按照官方教程的步骤：https://about.gitlab.com/downloads/#centos6
但是执行这一步
curl https://packages.gitlab.com/install/repositories/gitlab/gitlab-ce/script.rpm.sh | sudo bash
sudo yum install gitlab-ce会报错找不到镜像文件。
所以我自己下载了rpm 文件在安装。
步骤如下：
sudo yum install openssh-server
sudo yum install postfix # sendmail or exim is also OK
sudo rpm -i gitlab-6.9.2_omnibus.1-1.el6.x86_64.rpm # this is the .rpm you downloaded
sudo gitlab-ctl reconfigure //可能会报错：External URL must include a FQDN（解决办法在下面）
sudo lokkit -s http -s ssh # open up the firewall for HTTP and SSH requests
ok!
sudo gitlab-ctl status; #查看安装后的程序运行情况！输出如下：
run: nginx: (pid 3012) 53s; run: log: (pid 3011) 53s
run: postgresql: (pid 2857) 87s; run: log: (pid 2856) 87s
run: redis: (pid 2759) 98s; run: log: (pid 2758) 98s
run: sidekiq: (pid 2967) 60s; run: log: (pid 2966) 60s
run: unicorn: (pid 2938) 66s; run: log: (pid 2937) 66s
说明安装成功。
通过浏览器访问：http://localhost 或者 http://ip
OK，可以了用户名和密码默认是root/5iveL!fe
遇到的问题：
1. 报错：External URL must include a FQDN
/etc/gitlab/gitlab.rb默认没有“=”，要自己加上
external_url = 'gitlab.thefallenphoenix.net'
附上gitlab网盘地址：http://pan.baidu.com/s/1nt7xeEP
官方安装方法：https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/install/installation.md
来源：oschina
链接：https://my.oschina.net/u/1052441/blog/528035