按官方手册，这样弄：
yum -y install yum-utils
yum-config-manager --add-repo https://rpm.kamailio.org/centos/kamailio.repo
yum install -y kamailio
yum install -y kamailio*
但有的系统有冲突，部分组件安装失败，后来改成下面这样：
yum -y install yum-utils
yum-config-manager --add-repo https://rpm.kamailio.org/centos/kamailio.repo
yum install -y kamailio
yum install -y kamailio-carrierroute
yum install -y kamailio-cpl
yum install -y kamailio-dialplan
yum install -y kamailio-evapi
yum install -y kamailio-geoip
yum install -y kamailio-gzcompress
yum install -y kamailio-jansson
yum install -y kamailio-json
yum install -y kamailio-lua
yum install -y kamailio-memcached
yum install -y kamailio-mongodb
yum install -y kamailio-mysql
yum install -y kamailio-outbound
yum install -y kamailio-postgresql
yum install -y kamailio-presence
yum install -y kamailio-redis
yum install -y kamailio-regex
yum install -y kamailio-snmpstats
yum install -y kamailio-sqlite
yum install -y kamailio-tls
yum install -y kamailio-unixodbc
yum install -y kamailio-utils
yum install -y kamailio-uuid
yum install -y kamailio-websocket
yum install -y kamailio-xhttp-pi
yum install -y kamailio-xmlops
yum install -y kamailio-xmlrpc
yum install -y kamailio-xmpp
yum install -y kamailio-cnxcc
yum install -y kamailio-crypto
yum install -y kamailio-dmq_userloc
yum install -y kamailio-http_async_client
yum install -y kamailio-http_client
yum install -y kamailio-lost
yum install -y kamailio-rabbitmq
yum install -y kamailio-slack
yum install -y kamailio-acc_json
yum install -y kamailio-auth-xkeys
yum install -y kamailio-rtjson
yum install -y kamailio-secfilter
yum install -y kamailio-sipcapture-daemon-config
yum install -y kamailio-sipdump
yum install -y kamailio-sipjson
yum install -y kamailio-statsd
yum install -y kamailio-tcpops
有些组件用不到，比如ims，不安装
目前安装的是5.7.3版本
如果要安装老版本，可以先修改/etc/yum.repos.d/kamailio.repo
如果普通用户ssh登录，PATH可能没包含/usr/sbin，于是创建下面二个软链接是很有必要的：
ln -sf /usr/sbin/kamailio /usr/bin
ln -sf /usr/sbin/kamcmd /usr/bin