HTTP 502: Whoops, GitLab is taking too much time to respond.

這次排錯過程主要是思路，視野打開後會覺得豁然開朗，原來這其實是個小問題[尴尬]。

1、沒注重應用啟動的各服務及其用途，隻會簡單檢視 status；

2、看到錯誤第一時間想到的是 Baidu（沒其他意思），找找 logpath 先看日志不好嗎？

3、未認識到服務之間的關聯關系（比如 postgresql 與 unicorn 之間），前面一直知道 unicorn 啟動後沒正常監聽到端口，但是日志并沒啥特别資訊（嗯，可能是因為看錯了檔案）[苦笑]

 一、錯誤資訊

二、排錯過程

1、啟動 unicorn 未監聽端口

日志路徑 :   /var/log/gitlab/unicorn/unicorn_stderr.log

PG::ConnectionBad: could not connect to server: No such file or directory
        Is the server running locally and accepting
        connections on Unix domain socket "/var/opt/gitlab/postgresql/.s.PGSQL.5432"?

  /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/activerecord-4.2.10/lib/active_record/connection_adapters/postgresql_adapter.rb:651:in `initialize'
  /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/activerecord-4.2.10/lib/active_record/connection_adapters/postgresql_adapter.rb:651:in `new'
  /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/activerecord-4.2.10/lib/active_record/connection_adapters/postgresql_adapter.rb:651:in `connect'
  /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/activerecord-4.2.10/lib/active_record/connection_adapters/postgresql_adapter.rb:242:in `initialize'
  /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/activerecord-4.2.10/lib/active_record/connection_adapters/postgresql_adapter.rb:44:in `new'
  /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/activerecord-4.2.10/lib/active_record/connection_adapters/postgresql_adapter.rb:44:in `postgresql_connection'

··· ···
··· ···           

資訊顯示是因為連不上PG，是以啟動 postgresql 後重新開機即可正常（嗯，是醬）。。

2、postgresql down

down: postgresql: 0s, normally up, want up; run: log: (pid 623) 15816094s
           

通過 PG 的日志路徑 ： /var/log/gitlab/postgresql/current 可以檢視到如下資訊

2018-11-01_08:18:09.49669 FATAL:  could not map anonymous shared memory: Cannot allocate memory
2018-11-01_08:18:09.49671 HINT:  This error usually means that PostgreSQL's request for a shared memory segment exceeded available memory, swap space, or huge pages. To reduce the request size (currently 4292984832 bytes), reduce PostgreSQL's shared memory usage, perhaps by reducing shared_buffers or max_connections.
2018-11-01_08:18:09.49671 LOG:  database system is shut down           

也可以通過指令 `gitlab-ctl tail postgresql`，得到一樣的資訊，于是可以确定問題。。

This error usually means that PostgreSQL's request for a shared memory segment exceeded available memory, swap space, or huge pages. To reduce the request size (currently 4292984832 bytes), reduce PostgreSQL's shared memory usage, perhaps by reducing shared_buffers or max_connections.
2018-11-01_07:52:06.63024 LOG:  database system is shut down           

于是在配置檔案中對 postgresql 的 shared_buffers 和 max_connections 兩項進行了限制

[root@V2 ~]# cat /etc/gitlab/gitlab.rb |grep -v ^$ |grep -v ^#
external_url 'http://xxx.xxx.xxx.xxx.xxx:8090'
unicorn['worker_timeout'] = 60
unicorn['worker_processes'] = 3
unicorn['listen'] = 'xxx.xxx.xxx.xxx.xxx'
unicorn['port'] = 8870
postgresql['enable'] = true
postgresql['data_dir'] = "/var/opt/gitlab/postgresql/data"
postgresql['shared_buffers'] = "256MB"   # ! **recommend value is 1/4 of total RAM, up to 14GB.**      
postgresql['max_connections'] = 200
nginx['listen_addresses'] = ['*']
nginx['listen_port'] = 8090           

配置完成儲存，之後更新配置，重新開機應用即可。

gitlab-ctl reconfigure       # 更新配置
gitlab-ctl restart           # 重新開機應用
gitlab-ctl status            # 檢視服務狀态           

參考資料

1. 

502-Whoops, GitLab is taking too much time to respond

2. 

gitlab安裝以及安裝過程中遇到的問題

3. 

Postgresql down

4. 

centos7安裝部署gitlab伺服器

5. 

我所遇到的GitLab 502問題的解決

6. 

HTTP 502: Whoops, GitLab is taking too much time to respond. Even after Server restart