How to Set Up Splunk DB Connect to Connect to Multiple MSSQL Databases and Some Tips & Tricks
By: Jon Walthour |Team Lead, Senior Splunk Consultant
Over the years, I have found one tried and true method for getting Splunk connected to multiple Microsoft SQL Server instances spread across a corporate network—connect to Windows from Windows. That is to say, run the DB Connect application from Splunk on a Splunk Enterprise Heavy Forwarder, installed on a Windows environment. Why must Splunk be running Windows? It certainly doesn’t if you’re going to authenticate to the MSSQL instances with local database accounts. That authentication process can be handled by the database driver. However, when multiple connections to multiple MSSQL instances are required, as is often the case, a bunch of local account usernames and passwords can be a nightmare to manage for everyone involved. So, Windows AD authentication is preferred. When that becomes a requirement, you need a Windows server running Splunk. I tried getting Splunk running on Linux to connect to SQL Server using AD authentication via Kerberos for a month and never got it to work. Using a Windows server is so much simpler.
To accomplish this, the first thing you need to do is request two things from your Infrastructure teams—a service account for Splunk to use to connect to all the SQL Server instances and a server running Microsoft Windows. The service account must have “logon as a service” rights and the Windows server must meet the requirements for Splunk reference hardware with regards to CPUs, memory and storage. The best practice for Splunk generally speaking is to use General Policy Objects (GPOs) to define permissions so that they are consistent across a Windows environment. Relying on local Admin accounts can result in challenges, particularly across some of the “back-end” Splunk instances such as Splunk Search Head to Indexer permissions.
Once the server and service account have been provisioned, install Splunk Enterprise and Splunk DB Connect (from Splunkbase) on the it. Here’s the first trick: go into Settings > Control Panel > Services and configure the splunkd service to run under the service account. This is crucial. You want not just the database connections to be made using the service account, but the Splunk executables to be running under that account. This way, all of Splunk is authenticated to Active Directory and there are no odd authentication issues.
After you have Splunk running under the MSSQL service account with DB Connect installed as an app in the Splunk instance, you’ll want to install the Java Runtime Environment (JRE) software, either version 8 (https://www.oracle.com/java/technologies/javase-jre8-downloads.html) or version 11 (https://www.oracle.com/java/technologies/javase-jdk11-downloads.html), and download the appropriate MSSQL driver based on Splunk’s documentation (https://docs.splunk.com/Documentation/DBX/latest/DeployDBX/Installdatabasedrivers), which either the Microsoft drivers for the open source jTDS drivers. Personally, I’ve had better outcomes with the Microsoft drivers in this scenario.
Once you’ve downloaded the SQL database driver archive, unzip it. In the installation media, find the library “mssql-jdbc_auth-<version>.<arch>.dll” appropriate to the version and architecture you downloaded and copy it to the C:\Windows\System32 directory. Then, find the file jar “mssql-jdbc-<version>.<jre version>.jar” appropriate to your JRE version and copy it to $SPLUNK_HOME\etc\apps\splunk_app_db_connect\drivers.
Now, log into Splunk and go the Splunk DB Connect app. It will walk you through the configuration of DB Connect. In the “General” section, fill in the path to where you installed the JRE (JAVA_HOME). This is usually something like “C:\Program Files\Java\jre<version>”. The remaining settings you can leave blank. Just click “Save”. This will restart the task server, which is the java-based processing engine of DB Connect that runs all the database interactions.
In the “Drivers” section, if the MS SQL drivers are not listed with green checkmarks under the “Installed” column, click the “Reload” button to have the task server rescan the drivers folder for driver files. If they still do not have green checkmarks, ensure the right driver files are properly placed in $SPLUNK_HOME/etc/apps/splunk_app_db_connect/drivers.
Next, navigate to Configuration > Databases > Identities and click “New Identity”. Enter the username and password of the service account you’re using for the MSSQL connections and give it an appropriate name. Check “Use Windows Authentication Domain” and enter the appropriate value for your Active Directory domain. Save the identity.
Navigate to Configuration > Databases > Connections and click “New Connection”. Pick the identity you just created and use the “MS-SQL Server using MS Generic Driver With Windows Authentication” connection type. Select the appropriate timezone the database you’re connecting to is in. This is especially important so that Splunk knows how to interpret the timestamps it will ingest in the data. For the “host” field, enter the hostname or IP address of the MSSQL server. Usually the default port of 1433 doesn’t need to be changed nor the default database of “master”. Enable SSL if you’re connection is to be encrypted and I always select “Read Only” when creating a database input to make sure there is no way to input can change any data in the connected database.
Finally, a few miscellaneous tips for you.
For the “Connection Name” of database connections, I always name them after their hostname and port from the JDBC URL Settings. This is because in a complex DB Connect environment, you can have many inputs coming from many different databases. A hostname/port number combination, however, is unique. So, naming them with a pattern of “hostname-port#” (e.g., “sql01.mycompany.com-1433”) will prevent you from establishing duplicate connections to the same MSSQL installation.
Another tip is that you can edit the connection settings for your JDBC driver directly in the configuration. This is typically only useful when your development team has come up with specific, non-standard configurations they use for JDBC drivers.
Sometimes complex database queries that call stored procedures or use complex T-SQL constructions can be more than the JDBC driver and Task Server can handle. In that case, I ask the MSSQL DBAs if they will create a view for me constructed of the contents of the query and provide me select rights on the view. That leaves all the complex query language processing with SQL server rather than taxing the driver and DB Connect.
When dealing with ingesting data from a SQL server cluster, the usual construction of the JDBC connection string created by DB Connect won’t do. With a clustered environment, you also need to specify the instance name in addition to the hostname and port of the SQL Server listener. So, after setting up the connection information where the host is the listener and the port is the listener port, click the “Edit JDBC URL” checkbox and add “;instance=<database instance name>” to the end of the JDBC URL to ensure you connect to the proper database instance in the cluster. For example, the get to the “testdb” instance in the “sql01” cluster, you’d have a JDBC URL like: “jdbc:sqlserver://sql01.mycompany.com:1433;databaseName=master;selectMethod=cursor;integratedSecurity=true;instance=testdb”
I hope these directions and tips have been helpful in making your journey into Splunk DB Connect simpler and straightforward.
Happy Splunking!
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