redis演練(8) redis Cluster 集羣環境安裝

時間 2020-07-21

原文原文鏈接

redis是個分佈式緩存，與傳統數據庫最大的優點，在於它的「分佈式」上。html

分佈式的優點：node

容易實現容量的擴展
git
數據的均等分佈github
很好的高可用性redis

redis 和memcached是分佈式緩存的兩款流行方案，他們之間的對比數據庫

	redis	memcached
主從功能	Replication 支持緩存主備自動切換 ruby	自己不支持，能夠經過客戶端本身實現
鍵值一致性	哈希槽	一致性哈希
集羣	服務端支持（可是beta版） unstable	由客戶端實現
工具支持	提供自帶的工具（客戶端redis-cli,check-rdb...）	較弱
數據存儲	支持	不支持，重啓數據丟失

本章主要內容bash

安裝一個三主的redis集羣環境。網絡

準備

因爲本人沒有接觸過ruby語言，在安裝以前作功課時，須要安裝ruby環境等，心理上有了點小負擔，擔憂遇到麻煩。後來，不出所料遇到了點麻煩。最後，仍是安裝成功了，回頭想一想，沒有什麼可擔憂的，無外乎失敗了重裝，真是年紀越大，膽子越小啊。我採用的方式，「兵來將擋，水來土掩」，有錯就解決錯，一步步安裝。藉助網絡的力量，逐個把問題擊破。

安裝ruby環境

1.安裝ruby

遇到的問題

未安裝ruby

版本太低

未安裝rubygem

gem源出錯

請參考

http://blog.csdn.net/c77_cn/article/details/38227797

2. 編譯redis cluster

從https://github.com/antirez/redis/branches下載unstable版本。

編譯
make

此時,在/usr/local/src/redis-unstable/src 目錄下生成了支持cluster的redis-server

3.創建集羣環境

1.創建目錄
cp /usr/local/redis
mkdir cluster-test
cd cluster-test/
mkdir 7000
mkdir 7001
mkdir 7002
2.複製redis-server
 cp /usr/local/src/redis-unstable/src/redis-server  /usr/local/redis/cluster-test/7001
 cp /usr/local/src/redis-unstable/src/redis-server  /usr/local/redis/cluster-test/7000
 cp /usr/local/src/redis-unstable/src/redis-server  /usr/local/redis/cluster-test/7002
 #集羣管理工具（爲了方便，將他複製到合適位置）
 cp /usr/local/src/redis-unstable/src/redis-trib.rb /usr/local/redis/cluster-test

3.創建3個cluster 節點對應的redis.conf文件

[root@hadoop2 cluster-test]# vi 7000/redis.conf 
port 7000
cluster-enabled yes
cluster-config-file nodes.conf
cluster-node-timeout 5000
appendonly yes
daemonize yes
logfile "redis7000.log"

#這是最簡單的集羣參數

其餘7001/redis.conf,7002.conf文件，僅僅port和logfile參數不一樣，其餘同樣。

此時 7000, 7001,7002目錄下，只有2個文件,分別是 redis-server,redis.conf

4. 啓動（分別啓動3個主節點）

  cd 7000
  ./redis-server ./redis.conf
  cd ../7001/
  ./redis-server ./redis.conf
  cd ../7002
  ./redis-server ./redis.conf

對應某個節點日誌

26361:M 10 Sep 21:13:22.054 * No cluster configuration found, I'm 7f242cf2c7ce5d84103638c5017f2204e1509f4c
                _._
           _.-``__ ''-._
      _.-``    `. `_. ''-._           Redis 3.2.3 (00000000/0) 32 bit
.-`` .-```. ```\/    _.,_ ''-._
(    '      ,       .-` | `,    )     Running in cluster mode
|`-._`-...-` __...-.``-._|'` _.-'|     Port: 7001
|    `-._   `._    /     _.-'    |     PID: 26361
`-._    `-._ `-./ _.-'    _.-'
|`-._`-._    `-.__.-'    _.-'_.-'|
|    `-._`-._        _.-'_.-'    |           http://redis.io
`-._    `-._`-.__.-'_.-'    _.-'
|`-._`-._    `-.__.-'    _.-'_.-'|
|    `-._`-._        _.-'_.-'    |
`-._    `-._`-.__.-'_.-'    _.-'
      `-._    `-.__.-'    _.-'
          `-._        _.-'
              `-.__.-'

26361:M 10 Sep 21:13:22.075 # Server started, Redis version 3.2.3
26361:M 10 Sep 21:13:22.075 * DB loaded from append only file: 0.000 seconds
26361:M 10 Sep 21:13:22.076 # I have keys for unassigned slot 5659. Taking responsibility for it.
26361:M 10 Sep 21:13:22.076 # I have keys for unassigned slot 9980. Taking responsibility for it.
26361:M 10 Sep 21:13:22.080 * The server is now ready to accept connections on port 7001

5. 創建集羣

 ./redis-trib.rb create  127.0.0.1:7000 127.0.0.1:7001 127.0.0.1:7002

[root@hadoop2 cluster-test]# ./redis-trib.rb create 127.0.0.1:7000 127.0.0.1:7001 127.0.0.1:7002
>>> Creating cluster
>>> Performing hash slots allocation on 3 nodes...
Using 3 masters:
127.0.0.1:7000
127.0.0.1:7001
127.0.0.1:7002
M: 5ad201ebdf0553690295dcd06f89f15750e73989 127.0.0.1:7000
   slots:0-5460 (5461 slots) master
M: 7f242cf2c7ce5d84103638c5017f2204e1509f4c 127.0.0.1:7001
   slots:5461-10922 (5462 slots) master
M: 8ea7b0976e4848653435e4e77af311a6ade330a8 127.0.0.1:7002
   slots:10923-16383 (5461 slots) master
Can I set the above configuration? (type 'yes' to accept): yes
>>> Nodes configuration updated
>>> Assign a different config epoch to each node
>>> Sending CLUSTER MEET messages to join the cluster
Waiting for the cluster to join.
>>> Performing Cluster Check (using node 127.0.0.1:7000)
M: 5ad201ebdf0553690295dcd06f89f15750e73989 127.0.0.1:7000
   slots:0-5460 (5461 slots) master
   0 additional replica(s)
M: 8ea7b0976e4848653435e4e77af311a6ade330a8 127.0.0.1:7002
   slots:10923-16383 (5461 slots) master
   0 additional replica(s)
M: 7f242cf2c7ce5d84103638c5017f2204e1509f4c 127.0.0.1:7001
   slots:5461-10922 (5462 slots) master
   0 additional replica(s)
[OK] All nodes agree about slots configuration.
>>> Check for open slots...
>>> Check slots coverage...
[OK] All 16384 slots covered.

這時候主節點日誌

26536:M 10 Sep 21:25:32.360 * DB loaded from append only file: 0.000 seconds
26536:M 10 Sep 21:25:32.361 * The server is now ready to accept connections on port 7000
26536:M 10 Sep 21:27:54.651 # configEpoch set to 1 via CLUSTER SET-CONFIG-EPOCH
26536:M 10 Sep 21:27:54.660 # IP address for this node updated to 127.0.0.1
26536:M 10 Sep 21:27:59.619 # Cluster state changed: ok

6.測試

[root@hadoop2 cluster-test]#  /usr/local/redis/bin/redis-cli  -c -p 7000
127.0.0.1:7000> keys *
(empty list or set)
127.0.0.1:7000> set title "cluster1"
OK
127.0.0.1:7000> set title1 "cluster1"
OK
127.0.0.1:7000> set title2 "cluster1"
-> Redirected to slot [14045] located at 127.0.0.1:7002
OK

127.0.0.1:7002> set title5 "cluster4"
-> Redirected to slot [1594] located at 127.0.0.1:7000
OK
127.0.0.1:7000> set title3 "cluster4"
-> Redirected to slot [9980] located at 127.0.0.1:7001
OK
127.0.0.1:7001> get title
-> Redirected to slot [2217] located at 127.0.0.1:7000
"cluster1"
127.0.0.1:7000> get title2
-> Redirected to slot [14045] located at 127.0.0.1:7002
"cluster8111"
127.0.0.1:7002> get title3
-> Redirected to slot [9980] located at 127.0.0.1:7001
"cluster4"

#節點間來回重定向

到了這裏，環境算是搭建好了。固然，這是最簡單的集羣了。之後隨着演練的深刻，也會對集羣進行深刻探討。

遇到問題

可能遇到的錯誤（是第二次創建集羣時報錯）

ERR Slot 2217 is already busy (Redis::CommandError)

解決方法： (in all nodes did FLUSHALL and then CLUSTER RESET SOFT)

Either the node already knows other nodes

[root@hadoop2 cluster-test]# ./redis-trib.rb create 127.0.0.1:7000 127.0.0.1:7001 127.0.0.1:7002
>>> Creating cluster
[ERR] Node 127.0.0.1:7000 is not empty. Either the node already knows other nodes (check with CLUSTER NODES) or contains some key in database 0.

解決方法：這是由於重複設置集羣。

重啓集羣，發現數據丟失

集羣建立完成後，當關機或者關閉集羣再次啓動的時候，必定要在node-conf所在的目錄啓動各個節點，

集羣才能正常鏈接。

參考資源

http://blog.csdn.net/c77_cn/article/details/38227797

http://redis.io/topics/cluster-tutorial

http://redisdoc.com/topic/cluster-tutorial.html