HOWTO: Automatically import your public SSH keys into LXD Instances

Just another reason why LXD is so awesome...

You can easily configure your own cloud-init configuration into your LXD instance profile.

In my case, I want cloud-init to automatically ssh-import-id kirkland, to fetch my keys from Launchpad.  Alternatively, I could use gh:dustinkirkland to fetch my keys from Github.

Here's how!

First, edit your default LXD profile (or any other, for that matter):

$ lxc profile edit default

Then, add the config snippet, like this:

config:
  user.vendor-data: |
    #cloud-config
    users:
      - name: root
        ssh-import-id: gh:dustinkirkland
        shell: /bin/bash
description: Default LXD profile
devices:
  eth0:
    name: eth0
    nictype: bridged
    parent: lxdbr0
    type: nic
name: default

Save and quit in your interactive editor, and then launch a new instance:

$ lxc launch ubuntu:x
Creating amazed-manatee
Starting amazed-manatee

Find your instance's IP address:

$ lxc list
+----------------+---------+----------------------+----------------------------------------------+------------+-----------+
|      NAME      |  STATE  |         IPV4         |                     IPV6                     |    TYPE    | SNAPSHOTS |
+----------------+---------+----------------------+----------------------------------------------+------------+-----------+
| amazed-manatee | RUNNING | 10.163.22.135 (eth0) | fdce:be5e:b787:f7d2:216:3eff:fe1c:773 (eth0) | PERSISTENT | 0         |
+----------------+---------+----------------------+----------------------------------------------+------------+-----------+

And now SSH in!

$ ssh ubuntu@10.163.22.135
$ ssh -6 ubuntu@fdce:be5e:b787:f7d2:216:3eff:fe1c:773

Enjoy!
:-Dustin

HOWTO: Launch an Ubuntu Cloud Image with KVM from the Command Line

I reinstalled my primary laptop (Lenovo x250) about 3 months ago (June 30, 2016), when I got a shiny new SSD, with a fresh Ubuntu 16.04 LTS image.

Just yesterday, I needed to test something in KVM.  Something that could only be tested in KVM.

kirkland@x250:~⟫ kvm
The program 'kvm' is currently not installed. You can install it by typing:
sudo apt install qemu-kvm
127 kirkland@x250:~⟫ 

I don't have KVM installed?  How is that even possible?  I used to be the maintainer of the virtualization stack in Ubuntu (kvm, qemu, libvirt, virt-manager, et al.)!  I lived and breathed virtualization on Ubuntu for years...

Alas, it seems that I've use LXD for everything these days!  It's built into every Ubuntu 16.04 LTS server, and one 'apt install lxd' away from having it on your desktop.  With ZFS, instances start in under 3 seconds.  Snapshots, live migration, an image store, a REST API, all built in.  Try it out, if you haven't, it's great!

kirkland@x250:~⟫ time lxc launch ubuntu:x
Creating supreme-parakeet
Starting supreme-parakeet
real    0m1.851s
user    0m0.008s
sys     0m0.000s
kirkland@x250:~⟫ lxc exec supreme-parakeet bash
root@supreme-parakeet:~# 

But that's enough of a LXD advertisement...back to the title of the blog post.

Here, I want to download an Ubuntu cloud image, and boot into it.  There's one extra step nowadays.  You need to create your "user data" and feed it into cloud-init.

First, create a simple text file, called "seed":

kirkland@x250:~⟫ cat seed
#cloud-config
password: passw0rd
chpasswd: { expire: False }
ssh_pwauth: True
ssh_import_id: kirkland

Now, generate a "seed.img" disk, like this:

kirkland@x250:~⟫ cloud-localds seed.img seed
kirkland@x250:~⟫ ls -halF seed.img 
-rw-rw-r-- 1 kirkland kirkland 366K Sep 20 17:12 seed.img

Next, download your image from cloud-images.ubuntu.com:

kirkland@x250:~⟫ wget http://cloud-images.ubuntu.com/xenial/current/xenial-server-cloudimg-amd64-disk1.img                                                                                                                                                          
--2016-09-20 17:13:57--  http://cloud-images.ubuntu.com/xenial/current/xenial-server-cloudimg-amd64-disk1.img
Resolving cloud-images.ubuntu.com (cloud-images.ubuntu.com)... 91.189.88.141, 2001:67c:1360:8001:ffff:ffff:ffff:fffe
Connecting to cloud-images.ubuntu.com (cloud-images.ubuntu.com)|91.189.88.141|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 312606720 (298M) [application/octet-stream]
Saving to: ‘xenial-server-cloudimg-amd64-disk1.img’
xenial-server-cloudimg-amd64-disk1.img 
100%[=================================] 298.12M  3.35MB/s    in 88s     
2016-09-20 17:15:25 (3.39 MB/s) - ‘xenial-server-cloudimg-amd64-disk1.img’ saved [312606720/312606720]

In the nominal case, you can now just launch KVM, and add your user data as a cdrom disk.  When it boots, you can login with "ubuntu" and "passw0rd", which we set in the seed:

kirkland@x250:~⟫ kvm -cdrom seed.img -hda xenial-server-cloudimg-amd64-disk1.img

Finally, let's enable more bells an whistles, and speed this VM up.  Let's give it all 4 CPUs, a healthy 8GB of memory, a virtio disk, and let's port forward ssh to 2222:

kirkland@x250:~⟫ kvm -m 8192 \
    -smp 4 \
    -cdrom seed.img \
    -device e1000,netdev=user.0 \
    -netdev user,id=user.0,hostfwd=tcp::5555-:22 \
    -drive file=xenial-server-cloudimg-amd64-disk1.img,if=virtio,cache=writeback,index=0

And with that, we can how ssh into the VM, with the public SSH key specified in our seed:

kirkland@x250:~⟫ ssh -p 5555 ubuntu@localhost
The authenticity of host '[localhost]:5555 ([127.0.0.1]:5555)' can't be established.
RSA key fingerprint is SHA256:w2FyU6TcZVj1WuaBA799pCE5MLShHzwio8tn8XwKSdg.
No matching host key fingerprint found in DNS.
Are you sure you want to continue connecting (yes/no)? yes

Welcome to Ubuntu 16.04.1 LTS (GNU/Linux 4.4.0-36-generic x86_64)

 * Documentation:  https://help.ubuntu.com
 * Management:     https://landscape.canonical.com
 * Support:        https://ubuntu.com/advantage

  Get cloud support with Ubuntu Advantage Cloud Guest:
    http://www.ubuntu.com/business/services/cloud

0 packages can be updated.
0 updates are security updates.

ubuntu@ubuntu:~⟫ 

Cheers,
:-Dustin

HOWTO: Host your own SNAP store!

SNAPs are the cross-distro, cross-cloud, cross-device Linux packaging format of the future.  And we're already hosting a fantastic catalog of SNAPs in the SNAP store provided by Canonical.  Developers are welcome to publish their software for distribution across hundreds millions of Ubuntu servers, desktops, and devices.

Several people have asked the inevitable open source software question, "SNAPs are awesome, but how can I stand up my own SNAP store?!?"

The answer is really quite simple...  SNAP stores are really just HTTP web servers!  Of course, you can get fancy with branding, and authentication, and certificates.  But if you just want to host SNAPs and enable downstream users to fetch and install software, well, it's pretty trivial.

In fact, Bret Barker has published an open source (Apache License) SNAP store on GitHub.  We're already looking at how to flesh out his proof-of-concept and bring it into snapcore itself.

Here's a little HOWTO install and use it.

First, I launched an instance in AWS.  Of course I could have launched an Ubuntu 16.04 LTS instance, but actually, I launched a Fedora 24 instance!  In fact, you could run your SNAP store on any OS that currently supports SNAPs, really, or even just fork this GitHub repo and install it stand alone..  See snapcraft.io.

Now, let's find and install a snapstore SNAP.  (Note that in this AWS instance of Fedora 24, I also had to 'sudo yum install squashfs-tools kernel-modules'.

At this point, you're running a SNAP store (webserver) on port 5000.

Now, let's reconfigure snapd to talk to our own SNAP store, and search for a SNAP.

Finally, let's install and inspect that SNAP.

How about that?  Easy enough!

Cheers,
Dustin