Connection string to connect to a SQL cluster

Question

Connection string to connect to a SQL cluster

NM 41

Hello,

How can i connect to a SQL cluster instance using javascript. Do i have to configure a listener ?

or is there some other standard way of doing this. Please, sugget.

Thanks,
NM

2 answers

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Answer 1

Cris Zhan-MSFT 6,661

Hi @NM ,

The "Listener" is the component/method of connecting the Always on availability group.

To connect to SQL Server FCI (Failover Cluster Instance), you need to specify the cluster network name or IP address (if it is a named instance, you must specify the cluster name or IP address\instance name) so that the application can be transparent Connect to the active node without being affected by failover.

There are two resources of the SQL Server FCI's own dedicated virtual network name and IP address in the SQL Server resource group (ie SQL Server FCI) on the Windows failover cluster, They provide the server name or IP address used by the application to access the SQL Server FCI.

Cris Zhan-MSFT 6,661 Reputation points

2021-04-19T02:12:22.8+00:00

Hi @NM ,

For a multi-subnet cluster, each site in the cluster needs to be configured with a virtual IP address, and the "virtual network name" resource will depend on all these IP address resources. The virtual network name resource can be configured to rely on these IP address resources in an "OR" relationship.

Answer 2

NM 41

Thanks for the reply but i am still not able to connect to the instance.

My configuration -

It's a 2 node Fail over cluster.
Both the nodes are on 2 different subnet.
Node 1 IP - 192.168.10.1
Node 2 IP - 192.169.10.1
My SQL instance name - sqlcluster
When i installed SQL(cluster install) on Node 1 it took ip as 192.168.10.80
When i installed and added SQL to the above cluster it took another ip as 192.169.10.80
So, now instance sqlcluster has 2 ip's - 192.168.10.80, 192.169.10.80

IS there any additional configuration that i would have to do.

Please suggest.

Erland Sommarskog 121.4K Reputation points MVP Volunteer Moderator

2021-04-17T11:04:14.877+00:00

Permit me a stupid question, but does that cluster work at all?

192.169.10.1 is a public address on the internet, and I can ping it successfully from my computer. That may or may not be you server. Most likely it is not, and this net is allocated to someone else since way back them.

192.168.10.1 is a private C-net which cannot be reached from the outside internet. These are addresses you can toy around with as you which.

I have not played with TCP routing for a long time, but I think you need to change the IP of 192.169.10.1 to be somewhere in the 192.168 range.
NM 41 Reputation points

2021-04-17T14:17:18.407+00:00

Thanks for the reply.

its a lab environment created for testing in Azure VM....where the network is mostly internal with a Jump box on public network.

The cluster validation report does shows a warning for the ip configuration but other than that the failover and SQL service hosting is working fine.

So, does a cluster does not work in the case when nodes are on different subnets ?

Please, suggest.
Erland Sommarskog 121.4K Reputation points MVP Volunteer Moderator

2021-04-17T16:10:30.313+00:00

So, does a cluster does not work in the case when nodes are on different subnets ?

I can't answer that question, because clustering is not witin my realm of expertise. However, I noticed the very odd combination of IP addresses, and wanted to raise your attention on it.

I realise that if this is in a sheltered environment, there cannot be conflicts with the outside world. I would definitely move the one in 192.169 somewhere into 192.168. Note that 192.168. is not a single subnet, but 255 different ones. Or at least it was when I learnt TCP/IP which was many many moons ago.
Alberto Poblacion 1,571 Reputation points

2021-04-17T17:23:49.433+00:00

So, now instance sqlcluster has 2 ip's - 192.168.10.80, 192.169.10.80

Something is missing. Your cluster should have three addresses: one for each machine, plus another one for the cluster as a whole. Your client code should be connecting to this third address, and the internal cluster infrastructure would redirect the connection to the active node.
The individual addresses for each node should not be used from the client code. You would normally only connect to them in case you need to do a maintenance operation on one specific node.
NM 41 Reputation points

2021-04-19T13:37:55.25+00:00

Hello,

My SQL cluster is a multi subnet failover cluster...failover is working fine but the i am not able to ping the SQL cluster with the name of the instance. It's a 2 node cluster and i can ping within the node when it's active but can't ping from another node or from outside.

I have checked/rechecked all the settings related to DNS, Network and everything seems to be fine at this stage.
But because i can't ping the cluster i can not access it using my connection string.

What should be the next set of troubleshooting i can do?
Tom Phillips 17,771 Reputation points

2021-04-19T15:15:48.54+00:00

There is no reason to ping the node.

Are you having an actual problem connecting to the SQL Server instance using the cluster resource network name?

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Connection string to connect to a SQL cluster

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