My jump into coreos, the tiny, docker-centric distribution:)

Booting into the livecd, its pretty basic:

Setup networking with “ip addr add” etc.. commands:

# ip addr add <address>/<masklen> dev eth0 
# ip link set dev eth0 up 
# ip route add default via <default gw>

Set root user password and log in via ssh
Do something similar to below, basically create a cloud-config, and call the coreos-install command.

?[~]> sh [email protected]
[email protected]'s password:
[email protected]'s password:
CoreOS (stable)
Update Strategy: No Reboots
[email protected] ~ # export http_proxy=http://proxy.com:3128 (needed to use a proxy in my environment, which works fine with the coreos installer)
[email protected] etc # rm resolv.conf (had to do this to tear it away from systemd)
[email protected] etc # vim resolv.conf (and then threw in what I needed)
[email protected] etc # cd /home/core/
[email protected] core # coreos-
coreos-cloudinit    coreos-install      coreos-postinst     coreos-setgoodroot  coreos-tmpfiles
[email protected] core # coreos-install -d /dev/sda -C stable -c cloud-config.yaml
Downloading the signature for http://stable.release.core-os.net/amd64-usr/410.2.0/coreos_production_image.bin.bz2...
2014-10-10 02:36:58 URL:http://stable.release.core-os.net/amd64-usr/410.2.0/coreos_production_image.bin.bz2.sig [543/543] -> "/tmp/coreos-install.DVoGTAwr2J/coreos_production_image.bin.bz2.sig" [1]
Downloading, writing and verifying coreos_production_image.bin.bz2...
2014-10-10 02:37:36 URL:http://stable.release.core-os.net/amd64-usr/410.2.0/coreos_production_image.bin.bz2 [188892013/188892013] -> "-" [1]
gpg: Signature made Thu Oct  2 02:52:46 2014 UTC using RSA key ID E5676EFC
gpg: key 93D2DCB4 marked as ultimately trusted
gpg: checking the trustdb
gpg: 3 marginal(s) needed, 1 complete(s) needed, PGP trust model
gpg: depth: 0  valid:   1  signed:   0  trust: 0-, 0q, 0n, 0m, 0f, 1u
gpg: Good signature from "CoreOS Buildbot (Offical Builds) <[email protected]>" [ultimate]
Installing cloud-config...
Success! CoreOS stable 410.2.0 is installed on /dev/sda
[email protected] core #

Using the following “cloud-config”, you can specify configuration for the resulting installed system. Here, i set a ssh key for the “core” user, a hostname, setup resolv.conf, and static ip assignment. See this page for more info.

Keep in mind, this cloud-config is run at every boot. The file you apply when running coreos-install gets copied into a directory on the hard disk “/var/lib/coreos-install/user_data”, so you can edit further to add more things the system should do at start:)

#cloud-config

ssh_authorized_keys:
  - ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDAvAV7ehmYlZ0kZm9anXnSalFgP3YBie8Zbez...

hostname: cartman

write_files:
  - path: /etc/resolv.conf
    permissions: 0644
    owner: root
    content: |
      nameserver 10.1.0.1
      nameserver 10.1.1.1

coreos:
  units:
  - name: static.network
    runtime: yes
    content: |
      [Match]
      MACAddress=00:50:56:b5:ce:ff

      [Network]
      Gateway=10.10.10.1
      Address=10.10.10.10/23
      DNS=10.1.0.1

If I had to do this again, I would have probably just made a user account for myself and setup my groups and key right there:

users:
  - name: elroy
    passwd: $6$5s2u6/jR$un0AvWnqilcgaNB3Mkxd5yYv6mTlWfOoCYHZmfi3LDKVltj.E8XNKEcwWm...
    groups:
      - sudo
      - docker
    ssh-authorized-keys:
      - ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQC0g+ZTxC7weoIJLUafOgrm+h...

Ohh wait, you want to switch to the beta channel?

echo "GROUP=beta" > /etc/coreos/update.conf  
sudo systemctl restart update-engine

It’s probably also important that you know about the available update strategies. The default is most likely fine for most people.