1、IOException thrown while collecting data from host: No route to host

原因：agent開啟了防火牆

解決：service iptables stop（不推薦）

2、Cloudera recommendssetting /proc/sys/vm/swappiness to 0. Current setting is 60. Use the sysctlcommand to change this setting at runtime and edit /etc/sysctl.conf for thissetting to be saved after a reboot. You may continue with installation, but youmay run into issues with Cloudera Manager reporting that your hosts areunhealthy because they are swapping. The following hosts are affected:

解決：

# echo 0 >/proc/sys/vm/swappiness （to apply for now）

# sysctl -wvm.swappiness=0  （to make this persistentacross reboots）

3、時鐘不同步（同步至中科大時鐘伺服器202.141.176.110）

# echo "0 3 * ** /usr/sbin/ntpdate 202.141.176.110;/sbin/hwclock –w">>/var/spool/cron/root

# service crondrestart

# ntpdate202.141.176.110

4、The host's NTP service didnot respond to a request for the clock offset.

#service ntpd start

# ntpdc -c loopinfo (thehealth will be good if this command executed successfully)

5、The Cloudera Manager Agentis not able to communicate with this role's web server.

一種原因是元資料資料庫無法連線，請檢查資料庫配置：

6、Hive Metastore Server無法啟動，修改Hive元資料資料庫配置（當我們修改主機名後即應修改元資料資料庫配置）：