I would like to add Cassandra to CloudFoundry. How can that be achieved? I was looking at the information posted here: CouchDB in CloudFoundry? but that is using the included CouchDB.
I also have been combing through this wiki https://github.com/cloudfoundry/oss-docs/tree/master/vcap/adding_a_system_service, but that doesn't give me enough information on how to point to my externally hosted Cassandra service.
Any help would be appreciated.
Although there's not much information on it, the Service Broker tool will let you expose an external service to a VCAP deployment (so that the service is displayed when running vmc services).
https://github.com/cloudfoundry/vcap-services/tree/master/service_broker
There isn't a how-to or other docs to speak of, so your best bet is to read the source and post questions on the vcap-dev google group. Here's an existing thread on Service Broker:
https://groups.google.com/a/cloudfoundry.org/d/topic/vcap-dev/sXF9rWzMMHc/discussion
If you want to connect directly your existing services from your private cloud, I then see 2 solutions :
Do nothing special and have your code connect to those services, assuming they are visible from the network and no firewall sits between them. Of course, you'll want to make their address configurable, but other than that, it is as if you were hitting a third party
create some kind of "gateway" service whose role would be to proxy the connection to your private service
Of course, a third solution would be to have a real "CloudFoundry" oriented Cassandra service, and migrate your existing data to it (but then it would not be accessible from the rest of your IS, unless you create a bridge the other way around)
I would start with option 1) and depending on your processes and usage, research solution 2) afterwards.
Related
I have managed to get the C# and db setup using ListMappings. However, when I try to deploy the split/merge tool to Azure cloud classic the service it states 'The requested VM tier is currently not available in East US for this subscription. Please try another tier or deploy to a different location.' We tried a few other regions with the same result. Do you know if there is a workaround or updated version? Is the split / merge service even still relevant? Has anyone got this service to run on Azure lately?
https://learn.microsoft.com/en-us/azure/azure-sql/database/elastic-scale-overview-split-and-merge
The answer to the question on whether it is still relevant, in my opinion is ...no. Split\merge is no longer relevant with the maturation of elastic pools. Elastic pools with one data base per tenant seem the sustainable way to implement multi tenancy with legacy code. The initial plan was to add keys to each of our tables to have multiple tenants per database. Elastic pools give us the same flexibility without having to make breaking changes our existing code.
Late post here, but we are implementing ElasticScale for a client to split ~50 clients into a database-per-tenant model. I don't think the SplitMerge tool will be used over the long term, just for the initial data migration from one db to many shards, but it has been handy for that purpose. We are using the ElasticScale SDK to allow a single API to route queries to the appropriate shard(s) based on sharding key. Happy to compare notes with you if you are still working on this.
If one application have Azure serviceBus, EventHub in diff Azure Namesapces, web application and also other azure services (eg: cognitive services). can these be accessed with one URL by using Gateway or Load balancer or traffic manager or any other option ?
My problem is - if we have diff namesapces, we need to whitelist every time when there is new Namespaces and it could so too much of a work. so wondering if we can have one common DNS/URL that would make life easier.
Today, Service Bus and Event Hubs don't support any sort of network gateway. This is due to fact that namespace in the connection string used for authorization purpose at the service side.
To add a bit of context to Serkant's statement, support for this scenario is something that is on our roadmap, and hopefully in the near term. Unfortunately, I don't have a date to share currently. The work is being tracked [here] should you wish to keep an eye on it.
I am trying to make my Service Fabric service, which makes a SOAP call to an external service, such that if deployed over 2 or more clusters, it can still work, in that if one service has made the connection to the external service, then the service in the other cluster doesn't try to make the connection, and vice versa.
I can't think of a better way to design this without storing the state in a database, which introduces a host of issues such as locking and race conditions, etc. What are some designs that can fit in this scenario. Any suggestions would be highly appreciated.
There is no way to do that out of the box on Service Fabric.
You have to find an approach to orchestrate these calls between clusters\services, you could:
Create a service in one of the clusters to delegate the calls to other services, and store the info about connections on a single service.
put a message in a queue and each service get one message to open a connection(this can be one of the approaches used above)
Store in a shared cache(redis) every active call, before you attempt to make the call you check if the connection is already active somewhere, when the connection close you remove from the cache for other services be able to open the connection, also enable expiration to close these connections in case of service failure.
Store the state in a database as you suggested
Currently our DB works in customer's local network and we have client app on C# to consume data. Due to some business needs, we got order to start moving everything to Azure. DB will be moving to Azure SQL.
We had discussion about accessing DB. There are two points:
One guy said that we have to add one more layer between our app (that will be working outside Azure at end-user PCs) and SQL Azure. In other words he suggested adding API service that will be translated all requests to DB, i.e. app(on-premises) -> API service (on Azure)-> SQL Azure. This approach looks more reliable and secure, since we are hiding SQL Azure behind facade of API service and the app talks to our API service only. It looks more like a reverse proxy. Obviously, behind this API we can build more sophisticated structure of DBs.
Another guy suggested connecting directly to DB, i.e. app(on-premises) -> SQL Azure. So far we don't have any plans to change structure of DB or even increase count of DBs. He claims it more simple and we can secure our connection the same way. Having additional service that just re-translates our queries to DB and back looks like wasting time.In the future, if needed, we would add this API.
What would you select and recommend, and why ?
Few notes:
We are going to use Azure AD to authenticate users.
Our application will be moving to Azure too, but later (in 1-2 years), we have plans to create REST API and move to thin client instead of fat client we have right now.
Good performance is our goal, we don't want to add extra things that can decrease it, but security is our most important goal as well.
Certainly an intermediate layer is one way to go. There isn't enough detail to be sure, but I wonder why you don't try the second option. Usually some redevelopment is normal. But if you can get away without it, and you get sufficient performance then that's even better.
I hope this helps.
Thank you.
Guy
If your application is not just a prototype (it sounds like it is not), then I advise you to build the intermediate API. The primary reasons for this are:
Flexibility
Rolling out a new version of an API is simple: You have either only one deployment or you have something like Octopus Deploy that deploys to a few instances at the same time for you. Deploying client applications is usually much more involved: Creating installers, distributing them, making sure users install them, etc.
If you build the API, you will be able to make changes to the DB and hide these changes from the client applications by just modifying the API implementation, but keeping the API interfaces the same. Moving forward, this will simplify the tasks for your team considerably.
Security
As soon as you have different roles/permissions in your system, you will need to implement them with DB security features if you connect to the DB directly. This may work for simple cases, but even there it is a pain to manage.
With an API, you can implement authorization in the API using C#. Like this, you can build whatever you need and you're not restricted by the security features the DB offers.
Also, if you don't take extra care about this, you may end up exposing the DB credentials to the client app, which will be a major security flaw.
Conclusion
Build the intermediate API. Except you have strong reasons not to. As always with architecture considerations, I'm sure there are cases where the above points don't apply. Just make sure you understand all the implications if you decide to go the direct route.
We are experiencing a very serious unscheduled downtime of our Azure application today for what is now coming up to 9 hours. We reported to Azure support and the ops team is actively trying to fix the problem and I do not doubt that. We managed to get our application running on another "test" hosted service that we have and redirected our CNAME to point at the instance so our customers are happy, but the "main" hosted service is still unavailable.
My own "finger in the air" instinct is that the issue is network related within our data center (west europe), and indeed, later on in the day the service dash board has gone red for that region with a message to that effect. (Our application is showing as "Healthy" in the portal, but is unreachable via our cloudapp.net URL. Additionally threads within our application are logging sql connection exceptions into our storage account as it cannot contact the DB)
What is very strange, though, is that the "test" instance I referred to above is also in the same data centre and has no issues contacting the DB and it's external endpoint is fully available.
I would like to ask the community if there is anything that I could have done better to avoid this downtime? I obeyed the guidance with respect to having at least 2 roles instances per role, yet I still got burned. Should I move to a more reliable data centre? Should I deploy my application to multiple data centres? How would I manage the fact that my SQL-Azure DB is in the same datacentre?
Any constructive guidance would be appreciated - being a techie, I've never had a more frustrating day being able to do nothing to help fix the issue.
There was an outage in the European data center today with respect to SQL Azure. Some of our clients got hit and had to move to another data center.
If you are running mission critical applications that cannot be down, I would deploy the application into multiple regions. DNS resolution is obviously a weak link right now in Azure, but can be worked around (if you only run a website it can be done very simply using Response.Redirects or similar)
Now, there is a data synchronization service from Microsoft that will sync up multiple SQL Azure databases. Check here. This way, you can have mirror sites up in different regions and have them be in sync with SQL Azure perspective
Also, be a good idea to employ a 3rd party monitoring service that would detect problems with your deployed instances externally. AzureWatch can notify or even deploy new nodes if you choose to, when some of the instances turn "Unresponsive"
Hope this helps
I can offer some guidance based on our experience:
Host your application in multiple data centers, complete with Sql Azure databases. You can connect each application to its data center specific Sql Server. You can also cache any external assets (images/JS/CSS) on the data center specific Windows Azure machine or leverage Azure Blog Storage. Note: Extra costs will be incurred.
Setup one-way SQL replication between your primary Sql Azure DB and the instance in the other data center. If you want to do bi-rectional replication, take a look at the MSDN site for guidance.
Leverage Azure Traffic Manager to route traffic to the data center closest to the user. It has geo-detection capabilities which will also improve the latency of your application. So you can redirect map http://myapp.com to the internal url of your data center and a user in Europe should automatically get redirected to the European data center and vice versa for USA. Note: At the time of writing this post, there is not a way to automatically detect and failover to a data center. Manual steps will be involved, once a failover is detected and failover is a complete set (i.e. you will failover both the Windows Azure AND Sql Azure instances). If you want micro-level failover, then I suggest putting all your config the in the service config file and encrypt the values so you can edit the connection string to connect instance X to DB Y.
You are all set now. I would create or install a local application to detect the availability of the site. A better solution would be to create a page to check for the availability of application specific components by writing a diagnostic page or web service and then poll it from a local computer.
HTH
As you're deploying to Azure you don't have much control about how SQL server is setup. MS have already set it up so that it is highly available.
Having said that, it seems that MS has been having some issues with SQL Azure over the last few days. We've been told that it only affected "a small number of users". At one point the service dashboard had 5 data centres affected by a problem. I had 3 databases in one of those data centres down twice for about an hour each time, but one database in another affected data centre that had no interruption.
If having a database connection is critical to your app, then the only way in the Azure environment to ensure against problems that MS haven't prepared against (this latest technical problem, earthquakes, meteor strikes) would be to co-locate your sql data in another data centre. At the moment the most practical way to do this is to use the synch framework. There is an ability to copy SQL Azure databases, but this only works within a data centre. With your data located elsewhere you could then point your app at the new database if the main one becomes unavailable.
While this looks good on paper though, this may not have helped you with the latest problem as it did affect multiple data centres. If you'd just been making database copies on a regular basis, that might have been enough to get you through. Or not.
(I would have posted this answer on server fault, but I couldn't find the question)
This is just about a programming/architecture issue, but you amy also want to ask the question on webmasters.stackexchange.com
You need to find out the root cause before drawing any conclusions.
However. my guess one of two things was the problem
The ISP connectivity differs for the test system and your production system. Either they use different ISPs, or different lines from the same ISP. When I worked in a hosting company we made sure that ou IP connectivity went through at least two different ISPS who did not share fibre to our premises (and where we could, they had different physical routes to the building - the homing ability of backhoes when there's a critical piece of fibre to dig up is well proven
Your datacentre had an issue with some shared production infrastructure. These might be edge routers, firewalls, load balancers, intrusion detection systems, traffic shapers etc. These typically are also often only installed on production systems. Defences here involve understanding the architecture and making sure the provider has a (tested!) DR plan for restoring SOME service when things go pair shaped. Neatest hack I saw here was persuading an IPS (intrusion prevention system) that its own management servers were malicious. And so you couldn't reconfigure it at all.
Just a thought - your DC doesn't host any of the Wikileaks mirrors, or Paypal/Mastercard/Amazon (who are getting DDOS'd by wikileaks supporters at the moment)?