How to extend an existing docker image?

Question

I'm using the official elasticsearch Docker image instead of setting up my own elastic search instance. And that works great, up to the point when I wanted to extend it. I wanted to install marvel into that ElasticSearch instance to get more information.

Now dockerfile/elasticsearch automatically runs ElasticSearch and setting the command to /bin/bash doesn't work, neither does attaching to the container or trying to access it over SSH, nor installing ssh-daemon with apt-get install -y openssh-server.

In this particular case, I could just go into the container's file system and execute opt/elasticsearch/bint/plugin -i elasticsearch/marvel/latest and everything worked.

But how could I install an additional service which needs to be installed with apt-get when I can't have a terminal inside the running container?

Answer 1

Simply extend it using a Dockerfile that start with

FROM dockerfile/elasticsearch

and install marvel or ssh-server or whatever you need. Then, end with the correct command to start your services. You can use supervisor to start multple services, see Run a service automatically in a docker container for more info on that.

Answer 2

If you don't mind using docker-compose, what I usually do is to add a first section for the base image you plan to reuse, and then use that image as the base in the rest of the services' Dockerfiles, something along the lines of:

---
version: '2'
services:
    base:
        build: ./images/base

    collector:
         build: ./images/collector

Then, in images/collector/Dockerfile, and since my project is called webtrack, I'd type

FROM webtrack_base
...

And now it's done!

Answer 3

Update August 2016

Having found very little current information on how to do this with latest versions of ElasticSearch (2.3.5 for example), Kibana (4.5.3) and Marvel & Sense plugins, I opted to take the steeper path and write my own image.

Please find the source code (Dockerfile) and README here

FROM java:jre-alpine

MAINTAINER arcseldon <arcseldon@gmail.com>

ENV ES_VERSION=2.3.5 \
    KIBANA_VERSION=4.5.3

RUN apk add --quiet --no-progress --no-cache nodejs \
  && adduser -D elasticsearch

USER elasticsearch

WORKDIR /home/elasticsearch

RUN wget -q -O - http://download.elastic.co/elasticsearch/release/org/elasticsearch/distribution/tar/elasticsearch/${ES_VERSION}/elasticsearch-${ES_VERSION}.tar.gz \
 |  tar -zx \
 && mv elasticsearch-${ES_VERSION} elasticsearch \
 && wget -q -O - http://download.elastic.co/kibana/kibana/kibana-${KIBANA_VERSION}-linux-x64.tar.gz \
 |  tar -zx \
 && mv kibana-${KIBANA_VERSION}-linux-x64 kibana \
 && rm -f kibana/node/bin/node kibana/node/bin/npm \
 && ln -s $(which node) kibana/node/bin/node \
 && ln -s $(which npm) kibana/node/bin/npm \
 && ./elasticsearch/bin/plugin install license \
 && ./elasticsearch/bin/plugin install marvel-agent \
 && ./kibana/bin/kibana plugin --install elasticsearch/marvel/latest \
 && ./kibana/bin/kibana plugin --install elastic/sense 

CMD elasticsearch/bin/elasticsearch --es.logger.level=OFF --network.host=0.0.0.0 & kibana/bin/kibana -Q

EXPOSE 9200 5601

If you just want the pre-built image then please do:

docker pull arcseldon/elasticsearch-kibana-marvel-sense

You can visit the repository on hub.docker.com here

Usage:

docker run -d -p 9200:9200 -p 5601:5601 arcseldon/elasticsearch-kibana-marvel-sense

You can connect to Elasticsearch with http://localhost:9200 and its Kibana front-end with http://localhost:5601.

You can connect to Marvel with http://localhost:5601/app/marvel and Sense with http://localhost:5601/app/sense

Hope this helps others and saves some time!