Cannot edit configuration file of tomcat instance made in docker

General Discussions
1

I have downloaded a tomcat image from docker hub and made three instance in an docker container of that tomcat . now issue i cant edit the configuration file of instance . so can anyone help how can i edit the conf file to change server , http,ajp ports of the conf file and make instance according to my choice of port so that i can make multiple instance in tomcat.

2

Create the file on the host. Then either

Copy it from host to containers ( see the dockerfile ADD command)
Or
Use the volume option on docker run command to map that folder into the container at the right location

3

We have already tried this and could no changed ports. Are their any alternatives for the same ?

4

sorry, I do not understand… this is what I do for a custom deployment

you create a customized image using the docker build command, and some local files

Dockerfile
from tomcat:latest (or whatever source image u are using)

Update the default apache site with the config we created.

ADD ports.conf /etc/apache2/ports.conf

note that virtual host port must match ports.conf setting

ADD apache-config.conf /etc/apache2/sites-enabled/000-default.conf
ADD apache.conf /etc/apache2/apache2.conf

— if u change the default port, you should add an expose for that
expose ??? (same port as in ports.conf)

CMD /usr/sbin/apache2ctl -D FOREGROUND

then docker build -t your_image_name .
then docker run your_image_name

5

OR

you could make folders on the docker host that have the apache config files in them
and then use -v or --volume to map those folders over the source image versions on docker run.
then u wouldn’t have to create a new image.

6

we are not facing issue with Apache but we are facing issues in tomcat instances as we are running multiple tomcat instances on the server and that I need to do using docker.

7

ok, explain more… i see the tomcat image uses port 8080 as default.

8

for eg. I am having a tomcat which contains 3 instances.

Tomcat A is using shutdown port : 8005, http : 8080 and ajp : 8009
Tomcat B is using shutdown port : 8006, http : 8081 and ajp : 8010
Tomcat C is using shutdown port : 8007, http : 8082 and ajp : 8011

How I can do such using docker?

9

ok… according to the tomcat/conf/server.xml in the tomcat image (tomcat:latest)

the image shutdown is 8005, http is 8080, and ajp is 8009.

So,
mapping each container port :xxxx to a host port yyyy:

# Tomcat A
docker run -d -p 8005:8005 -p 8009:8009 -p 8080:8080 tomcat
# Tomcat B
docker run -d -p 8006:8005 -p 8010:8009 -p 8081:8080 tomcat
# Tomcat C
docker run -d -p 8007:8005 -p 8011:8009 -p 8082:8080 tomcat