If it's the first time you have run Metasploit Framework, you need to start the database service and initialize it. Metasploit uses a PostgreSQL database to store the logs and results, so the first thing we do is start the service:

service postgresql start

Then, we use the Metasploit database tool to create and initialize the database:

msfdb init

Then, we start the Metasploit console:

msfconsole