I have a solution that has a self hosted WCF Service. That service connects to EF and can read and write just fine.
In the same solution I also host an NServiceBus endpoint. It gets event from a separate running solution.
When I run the NServiceBus project (by itself) it seems to be working fine, until I try to query my database. When I do that I get this EntityException:
The underlying provider failed on Open.
The inner exception is a TransactionException with a message of:
The partner transaction manager has disabled its support for remote/network transactions
Both my NServiceBus and WCF Service projects are using the exact same configurations and EF Projects. I don't get why one is failing and the other is not.
I did some Googling and came across this page: http://msdn.microsoft.com/en-us/library/aa561924%28BTS.20%29.aspx that showed me how to setup MSDTC, and I did it on my client machine. But it had no effect.
I also found this question that says it needs to be set: NServiceBus: System.Transactions.TransactionException: The partner transaction manager has disabled its support for remote/network transactions. But it does not say why or where.
Do I need to setup MSDTC on my db server? If so, why? What is MSDTC?
Why does running from an NServiceBus hosted process cause this error?
UPDATE: I found this link that helped me understand what DTC does. It also showed me how to turn it off if needed:
using (TransactionScope sc=new TransactionScope(TransactionScopeOption.Suppress))
YourDatabaseHandler.SaveMyStuff(whatever);
Though it sounds like it is a good thing in many situations.
Since NSB is using a transactional queue, your going to be participating in a distributed transaction. This means that each machine participating will have to vote on whether or not to complete a transaction. This is done via the Distributed Transaction Coordinator(MSDTC). This will have to be running on both machines(and if you are using other DBs like Oracle there is an additional service). To manage MSDTC, go to Component Services -> Computers -> My Computer -> Distributed Transaction Coordinator -> Local DTC. Right clicking on that node you will find all the configuration including security.
Related
This question is purposefully general because I'm trying to understand things more from an architectural perspective, because that will impact which group I need to contact. My team is using Azure DevOps (cloud) with on-prem build agents. The agents connect to ADO via a proxy.
We use several tools in-house provided by vendors with ADO plugins in the Marketplace that require us to set up service connections. Because the services are installed on-prem, the endpoints we enter are not available via the Web (e.g. https://vendor-product.my-company.com).
If I log into the build machine and open up IE, I am able to connect to the service endpoint URL. However, whenever I try to run a task from ADO, it fails with some kind of connection-related issue ("The underlying connection was closed: An unexpected error occurred on a send", "Task ended with an exception: Error: read ECONNRESET", etc.).
The way I thought it worked, all the work takes place on the build machine itself, so the calls would be going from my-build-server.my-company.com to https://vendor-product.my-company.com. Those error messages though make me wonder if the connection is actually coming from https://dev.azure.com.
So the questions I have are:
For situations like this, is the connection to a service endpoint going to be seen as coming from my on-prem build agent, or from ADO (or does it vary based on how the vendor writes their plugin)?
If the answer to #1 is "it varies", is there any way for me to tell just from the plugin itself without having to contact the vendor? (In my experience some of the vendor reps don't understand how the cloud works.)
and/or
Because my build agent was configured to use a proxy when I set it up, is it going to use that proxy for all connections, even internal ones? I think I can set up a proxy bypass list for the agents but I presently only have read access to the build box. I can request temporary elevated access but I'd need some level of confidence that's what the issue is.
Hope I explained the situation clearly, thanks in advance for any insight.
I am using wildfly-8.2.0.Final.
There are several databases that i have to connect to. However, some of them are only used for certain functionalities on the web application and they are not needed to be online all the time. So when the wildfly starts, some of the datasources may not be online. However, disconnection to any datasource causes wildfly to not deploy .war deployment and i cannot find any way to solve this problem. Is there a way?
UPDATE:
I have a single table on a remote database server. The user will be able to query the table via my web application. The thing is, I have almost no control over the mentioned database. When the web application starts, it could be offline. However, this would cause my web application to fail to start. What I want is being able to run queries on a remote database if it is online. If it is offline, the web page could fail or the query can be canceled. But the only thing that I don’t want is that my web application to be limited by a remote database that I may have no control over.
My previous solution was a workaround. I would run queries on the remote database via a local database which has a foreign table to the remote one. However, the local one reads all data on the remote table before applying any constraints on postgresql 9.5. As the remote table has a large number of rows and I am using lazy loading, it takes so long for a single query and defeats the whole purpose of the lazy loading.
I found a similar question, but there is no answer.
On wildfly, you can set the datasource so that it tries to reconnect periodically when it disconnects. In my case, the deployment should be successful initially for this to be helpful.
The deployment will failed if it references those datasources.
Also you could define but disable those datasources.
I'm writing my first application using MSMQ and everything works well with local queues on my development machine. I cannot seem to connect to a remote queue when I tested it.
I have 10 Windows 10 Pro installation (not domain joined, but I have also tried this on two domain joined machines), both with MSMQ installed. I have disabled the firewall on both machines, unchecked the 'Disable un-authenticated RPC calls" on both machines. Changed the permissions on the queue to full control for everyone and anonymous.
I'm using .NET and the system.messaging namespace. When I call the messagequeue constructor, I can see that most of the properties are in a exception state.
VB code New MessageQueue("FormatName:Direct=TCP:x.x.x.x\private$\test")
I found an article detailing a registry entry NewRemoteReadServerAllowNoneSecurityClient I thought might work but got the same result. I'm sure this is some sort of security issue but I have no idea what I'm doing wrong.
Anyone have any ideas? Seems like this should be much easier than I am experiencing.
I've read some articles recently on setting up AWS infrastructure w/o enabling SSH on Ec2 instances. My web app requires a binary to run. So how can I deploy my application to an ec2 instance w/o using ssh?
This was the article in question.
http://wblinks.com/notes/aws-tips-i-wish-id-known-before-i-started/
Although doable, like the article says, it requires to think about servers as ephemeral servers. A good example of this is web services that scale up and down depending on demand. If something goes wrong with one of the servers you can just terminate your server and spin up another one.
Generally, you can accomplish this using a pull model. For example at bootup pull your code from a git/mecurial repository and then execute scripts to setup your instance. The script will setup all the monitoring required to determine whether your server and application are up and running appropriately. You would still need an SSH client for this if you want to pull your code using ssh. (Although you could also do it through HTTPS)
You can also use configuration management tools that don't use ssh at all like Puppet or Chef. Essentially your node/server will pull all your application and server configuration from the Puppet master or the Chef server. The Puppet agent or Chef client would then perform all the configuration/deployment/monitoring changes for your application to run.
If you with this model I think one of the most critical components is monitoring. You need to know at all times if there's something wrong with one of your server and in the event something goes wrong discard the server and spin up a new one. (Even better if this whole process is automated)
Hope this helps.
It seems I am running into the Microsoft Distributed Transaction Coordinator (MSDTC) related issue.
SCENARIO
I am using TransactionScope and with in the single scope it hits two different databases on different servers (for instance, DB_A running Windows Server 2003 and DB_B running Windows Server 2008). One database is accessed using Entity Framework 4.0 and another using normal ADO.NET APIs.
When I run the application from my development machine (running WinXP) it commits and rollbacks both the connections accurately. But when I run the application, deployed on another server (for instance WAS_A running Windows Server 2003) it commits correctly but in case of exception is doesn't roll back the database activities on both the servers.
I thought it would be the MSDTC configuration issue on the WAS_A. So I went to the MSDTC -> Security Configuration and checked all the available options (as I did previously on other machines). But still I am facing the same issue.
Looking for your expert advices. :)
I believe that you need to look into Enabling Transaction Flow. Specifically, take a look at how one may error and the other complete as described in TransactionScope and WCF Services:
an error in a second WCF service call was NOT rolling back the changes made in a previous WCF service call...
In order to create an ambient transaction in your client and ensure that it is used by your WCF services...
The article then details the following steps:
Configure Your Binding with transactionFlow
Decorate Your Interface with [TransactionFlow(TransactionFlowOption)]
Decorate Your Method with [OperationBehavior(TransactionScopeRequired)]
Optionally update your Connection Strings with Transaction Binding*
*Note: This is optional in my opinion.