Corvus
Corvus is a fast and lightweight redis cluster proxy for redis 3.0 with cluster mode enabled.
Why
Most redis client implementations don't support redis cluster. We have a lot of services relying
on redis, which are written in Python, Java, Go, Nodejs etc. It's hard to provide redis client
libraries for multiple languages without breaking compatibilities. We used twemproxy
before, but it relies on sentinel for high availabity, it also requires restarting to add or
remove backend redis instances, which causes service interruption. And twemproxy is single
threaded, we have to deploy multiple twemproxy instances for large number of clients, which
causes the sa headaches.
Therefore, we made corvus.
Features
- Fast.
- Lightweight.
- Painless upgrade to official redis cluster from twemproxy.
- Multiple threading.
- Reuseport support.
- Pipeline support.
- Statsd integration.
- Syslog integration.
- Can direct read operations to slaves.
Performance
See details in our test results.
Requirements
- Linux >= 3.9
- Redis <= 3.0.7 (For version up to/including 0.2.3)
Build
If use the releases downloaded from
releases page, just make:
$ make
With debug mode enabled:
make debug
If build from latest source:
git clone https://github.com/eleme/corvus.git
cd corvus
git submodule update --init
make deps # need autoconf
make
Binary can be found at ./src/corvus.
Configuration
Example configuration file is at corvus.conf.
Usage
$ ./src/corvus path/to/corvus.conf
Commands
- All single-key commands (like
SET,GET,INCR..) are supported. - Batch commands are split into multiple single-key commands.
- Commands performing complex multi-key operations like unions or intersections
are available as well as long as the keys all belong to the same node.
Modified commands
MGET: split to multipleGET.MSET: split to multipleSET.DEL: split to multiple single keyDEL.EXISTS: split to multiple single keyEXISTS.PING: ignored and won't be forwarded.INFO,TIME: won't be forwarded to backend redis, information collected in proxy
will be returned.SLOWLOG: return the slowlogs saved by corvus itself. Note that unlike redis,
in the slowlog entry there's an additionalremote latencyfield before
thetotal latencyfield. The slowlog will also log the slowest
sub command for multiple-key commands:MGET,MSET,DEL,EXISTS.
The total latency of sub cmd entry will just be the same as its parent cmd.AUTH: do authentication in proxy.CONFIG: supportget,set, andrewritesub-command to retrieve and manipulate corvus config.SELECT: ignored if index is0, won't be forwarded.
Restricted commands
EVAL: at least one key should be given. If there are multiple keys, all of
them should belong to the same node.
The following commands require all argument keys to belong to the same redis node:
SORT.RPOP,LPUSH.SDIFF,SDIFFSTORE,SINTER,SINTERSTORE,SMOVE,SUNION,SUNIONSTORE.ZINTERSTORE,ZUNIONSTORE.PFCOUNTE,PFMERGE.
Unsupported commands
The following commands are not available, such as KEYS, we can't search keys across
all backend redis instances.
KEYS,MIGRATE,MOVE,OBJECT,RANDOMKEY,RENAME,RENAMENX,SCAN,WAIT.BITOP,MSETNXBLPOP,BRPOP,BRPOPLPUSH.PSUBSCRIBE,PUBLISH,PUBSUB,PUNSUBSCRIBE,SUBSCRIBE,UNSUBSCRIBE.EVALSHA,SCRIPT.DISCARD,EXEC,MULTI,UNWATCH,WATCH.CLUSTER.ECHO,QUIT.BGREWRITEAOF,BGSAVE,CLIENT,COMMAND,CONFIG,DBSIZE,DEBUG,FLUSHALL,
FLUSHDB,LASTSAVE,MONITOR,ROLE,SAVE,SHUTDOWN,SLAVEOF,SYNC.
License
MIT. Copyright (c) 2016 Eleme Inc.
See LICENSE for details.