cloud | 易学教程

How do I scale a Java app with a REST API and a Database?

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I have a typical stateless Java application which provides a REST API and performs updates (CRUD) in a Postgresql Database. However the number of clients is growing and I feel the need to Increase redundancy, so that if one fails another takes place For this I will probably need a load balancer? Increase response speed by not flooding the network and the CPU of just one server (however how will the load balancer not get flooded?) Maybe I will need to distribute the Database? I want to be able to update my app seamlessly (I have seen a thingy called kubernetes doing this): Kill each redundant

How do I establish clock synchronization in the cloud (AWS, heroku, etc) across many nodes?

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问题 I would like to run a large cluster of nodes in the cloud (AWS, Heroku, or maybe self-manged VMS), whose clocks must be synchronized with a predefined tolerance in mind. I'm looking for a tolerance of maybe 200 ms. That means if I have 250 nodes, the largest clock difference between any of the 250 nodes should never exceed 200 ms. I don't really care about the actual date / time with respect to the world. The solution has to be fault tolerant, and should not need to rely on the accuracy of

Renamed Heroku's hostname, now it can't find the application

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问题 I previously had my Heroku's application name at: shielded-meadow-9293.heroku.com This was the name when I created the Heroku remote and fired up the dyno. After everything was running smooth, I changed the name to platformdesignmadness.heroku.com The site works, but in the same terminal, when I do a command such as heroku ps I get a $> ! Couldn't find that app. error. Why is this? 回答1: In your terminal: git remote rm heroku git remote add heroku git@heroku.com:yourappname.git See here Heroku

Firebase Functions for Firestore Failing due to NanoMatch Issue

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问题 I am new to cloud functions and was testing this sample code https://github.com/firebase/functions-samples/tree/master/quickstarts/uppercase-firestore This fails to execute due to an error from nanomatch. Looking at nanomatch repository on GitHub This is a listed issue and reverting back to 1.2.9 takes care of this error. I am trying to fix this on my end - but how do I do this? Can somebody guide me on this. Thank you for the help. TypeError: Cannot read property 'addQmark' of undefined at

How to deploy only worker/web role in Azure

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If you have a web AND a worker role in an Azure solution, all the waiting for the publishing an update package, uploading to the cloud storage, waiting for the package to be deployed could be exhausting, an waste a lot of time. How to upload/deploy only the worker or web role of an Microsoft Azure Solution, that contains both roles, and save both internet traffic and time? There is no option to build a package for only one of the both roles, but if you have limited bandwidth or traffic, and want to save from the upload time (which can be quite a big portion if you have a lot of static content:

Any good distributed agent/service models for .NET? [closed]

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问题 As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance. Closed 7 years ago . I'm looking for tools that implement the distributed agent/service model ... I guess we could also call this grid or cloud computing,

What are some big sites that are using Amazon EC2 [closed]

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问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 6 years ago . I'm looking for examples of large websites that are hosted on Amazon EC2/S3/Cloudfront/etc. I worked at a company where we ran a site that did 500k unique visitors per month on EC2 running 10 instances but that's still relatively small potatoes compared to some larger sites. I know smug mug and foursquare are

Connecting Android app to amazon RDS

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I have an Android application and I want to move my local database in the cloud. I decided for a SQL database and not for a NoSQL, because I want to execute complex queries. I created a database instance in RDS from Amazon and I populated the database. Now I want to connect my mobile app to my cloud database. I sow samples for NoSQL database connection, but I wasn't able to find examples for RDS. I saw that it is recommended to create a web service and connect to that web service, but it seems much more complicated than using a NoSQL and this doesn't feel right. Does Amazon offer some API

Couple of questions about Amazon EC2

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Amazon measures their CPU allotment in terms of virtual cores and EC2 Compute Units. EC2 Compute Units are defined as: The amount of CPU that is allocated to a particular instance is expressed in terms of these EC2 Compute Units. We use several benchmarks and tests to manage the consistency and predictability of the performance from an EC2 Compute Unit. One EC2 Compute Unit provides the equivalent CPU capacity of a 1.0-1.2 GHz 2007 Opteron or 2007 Xeon processor. This is also the equivalent to an early-2006 1.7 GHz Xeon processor referenced in our original documentation. My question is, say I

What is the best local-database solution for WPF applications?

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问题 What is currently the best solution for WPF applications which are meant to be used on one computer where various users log into them and use them to get/save information locally? Here's how I see the options: MDF would seem to be the best choice since I assume you can lock it down quite well so that even though users can access the .mdf file, they still couldn't access the data in it except through the application itself. I assume the .MDF file would have to exist separately from the