CDH集群的安装部署虽然步骤比较多，但只要严格按照文档操作，一般不会有太大问题。然而，如果安装过程中出错，或因为其它原因需要重新安装CDH，在不重装操作系统的前提下，是比较困难的。难点在于需要删除的东西太多，不删干净了非常容易造成安装失败。网上找的所谓“CDH完全卸载”其实都不够完全。经过一天的反复尝试，终于写了一个一键式删除CDH脚本，在我自己的测试环境下是可行的。删除脚本文件remove_cloudera.sh内容如下：
#!/bin/bash
# 停止CM服务
service cloudera-scm-server stop
service cloudera-scm-agent stop
# 卸载CM软件包
yum -y remove cloudera-manager-daemons cloudera-manager-agent cloudera-manager-server
# 卸载装载点
umount cm_processes
umount cm_processes
umount cm_processes
# 删除文件
rm -rf /var/log/*
rm -rf /opt/cloudera*
rm -rf /etc/systemd/system/multi-user.target.wants/cloudera*
rm -rf /etc/default/cloudera*
rm -rf /etc/cloudera*
rm -rf /var/lib/cloudera*
rm -rf /var/log/cloudera*
rm -rf /usr/lib/systemd/system/cloudera*
rm -rf /run/cloudera*
rm -rf /sys/fs/cgroup/systemd/system.slice/cloudera*
rm -rf /etc/security/limits.d/cloudera*
rm -rf /var/lib/yum/repos/x86_64/7/cloudera*
rm -rf /var/cache/yum/x86_64/7/cloudera*
rm -rf /tmp/*
rm -rf /var/lib/hadoop-*
rm -rf /var/lib/impala
rm -rf /var/lib/solr
rm -rf /var/lib/zookeeper
rm -rf /var/lib/hue
rm -rf /var/lib/oozie
rm -rf /var/lib/pgsql
rm -rf /var/lib/sqoop2
rm -rf /data/dfs/
rm -rf /data/impala/
rm -rf /data/yarn/
rm -rf /dfs/
rm -rf /impala/
rm -rf /yarn/
rm -rf /var/run/hadoop-*/
rm -rf /var/run/hdfs-*/
rm -rf /usr/bin/hadoop*
rm -rf /usr/bin/zookeeper*
rm -rf /usr/bin/hbase*
rm -rf /usr/bin/hive*
rm -rf /usr/bin/hdfs
rm -rf /usr/bin/mapred
rm -rf /usr/bin/yarn
rm -rf /usr/bin/sqoop*
rm -rf /usr/bin/oozie
rm -rf /etc/hadoop*
rm -rf /etc/zookeeper*
rm -rf /etc/hive*
rm -rf /etc/hue
rm -rf /etc/impala
rm -rf /etc/sqoop*
rm -rf /etc/oozie
rm -rf /etc/hbase*
rm -rf /etc/hcatalog
rm -rf /var/lib/alternatives/impala-conf
rm -rf /var/lib/alternatives/impalad
rm -rf /var/lib/alternatives/impala-collect-diagnostics
rm -rf /var/lib/alternatives/impala-shell
rm -rf /var/lib/alternatives/impala-collect-minidumps
rm -rf /etc/alternatives/impala-shell
rm -rf /etc/alternatives/impalad
rm -rf /etc/alternatives/impala-collect-diagnostics
rm -rf /etc/alternatives/impala-conf
rm -rf /etc/alternatives/impala-collect-minidumps
rm -rf /var/log/impala*
rm -rf /var/lib/alternatives/zookeeper-client
rm -rf /var/lib/alternatives/zookeeper-server
rm -rf /var/lib/alternatives/zookeeper-conf
rm -rf /var/lib/alternatives/zookeeper-server-initialize
rm -rf /var/lib/alternatives/zookeeper-server-cleanup
rm -rf /var/lib/alternatives/zookeeper-security-migration
rm -rf /etc/alternatives/zookeeper-conf
rm -rf /etc/alternatives/zookeeper-server
rm -rf /etc/alternatives/zookeeper-server-cleanup
rm -rf /etc/alternatives/zookeeper-server-initialize
rm -rf /etc/alternatives/zookeeper-security-migration
rm -rf /etc/alternatives/zookeeper-client
rm -rf /var/log/zookeeper
# 重建数据库
mysql -uroot -p123456 -e "drop database if exists scm;drop database if exists hive;drop database if exists oozie;drop database if exists hue;create database scm DEFAULT CHARACTER SET utf8;create database hive DEFAULT CHARACTER SET utf8;create database oozie DEFAULT CHARACTER SET utf8;create database hue DEFAULT CHARACTER SET utf8;"
# 删除用户和组
userdel -r cloudera-scm
userdel -r ambari-qa
userdel -r appmon
userdel -r falcon
userdel -r gpadmin
userdel -r hcat
userdel -r hive
userdel -r kafka
userdel -r mapred
userdel -r spark
userdel -r tez
userdel -r yarn
userdel -r zookeeper
userdel -r ams
userdel -r atlas
userdel -r flume
userdel -r hbase
userdel -r hdfs
userdel -r infra-solr
userdel -r livy
userdel -r mongodb
userdel -r oozie
userdel -r sqoop
userdel -r zeppelin
userdel -r impala
userdel -r kudu
userdel -r hadoop
groupdel hadoop
groupdel cloudera-scm
groupdel ambari-qa
groupdel appmon
groupdel falcon
groupdel gpadmin
groupdel hcat
groupdel hive
groupdel kafka
groupdel mapred
groupdel spark
groupdel tez
groupdel yarn
groupdel zookeeper
groupdel ams
groupdel atlas
groupdel flume
groupdel hbase
groupdel hdfs
groupdel infra-solr
groupdel livy
groupdel mongodb
groupdel oozie
groupdel sqoop
groupdel zeppelin
groupdel impala
groupdel kudu
# 删除其它节点上的CDH
ssh [email protected] /root/remove_cloudera.sh
ssh [email protected] /root/remove_cloudera.sh
ssh [email protected] /root/remove_cloudera.sh说明：
- 在Cloudera Manager节点执行此脚本。
- 其它节点上的remove_cloudera.sh文件只是少了重建数据库一步，其它内容与此脚本一致。
- 脚本执行过程中的错误是由于被删除的对象尚不存在，可以忽略。
- 如果已经安装好了CDH，先在CM中停止所有服务后再执行此脚本。
- 删除脚本一般都具有幂等性，可以多次执行。
