docker - 系统重启后 Mnesia 无法识别数据(no_exists 错误)

Question

我正在 docker 容器中构建一个 erlang 应用程序。
我的数据目录作为 docker 卷连接。
我正在使用:application:set_env(mnesia, schema_location, disc),和 {disc_copies, Nodes} .

当我重新启动应用程序时:

docker-composer stop myapp && docker-composer up myapp

一切正常，但是当我完全关闭它时:

sudo systemctl restart docker
docker-composer up -d

Mnesia 停止识别我的数据。当我重新启动计算机时也是如此。

基本上(在这个“硬”重启之后)Mnesia 正常启动，但是当我尝试从中读取任何内容时，我得到一个错误:

{running_method,getTasksByProjectId}
terminate reason: {aborted,{no_exists,mtm_tasks}}
terminate reason: {{aborted,{no_exists,mtm_tasks}},
                   {gen_server,call,
                       [{global,tasks_da_serv},
                        {get_tasks_by_project_id,
                            "j1xvqric-2oj2q784xieccowg8880"}]}}

=ERROR REPORT==== 8-Jun-2017::10:29:04 ===
** Generic server tasks_da_serv terminating 
** Last message in was {get_tasks_by_project_id,
                           "j1xvqric-2oj2q784xieccowg8880"}
** When Server state == {tasks_da_state}
** Reason for termination == 
** {{aborted,{no_exists,mtm_tasks}},
    [{mnesia,wrap_trans,6,[{file,"mnesia.erl"},{line,404}]},
     {tasks_logic,get_tasks_by_project_id,1,
                  [{file,"/release/_build/default/lib/tasks/src/tasks_logic.erl"},
                   {line,70}]},
     {tasks_da_serv,handle_call,3,
                    [{file,"/release/_build/default/lib/tasks/src/tasks_da_serv.erl"},
                     {line,52}]},
     {gen_server,try_handle_call,4,[{file,"gen_server.erl"},{line,615}]},
     {gen_server,handle_msg,5,[{file,"gen_server.erl"},{line,647}]},
     {proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,247}]}]}
Starting {global,tasks_da_serv} (<0.492.0>)
Starting {global,tasks_manager_serv} (<0.497.0>)

=ERROR REPORT==== 8-Jun-2017::10:29:04 ===
** Generic server tasks_manager_serv terminating 
** Last message in was {{'basic.deliver',
                            <<"amq.ctag-pt-OySikx5BShVLRASvIPw">>,1,false,
                            <<>>,<<"tasks">>},
                        {amqp_msg,
                            {'P_basic',undefined,undefined,[],undefined,
                                undefined,undefined,undefined,undefined,
                                undefined,undefined,undefined,undefined,
                                undefined,undefined},
                            <<"{\"correlationId\":\"j3oa5b84-pcxn9ld6mswsck8kw48\",\"replyTo\":\"amq.gen-8h_kLqz4sHB-qjJ2cj8Y6w\",\"method\":\"getTasksByProjectId\",\"params\":{\"projectId\":\"j1xvqric-2oj2q784xieccowg8880\"}}">>}}
** When Server state == {tasks_manager_state,<0.481.0>,<0.490.0>}
** Reason for termination == 
** {{{aborted,{no_exists,mtm_tasks}},
     {gen_server,call,
                 [{global,tasks_da_serv},
                  {get_tasks_by_project_id,"j1xvqric-2oj2q784xieccowg8880"}]}},
    [{gen_server,call,2,[{file,"gen_server.erl"},{line,204}]},
     {tasks_manager_logic,handle_message,2,
                          [{file,"/release/_build/default/lib/tasks/src/tasks_manager_logic.erl"},
                           {line,7}]},
     {tasks_manager_serv,handle_info,2,
                         [{file,"/release/_build/default/lib/tasks/src/tasks_manager_serv.erl"},
                          {line,45}]},
     {gen_server,try_dispatch,4,[{file,"gen_server.erl"},{line,601}]},
     {gen_server,handle_msg,5,[{file,"gen_server.erl"},{line,667}]},
     {proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,247}]}]}

此时，使其再次工作的唯一方法是从 docker 卷中删除数据。

Answer 1

我已经想通了。问题是 docker 正在为容器分配自定义主机名，而 Mnesia 磁盘副本显然绑定(bind)到主机名。
现在我在 docker-compose.yaml 文件中修复了主机名:

version: '2'
services:
  myapp:
    build: './myapp'
    hostname: 'myapp'
    volumes:
      ...

现在可以重新启动它而不会丢失数据。