Question

why i am getting error Could not obtain connection to query metadata com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications li

Posted on January 16, 2024
Creating your tech stack
Asked by Vidya

I have DB @DigitalOcean, from my local to @DigitalOcean DB ,i am able to connect @DigitalOcean mySQL DB. from my local i am using SSL VPN-plus client, But when I am deploying my application/service @@DigitalOcean geeting error. kindly help getting an error ‘Could not obtain connection to query metadata com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure’

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Bobby Iliev

Site Moderator

• January 17, 2024

Hi Vidya,

The error message you’re encountering, com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure, typically indicates that your application is unable to establish a network connection to your MySQL database. Since you mentioned that you can connect to the DigitalOcean MySQL database from your local environment but encounter issues when deploying your application on DigitalOcean, let’s consider a few possible causes and solutions:

Ensure that your DigitalOcean Droplet (where your application is deployed) is configured to access the MySQL database. This includes checking firewall rules and network policies that might be blocking connections from your application’s server to the MySQL database server.
Verify that the MySQL user you’re using in your application has the necessary permissions and is allowed to connect from your application’s server. MySQL users are often restricted to specific hosts for security reasons.
Double-check your application’s database connection settings (host, port, username, password, database name). A common mistake is to use localhost or 127.0.0.1 as the host address, which refers to the local machine. Ensure you’re using the correct address for your DigitalOcean MySQL database.
Check if there are any resource limits being hit on your DigitalOcean database or the Droplet. This can include connection limits, memory, CPU, etc.
Ensure that the environment where your application is running on DigitalOcean is configured similarly to your local environment. Differences in Java versions, library versions, etc., can sometimes lead to unexpected issues.

Also, you can use a simple database connection test script to isolate the problem from your application. If the test script works, the issue might be in the application’s code or configuration.

Let me know how it goes!

Best,

Bobby