Build docker image without docker installed

I don't want to force others to install docker on their machines.

If by "without Docker installed" you mean without having to install Docker locally on every machine running the build, you can leverage the Docker Engine API which allow you to call a Docker Daemon from a distant host.

The Docker Engine API is a RESTful API accessed by an HTTP client such as wget or curl, or the HTTP library which is part of most modern programming languages.

For example, the Fabric8 Docker Maven Plugin does just that using the DOCKER_HOST parameter. You'll need a recent Docker version and you'll have to configure at least one Docker Daemon properly so it can securely accept remote requests (there are lot of resources on this subject, such as the official doc, here or here). From then on, your Docker build can be done remotely without having to install Docker locally.


We can create Docker image without Docker being installed.

Jib Maven and Gradle Plugins

Google has an open source tool called Jib that is relatively new, but quite interesting for a number of reasons. Probably the most interesting thing is that you don’t need docker to run it - it builds the image using the same standard output as you get from docker build but doesn’t use docker unless you ask it to - so it works in environments where docker is not installed (not uncommon in build servers). You also don’t need a Dockerfile (it would be ignored anyway), or anything in your pom.xml to get an image built in Maven (Gradle would require you to at least install the plugin in build.gradle).

Another interesting feature of Jib is that it is opinionated about layers, and it optimizes them in a slightly different way than the multi- layer Dockerfile created above. Just like in the fat jar, Jib separates local application resources from dependencies, but it goes a step further and also puts snapshot dependencies into a separate layer, since they are more likely to change. There are configuration options for customizing the layout further.

Pls refer this link https://cloud.google.com/blog/products/gcp/introducing-jib-build-java-docker-images-better

For example with Spring Boot refer https://spring.io/blog/2018/11/08/spring-boot-in-a-container


Have a look at the following tools:

  1. Fabric8-maven-plugin - http://maven.fabric8.io/ - good maven integration, uses a remote docker (openshift) cluster for the builds.
  2. Buildah - https://github.com/containers/buildah - builds without a docker daemon but does have other pre-requisites.

Fabric8-maven-plugin

The fabric8-maven-plugin brings your Java applications on to Kubernetes and OpenShift. It provides a tight integration into Maven and benefits from the build configuration already provided. This plugin focus on two tasks: Building Docker images and creating Kubernetes and OpenShift resource descriptors.

fabric8-maven-plugin seems particularly appropriate if you have a Kubernetes / Openshift cluster available. It uses the Openshift APIs to build and optionally deploy an image directly to your cluster.

I was able to build and deploy their zero-config spring-boot example extremely quickly, no Dockerfile necessary, just write your application code and it takes care of all the boilerplate.

Assuming you have the basic setup to connect to OpenShift from your desktop already, it will package up the project .jar in a container and start it on Openshift. The minimum maven configuration is to add the plugin to your pom.xml build/plugins section:

<plugin>
    <groupId>io.fabric8</groupId>
    <artifactId>fabric8-maven-plugin</artifactId>
    <version>3.5.41</version>
</plugin>

then build+deploy using

$ mvn fabric8:deploy

If you require more control and prefer to manage your own Dockerfile, it can handle this too, this is shown in samples/secret-config.

Buildah

Buildah is a tool that facilitates building Open Container Initiative (OCI) container images. The package provides a command line tool that can be used to:

  • create a working container, either from scratch or using an image as a starting point
  • create an image, either from a working container or via the instructions in a Dockerfile
  • images can be built in either the OCI image format or the traditional upstream docker image format
  • mount a working container's root filesystem for manipulation
  • unmount a working container's root filesystem
  • use the updated contents of a container's root filesystem as a filesystem layer to create a new image
  • delete a working container or an image
  • rename a local container

Tags:

Docker

Build

Maven

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