rcm.cr

Redis Cluster Manager in Crystal

• binary download: https://github.com/maiha/rcm.cr/releases

Usage (information features)

nodes

• provides human-friendly output rather than redis-cli

% rcm -p 7001 nodes
b98ca1 [127.0.0.1:7001](0)  [0-5000     ] master(*)
835bea [127.0.0.1:7004](0)    +slave(*) of 127.0.0.1:7001
8a3c07 [127.0.0.1:7002](0)  [5001-10000 ] master(*)
0d0c75 [127.0.0.1:7005](0)    +slave(*) of 127.0.0.1:7002
33d324 [127.0.0.1:7003](0)  [10001-16383] master(*)
4a4da6 [127.0.0.1:7006](0)    +slave(*) of 127.0.0.1:7003
2581a1 [127.0.0.1:7007](0)  standalone master(*)
[OK] All 16384 slots are covered by 3 masters and 3 slaves.
[OK] All slots are available with 2 replication factor(s).

• NOTICE: This sends INFO keyspace to all nodes.

info

• summarize INFO for each nodes

% rcm -p 7001 info
edb22e [127.0.0.1:7001]  ver(3.2.0), cnt(7633), mem(2.27M;noev;0%), days(0)
f0da61 [127.0.0.1:7002]  ver(3.2.0), cnt(8751), mem(2.61M;noev;0%), days(0)

• arg can be used to select a specific line like grep arg INFO

% rcm -p 7001 info role,cnt,day
edb22e [127.0.0.1:7001]  role(master), cnt(7633), days(0)
f0da61 [127.0.0.1:7002]  role(master), cnt(8751), days(0)

• reserved field names for easy access

  • v , ver , version : delegate to redis_version
  • m , mem , memory : summarize used_memory_human , maxmemory_policy and maxmemory_human
  • cnt, count : extract db0:keys=(\d+)
  • d, day : delegate to uptime_in_days

• NOTICE: This sends INFO to all nodes.

Usage (replication features)

become slave

• meet and replicate (ex. make :7004 slaveof :7001)

% rcm -p 7004 meet 127.0.0.1:7001       # same as "meet :7001" for localhost
% rcm -p 7004 replicate 127.0.0.1:7001  # same as "replicate :7001" for localhost

advise

• In biased replications, nodes and advise advise a command to fix it.

% rcm -p 7001 nodes
...
[OK] All slots are available with 2+ replication factor(s).
advise: This can provide better replication. (rf of '127.0.0.1:7017': 2 -> 3)
  rcm -h '127.0.0.1' -p 7011 REPLICATE 127.0.0.1:7017

% rcm -h '127.0.0.1' -p 7011 REPLICATE 127.0.0.1:7017
REPLICATE 127.0.0.1:7017
OK

% rcm -p 7001 nodes
...
[OK] All slots are available with 3 replication factor(s).

• advise --yes is suit for batch.

# NOP when replication is well balanced
% rcm -p 7001 advise --yes

# `replicate` command is executed automatically when unblanaced
% rcm -p 7001 advise --yes
2016-06-23 21:21:49 +0900: BetterReplication: rf of '127.0.0.1:7016': 2 -> 3
rcm -h '127.0.0.1' -p 7012 REPLICATE 127.0.0.1:7016
REPLICATE 127.0.0.1:7016
OK

Usage (utility features)

ping (experimental)

• provides continual monitoring using curses
• ex) rcm -p 7001 ping

2016-06-27 09:54:36 +0900

[0-5000     ] 127.0.0.1:7001(5001) .........++..................
    +slave    127.0.0.1:7004(5001) .........++..................
[5001-10000 ] 127.0.0.1:7005(5000) ..........++.................
    +slave    127.0.0.1:7002(5000) ..........++.....EEEEEEE.....
[10001-16383] 127.0.0.1:7003(6384) ...........++................
    +slave    127.0.0.1:7006(6384) .......EEEEEEE.+.............
 ( no slots ) 127.0.0.1:7007(0)    .............................

import

• (experimental) This is too slow deu to step import by one by

% rcm -p 7001 import foo.tsv

Installation

% make
% cp bin/rcm ~/bin/

TODO

• [ ] Dryrun
• [ ] Check
  • [x] Nodes health check
  • [x] Slots coverage check
  • [x] detect orphaned master
  • [x] detect orphaned slave
• [ ] Advise
  • [x] Rebalance nodes
  • [ ] Rebalance slots
• [ ] Utils
  • [ ] Create cluster
  • [x] Rebalance nodes
  • [ ] Rebalance slots
  • [ ] Bulkinsert on import
  • [x] Ping monitoring
• [ ] Debug
  • [ ] Scan slots

Contributing

1. Fork it ( https://github.com/maiha/rcm.cr/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Contributors

• maiha maiha - creator, maintainer