====== Docker - Networking - Ping command not found ======

===== Check if ping works =====

Run a Docker container with Ubuntu:

<code bash>
docker run -it ubuntu /bin/bash
</code>

Then try a ping:

<code bash>
ping somesite.com
bash: ping: command not found
</code>

----

===== Install ping =====

Docker images are pretty minimal, but you can install ping in the official Ubuntu docker image via:

<code bash>
apt-get update
apt-get install iputils-ping
</code>



But if you need ping to exist on your image, you can create a Dockerfile or commit the container you ran the above commands in to a new image.

Commit:

<code bash>
docker commit -m "Installed iputils-ping" --author "Your Name <name@domain.com>" ContainerNameOrId yourrepository/imagename:tag
</code>

Dockerfile:

<file bash Dockerfile>
FROM ubuntu
RUN apt-get update && apt-get install -y iputils-ping
CMD bash
</file>

Please note there are best practices on creating docker images, Like clearing apt cache files after etc.

**apt-get** fails with Temporary failure resolving 'security.ubuntu.com' obviously because networking is not present.

----

===== Example Dockerfile for Ubuntu with ping =====

<code>
mkdir ubuntu_with_ping
cat >ubuntu_with_ping/Dockerfile <<'EOF'
FROM ubuntu
RUN apt-get update && apt-get install -y iputils-ping
CMD bash
EOF
docker build -t ubuntu_with_ping ubuntu_with_ping
docker run -it ubuntu_with_ping
</code>

----