查找tomcat的containerID,进入tomacat目录：

[root@promote ~]# docker ps 
CONTAINER ID  IMAGE    COMMAND     CREATED    STATUS    PORTS     NAMES
b52c4a46a432  nginx    "/docker-entrypoin..." 4 minutes ago  Up 4 minutes  0.0.0.0:8081->80/tcp  nginx-test
02ffbf387631  tomcat    "catalina.sh run"  45 minutes ago  Up 45 minutes  0.0.0.0:8080->8080/tcp mytomcat

  查看webapps发现里面为空

[root@promote ~]# docker exec -it 02ffbf387631 /bin/bash
root@02ffbf387631:/usr/local/tomcat# ls -l
total 124
-rw-r--r--. 1 root root 18982 Sep 10 08:25 BUILDING.txt
-rw-r--r--. 1 root root 5409 Sep 10 08:25 CONTRIBUTING.md
-rw-r--r--. 1 root root 57092 Sep 10 08:25 LICENSE
-rw-r--r--. 1 root root 2333 Sep 10 08:25 NOTICE
-rw-r--r--. 1 root root 3257 Sep 10 08:25 README.md
-rw-r--r--. 1 root root 6898 Sep 10 08:25 RELEASE-NOTES
-rw-r--r--. 1 root root 16262 Sep 10 08:25 RUNNING.txt
drwxr-xr-x. 2 root root 4096 Sep 15 22:33 bin
drwxr-xr-x. 1 root root 22 Oct 10 01:45 conf
drwxr-xr-x. 2 root root 4096 Sep 15 22:33 lib
drwxrwxrwx. 1 root root 177 Oct 10 01:45 logs
drwxr-xr-x. 2 root root 134 Sep 15 22:33 native-jni-lib
drwxrwxrwx. 2 root root 30 Sep 15 22:33 temp
drwxr-xr-x. 2 root root  6 Sep 15 22:33 webapps
drwxr-xr-x. 7 root root 81 Sep 10 08:23 webapps.dist
drwxrwxrwx. 2 root root  6 Sep 10 08:20 work
root@02ffbf387631:/usr/local/tomcat# cd webapps
root@02ffbf387631:/usr/local/tomcat/webapps# ls -l
total 0

  删除webapps,将webapps.dist修改名称为webapps

root@02ffbf387631:/usr/local/tomcat/webapps# cd ..
root@02ffbf387631:/usr/local/tomcat# rm -rf webapps
root@02ffbf387631:/usr/local/tomcat# mv webapps.dist webapps
root@02ffbf387631:/usr/local/tomcat# cd webapps
root@02ffbf387631:/usr/local/tomcat/webapps# ls -l
total 8
drwxr-xr-x. 3 root root 4096 Sep 15 22:33 ROOT
drwxr-xr-x. 15 root root 4096 Sep 15 22:33 docs
drwxr-xr-x. 6 root root 83 Sep 15 22:33 examples
drwxr-xr-x. 5 root root 87 Sep 15 22:33 host-manager
drwxr-xr-x. 6 root root 114 Sep 15 22:33 manager

  重新在浏览器中访问：

没有提交的话，在镜像重启后，又会报404错误，要commit一下

[root@promote ~]# docker ps
CONTAINER ID  IMAGE    COMMAND     CREATED    STATUS    PORTS     NAMES
b52c4a46a432  nginx    "/docker-entrypoin..." 43 minutes ago  Up 42 minutes  0.0.0.0:8081->80/tcp  nginx-test
02ffbf387631  tomcat    "catalina.sh run"  About an hour ago Up About an hour 0.0.0.0:8080->8080/tcp mytomcat
[root@promote ~]# docker commit 02ffbf387631 mytomcat
sha256:b2c4b37c92c5c26b1285756bf04365b8f5a42a86d519a767ea528cda1af9a81a

再次访问就不需要配置，直接访问tomcat页面了