Install Zabbix 4.0 agent on CentOS 6

Install repository:

rpm -ivh http://repo.zabbix.com/zabbix/4.0/rhel/6/x86_64/zabbix-release-4.0-1.el6.noarch.rpm

Install agent:

yum clean all && yum makecache
yum -y instal zabbix-agent

If you receive:

Error: Package: zabbix-agent-4.0.2-1.el7.x86_64 (zabbix)
           Requires: libc.so.6(GLIBC_2.17)(64bit)
Error: Package: zabbix-agent-4.0.2-1.el7.x86_64 (zabbix)
           Requires: libpcre.so.1()(64bit)
Error: Package: zabbix-agent-4.0.2-1.el7.x86_64 (zabbix)
           Requires: systemd

That means you accidentally installead "zabbix-release" file which are dediceted for CentOS 7

Enable agent at system startup:

chkconfig zabbix-agent on

Start agent now:

/etc/init.d/zabbix-agent start

Check status:

/etc/init.d/zabbix-agent status