Problem

The following describes the process of trying out Quay Container Registry and Buildah using an installation of RHEL/CentOS.

Solution

The first step is to install the dependencies for Buildah.

[IMPORTANT] To run Buildah on Red Hat Enterprise Linux or CentOS, version 7.4 or higher is required.

 yum -y install make \
                golang \
                bats \
                btrfs-progs-devel \
                device-mapper-devel \
                glib2-devel \
                gpgme-devel \
                libassuan-devel \
                libseccomp-devel \
                ostree-devel \
                git \
                bzip2 \
                golang-github-cpuguy83-go-md2man \
                runc \
                skopeo-containers

Install the latest golang locally.

On RHEL 7.4, I was unable to make Buildah using go version go1.3.3 linux/amd64, so I prioritized ~/.local/bin over /usr/bin.

First, install Golang outside of ‘yum’ package manager.

 $ curl -L 'https://dl.google.com/go/go1.10.3.linux-amd64.tar.gz' | tar -xvzf - -C $HOME/.local --strip 1 &>/dev/null

Then setup the environment to manage projects and public packages independently.

 $ cat <<EOF >>~/.bashrc
 export GOROOT=$HOME/.local
 export GOPATH=$HOME/.go/Projects
 export GOPATH=$HOME/.go/PublicPackages:$GOPATH
 export GOBIN=$HOME/.local/bin
 export PATH=$GOROOT/bin:$PATH
 # export GOMAXPROCS='1'
 EOF

Optionally, add support for uninstalling custom go packages via shell script.

Thanks to Abhishek Kumar for providing enhancement and credit for my original script.
Prefer to use upstream go-md2man (source of Buildah issues mentioned in Step 2).
```
 $ go get github.com/cpuguy83/go-md2man
```

Install Buildah

 $ mkdir ~/buildah
 $ cd ~/buildah
 $ export GOPATH=`pwd`
 $ git clone https://github.com/projectatomic/buildah ./src/github.com/projectatomic/buildah
 $ cd ./src/github.com/projectatomic/buildah
 $ make
 $ sudo make install
 $ buildah --help

Create a Quay.io user account

In order to be able to log into Quay Container Registry using the Docker CLI you need to create a user account first.

I did this by using my GitHub account to sign in and then reset my password because when I tried to create a new account I never received an email.

¯\(ツ)/¯
Create a Docker CLI Password

Go to your Quay account settings page and create an encrypted password for more security.
Sign into Quay.io

To sign into Quay.io, execute the docker login quay.io command:
```
 $ docker login quay.io
 Username: myusername
 Password: myencryptedpassword
```

Create a new container

First we’ll create a container with a single new file based off of the CentOS base image:

 # ctr1=`buildah from ${1:-docker.io/centos}`
 # buildah run $ctr1 -- /bin/bash -c 'echo "Hello Buildah!" >> /tmp/newfile'

Use buildah containers to list running containers:

CONTAINER ID  BUILDER  IMAGE ID     IMAGE NAME                       CONTAINER NAME
71d3440c6064     *     5182e96772bf docker.io/library/centos:latest  centos-working-container

Make note of the container id; we’ll need it for the commit command.

Tag the container to an image

We next need to tag the container to a known image name

Note that the username must be your Quay.io username and reponame is the new name of your repository.

# buildah commit 71d3440c6064 quay.io/myusername/echofun
Getting image source signatures
Skipping fetch of repeat blob sha256:1d31b5806ba40b5f67bde96f18a181668348934a44c9253b420d5f04cfb4e37a
Copying blob sha256:0d8fede6b2c6d05d95edc1c5d0b8dba4e6c7e31628e0a8dfb4eb419f3d05cdf4
 161 B / 161 B [============================================================] 0s
Copying config sha256:ae853012674b8421cd3155a29a5e28c01660c3eff1309309ba3f23d973006a4c
 1.18 KiB / 1.18 KiB [======================================================] 0s
Writing manifest to image destination
Storing signatures
ae853012674b8421cd3155a29a5e28c01660c3eff1309309ba3f23d973006a4c

Get the image ID

# buildah images
IMAGE ID             IMAGE NAME                                               CREATED AT             SIZE
5182e96772bf         docker.io/library/centos:latest                          Aug 6, 2018 15:21      208 MB
ae853012674b         quay.io/myusername/echofun:latest                           Aug 20, 2018 15:10     208 MB

Push the image to Quay.io

# buildah push --authfile /home/username/.docker/config.json ae853012674b docker://quay.io/myusername/echofun:latest
Getting image source signatures
Copying blob sha256:1d31b5806ba40b5f67bde96f18a181668348934a44c9253b420d5f04cfb4e37a
 198.64 MiB / 198.64 MiB [=================================================] 15s
Copying blob sha256:07ed723f8db4953eb6c86d436d3a5e411b5adf572215e791bfad0f3b2030a33a
 3.00 KiB / 3.00 KiB [======================================================] 0s
Copying config sha256:ae853012674b8421cd3155a29a5e28c01660c3eff1309309ba3f23d973006a4c
 1.18 KiB / 1.18 KiB [======================================================] 1s
Writing manifest to image destination
Copying config sha256:ae853012674b8421cd3155a29a5e28c01660c3eff1309309ba3f23d973006a4c
 0 B / 1.18 KiB [-----------------------------------------------------------] 0s
Writing manifest to image destination
Writing manifest to image destination
Storing signatures

Pull the image from Quay.io using Docker

A docker pull could be used to update the repository locally
```
$ docker pull quay.io/myusername/echofun
```

Run the image locally in order to verify the the /tmp/newfile exists

$ docker run -detach --name echofun quay.io/myusername/echofun sh -c 'while true; do sleep 1000; done'
$ docker exec -it echofun /bin/bash
[root@c6328f332102 /]# cat /tmp/newfile
Hello Buildah!
[root@c6328f332102 /]#

Summary

The purpose of this tutorial is to demonstrate how Buildah can be used to build container images compliant with the Open Container Initiative (OCI) image specification, checked into a remote registry, and run locally using the Docker daemon.

Buildah is a tool that facilitates building OCI container images and I suggest checking out Dan Walsh: Latest Container Technologies, as well as Getting Started with Buildah.

Whereas, Quay provides a market leading enterprise container registry solution, available as both software and hosted service, usable standalone or with OpenShift, fully supported by Red Hat.

Also, the inspiration for this post was Getting Started with Quay.io and you could even use the Red Hat Container Development Kit’s minishift ssh command to perform the step above if you do not have docker locally installed and need an all-in-one pre-built container development environment.

That’s all for now, and I hope this helps you get started with some of the latest container tech!