I’m new on using the knime server, and now im trying to feed databases in MySQL on a daily basis.
The worlflows are fine when executed in Knime Platform (localhost). However, when I try to go through them in the Knime Server it seems that they’re unable to connect to MySQL.
This is what the error message:
ERROR MySQL Connector 0:939: Execute failed: Communications link failure The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
Investigating this error with the IT team (the team is responsible for the DB management on MySQL), we’ve thought that error was due to the Knime Server’s IP has not been granted access to the MySQL. Thus, they changed the configuration so the Knime Server could access the DB from MySQL. However, the error still persists.
Do you guys know how to handle this error? Is there any config that needs to be adjusted?
Here’s a print of the workflow and the error on the knime server:
Hi @alanmdias , is the network opened between the Knime Server and the Mysql server? Can you try to connect to your mysql server with the same credentials from the Knime server, but using a client other than Knime?
Hi @alanmdias , you have not confirmed if you connected via workbench from the Knime server though. This is to test if you are actually able to connect to your mysql server from the Knime server in order to determine if the issue that you are having is related to knime (that is you can connect to mysql from the knime server, but not via Knime, in which case it would be a knime issue), or if the issue is related to the fact that your server does not have an open connection to your mysql (in which case, nothing would be able to connect to mysql from the Knime server, and it’s a firewall issue, not a knime issue)
If yes, I can connect when I run this workflow in Knime desktop (as in print below), but when I run this same workflow in Knime Server, MySQL node can’t connect
obs: the credentials configured in MySQL node are not the same credentials as my Knime Server user. I couldn’t connect to MySQL node using Knime Server credentials even though running node from Knime desktop
or from MySQL workbench using Knime Server credentials?
If yes, I also tried to connect to mysql server through mysql workbench using Knime Server credentials, but it was not possible. However, I am able to connect to the MySQL server using the user credentials that TI on the aws server.
To simplify:
user alan.dias (knime server) = not ok
user alan_dias (dw aws) = ok
If it is neither of these two alternatives, could you guide me on how to perform this test to connect to my mysql server from the Knime server?
I hope I clarified it better. Thanks for your help and patience
Simply put, the idea is to figure out if the issue you are having is because:
Your Knime server can’t connect to your mysql server (not allowed to), so it’s not an issue with Knime, but rather a networking issue between the 2 systems, and this would have to be resolved by your IT or sys admin
or
Your Knime software cannot connect to your mysql server, so it’s an issue that we and the Knime Community can try to help with.
Actually, for case 1, your IT or sys admin person can help you determine this.
I tried asking about the meaning of “connect via workbench from the Knime server”, as i had not confirmed. In case if one of the alternatives would be valid to confirm if I could connect via workbench from the knime server.
Anyway, i got your idea
But how can i figure out 1 (issue between the 2 systems)?
According to the IT team, there is no active firewall between the mysql server (aws rds) and the Knime server, and all releases have been made, including the release for the knime server IP to access the mysql server (aws rds). They gave me admin access on the knime server.
We installed the knime server last week, version 4.14. I’m using Knime Platform version 4.5. As the two versions are compatible, and we haven’t used Knime Server yet, do you think the update might help?
The first workflow that I deployed to Knime Server was exactly the same that i’m having problem connecting to mysql hehe
Just to circle back on this and close it out, the ultimate root cause was related to the settings within Linux regarding the Mysql routes. This issue was resolved by their IT department.
