distributed-system | 易学教程

Hyperledger fabric : How to set up a distributed network of peer nodes?

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问题 How to set-up distributed system of peer nodes in different machines in hyperledger-fabric v1.0.0 beta ? 回答1: First of all, you should define how is going to be your network, i.e. how many and wich nodes are going to be started up in each machine. Then, you should define the docker-compose files for each machine. There you define the nodes that you will put up in each machine. At the end, you will start up the nodes. Make sure that you define well the configuration of all the config files,

How does node know which nodes have seen the cluster current state?

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问题 I'm reading akka documentation and come up with some troubles of undertanding the way they implemented Gossip . (docs here). The part that confused me, (emphasized mine): Periodically, the default is every 1 second, each node chooses another random node to initiate a round of gossip with. If less than ½ of the nodes resides in the seen set (have seen the new state) then the cluster gossips 3 times instead of once every second. This adjusted gossip interval is a way to speed up the convergence

In RAFT is it possible to have a majority consensus on a log entry but the entry is not committed?

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问题 Consider this simulation in the official raft webpage Why is term 2 index 1 not committed despite S2 (leader) , S3 and S4 agreeing on the log? I run this multiple minutes to make sure all communication has taken place. Weirdly enough, if I add one more log entry term 6 index 2 then term 2 index 1 will be committed. Does anyone know what is the rule that is preventing term 2 index 1 to be committed? 回答1: Your leader is in term 6, but none of the log entries are from term 6; this invokes a

what is the Vertical and Horizontal distribution?

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问题 Vertical distribution : Distributed processing is equivalent to organizing a client-server application as a multitiered architecture . Place logically different components on different machines . Horizontal distribution : Distribution of the clients and servers - more common in modern architecture . A client or server may be physically split up into logically equivalent parts, but each part is operating on its own share of the complete data set, thus balancing the load . i tried to understand

PBFT: Why cant the replicas perform the request after 2/3 have prepared? why do we need commit phase?

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问题 I know there are some questions on this website that asks the same questions. However the answer is never clear: In PBFT, why cant the replicas execute the requests after 2/3s have prepared? why is commit phase needed? if 2/3 + 1 replica have agreed to prepared, then I owuld think they can execute the request without broadcasting again? 回答1: (Edited) In addition to previous (incomplete) answer, a quote from from Practical Byzantine Fault Tolerance and Proactive Recovery might help. Note that

Serialize vector in C++ to send over UDP Socket?

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问题 As a part of our end semester project we are required to implement a distributed chat system. The system needs to be scalable and robust. Keeping these criteria in mind I am confused as to how do we send a vector object over the socket. Since the vector is dynamically allocated sending it's object as such would not work as the memory to which it points is not copied. In order to accomplish this serialization would be the best option. But, as required by our project we are not suppose to use

What is a proxy? What is it in Apache? Does it have many different meanings?

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问题 It has nothing to do file-descriptors. Is it some sort of connection between different protocols? Does there exist more like that? Reverse -proxy? Direct -proxy? Indirect -proxy? Does proxy mean 3-layer, 7-layer or different layer in OSI reference model? If you have NAT, you have 3-layer while 7-layer is the common proxy according to Wikipedia here. The Wikipedia continues "Because NAT operates at layer-3, it is less resource-intensive than the layer-7 proxy, but also less flexible" -- there

How to classify a failure detector?

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问题 I understand that failure detectors in asynchronous systems are basically classified as (eventually)perfect/(eventually)strong and how those classes are defined, but I kind of struggle to get the intuition behind it. Suppose I have a concrete implementation of a failure detector, which periodically listens for heartbeat messages from each process. If a process hasn't sent its heartbeat message for a while, the process will be added to a list of suspects until a message is received from the

How to classify a failure detector?

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I understand that failure detectors in asynchronous systems are basically classified as (eventually)perfect/(eventually)strong and how those classes are defined, but I kind of struggle to get the intuition behind it. Suppose I have a concrete implementation of a failure detector, which periodically listens for heartbeat messages from each process. If a process hasn't sent its heartbeat message for a while, the process will be added to a list of suspects until a message is received from the process. Now, how do I know which class is this implementation of an FD? Would that require a formal

How to best set up a “central” git repository from a current existing local git repository?

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问题 I know git is distributed, and frankly I like that property about it. The situation is that I have been a sole developer of a piece of software that I have been managing by git since its inception, on my local storage. This has always been so - in other words, only a single repository exists currently, where I commit and merge stuff and keep the master branch in "public release" state. I am now on the verge of giving up exclusive control of the project and will be sharing its source code base