How to install packages inside a docker Ubuntu image

Question

After installing Ubuntu image on docker I tried to run packages inside the image. I get an error message which says “unable to locate package”. For example, when I run the below command, I get the following error:

apt-get install curl

Reading package lists... Done

Building dependency tree       

Reading state information... Done

E: Unable to locate package curl

How do I solve this?

Comments

Do apt-get update before installing the package

Answer 1

This happens when there is no package cache in the image, you need to run the following command before installing packages:

apt-get update

If you’re running in a Dockerfile, then you have to follow the below command:

apt-get -y install curl

Finally, to suppress the std o/p use -qq. Example,

apt-get -qq -y install curl

Answer 2

You could try something like this:

docker run ubuntu bash -c "apt-get -y install curl" 

Answer 3

Try this:

RUN apt-get update

And then install the package

Answer 4

Execute the update and the install command in the same line. Like this:

RUN apt-get update && apt-get install -y package-bar

Comments

This worked for me. But why?

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using apt-get update alone in a run statement can cause caching issues and subsequent apt-get update install fails.