https://github.com/xnnyygn/xraft
xnnyygn's raft implementation
https://github.com/xnnyygn/xraft
distributed-systems raft
Last synced: 6 months ago
JSON representation
xnnyygn's raft implementation
- Host: GitHub
- URL: https://github.com/xnnyygn/xraft
- Owner: xnnyygn
- License: mit
- Created: 2018-06-16T09:58:43.000Z (about 8 years ago)
- Default Branch: master
- Last Pushed: 2025-02-10T17:42:06.000Z (over 1 year ago)
- Last Synced: 2025-04-18T06:51:47.026Z (about 1 year ago)
- Topics: distributed-systems, raft
- Language: Java
- Homepage:
- Size: 1.03 MB
- Stars: 234
- Watchers: 9
- Forks: 109
- Open Issues: 16
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-java - xRaft
README
# xraft
A raft implementation of XnnYygn's.
I want to make something with netty framework, and I found raft. Raft is interesting. As the first distributed consensus algorithm I learnt, I read the paper and implemented almost all of the feature of raft including
* Leader election and log replication
* Membership change(one server change)
* Log compaction
All these feature are implemented in xraft-core. And the client interaction in raft, I thought, should be the feature of service based on xraft-core. Until now, I made a simple key value store based on xraft-core, called xraft-kvstore. It supports GET and SET command.
## Demostration
To test xraft with xraft-kvstore, you can download xraft and run xraft-kvstore, xraft-kvstore-cli.
### Prerequistes
Java 1.8+ is required to run xraft. You can run `java -version` to check the version of java on your computer.
### Download
You can get complied xraft in releases.
### Run Server
`xraft-kvstore` under the `bin` directory is the command to run xraft kvstore server.
To demostrate a xraft cluster with 3 nodes(memory log mode),
* node A, host localhost, port raft node 2333, port kvstore 3333
* node B, host localhost, port raft node 2334, port kvstore 3334
* node C, host localhost, port raft node 2335, port kvstore 3335
start servers with commands below
Terminal A
```
$ bin/xraft-kvstore -gc A,localhost,2333 B,localhost,2334 C,localhost,2335 -m group-member -i A -p2 3333
```
Terminal B
```
$ bin/xraft-kvstore -gc A,localhost,2333 B,localhost,2334 C,localhost,2335 -m group-member -i B -p2 3334
```
Terminal C
```
$ bin/xraft-kvstore -gc A,localhost,2333 B,localhost,2334 C,localhost,2335 -m group-member -i C -p2 3335
```
Since the minimum election timeout is 3 seconds, if you cannot execute all 3 commands within 3 seconds, you will get some error like `failed to connect ....`. But after you started all nodes, the error will disapper.
After start, you will see something like `become leader`, `current leader is xxx` and it shows the cluster is started and leader election is ok.
### Run Client
Run `xraft-kvstore-cli` with the cluster configuration. The client will not connect to any node in cluster so it is ok to run client before cluster starts.
```
$ bin/xraft-kvstore-cli -gc A,localhost,3333 B,localhost,3334 C,localhost,3335
```
It will run an interative console, press TAB two times and you will get the available commands. For this demostration, firstly run
```
> kvstore-get x
```
and you should get the result `null`. Then run
```
> kvstore-set x 1
```
nothing will be printed, now you can run get again.
```
> kvstore-get x
```
`1` should be printed.
## New Service
How to create new service based on xraft-core?
* [Node & NodeBuilder](https://github.com/xnnyygn/xraft/wiki/Node-&-NodeBuilder)
* [StateMachine](https://github.com/xnnyygn/xraft/wiki/StateMachine)
For more detailed implementation of new service, see the source code of xraft-kvstore.
## Build
xraft use [Maven](https://maven.apache.org/) as build system.
```
$ mvn clean compile install
```
To package xraft-kvstore
```
$ cd xraft-kvstore
$ mvn package assembly:single
```
## About PreVote
If you are looking for Raft optimization `PreVote`, please check `develop` branch.
## Consistency in xraft-kvstore
To make the implmenetation simple, the `xraft-kvstore` just reads the value in the concurrent hash map, which actually could be a stale value. There is an optimiation in `develop` branch called `readindex` to offer consistent read. If you need consistent read or want to know how to implement it, please refer to `develop` branch.
## License
This project is licensed under the MIT License.
## 关于《分布式一致性算法开发实战》和相关讨论
2020年5月，我出版了一本书，名字叫做[《分布式一致性算法开发实战》](https://book.douban.com/subject/35051108/)。书里面大部分代码都是参考我的这个项目，或者说我是先完成了这个项目然后再写了书。如果你对项目本身的架构，设计选择或者算法本身等有兴趣的话，欢迎阅读《分布式一致性算法开发实战》，我在书里做了很多详细的讲解。
另外，如果你对书籍或者代码设计有疑问的话，或者想要交流的话，欢迎在[豆瓣页面的讨论区](https://book.douban.com/subject/35051108/)内发表话题，我会定期检查并回复。