Create update image from running container

Sometimes developers have to create or update an image from running container and push them to registry to make their changes available to others.

This is a step by step guide to create an image from locally runnning container and push it to the registry 10.84.34.155:5000.

• Follow https://github.com/Juniper/contrail-docker/wiki/Configure-docker-service-to-use-insecure-registry to configure docker with insecure registry
• Take a snapshot of running container

$ docker ps
CONTAINER ID        IMAGE                                COMMAND                  CREATED             STATUS              PORTS                    NAMES
207a65178c09        10.84.34.155:5000/contrail-kube-manager:4.0.0.0-3016   "/entrypoint.sh"                   14 seconds ago      Up 12 seconds                                contrail-kube-manager

# Need to take snapshot of contrail-kube-manager

$ docker commit contrail-kube-manager
sha256:f65aa930ccc560af7b1d44071b20e8d3ac820d4f896a5c63f9bd8428114350c0

# Note above id (f65aa930ccc560af7b1d44071b20e8d3ac820d4f896a5c63f9bd8428114350c0) - this need to be used in further steps

• Create a small dockerfile with below contents

$ mkdir /tmp/kube_manager # you can create the directory with any name btw
$ vi /tmp/kube_manager/Dockerfile

# Add below content to /tmp/kube_manager/Dockerfile 
# Change below id to valid image id you get from above step (docker commit)
FROM f65aa930ccc560af7b1d44071b20e8d3ac820d4f896a5c63f9bd8428114350c0
ENTRYPOINT /entrypoint.sh

• Build docker image

$ docker build -t 10.84.34.155:5000/contrail-kube-manager:4.0.0.0-3016 /tmp/kube_manager/

• Push new image to registry

$ docker push 10.84.34.155:5000/contrail-kube-manager:4.0.0.0-3016