CentOS 7上的Docker卷

Question

當試圖將卷映射到tomcat容器中的主機時，我在CentOS 7上遇到了一個問題。這發生在公共tomcat圖像以及我創建的圖像上（基於centos而不是debian）。

實例化一個容器如下就會成功： 搬運工運行 - 它-d tomcat的：8

實例化一個容器如下會成功，但隨着日誌中的錯誤和日誌不會被寫入到主機： 搬運工運行 - 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，並試圖也寫失敗。

[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 

我已經在CentOS創建的PostgreSQL容器的實例和成功的映射和使用量，通過創建一個數據庫，停止實例，然後重新運行容器驗證。

[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的別名，我創建了一個docker組並將自己添加到該組中，以消除對sudo的需求。

卷映射似乎在ubuntu上正常工作。在CentOS上，我嘗試了兩個軟件包版本（如下所示），並將它更新到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

我認爲你的卷是 working :-)你有權限問題。我經常遇到這種情況，主機和容器之間的用戶標識映射。在您的主機上，如果您查看/ usr/local/tomcat（ls -ld），您將看到所有者，組和權限。你可能有類似於0755的東西（所有者讀/寫/執行，組讀/執行，世界讀/執行）。你可以很容易地測試這個理論，簡單記住/ usr/local/tomcat/logs的當前設置，然後做：

chmod 777 /usr/local/tomcat/logs 

從泊塢窗主機（不是容器），然後運行您的容器上測試，否認權限應蒸發

這是不是一個很好的修復，雖然我不。不知道社區對docker的用戶標識映射有什麼看法，你可以做的一件事是找出你的主機上的用戶和組，然後當你創建你的映像時（或者在運行時）創建一個用戶同一個ID d在容器中具有相同ID的組。然後在容器中使用該用戶運行你的tomcat服務。

Answer 2

這是由於SELinux。

您必須附上正確類型的託管目錄：

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