cassandra3节点集群安装

操作系统 centos 7
1、安装java 8

[root@ca ~]# java -version
java version "1.8.0_111"
Java(TM) SE Runtime Environment (build 1.8.0_111-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.111-b14, mixed mode)

2、安装python 2

[root@ca ~]# python -V
Python 2.7.5

3、在/etc/hosts里面添加集群服务器信息

192.168.1.74 harbor
192.168.1.75 jenkins
192.168.1.76 ca

4、进行linux 系统内核 文件连接数的修改

vi /etc/sysctl.conf

vm.zone_reclaim_mode=0
vm.max_map_count = 262144
vm.swappiness = 1

sysctl -p

vi /etc/security/limits.conf
* soft nofile 65536
* hard nofile 65536
* soft nproc 65536
* hard nproc 65536

5、创建cassandra用户名和数据存放目录

useradd cassandra
mkdir /opt/data1
mkdir /opt/data2
chmod 777 -R /opt/data1
chmod 777 -R /opt/data2

6、下载客户端

cd /opt
wget http://mirrors.hust.edu.cn/apache/cassandra/3.11.3/apache-cassandra-3.11.3-bin.tar.gz
tar xvf apache-cassandra-3.11.3-bin.tar.gz -C /opt
mv /opt/apache-cassandra-3.11.3    /opt/cassandra
chown -R cassandra.cassandra /opt/cassandra

7、却换到cassandra用户下

su - cassandra
mkdir /opt/data1/commitlog
mkdir /opt/data1/data1file
mkdir /opt/data2/data2file
mkdir /opt/data2/saved_caches

cd /opt/cassandra/conf/
修改 cassandra.yaml 配置文件，配置第一台为seeds。
第一台配置：
cluster_name: 'prod Cluster'
data_file_directories:
     -  /opt/data1/data1file
     -  /opt/data2/data2file
commitlog_directory: /opt/data1/commitlog
saved_caches_directory: /opt/data2/saved_caches
- seeds: "192.168.1.74"
listen_address: 192.168.1.74
start_rpc: true
rpc_address: 192.168.1.74


第二台配置：
cluster_name: 'prod Cluster'
data_file_directories:
     -  /opt/data1/data1file
     -  /opt/data2/data2file
commitlog_directory: /opt/data1/commitlog
saved_caches_directory: /opt/data2/saved_caches
- seeds: "192.168.1.74"
listen_address: 192.168.1.75
start_rpc: true
rpc_address: 192.168.1.75

第三台配置：
cluster_name: 'prod Cluster'
data_file_directories:
     -  /opt/data1/data1file
     -  /opt/data2/data2file
commitlog_directory: /opt/data1/commitlog
saved_caches_directory: /opt/data2/saved_caches
- seeds: "192.168.1.74"
listen_address: 192.168.1.76
start_rpc: true
rpc_address: 192.168.1.76


然后重启启动，先启动seed
/opt/cassandra/bin/cassandra

启动完成后，可使用
/opt/cassandra/bin/nodetool status
查看集群状态
[cassandra@harbor conf]$ /opt/cassandra/bin/nodetool status
Datacenter: datacenter1
=======================
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
--  Address       Load       Tokens       Owns (effective)  Host ID                               Rack
UN  192.168.1.74  189.2 KiB  256          68.9%             98436d32-5d5d-4e5e-afe2-84550e56daa9  rack1
UN  192.168.1.75  161.43 KiB  256          64.7%             2f52f14c-acbb-4241-9eff-6ed13b2827e5  rack1
UN  192.168.1.76  120.67 KiB  256          66.4%             450b02db-90a1-4b76-831a-9b0b9aa42c27  rack1

8、如果节点的集群名字和seeds节点的集群名字不一样的，则启动会报错

ERROR [main] 2018-03-20 17:49:20,497 CassandraDaemon.java:708 - Exception encountered during startup
java.lang.RuntimeException: Unable to gossip with any seeds

如果配置文件修改成一致的集群名字后，再启动会出现

已经启动过的node，如果改了配置的clustername，再启动就会报错

org.apache.cassandra.exceptions.ConfigurationException: Saved cluster name Test Cluster != configured name xxx

这是因为已经写到系统表里了。改名字相当于换集群
因为理论上换了集群老数据就没用了，所以直接rm -rf /data/cassandra之类的数据目录，包括data, commitlog。删干净了再启动即可

9、cqlsh操作

[cassandra@harbor bin]$ ./cqlsh 192.168.1.74
Connected to prod Cluster at 192.168.1.74:9042.
[cqlsh 5.0.1 | Cassandra 3.11.3 | CQL spec 3.4.4 | Native protocol v4]
Use HELP for help.
cqlsh> 

10、停止

pkill -f CassandraDaemon