I have a base image which contains OS+JDK and building my image on top of this. I have "yum install sftp" in my Docker file right after the "FROM base image".
Now, I would like to include "yum install sftp" also to my base image, so that I don't have to have this step in my DockerFile. I do not have much experience on building base image.
Create your own base image is just same as your own image.
Old:
FROM openjdk:8u151
RUN yum install sftp
New:
dockerid/baseimage
FROM openjdk:8u151
RUN yum install sftp
app dockerfile
FROM dockerid/baseimage
Of course, you need to commit your base image.
Related
I am running a container built with FROM busybox:1.31.1-glibc as the base image, but now when I am in the container and I try to use apk to install packages it does not work. For example:
/ # apk add curl
/bin/sh: apk: not found
How do I go about adding packages to this running container if I want to?
The busybox image doesn't have a package manager. It's intended for final distribution of build artifacts like a binary, with a few shell utilities for convenience. Typical usage would be as as the final base image in a multi-stage build.
apk is the Alpine package manager. If you want to use it, you'll need to use alpine as your base image in your Dockerfile.
I have a script that encrypts the files that are created by my application. The script is a bat file, I am changing it to shell script because in openshift we use wildfly server in centOS and the script uses OpenSSL.
My question is
Is it possible to install OpenSSL in the container or image. If so, is there any issue?
Or do we need to create custom openshift container which has openssl installed.
I am new to openshift and all. So not aware of this.
The short answer is "Yes" - practically, you can add to a container image any tool that you need. It is usually regarded as a good practice to add only what you need to keep the image size small.
It is quite possible that there's an image already "out there" that has openssl installed on centos. You may have to build the image for reasons like security, company policies, etc.
First, create a new image from a base image. A sample Dockerfile:
FROM centos:centos7
# Switch to root to be able to install stuff
USER 0
# -y for unattended install
RUN yum install -y curl \
# clean up the yum cache
&& yum clean all
Build the image, then push it to a Docker registry. Next, reference the image in the deployment configuration as the image for a container.
With OpenShift you actually have the option of building images on OpenShift, including using Docker builds, and saving them automatically in OpenShift's integrated Docker registry.
I'm trying to install some libraries (specifically pytorch) in my docker image. I have a Dockerfile that installs anaconda properly, but now I'd like to use conda to install a few other things in the image. Is there a way to do this? I've tried
RUN /opt/anaconda/bin/conda install -y pytorch torchvision
And anaconda is installed in the right location. Am I doing this the right way?
First, check if the way you have added/installed anaconda in your own image reflects the ContinuumIO/docker-images/anaconda.
Second, you can test the installation dynamically, as the README recommends
docker run -it yourImage /bin/bash -c "/opt/conda/bin/conda install ...
If that is working correctly, you can do the same in your Dockerfile.
I'm trying to reduce the size of my docker image which is using Centos 7.2
The issue is that it's 257MB which is too high...
I have followed the best practices to write Dockerfile in order to reduce the size...
Is there a way to modify the image after the build and rebuild that image to see the size reduced ?
First of all if you want to reduce an OS size, don't start with big one like CentOS, you can start with alpine which is small
Now if you are still keen on using CentOS, do the following:
docker run -d --name centos_minimal centos:7.2.1511 tail -f /dev/null
This will start a command in the background. You can then get into the container using
docker exec -it centos_minimal bash
Now start removing packages that you don't need using yum remove or yum purge. Once you are done you can commit the image
docker commit centos_minimal centos_minimal:7.2.1511_trial1
Experimental Squash Image
Another option is to use an experimental feature of the build command. In this you can have a dockerfile like below
FROM centos:7
RUN yum -y purge package1 package2 package2
Then build this file using
docker build --squash -t centos_minimal:squash .
For this you need to add "experimental": true to your /etc/docker/daemon.json and then restart the docker server
It is possible, but not at all elegant. Just like you can add software to the base image, you could also remove:
FROM centos:7
RUN yum -y update && yum clean all
RUN yum -y install new_software
RUN yum -y remove obsolete_software
Ask yourself: does your OS have to be CentOS? Then I would recommend you use the default installation and make sure your have enough disk space and memory.
If it does not need to be CentOS, you should rather start with a more minimalistic image. See the discussion here:
Which Docker base image should be used to install Apps in a container without any additional OS?
I am trying to build an Docker image. My Dockerfile is like this:
FROM python:2.7
ADD . /code
WORKDIR /code
RUN pip install -r requirement.txt
CMD ["python", "manage.py", "runserver", "0.0.0.0:8300"]
And my requirement.txt file like this:
wheel==0.29.0
numpy==1.11.3
django==1.10.5
django-cors-headers==2.0.2
gspread==0.6.2
oauth2client==4.0.0
Now, I have a little change in my code, and i need pandas, so i add it in to requirement.txt file
wheel==0.29.0
numpy==1.11.3
pandas==0.19.2
django==1.10.5
django-cors-headers==2.0.2
gspread==0.6.2
oauth2client==4.0.0
pip install -r requirement.txt will install all packages in that file, although almost of them has installed before. My question is how to make pip install pandas only? That will save the time to build image.
Thank you
If you rebuild your image after changing requirement.txt with docker build -t <your_image> ., I guess it cann't be done because each time when docker runs docker build, it'll start an intermediate container from base image, and it's a new environment so pip obviously will need to install all of dependencies.
You can consider to build your own base image on python:2.7 with common dependencies pre-installed, then build your application image on your own base image. Once there's a need to add more dependencies, manually re-build the base image on the previous one with only extra dependencies installed, and then maybe optionally docker push it back to your registry.
Hope this could be helpful :-)