Archive for the ‘DBA’ Category

A simple MariaDB deployment with Ansible

Here’s a simple Ansible Playbook to create a basic MariaDB deployment. The basic steps the playbook will attempt are: Install a few libraries Setup Repos Install MariaDB packages Install Percona software Create MariaDB directories Copy my.cnf to server (note this is a template file and not supplied here) Run mysql_install_db if needed Start MariaDB Set […]

A dockerized mongod instance with authentication enabled

Here’s just a quick walkthrough showing how to create a dockerized instance of a standalone MongoDB instance. First, from within a terminal, create a folder to hold the Dockerfile… mkdir Docker_MongoDB_Image cd Docker_MongoDB_Image touch Dockerfile Edit the Dockerfile… vi Dockerfile Enter the following text. You may wish to modify the file slightly. For example; if […]

MongoDB: Making the most of a 2 Data-Centre Architecture

There’s a big initiative at my employers to improve the uptime of the services we provide. The goal is 100% uptime as perceived by the customer. There’s obviously a certain level of flexibility one could take in the interpretation of this. I choose to be as strict as I can about this to avoid any […]

MongoDB and the occasionally naughty query

It’s no secret that databases like uniqueness and high cardinality. Low cardinality columns do not make good candidates for indexes. A recent issue I had with MongoDB proved that NoSQL is no different in this regard. The MongoDB Query Planner is quite simple and works as follows (simplified)… If there are no usable indexes; perform a collation […]

A few Splunk queries for MongoDB logs

Here’s a few Splunk queries I’ve used to supply some data for a dashboard I used to manage a MongoDB Cluster. Election events If any MongoDB elections happen at 3AM on a Wednesday night I want to know about it. This query, added to a single value panel allows me to do this easily… host=mongo* […]