最近有臺雲上的服務器需要釋放,然後上面跑的 gitlab 也要挪個地方,如在 docker 內運行,gitlab 鏡像大約 1.56G,需佔用 4G 以上的內存,因資源有限,於是借在其他的服務器上搭建環境(可用內存小於4G),然鵝啓動的時候莫名出現 502,Excuse me?接着搜了一些 issue 博客上的解決方案(如修改端口、重啓或 hup 某個服務)無果,後來在調整的過程中從日誌裏發現了一些信息。
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[尷尬]。
1、不清楚應用啓動的各服務以及用途,只會簡單查看 status;
2、看到錯誤第一時間想到的是 Baidu(沒其他意思),找找 logpath 先看日誌不好嗎?
3、未認識到服務之間的關聯關係(比如 postgresql 與 unicorn 之間),前面一直知道 unicorn 啓動後沒正常監聽到端口,但是日誌並沒啥特別信息(嗯,可能是因爲看錯了文件)[苦笑]
一、錯誤信息
二、排錯過程
1、啓動 unicorn 未監聽端口
日誌路徑 : /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'
··· ···
··· ···
信息顯示是因爲連不上PG,所以啓動 postgresql 後重啓即可正常(嗯,是這樣的)。
2、postgresql down
down: postgresql: 0s, normally up, want up; run: log: (pid 623) 15816094s
通過 PG 的日誌路徑 : /var/log/gitlab/postgresql/current 可以查看到如下信息
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
也可以通過命令 `gitlab-ctl tail postgresql`,得到一樣的信息,於是可以確定問題。。
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
於是在配置文件中對 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
配置完成保存,之後更新配置,重啓應用即可。
gitlab-ctl reconfigure # 更新配置
gitlab-ctl restart # 重啓應用
gitlab-ctl status # 查看服務狀態
參考資料:
1. 502-Whoops, GitLab is taking too much time to respond
6. HTTP 502: Whoops, GitLab is taking too much time to respond. Even after Server restart