这篇文章不记录Gitlab的使用方法，更不说明Gitlab的特性，只记录的升级步骤以及遇到的问题。由于升级的版本跨度有点大，Gitlab本身的备份\还原并不适合此次的迁移。
部署环境：
阿里云ECS 4核\8G\40G CentOS 7.3.1611
阿里云RDS PostgreSQL 9.4
gitlab-ce-9.3.4-ce.0.el7.x86_64
nginx/1.10.2
迁移流程：
1、在新机器上部署GitLab，我们采用RPM包的方式安装。
2、编辑/etc/gitlab/gitlab.rb
external_url 'https://gitlab.xxxxx.com' #git的URL，启用SSL就写https，反之就写http
gitlab_rails['time_zone'] = 'UTC'
gitlab_rails['gitlab_email_enabled'] = true #启用Email
gitlab_rails['gitlab_email_from'] = 'user@host.com'
gitlab_rails['gitlab_email_display_name'] = 'Gitlab email notification'
gitlab_rails['db_adapter'] = "postgresql" #gitlab使用的数据库，mysql/postgresql
gitlab_rails['db_encoding'] = "utf8"
gitlab_rails['db_collation'] = nil
gitlab_rails['db_database'] = "gitlab_production"
gitlab_rails['db_pool'] = 10
gitlab_rails['db_username'] = "gitlab_user"
gitlab_rails['db_password'] = "*********"
gitlab_rails['db_host'] = "xxxx.pg.aliyun.com"
gitlab_rails['db_port'] = 3433
gitlab_rails['db_socket'] = nil
gitlab_rails['db_sslmode'] = nil
gitlab_rails['db_sslrootcert'] = nil
gitlab_rails['db_prepared_statements'] = true
gitlab_rails['db_statements_limit'] = 1000
gitlab_rails['smtp_enable'] = true
gitlab_rails['smtp_address'] = "smtpdm.aliyun.com"
gitlab_rails['smtp_port'] = 25
gitlab_rails['smtp_user_name'] = "user@host.com"
gitlab_rails['smtp_password'] = "******"
gitlab_rails['smtp_domain'] = "user@host.com"
gitlab_rails['smtp_authentication'] = "login"
gitlab_rails['smtp_enable_starttls_auto'] = true
gitlab_rails['smtp_tls'] = false
postgresql['enable'] = false #禁用自带postgressql
web_server['external_users'] = ['nginx']
nginx['enable'] = false #禁用自带nginx
prometheus['enable'] = true
prometheus['monitor_kubernetes'] = true
prometheus['username'] = 'gitlab-prometheus'
prometheus['uid'] = nil
prometheus['gid'] = nil
prometheus['shell'] = '/bin/sh'
prometheus['home'] = '/var/opt/gitlab/prometheus'
prometheus['log_directory'] = '/var/log/gitlab/prometheus'
prometheus['scrape_interval'] = 15
prometheus['scrape_timeout'] = 15
prometheus['chunk_encoding_version'] = 2
prometheus['listen_address'] = '0.0.0.0:9090' #修改prometheus的监听地址
prometheus_monitoring['enable'] = true
3、由于这台机器有好几个访问域名，需要共用一个nginx，所以就没用gitlab自带的Nginx。
配置nginx:
user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log;
pid /run/nginx.pid;
# Load dynamic modules. See /usr/share/nginx/README.dynamic.
include /usr/share/nginx/modules/*.conf;
events {
worker_connections 1024;
}
http {
log_format main '$remote_addr - $remote_user [$time_local] "$request" '
'$status $body_bytes_sent "$http_referer" '
'"$http_user_agent" "$http_x_forwarded_for"'
'$connection $upstream_addr '
'upstream_response_time $upstream_response_time';
access_log /var/log/nginx/access.log main;
sendfile on;
tcp_nopush on;
tcp_nodelay on;
keepalive_timeout 65;
types_hash_max_size 2048;
server_tokens off;
include /etc/nginx/mime.types;
default_type application/octet-stream;
client_body_buffer_size 3072k;
proxy_buffers 16 2048k;
proxy_buffer_size 512k;
connection_pool_size 256;
client_header_buffer_size 1k;
large_client_header_buffers 8 4k;
request_pool_size 4k;
client_max_body_size 128m ;
output_buffers 1 32k;
postpone_output 1460;
ignore_invalid_headers on;