How to use mongodrdrl to extract a MongoDB collection schema

mongodrdl : what is it ? It is a tool packaged with MongoDB BI Connector. It has a number of functions to assist is mapping and manipulating schemas. How can I use mongodrdl? This is an example of a mongodrdl command line request. In this example the mongodrdl command line tool samples the namespaces of the database and collection specified. For more options check the official MongoDB BI Connector documentation mongodrdl sample --host "myserver" --port 27017 --authenticationDatabase admin --username myAdmin --password myPw1 --db db1 --collection mycollection --out myCollection.drdl This is a snippet from the file output schema: - db: myDB... Read more →

How to fix Crontab -e - You are not allowed to use this program (crontab)

Question: I've received a new server and logon, trying to use Crontab but getting this error message: You (your_logon) are not allowed to use this program (crontab) See crontab(1) for more information How can I fix? Answer: It looks like you are experiencing a situation where only root can use crontab - but other logon accounts require some extra steps. On Linux there are two files which control the access to crontab: /etc/cron.allow /etc/cron.deny You will need to add the logon account to the /etc/cron.allow file. The way to add the logon account is to --su to root and then... Read more →

How to easily install Podman on Red Hat Linux

Databases on containers is going mainstream. A great way to get comfortable with Containers and exploring the difference between a more traditional DBMS to OS relationship is to install Podman on Linux , download some images and start learning. Podman is a daemonless, open source, Linux native for sharing and deploying applications using Open Containers Initiative (OCI) Containers and Container Images Some terminology: An image is a binary containing the requirements for running a single container. Metadata is included to describe various needs The basic unit of Podman apps are termed as containers. Containers isolate the running processes , and... Read more →

How to change PostgreSQL database data directory

Question: The Postgres data_directory is showing a value via the SHOW data_directory command. postgres=# SHOW data_directory; data_directory ------------------------ /var/lib/postgres/data (1 row) How can I change the database directory to another directory? Answer: The steps below are a standard approach. The steps will vary according to specific requirements, and may require a more customised approach Step 1 - Identify current data directory path SHOW data_directory; Step 2- Stop Postgresql services systemctl status systemctl stop Step 3 - create a blank directory on the target path e.g mkdir /mydirectory/data --change ownership to the postgres user , for example chown postgres:postgres... Read more →