Splunk DB Connect: How to resolve MySQL connection error "Failed to initialize pool: Communications link failure"?

[sshres5]

Trying to setup a connection through Splunk DB Connect to MySQL dB. However receiving following error:

com.zaxxer.hikari.pool.HikariPool$PoolInitializationException: Failed to initialize pool: 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.

Has anyone seen this error before? We just added mysql jar on the lib to have DB connection with mysql.
mysql-connector-java-5.1.40-bin.jar on our UNIX box

[sshres5 · Accepted solution]

So yes, Firewall turned out to be the culprit. Once the firewall rule was implemented, DB connect was able to connect the DB without any issues.

[kannu]

@sshres5 @aaraneta

I have disabled the firewall on my splunk server where i have installed db connect app on my centos 7
using

sudo systemctl disable firewalld

[root@dserver sys]# systemctl status firewalld
● firewalld.service - firewalld - dynamic firewall daemon
Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled)
Active: inactive (dead)

But still i am facing the same issue

[sshres5]

So, it might not be your host firewall that is causing the issue. It will be the connectivity between your DB connect host and where you are trying to query.
run following
nc -vz port

[sshres5]

Looks like it is a Firewall issue. Will let y'all know if that was the reason for this.

[aaraneta_splunk]

Hi @sshres5 - Just checking in. Did it end up being a firewall issue or no? Either way, if you found the solution, be sure to post the answer below and "Accept" it so that others will know your post is resolved. Thanks!