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搭建redis叢集-(偽分散式)

安裝redis

#關閉防火牆並且安裝iptables(防火牆) 並在防火牆中新增規則,也可以用firewalld.service 防火牆
#如果是用firewalld.service 的防火牆的話下面的步驟可以忽略

# service iptables save
The service command supports only basic LSB actions (start, stop, restart, try-restart, reload, force-reload, status). For other actions, please try to use systemctl.
的錯誤資訊。



解決方法:

先執行如下命令:

   systemctl stop firewalld

   systemctl mask firewalld

2.安裝iptables services

    yum install iptables-services

3.設定開機啟動

    systemctl enable iptables

4.重啟iptables service

    systemctl restart iptables

5.執行儲存配置命令

    service iptables save

防火牆中開啟儲存器埠

# vim /etc/sysconfig/iptables
 
新增如下埠行:
-A INPUT -m state --state NEW -m tcp -p tcp --dport 6379 -j ACCEPT
 
重啟防火牆:

# service iptables restart

安裝單機版redis(這個在我的部落格中有記錄,可以參照安裝)

然後開始準備安裝叢集版redis

#首先安裝ruby
yum install ruby
#安裝ruby的執行環境
yum install rubygems
#安裝ruby指令碼執行時使用的包
gem install redis-3.0.0.gem

剩下的安裝引用自:https://www.cnblogs.com/zacard-orc/p/3608638.html 懶癌症患者,ctrl +c 

Linux Redis叢集搭建與叢集客戶端實現

硬體環境

本文適用的硬體環境如下

Linux版本:CentOS release 6.7 (Final)
Redis版本:3.2.1

Redis已經成功安裝,安裝路徑為/home/idata/yangfan/local/redis-3.2.1。

我們要在單臺機器上搭建Redis叢集,方式是通過不同的TCP埠啟動多個例項,然後組成叢集。

 

1、啟動Redis多個例項

我們在Redis安裝目錄下建立目錄cluster,並編寫7000.conf~7005.conf 6個配置檔案,這6個配置檔案用來啟動6個例項,後面將使用這6個例項組成叢集。

以7000.conf為例,配置檔案需要填寫如下幾項。

 

port  7000                                        //埠7000,7002,7003        
bind 10.93.84.53                                     //預設ip為127.0.0.1 需要改為其他節點機器可訪問的ip 否則建立叢集時無法訪問對應的埠,無法建立叢集
daemonize    yes                               //redis後臺執行
pidfile  ./redis_7000.pid          //pidfile檔案對應7000,7001,7002
cluster-enabled  yes                           //開啟叢集  把註釋#去掉
cluster-config-file  nodes_7000.conf   //叢集的配置  配置檔案首次啟動自動生成 7000,7001,7002
cluster-node-timeout  15000                //請求超時  預設15秒,可自行設定
appendonly  yes                           //aof日誌開啟  有需要就開啟,它會每次寫操作都記錄一條日誌 

 

分別啟動6個例項

./bin/redis-server cluster/conf/7000.conf
./bin/redis-server cluster/conf/7001.conf 
./bin/redis-server cluster/conf/7002.conf 
./bin/redis-server cluster/conf/7003.conf 
./bin/redis-server cluster/conf/7004.conf 
./bin/redis-server cluster/conf/7005.conf 

啟動成功後,看一下程序

 

# ps -ef | grep redis | grep cluster
idata    15711 22329  0 18:40 pts/10   00:00:00 ./bin/redis-server 10.93.84.53:7000 [cluster]
idata    15740 22329  0 18:40 pts/10   00:00:00 ./bin/redis-server 10.93.84.53:7001 [cluster]
idata    15810 22329  0 18:40 pts/10   00:00:00 ./bin/redis-server 10.93.84.53:7002 [cluster]
idata    17023 22329  0 18:42 pts/10   00:00:00 ./bin/redis-server 10.93.84.53:7003 [cluster]
idata    17030 22329  0 18:42 pts/10   00:00:00 ./bin/redis-server 10.93.84.53:7004 [cluster]
idata    17035 22329  0 18:42 pts/10   00:00:00 ./bin/redis-server 10.93.84.53:7005 [cluster]

 

至此,ip=10.93.84.53機器上建立了6個例項,埠號為port=7000~7005。

 

Redis 3.0以上的叢集方式是通過Redis安裝目錄下的bin/redis-trib.rb指令碼搭建。

這個指令碼是用Ruby編寫的,嘗試執行,如果列印如下,你可以跳過本文的第二部分。

 

[email protected]:~/yangfan/local/redis-3.2.1/bin$ ruby redis-trib.rb 
Usage: redis-trib <command> <options> <arguments ...>

  create          host1:port1 ... hostN:portN
                  --replicas <arg>
  check           host:port
  info            host:port
  fix             host:port
                  --timeout <arg>
  reshard         host:port
                  --from <arg>
                  --to <arg>
                  --slots <arg>
                  --yes
                  --timeout <arg>
                  --pipeline <arg>
  rebalance       host:port
                  --weight <arg>
                  --auto-weights
                  --use-empty-masters
                  --timeout <arg>
                  --simulate
                  --pipeline <arg>
                  --threshold <arg>
  add-node        new_host:new_port existing_host:existing_port
                  --slave
                  --master-id <arg>
  del-node        host:port node_id
  set-timeout     host:port milliseconds
  call            host:port command arg arg .. arg
  import          host:port
                  --from <arg>
                  --copy
                  --replace
  help            (show this help)

For check, fix, reshard, del-node, set-timeout you can specify the host and port of any working node in the cluster.

 

如果執行失敗,那麼不幸的是你的機器沒有Ruby執行的環境,那麼你需要安裝Ruby。進入第二部分。

 

2、安裝ruby

下面的過程都是在root許可權下完成的。

1)yum安裝ruby和依賴的包。

# yum -y install ruby ruby-devel rubygems rpm-build 

一般來說,這一步是能正常完成的。

 

2)使用gem這個命令來安裝redis介面

gem是ruby的一個工具包

# gem install redis 

安裝過程出錯

鬱悶,看樣子要升級ruby版本。

 

3)升級Ruby的版本

安裝rvm,我不知道這是個什麼東西,但是感覺像是Ruby的一個包管理器。

# curl -L get.rvm.io | bash -s stable 

WTF,又出問題了

氣急敗壞的照著他說的做

 

# gpg2 --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3
gpg: keyring `/root/.gnupg/secring.gpg' created
gpg: requesting key D39DC0E3 from hkp server keys.gnupg.net
gpg: /root/.gnupg/trustdb.gpg: trustdb created
gpg: key D39DC0E3: public key "Michal Papis (RVM signing) <[email protected]>" imported
gpg: no ultimately trusted keys found
gpg: Total number processed: 1
gpg:               imported: 1  (RSA: 1)

 

然後重新下載rvm安裝,成功了。

 

# curl -L get.rvm.io | bash -s stable 
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 24090  100 24090    0     0  18023      0  0:00:01  0:00:01 --:--:--  129k
Downloading https://github.com/rvm/rvm/archive/1.29.3.tar.gz
Downloading https://github.com/rvm/rvm/releases/download/1.29.3/1.29.3.tar.gz.asc
gpg: Signature made Mon 11 Sep 2017 04:59:21 AM CST using RSA key ID BF04FF17
gpg: Good signature from "Michal Papis (RVM signing) <[email protected]>"
gpg:                 aka "Michal Papis <[email protected]>"
gpg:                 aka "[jpeg image of size 5015]"
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: 409B 6B17 96C2 7546 2A17  0311 3804 BB82 D39D C0E3
     Subkey fingerprint: 62C9 E5F4 DA30 0D94 AC36  166B E206 C29F BF04 FF17
GPG verified '/usr/local/rvm/archives/rvm-1.29.3.tgz'
Creating group 'rvm'

Installing RVM to /usr/local/rvm/
Installation of RVM in /usr/local/rvm/ is almost complete:

  * First you need to add all users that will be using rvm to 'rvm' group,
    and logout - login again, anyone using rvm will be operating with `umask u=rwx,g=rwx,o=rx`.

  * To start using RVM you need to run `source /etc/profile.d/rvm.sh`
    in all your open shell windows, in rare cases you need to reopen all shell windows.

 

接著,source環境,讓rvm可用。

# source /usr/local/rvm/scripts/rvm

檢視Ruby可用版本

 

# rvm list known
# MRI Rubies
[ruby-]1.8.6[-p420]
[ruby-]1.8.7[-head] # security released on head
[ruby-]1.9.1[-p431]
[ruby-]1.9.2[-p330]
[ruby-]1.9.3[-p551]
[ruby-]2.0.0[-p648]
[ruby-]2.1[.10]
[ruby-]2.2[.7]
[ruby-]2.3[.4]
[ruby-]2.4[.1]

 

可以看到最新的版本是2.4.1,那麼我們裝最新的吧。

 

# rvm install 2.4.1
Searching for binary rubies, this might take some time.
No binary rubies available for: centos/6/x86_64/ruby-2.4.1.
Continuing with compilation. Please read 'rvm help mount' to get more information on binary rubies.
Checking requirements for centos.
Installing requirements for centos.
Installing required packages: libffi-devel, libyaml-devel......
Requirements installation successful.
Installing Ruby from source to: /usr/local/rvm/rubies/ruby-2.4.1, this may take a while depending on your cpu(s)...
ruby-2.4.1 - #downloading ruby-2.4.1, this may take a while depending on your connection...

curl: (35) SSL connect error
There was an error(35).
Checking fallback: https://ftp.ruby-lang.org/pub/ruby/2.4/ruby-2.4.1.tar.bz2
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 11.9M  100 11.9M    0     0  1753k      0  0:00:07  0:00:07 --:--:-- 2919k
ruby-2.4.1 - #extracting ruby-2.4.1 to /usr/local/rvm/src/ruby-2.4.1....
ruby-2.4.1 - #applying patch /usr/local/rvm/patches/ruby/2.4.1/random_c_using_NR_prefix.patch.
ruby-2.4.1 - #configuring..................................................................
ruby-2.4.1 - #post-configuration..
ruby-2.4.1 - #compiling..............................................................................................
ruby-2.4.1 - #installing.........................
ruby-2.4.1 - #making binaries executable..
ruby-2.4.1 - #downloading rubygems-2.6.14
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  751k  100  751k    0     0   443k      0  0:00:01  0:00:01 --:--:--  628k
No checksum for downloaded archive, recording checksum in user configuration.
ruby-2.4.1 - #extracting rubygems-2.6.14....
ruby-2.4.1 - #removing old rubygems.........
ruby-2.4.1 - #installing rubygems-2.6.14...........................
ruby-2.4.1 - #gemset created /usr/local/rvm/gems/[email protected]
ruby-2.4.1 - #importing gemset /usr/local/rvm/gemsets/global.gems...............................................
ruby-2.4.1 - #generating global wrappers........
ruby-2.4.1 - #gemset created /usr/local/rvm/gems/ruby-2.4.1
ruby-2.4.1 - #importing gemsetfile /usr/local/rvm/gemsets/default.gems evaluated to empty gem list
ruby-2.4.1 - #generating default wrappers........
ruby-2.4.1 - #adjusting #shebangs for (gem irb erb ri rdoc testrb rake).
Install of ruby-2.4.1 - #complete 
Ruby was built without documentation, to build it run: rvm docs generate-ri

 

至此,我們升級了Ruby的版本。

 

4)安裝gem redis介面,成功!

 

gem install redis
Fetching: redis-4.0.1.gem (100%)
Successfully installed redis-4.0.1
Parsing documentation for redis-4.0.1
Installing ri documentation for redis-4.0.1
Done installing documentation for redis after 0 seconds
1 gem installed

 

 

5)安裝rubygems,成功!

# yum install -y rubygems
Loaded plugins: fastestmirror, security
Setting up Install Process
Loading mirror speeds from cached hostfile
base                                                                                                                                                   | 3.7 kB     00:00     
didi_jenkins_enable                                                                                                                                    | 1.5 kB     00:00     
didi_op_toa_enable                                                                                                                                     | 1.5 kB     00:00     
didi_txjenkins_enable                                                                                                                                  | 1.5 kB     00:00     
didi_update                                                                                                                                            | 1.5 kB     00:00     
epel                                                                                                                                                   | 4.3 kB     00:00     
extras                                                                                                                                                 | 3.4 kB     00:00     
tmprepo                                                                                                                                                | 1.5 kB     00:00     
updates                                                                                                                                                | 3.4 kB     00:00     
Package rubygems-1.3.7-5.el6.noarch already installed and latest version
Nothing to do

複製程式碼

至此,我們的Ruby和執行redis-trib.rb需要的環境安裝完成了。 

 

3、Redis叢集搭建

有了Ruby執行環境,可以開始將之前的6個例項組建成叢集了。

命令方式:

ruby ./bin/redis-trib.rb create --replicas 1 10.93.84.53:7000 10.93.84.53:7001 10.93.84.53:7002 10.93.84.53:7003 10.93.84.53:7004 10.93.84.53:7005
--replicas 1表示為叢集的master節點建立1個副本。那麼6個例項裡,有三個master,有三個是slave。

後面跟上6個例項就好了,形式就是ip:port

執行情況:

 

# ruby ./bin/redis-trib.rb create --replicas 1 10.93.84.53:7000 10.93.84.53:7001 10.93.84.53:7002 10.93.84.53:7003 10.93.84.53:7004 10.93.84.53:7005
>>> Creating cluster
>>> Performing hash slots allocation on 6 nodes...
Using 3 masters:
10.93.84.53:7000
10.93.84.53:7001
10.93.84.53:7002
Adding replica 10.93.84.53:7003 to 10.93.84.53:7000
Adding replica 10.93.84.53:7004 to 10.93.84.53:7001
Adding replica 10.93.84.53:7005 to 10.93.84.53:7002
M: 6346ae8c7af7949658619fcf4021cc7aca454819 10.93.84.53:7000
   slots:0-5460 (5461 slots) master
M: 5ac973bceab0d486c497345fe884ff54d1bb225a 10.93.84.53:7001
   slots:5461-10922 (5462 slots) master
M: cc46a4a1c0ec3f621b6b5405c6c10b7cffe73932 10.93.84.53:7002
   slots:10923-16383 (5461 slots) master
S: 92f62ec93a0550d962f81213ca7e9b3c9c996afd 10.93.84.53:7003
   replicates 6346ae8c7af7949658619fcf4021cc7aca454819
S: 942c9f97dc68198c39f425d13df0d8e3c40c5a58 10.93.84.53:7004
   replicates 5ac973bceab0d486c497345fe884ff54d1bb225a
S: a92a81532b63652bbd862be6f19a9bd8832e5e05 10.93.84.53:7005
   replicates cc46a4a1c0ec3f621b6b5405c6c10b7cffe73932
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 10.93.84.53:7000)
M: 6346ae8c7af7949658619fcf4021cc7aca454819 10.93.84.53:7000
   slots:0-5460 (5461 slots) master
   1 additional replica(s)
S: a92a81532b63652bbd862be6f19a9bd8832e5e05 10.93.84.53:7005
   slots: (0 slots) slave
   replicates cc46a4a1c0ec3f621b6b5405c6c10b7cffe73932
M: 5ac973bceab0d486c497345fe884ff54d1bb225a 10.93.84.53:7001
   slots:5461-10922 (5462 slots) master
   1 additional replica(s)
S: 942c9f97dc68198c39f425d13df0d8e3c40c5a58 10.93.84.53:7004
   slots: (0 slots) slave
   replicates 5ac973bceab0d486c497345fe884ff54d1bb225a
S: 92f62ec93a0550d962f81213ca7e9b3c9c996afd 10.93.84.53:7003
   slots: (0 slots) slave
   replicates 6346ae8c7af7949658619fcf4021cc7aca454819
M: cc46a4a1c0ec3f621b6b5405c6c10b7cffe73932 10.93.84.53:7002
   slots:10923-16383 (5461 slots) master
   1 additional replica(s)
[OK] All nodes agree about slots configuration.
>>> Check for open slots...
>>> Check slots coverage...
[OK] All 16384 slots covered.

 

 可以看到16384個slot都已經建立完成,並且建立了3個master和對應的replica:

 

Using 3 masters:
10.93.84.53:7000
10.93.84.53:7001
10.93.84.53:7002
Adding replica 10.93.84.53:7003 to 10.93.84.53:7000
Adding replica 10.93.84.53:7004 to 10.93.84.53:7001
Adding replica 10.93.84.53:7005 to 10.93.84.53:7002

。。。
[OK] All 16384 slots covered.

 

 

 

4、驗證叢集狀態

登入叢集客戶端,-c標識以叢集方式登入

./bin/redis-cli -h 10.93.84.53 -p 7000 -c

檢視叢集狀態

 

10.93.84.53:7000> cluster info
cluster_state:ok
cluster_slots_assigned:16384
cluster_slots_ok:16384
cluster_slots_pfail:0
cluster_slots_fail:0
cluster_known_nodes:6
cluster_size:3
cluster_current_epoch:8
cluster_my_epoch:8
cluster_stats_messages_sent:215
cluster_stats_messages_received:215
10.93.84.53:7000> cluster nodes
942c9f97dc68198c39f425d13df0d8e3c40c5a58 10.93.84.53:7004 slave 5ac973bceab0d486c497345fe884ff54d1bb225a 0 1507806791940 5 connected
5ac973bceab0d486c497345fe884ff54d1bb225a 10.93.84.53:7001 master - 0 1507806788937 2 connected 5461-10922
a92a81532b63652bbd862be6f19a9bd8832e5e05 10.93.84.53:7005 slave cc46a4a1c0ec3f621b6b5405c6c10b7cffe73932 0 1507806790939 6 connected
cc46a4a1c0ec3f621b6b5405c6c10b7cffe73932 10.93.84.53:7002 master - 0 1507806789937 3 connected 10923-16383
6346ae8c7af7949658619fcf4021cc7aca454819 10.93.84.53:7000 myself,slave 92f62ec93a0550d962f81213ca7e9b3c9c996afd 0 0 1 connected
92f62ec93a0550d962f81213ca7e9b3c9c996afd 10.93.84.53:7003 master - 0 1507806792941 8 connected 0-5460

 

 一些原理

redis cluster在設計的時候,就考慮到了去中心化,去中介軟體,也就是說,叢集中的每個節點都是平等的關係,都是對等的,每個節點都儲存各自的資料和整個叢集的狀態。每個節點都和其他所有節點連線,而且這些連線保持活躍,這樣就保證了我們只需要連線叢集中的任意一個節點,就可以獲取到其他節點的資料。

Redis叢集沒有並使用傳統的一致性雜湊來分配資料,而是採用另外一種叫做雜湊槽(hash slot)的方式來分配的,一致性雜湊對向叢集中新增和刪除例項的支援很好,但是雜湊槽對向叢集新增例項或者刪除例項的話,需要額外的操作,需要手動的將slot重新平均的分配到新叢集的例項中。

redis cluster 預設分配了 16384 個slot,當我們set一個key時,會用CRC16演算法來取模得到所屬的slot,然後將這個key分到雜湊槽區間的節點上,具體演算法就是:CRC16(key)%16384。

Redis 叢集會把資料存在一個master節點,然後在這個master和其對應的salve之間進行資料同步。當讀取資料時,也根據一致性雜湊演算法到對應的master節點獲取資料。只有當一個master 掛掉之後,才會啟動一個對應的salve節點,充當master。

需要注意的是:必須要3個或以上的主節點,否則在建立叢集時會失敗,並且當存活的主節點數小於總節點數的一半時,整個叢集就無法提供服務了。