CentOS 7上的Docker卷

Question

当试图将卷映射到tomcat容器中的主机时，我在CentOS 7上遇到了一个问题。这发生在公共tomcat图像以及我创建的图像上（基于centos而不是debian）。

实例化一个容器如下就会成功： 搬运工运行 - 它-d tomcat的：8

实例化一个容器如下会成功，但随着日志中的错误和日志不会被写入到主机： 搬运工运行 - 它-d -v在/ usr /本地/ Tomcat的：在/ usr /本地/ Tomcat的Tomcat的：8

[wpackard@eagle2 tomcat]$ dkr run -it -d -v 

/usr/local/tomcat:/usr/local/tomcat tomcat:8 
34075701b1436f83a24212170b4d2113ae698df244c449203b1c9af9814485c9 
[wpackard@eagle2 tomcat]$ dkr ps 
CONTAINER ID  IMAGE    COMMAND    CREATED    STATUS    PORTS    NAMES 
34075701b143  tomcat:8   "catalina.sh run" 5 seconds ago  Up 4 seconds  8080/tcp   sharp_einstein 
[wpackard@eagle2 tomcat]$ dkr logs sharp_einstein 
Using CATALINA_BASE: /usr/local/tomcat 
Using CATALINA_HOME: /usr/local/tomcat 
Using CATALINA_TMPDIR: /usr/local/tomcat/temp 
Using JRE_HOME:  /usr 
Using CLASSPATH:  /usr/local/tomcat/bin/bootstrap.jar:/usr/local/tomcat/bin/tomcat-juli.jar 
java.util.logging.ErrorManager: 4 
java.io.FileNotFoundException: /usr/local/tomcat/logs/catalina.2015-03-31.log (Permission denied) 

... 

31-Mar-2015 15:32:04.088 SEVERE [Catalina-startStop-1] org.apache.catalina.startup.HostConfig.start Unable to create directory for deployment: /usr/local/tomcat/conf/Catalina/localhost 
31-Mar-2015 15:32:04.097 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory /usr/local/tomcat/webapps/ROOT 
31-Mar-2015 15:32:04.468 WARNING [localhost-startStop-1] org.apache.catalina.core.StandardContext.postWorkDirectory Failed to create work directory [/usr/local/tomcat/work/Catalina/localhost/ROOT] for context [] 
31-Mar-2015 15:32:05.966 SEVERE [localhost-startStop-1] org.apache.jasper.EmbeddedServletOptions.<init> The scratchDir you specified: /usr/local/tomcat/work/Catalina/localhost/ROOT is unusable. 
31-Mar-2015 15:32:06.042 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory /usr/local/tomcat/webapps/ROOT has finished in 1,929 ms 
31-Mar-2015 15:32:06.043 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory /usr/local/tomcat/webapps/docs 
31-Mar-2015 15:32:06.093 WARNING [localhost-startStop-1] org.apache.catalina.core.StandardContext.postWorkDirectory Failed to create work directory [/usr/local/tomcat/work/Catalina/localhost/docs] for context [/docs] 
31-Mar-2015 15:32:06.216 SEVERE [localhost-startStop-1] org.apache.jasper.EmbeddedServletOptions.<init> The scratchDir you specified: /usr/local/tomcat/work/Catalina/localhost/docs is unusable. 
31-Mar-2015 15:32:06.219 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory /usr/local/tomcat/webapps/docs has finished in 176 ms 
31-Mar-2015 15:32:06.220 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory /usr/local/tomcat/webapps/examples 
31-Mar-2015 15:32:06.272 WARNING [localhost-startStop-1] org.apache.catalina.core.StandardContext.postWorkDirectory Failed to create work directory [/usr/local/tomcat/work/Catalina/localhost/examples] for context [/examples] 
31-Mar-2015 15:32:07.952 SEVERE [localhost-startStop-1] org.apache.jasper.EmbeddedServletOptions.<init> The scratchDir you specified: /usr/local/tomcat/work/Catalina/localhost/examples is unusable. 
[wpackard@eagle2 tomcat]$ 

Exec'ing到容器，并试图也写失败。

[wpackard@eagle2 tomcat]$ dkr ps 
CONTAINER ID  IMAGE    COMMAND    CREATED    STATUS    PORTS    NAMES 
34075701b143  tomcat:8   "catalina.sh run" 5 minutes ago  Up 5 minutes  8080/tcp   sharp_einstein 
[wpackard@eagle2 tomcat]$ dkr exec -it sharp_einstein /bin/bash 
root@34075701b143:/usr/local/tomcat# ls -l 
total 96 
-rw-rw-r--. 1 root root 56977 Jan 23 11:59 LICENSE 
-rw-rw-r--. 1 root root 1397 Jan 23 11:59 NOTICE 
-rw-rw-r--. 1 root root 6779 Jan 23 11:59 RELEASE-NOTES 
-rw-rw-r--. 1 root root 16204 Jan 23 11:59 RUNNING.txt 
drwxrwxr-x. 2 root root 4096 Mar 31 12:14 bin 
drwxrwxr-x. 2 root root 4096 Jan 23 11:59 conf 
drwxrwxr-x. 2 root root 4096 Mar 31 12:14 lib 
drwxrwxr-x. 2 root root  6 Jan 23 11:56 logs 
drwxrwxr-x. 2 root root 29 Mar 31 12:14 temp 
drwxrwxr-x. 7 root root 76 Jan 23 11:57 webapps 
drwxrwxr-x. 2 root root  6 Jan 23 11:56 work 
root@34075701b143:/usr/local/tomcat# cd logs 
root@34075701b143:/usr/local/tomcat/logs# echo "test" > test.log 
bash: test.log: Permission denied 

我已经在CentOS创建的PostgreSQL容器的实例和成功的映射和使用量，通过创建一个数据库，停止实例，然后重新运行容器验证。

[wpackard@eagle2 ~]$ uname --all 
Linux eagle2 3.10.0-123.20.1.el7.x86_64 #1 SMP Thu Jan 29 18:05:33 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux 
[wpackard@eagle2 ~]$ 

dkr是docker的别名，我创建了一个docker组并将自己添加到该组中，以消除对sudo的需求。

卷映射似乎在ubuntu上正常工作。在CentOS上，我尝试了两个软件包版本（如下所示），并将它更新到1.5。

[wpackard@eagle2 ~]$ dkr --version 
Docker version 1.3.2, build 39fa2fa/1.3.2 
[wpackard@eagle2 ~]$ 

如何使卷在CentOS上正常工作？

Answer 1

我认为你的卷是 working :-)你有权限问题。我经常遇到这种情况，主机和容器之间的用户标识映射。在您的主机上，如果您查看/ usr/local/tomcat（ls -ld），您将看到所有者，组和权限。你可能有类似于0755的东西（所有者读/写/执行，组读/执行，世界读/执行）。你可以很容易地测试这个理论，简单记住/ usr/local/tomcat/logs的当前设置，然后做：

chmod 777 /usr/local/tomcat/logs 

从泊坞窗主机（不是容器），然后运行您的容器上测试，否认权限应蒸发

这是不是一个很好的修复，虽然我不。不知道社区对docker的用户标识映射有什么看法，你可以做的一件事是找出你的主机上的用户和组，然后当你创建你的映像时（或者在运行时）创建一个用户同一个ID d在容器中具有相同ID的组。然后在容器中使用该用户运行你的tomcat服务。

Answer 2

这是由于SELinux。

您必须附上正确类型的托管目录：

host$ chcon -Rt svirt_sandbox_file_t /usr/local/tomcat