025-12-04 10:03:48 | INFO | Local configuration file does not exist. Creating it.
2025-12-04 10:03:48 | INFO | Copying template file '/u01/app/mongodb/local/dmk/templates/etc/dmk.conf.local.template' to '/home/mongodb/.dmk/dmk.conf.local'
2025-12-04 10:03:48 | INFO | Creating symlink '/u01/app/mongodb/local/dmk/etc/dmk.conf.local' to '/home/mongodb/.dmk/dmk.conf.local'
2025-12-04 10:03:48 | WARNING | MONGO_BASE environment variable is not set. Trying to retrieve it from DMK_HOME (/u01/app/mongodb/local/dmk).
2025-12-04 10:03:48 | WARNING | MONGO_BASE set to '/u01/app/mongodb' based on DMK_HOME location.
2025-12-04 10:03:48 | WARNING | If you're running DMK for the first time, you can ignore these warnings.
2025-12-04 10:03:48 | WARNING | Otherwise, please set MONGO_BASE in /home/mongodb/.DMK before sourcing DMK.
2025-12-04 10:03:48 | WARNING | File '/u01/app/mongodb/etc/mongodb.lst' does not exist. Creating an empty file.
2025-12-04 10:03:48 | INFO | Creating DMK source file at '/home/mongodb/.DMK' with the following content:
2025-12-04 10:03:48 | INFO | DMK_HOME=/u01/app/mongodb/local/dmk
2025-12-04 10:03:48 | INFO | PYTHON_BIN=/usr/bin/python3
2025-12-04 10:03:48 | INFO | MONGO_BASE=/u01/app/mongodb
2025-12-04 10:03:48 | WARNING | Please make sure to source the .DMK file in your shell profile (e.g., .bash_profile).
2025-12-04 10:03:48 | WARNING | An example is provided at /u01/app/mongodb/local/dmk/templates/profile/dmk.mongodb.profile

If you don’t follow the OFA, you should define the following mandatory variables before running the DMK, inside the /home/mongodb/.DMK file:

DMK_HOME: path to the DMK main folder
PYTHON_BIN: path to the Python binaries (3.6+ necessary, which is the default for Linux 8-like platforms)
MONGO_BASE

[root@vm00 ~]$ su - mongodb
[mongodb@vm00 ~]$ echo "DMK_HOME=/u01/app/mongodb/local/dmk" > ~/.DMK
[mongodb@vm00 ~]$ echo "PYTHON_BIN=/usr/bin/python3" >> ~/.DMK
[mongodb@vm00 ~]$ echo "MONGO_BASE=/u01/app/mongodb" >> ~/.DMK

[mongodb@vm00 ~]$ cat ~/.DMK
export DMK_HOME=/u01/app/mongodb/local/dmk
export PYTHON_BIN=/usr/bin/python3
export MONGO_BASE=/u01/app/mongodb

If you want the DMK to be loaded when logging in, you should add the following code block to the .bash_profile of the mongodb user:

# BEGIN DMK BLOCK
if [ -z "$DMK_HOME" ]; then
  if [ -f "$HOME/.DMK" ]; then
    . "$HOME/.DMK"
  else
    echo "$HOME/.DMK file does not exist"
    return 1
  fi
fi

# Launched at login
. ${DMK_HOME}/bin/dmk.sh && ${PYTHON_BIN} ${DMK_HOME}/bin/dmk_status.py --table --all
# END DMK BLOCK

After this, you can just log in again. The installation is complete !

Migrating from a former version of the DMK

If you already have the MongoDB DMK installed on your systems, there are a few more steps to take for this specific upgrade, because we switched from old Perl libraries to Python.

You first need to adapt the .DMK file, as described in the installation steps.

[mongodb@vm00 ~]$ cat ~/.DMK
export DMK_HOME=/u01/app/mongodb/local/dmk
export PYTHON_BIN=/usr/bin/python3
export MONGO_BASE=/u01/app/mongodb

Then, move the former DMK folder and unzip the new version of the DMK. The old DMK should be a hidden directory, otherwise DMK will consider it as a custom package !

mongodb@vm00:/home/mongodb/ [DUMMY] cd /u01/app/mongodb/local/
mongodb@vm00:/u01/app/mongodb/local/ [DUMMY] ls -l
drwxrwx---. 10 mongodb mongodb 118 Jul  1 04:34 dmk
mongodb@vm00:/u01/app/mongodb/local/ [DUMMY] mv dmk .dmk_old
mongodb@vm00:/u01/app/mongodb/local/ [DUMMY] unzip /u01/app/mongodb/artifacts/dmk_mongodb-2.3.1.zip
mongodb@vm00:/u01/app/mongodb/local/ [DUMMY] ls -ail
100690250 drwxrwx---.  8 mongodb mongodb  96 Jul  1 04:24 dmk
 33554663 drwxrwx---. 10 mongodb mongodb 118 Jul  1 04:34 .dmk_old

Update your .bash_profile to remove all traces of the former DMK loading mechanism. Here is an example of the minimal DMK block in the template file:

# BEGIN DMK BLOCK
if [ -z "$DMK_HOME" ]; then
    if [ -f "$HOME/.DMK" ]; then
        . "$HOME/.DMK"
    else
        echo "$HOME/.DMK file does not exist. It is needed to source DMK at login. Run '. <DMK_HOME>/bin/dmk.sh' or 'source <DMK_HOME>/bin/dmk.sh' to source DMK manually this time."
        return 1
    fi
fi

# Launched at login
. ${DMK_HOME}/bin/dmk.sh && ${PYTHON_BIN} ${DMK_HOME}/bin/dmk_status.py --table --all
# END DMK BLOCK

Last but not least, you will have to customize your local DMK configuration file ~/.dmk/dmk.conf.local. You can use the set_local_dmk_config.py script to help yourself with the modifications.

mongodb@vm00:/u01/app/mongodb/admin/ [mdb01] set_local_dmk_config.py INSTANCE MONGO_JOURNAL "\${MONGO_DATA_ROOT}/\${MONGO_INSTANCE}/journal"
Backup created: /home/mongodb/.dmk/dmk.conf.bak_20251024_084959
Updated MONGO_JOURNAL in [INSTANCE]
Old value: var::MONGO_JOURNAL::=::nowarn::"${MONGO_JOURNAL_ROOT}/${MONGO_INSTANCE}"::
New value: var::MONGO_JOURNAL::=::nowarn::"${MONGO_DATA_ROOT}/${MONGO_INSTANCE}/journal"::
Use 'dmkc' and 'dmkl' aliases to quickly view default and local configuration files.

For any questions regarding the MongoDB DMK, take a look at the documentation or feel free to contact me.

Post Views: 12

MongoDB DMK 2.3: new features

New features of the MongoDB DMK

Rewriting of the project

DMK configuration file

New default directories and more versatility

New aliases and environment variables

Other changes

Installing the DMK for the first time

Migrating from a former version of the DMK

Julien Delattre

Leave a Reply:

Related blog articles

New features of the MongoDB DMK

Rewriting of the project

DMK configuration file

New default directories and more versatility

New aliases and environment variables

Other changes

Installing the DMK for the first time

Loading DMK at login

Migrating from a former version of the DMK

Julien Delattre

Leave a Reply:

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