Docker中查看已经崩溃的容器的日志

1. 1. 概述

容器崩溃后，查看该容器的日志，有助于分析崩溃的原因，并在后续迭代版本中修复问题。

1. 2. docker ps

一般情况下，使用docker ps命令可以列出正在运行的容器的列表。例如：

[root@li1102-98 ~]# docker ps
CONTAINER ID        IMAGE                            COMMAND                  CREATED             STATUS              PORTS                      NAMES
96d8758da4f5        hxcan/assess-stock-serrver:501   "./AssessStockServ..."   8 hours ago         Up 8 hours          0.0.0.0:12091->12091/udp   nostalgic_bardeen

如果上面列出的 96d8758da4f5容器在某个时刻崩溃了，之后你再docker ps，就看到一个空列表了。例如：

[g@c ~]$ docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES

1. 3. docker container

要对容器进行查询或操作的话，需使用docker container命令。具体地，要列出容器列表的话，使用docker container ls命令。此处我们需要将已经崩溃的容器也列出，就需要加上-a参数，也就是docker container ls -a。例如：

[root@li1102-98 ~]# docker container ls -a
CONTAINER ID        IMAGE                            COMMAND                  CREATED             STATUS                   PORTS                      NAMES
96d8758da4f5        hxcan/assess-stock-serrver:501   "./AssessStockServ..."   8 hours ago         Up 8 hours               0.0.0.0:12091->12091/udp   nostalgic_bardeen
94b6f0f580fa        hxcan/assess-stock-serrver:498   "./AssessStockServ..."   9 hours ago         Exited (1) 9 hours ago                              infallible_goldwasser
5152c990fb1e        hxcan/assess-stock-serrver:494   "./AssessStockServ..."   4 days ago          Exited (1) 9 hours ago                              romantic_goldstine
10355709d6cf        hxcan/assess-stock-serrver:491   "./AssessStockServ..."   4 days ago          Exited (1) 4 days ago                               unruffled_goodall
7d55d01f934c        hxcan/assess-stock-serrver:488   "./AssessStockServ..."   5 days ago          Exited (1) 4 days ago                               vibrant_murdock
54d834caae08        hxcan/assess-stock-serrver:475   "./AssessStockServ..."   7 days ago          Exited (1) 5 days ago                               adoring_ramanujan
a5052c02c6bd        hxcan/assess-stock-serrver:477   "./AssessStockServ..."   7 days ago          Exited (1) 7 days ago                               naughty_babbage
e29d97a00da4        hxcan/assess-stock-serrver:467   "./AssessStockServ..."   12 days ago         Exited (1) 7 days ago                               kind_brown
3426f7a91557        hxcan/assess-stock-serrver:461   "./AssessStockServ..."   12 days ago         Exited (1) 12 days ago                              lucid_panini
bf7c24d496bd        hxcan/assess-stock-serrver:451   "./AssessStockServ..."   2 weeks ago         Exited (1) 12 days ago                              modest_haibt
808f751a5be8        hxcan/assess-stock-serrver:447   "./AssessStockServ..."   2 weeks ago         Exited (1) 2 weeks ago                              hungry_visvesvaraya
9fd2eecf6131        hxcan/assess-stock-serrver:435   "./AssessStockServ..."   2 weeks ago         Exited (1) 2 weeks ago                              laughing_brown
361b033bae66        hxcan/assess-stock-serrver:413   "./AssessStockServ..."   2 weeks ago         Exited (1) 2 weeks ago                              clever_ritchie
59c4931007c2        hxcan/assess-stock-serrver:366   "./AssessStockServ..."   3 weeks ago         Exited (1) 2 weeks ago                              stupefied_lewin
bc5ff8358f1a        hxcan/assess-stock-serrver:299   "./AssessStockServ..."   3 weeks ago         Exited (1) 3 weeks ago                              pedantic_archimedes
3834633c2587        hxcan/assess-stock-serrver:299   "./AssessStockServ..."   3 weeks ago         Exited (1) 3 weeks ago                              frosty_brattain

从上面的结果可以看到 ， 94b6f0f580fa以及下面的容器，都是处于退出状态。它们可能是之前明确地手动终止掉的，也可能是之前崩溃了的。此处，作者明确地知道， 94b6f0f580fa是崩溃了的。下面就看它的日志。

1. 4. docker logs

使用docker logs命令来查看指定容器的日志。例如：

[root@li1102-98 ~]# docker logs 94b6f0f580fa
……省掉一部分……
2020-08-11T02:14:55+00:00 : Received �hfunctionwGenerateRandomStockCode
2775
002711
2020-08-11T02:14:57+00:00 : Received �hfunctionrStockAssessRequestistockCodef002711jmoneyInput�@�F�nexpectedProfit�@��
       from /usr/src/app/AssessStock/AA1FA62F0BE8DCDD7C1C4A739AA0CE97.jpg_.rb:97:in `calculateHoldResult'
       from /usr/src/app/AssessStock/AA1FA62F0BE8DCDD7C1C4A739AA0CE97.jpg_.rb:202:in `block in assessStock'
       from /usr/src/app/AssessStock/AA1FA62F0BE8DCDD7C1C4A739AA0CE97.jpg_.rb:198:in `each'
       from /usr/src/app/AssessStock/AA1FA62F0BE8DCDD7C1C4A739AA0CE97.jpg_.rb:198:in `assessStock'
       from ./AssessStockServer.cache.rb:62:in `assessStock'
       from ./AssessStockServer.cache.rb:37:in `processMessage'
       from ./AssessStockServer.cache.rb:19:in `receive_data'
       from /usr/local/bundle/gems/eventmachine-1.2.7/lib/eventmachine.rb:195:in `run_machine'
       from /usr/local/bundle/gems/eventmachine-1.2.7/lib/eventmachine.rb:195:in `run'
       from ./AssessStockServer.cache.rb:73:in `<main>'

作为这个容器中代码的作者，看到这里，就知道是代码的哪里出错了，并且知道了触发该错误的参数。之后使用这样的参数在本地复现，就可以找到崩溃的原因，再对应地处理掉问题了。

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