getting started with CoreOS via QEMU

Install QEMU

sudo apt-get install qemu-system-x86 qemu-utils

Grab everything required from coreos.com

mkdir coreos; cd coreos
wget http://stable.release.core-os.net/amd64-usr/current/coreos_production_qemu.sh
wget http://stable.release.core-os.net/amd64-usr/current/coreos_production_qemu_image.img.bz2 -O - | bzcat > coreos_production_qemu_image.img
chmod +x coreos_production_qemu.sh

Copy over your public keys that you have authorized on you machine to the machine we going to start running CoreOS

./coreos_production_qemu.sh -a ~/.ssh/authorized_keys -- -nographic

Configure your ssh

cat << EOF >> ~/.ssh/config
Host coreos
    HostName localhost
    Port 2222
    User core
    StrictHostKeyChecking no
    UserKnownHostsFile /dev/null
EOF

Connect to your newly built CoreOS machine

ssh coreos

Test our CoreOS by running busybox

docker run busybox /bin/echo hello world

Startup etcd and fleet via systemd

sudo systemctl start etcd
sudo systemctl start fleetctl

Testing CoreOS with fleet

cat << EOF > hello.service
[Unit]
Description=My Service
After=docker.service

[Service]
TimeoutStartSec=0
ExecStartPre=-/usr/bin/docker kill hello
ExecStartPre=-/usr/bin/docker rm hello
ExecStartPre=/usr/bin/docker pull busybox
ExecStart=/usr/bin/docker run --name hello busybox /bin/sh -c "while true; do echo Hello World; sleep 1; done"
ExecStop=/usr/bin/docker stop hello
EOF

Load the hello.service via fleet

fleetctl load hello.service
Unit hello.service loaded on e81bb63c.../10.0.2.15

Start the hello.service via fleet

fleetctl start hello.service
Unit hello.service launched on e81bb63c.../10.0.2.15

Verify its working via systemd and docker

fleetctl start hello.service
● hello.service
  Loaded: loaded (/run/fleet/units/hello.service; linked-runtime)
  Active: active (running) since Mon 2015-02-02 04:38:40 UTC; 4s ago
Process: 1118 ExecStop=/usr/bin/docker stop hello (code=exited, status=0/SUCCESS)
Process: 1400 ExecStartPre=/usr/bin/docker pull busybox (code=exited, status=0/SUCCESS)
Process: 1391 ExecStartPre=/usr/bin/docker rm hello (code=exited, status=1/FAILURE)
Process: 1383 ExecStartPre=/usr/bin/docker kill hello (code=exited, status=1/FAILURE)
Main PID: 1435 (docker)
  CGroup: /system.slice/hello.service
  └─1435 /usr/bin/docker run --name hello busybox /bin/sh -c while true; do echo Hello World; sleep 1; done
Feb 02 04:38:40 coreos_production_qemu-522-6-0 systemd[1]: Started hello.service.
Feb 02 04:38:40 coreos_production_qemu-522-6-0 docker[1400]: Status: Image is up to date for busybox:latest
Feb 02 04:38:41 coreos_production_qemu-522-6-0 docker[1435]: Hello World
Feb 02 04:38:42 coreos_production_qemu-522-6-0 docker[1435]: Hello World
Feb 02 04:38:43 coreos_production_qemu-522-6-0 docker[1435]: Hello World
Feb 02 04:38:44 coreos_production_qemu-522-6-0 docker[1435]: Hello World
Feb 02 04:38:45 coreos_production_qemu-522-6-0 docker[1435]: Hello World

/ daniellawrence