Cloud SlashDB VM can't connect with Azure SQL DB - azure-sql-database

Question

I set up a SlashDB instance in Azure following the instructions here.
I set up an Azure DB which I can access just fine from SSMS using the server admin account. The DB server firewall seems to be properly connected to the SlashDB server vnet subnet's service endpoint.
When I let SlashDB compose the connection string based on host & DB names, I get this error:
Couldn't load model bromach_dev due to OperationalError. (pyodbc.OperationalError) ('08001', u'[08001] [unixODBC][FreeTDS][SQL Server]Unable to connect to data source (0) (SQLDriverConnect)') (Background on this error at: http://sqlalche.me/e/e3q8)
Connection Error (Default Connection String)
When I override the connection string with the ODBC connection string from the Azure Portal, I get this error instead:
Couldn't load model bromach_dev due to InterfaceError. (pyodbc.InterfaceError) ('IM002', u'[IM002] [unixODBC][Driver Manager]Data source name not found, and no default driver specified (0) (SQLDriverConnect)') (Background on this error at: http://sqlalche.me/e/rvf5)
Connection Error (Azure Connection String)
In this case, the connection string I am using is:
Driver={ODBC Driver 13 for SQL Server};Server=tcp:org-dev.database.windows.net,1433;Database=bromach_dev;Uid=serveradmin#org-dev;Pwd=****************;Encrypt=yes;TrustServerCertificate=no;Connection Timeout=30;
Ideas?

Answer 1

In order for SlashDB to connect there must be an open TCP/IP route from its virtual machine instance to the Azure SQL Server (sorry if I am stating the obvious).
Also, there must be a working DNS resolver on SlashDB instance so it can obtain the IP address for your database host as configured in the connection string.
DNS Fix -- NO LONGER REQUIRED --
Let's begin with the latter. The new SlashDB image had a bug, which is caused by a bug in the Azure's publishing process https://github.com/Azure/WALinuxAgent/issues/1151. We have already published a corrected image to the marketplace. The following workaround is no longer requried:
Log in to your SlashDB instance via SSH using credentials you set at when you launched the instance.
Issue the following command
sudo ln -s /run/systemd/resolve/stub-resolv.conf /etc/resolv.conf
Firewall settings (easy) -- START HERE --
Using Azure portal, navigate to your database resource and click on the "Set server firewall" button.
Check if "Allow access to Azure services" is switched on. In our testing, a SlashDB instance running in the same location as the database server (East US in our case) with this setting turned on connected without problems.
Firewall settings (safer)
Using the same Firewall settings panel as above, turn off the "Allow access to Azure services". Instead we will add a network route for your SlashDB instance to connect. It's preferable to do so using virtual network rules as follows.
Click on the "Add existing virtual network" button in the bottom portion of the screen. A side panel will open.
Fill in the required details, most important the name of the virtual network of your SlashDB instance (you can find that in its "Overview" page in Azure Portal). Click OK.
Hit "Save".
Database Connection in SlashDB
Open your SlashDB user interface in the browser, navigate to Configure/Databases and click the "edit" button next to your database connection.
There is no need do override the connection string. Your database connection configuration should look something like this:
Once that's done click Save, then Close. You should now be able to successfully connect.

Answer 2

If your Azure SQL DB is not a Managed Instance, the SlashDB VM could not connect to it.
And please ensure the Azure SQL Database server firewall is properly connected to the SlashDB server vnet subnet's service endpoint.
The instructions about SlashDB also provides two solutions about how to solve the failed connection:
In addition, I think you maybe you can read this link for a reference:Configure Azure VM to connect to an Azure SQL Database Managed Instance
I hope this can helps you.