Linux Containers (LXC) in Fedora 22 Rawhide - Part 2

In Part 1, we've learned on how to set up LXC in Fedora 22 and at the same time, we have also encountered quite a few issues and the possible workarounds to get it working. In this post, we'll still looking into these workarounds to find a better or alternative solutions

One of the issue is the deprecation of YUM in favour of DNF command to manage packages. The changes are not supposed to be backward compatible and breakage is certain. Instead of creating a container and download all the basic packages, we can build a container using download template.

Let's try the download template method. Once you've run the command below, a list of distro images will be shown. Note that not all distros can be created through this method, for example, Arch Linux is missing from the image list below. You still have to fallback to file template for container creation.

Next, you will be prompted to key in your distribution, release, and architecture. Once you've keyed in your selection, the command will continue to download the image. This may take a while, depending on your Internet speed.
$ sudo lxc-create -t download -n download-test
Setting up the GPG keyring
Downloading the image index

centos  6       amd64   default 20150507_02:16
centos  6       i386    default 20150507_02:16
centos  7       amd64   default 20150507_02:16
debian  jessie  amd64   default 20150506_22:42
debian  jessie  armel   default 20150506_22:42
debian  jessie  armhf   default 20150503_22:42
debian  jessie  i386    default 20150506_22:42
debian  sid     amd64   default 20150506_22:42
debian  sid     armel   default 20150506_22:42
debian  sid     armhf   default 20150506_22:42
debian  sid     i386    default 20150506_22:42
debian  wheezy  amd64   default 20150506_22:42
debian  wheezy  armel   default 20150505_22:42
debian  wheezy  armhf   default 20150506_22:42
debian  wheezy  i386    default 20150506_22:42
fedora  19      amd64   default 20150507_01:27
fedora  19      armhf   default 20150507_01:27
fedora  19      i386    default 20150507_01:27
fedora  20      amd64   default 20150507_01:27
fedora  20      armhf   default 20150507_01:27
fedora  20      i386    default 20150507_01:27
gentoo  current amd64   default 20150507_14:12
gentoo  current armhf   default 20150507_14:12
gentoo  current i386    default 20150507_14:12
opensuse        12.3    amd64   default 20150507_00:53
opensuse        12.3    i386    default 20150507_00:53
oracle  6.5     amd64   default 20150507_11:40
oracle  6.5     i386    default 20150507_11:40
plamo   5.x     amd64   default 20150506_21:36
plamo   5.x     i386    default 20150506_21:36
ubuntu  precise amd64   default 20150507_03:49
ubuntu  precise armel   default 20150507_03:49
ubuntu  precise armhf   default 20150507_03:49
ubuntu  precise i386    default 20150507_03:49
ubuntu  trusty  amd64   default 20150507_03:49
ubuntu  trusty  armhf   default 20150507_03:49
ubuntu  trusty  i386    default 20150506_03:49
ubuntu  trusty  ppc64el default 20150507_03:49
ubuntu  utopic  amd64   default 20150507_03:49
ubuntu  utopic  armhf   default 20150507_03:49
ubuntu  utopic  i386    default 20150507_03:49
ubuntu  utopic  ppc64el default 20150507_03:49
ubuntu  vivid   amd64   default 20150507_03:49
ubuntu  vivid   armhf   default 20150507_03:49
ubuntu  vivid   i386    default 20150506_03:49
ubuntu  vivid   ppc64el default 20150507_03:49

Distribution: centos
Release: 6
Architecture: amd64

Downloading the image index
Downloading the rootfs 
Downloading the metadata
The image cache is now ready
Unpacking the rootfs

You just created a CentOS container (release=6, arch=amd64, variant=default)

To enable sshd, run: yum install openssh-server

For security reason, container images ship without user accounts
and without a root password.

Use lxc-attach or chroot directly into the rootfs to set a root password
or create user accounts.

Once the container has been created. We start and attach to the container.
$ sudo lxc-start -n download-test
$ sudo lxc-attach -n download-test

# uname -a
Linux download-test 4.0.1-300.fc22.x86_64 #1 SMP Wed Apr 29 15:48:25 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
# cat /etc/centos-release 
CentOS release 6.6 (Final)

Instead of prompting your for the distribution, release, and architecture choices, you can simply create a container in one line of command. Note the extra double dashes (--) before you set the requirements arguments. All parameters after the (--) are passed to the template rather than the lxc-create command. Container creation should be very fast on second time as the program cached the downloaded images.
$ sudo lxc-create -t download -n download-test -- -d centos -r 6 -a amd64

To see the available options available for a particular template, use the command below. You can substitute the template name 'download' found in /usr/share/lxc/templates/.
$ lxc-create -t download -h

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