目的：
为impala jdbc提供统一的接口，作用参照http://www.cloudera.com/content/cloudera/en/documentation/core/latest/topics/impala_proxy.html
步骤：
安装haproxy
选择一台非impalad的机器安装haproxy
yum install haproxy
编辑/etc/haproxy/haproxy.cfg，参考
global
# To have these messages end up in /var/log/haproxy.log you will
# need to:
#
# 1) configure syslog to accept network log events. This is done
# by adding the '-r' option to the SYSLOGD_OPTIONS in
# /etc/sysconfig/syslog
#
# 2) configure local2 events to go to the /var/log/haproxy.log
# file. A line like the following can be added to
# /etc/sysconfig/syslog
#
# local2.* /var/log/haproxy.log
#
log 127.0.0.1 local0
log 127.0.0.1 local1 notice
chroot /var/lib/haproxy
pidfile /var/run/haproxy.pid
maxconn 4000
user haproxy
group haproxy
daemon
# turn on stats unix socket
#stats socket /var/lib/haproxy/stats
#---------------------------------------------------------------------
# common defaults that all the 'listen' and 'backend' sections will
# use if not designated in their block
#
# You might need to adjust timing values to prevent timeouts.
#---------------------------------------------------------------------
defaults
mode http
log global
option httplog
option dontlognull
option http-server-close
#option forwardfor except 127.0.0.0/8
option redispatch
retries 3
maxconn 3000
timeout connect 5000
timeout client 50000
timeout server 50000
#
# This sets up the admin page for HA Proxy at port 25002.
#
listen stats :25002
balance
mode http
stats enable
stats auth username:password
# This is the setup for Impala. Impala client connect to load_balancer_host:25003.
# HAProxy will balance connections among the list of servers listed below.
# The list of Impalad is listening at port 21000 for beeswax (impala-shell) or original ODBC driver.
# For JDBC or ODBC version 2.x driver, use port 21050 instead of 21000.
listen impala :25003
mode tcp
option tcplog
balance leastconn
server cdhslave1 cdhslave1.yeahmobi.com:21050 check
server cdhslave2 cdhslave2.yeahmobi.com:21050 check
server cdhslave3 cdhslave3.yeahmobi.com:21050 check
启动haproxy
haproxy -f /etc/haproxy/haproxy.cfg
关闭service haproxy stop
impala配置
impala daemon group->advanced->Impala Daemon Command Line Argument Advanced Configuration Snippet (Safety Valve)
-principal=impala/[email protected]
-be_principal=impala/[email protected]
测试
private static final String IMPALAD_HOST = "cdhmaster.yeahmobi.com";//haproxy server的hostname
private static final String IMPALAD_JDBC_PORT = "25003";//端口选择haproxy的代理端口
private static final String CONNECTION_URL = "jdbc:hive2://" + IMPALAD_HOST + ':' + IMPALAD_JDBC_PORT + "/data_system;user=hive;password=111111";//ldap用户及密码
使用时发现，impala-shell不好使了，不能正常连接，去除如上粗体步骤后，impala-shell正常，jdbc HAproxy也正常使用。