[Unit]

Description=busybox

Requires=docker.service

After=docker.service

[Service]

TimeoutStartSec=0

ExecStartPre=-/usr/bin/docker kill busybox

ExecStartPre=-/usr/bin/docker rm busybox

ExecStartPre=/usr/bin/docker pull busybox

ExecStart=/usr/bin/docker run --name busybox busybox /bin/sh -c "while

true; do echo Hello World; sleep 1; done"

ExecStop=/usr/bin/docker stop busybox

[X-Fleet]

X-Conflicts=busybox@*.service

coreos: etcd: discovery: https://discovery.etcd.io/<token> addr: $private_ipv4:4001 peer-addr: $private_ipv4:7001 units: - name: etcd.service command: start - name: fleet.service command: start

ssh_authorized_keys: - ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQC0g+ZTxC7weoIJLUafOgrm+h...

write_files: - path: /etc/motd permissions: 0644 owner: root content: | Good news, everyone!

#cloud-config

coreos: update: reboot-strategy: best-effort etcd: # generate a new token for each unique cluster from https://discovery.etcd.io/new discovery: https://discovery.etcd.io/<token> addr: $private_ipv4:4001 peer-addr: $private_ipv4:7001 units: - name: etcd.service command: start - name: fleet.service command: start

write_files:

- path: /tmp/busybox@.service

content: |

[Unit]

Description=busybox

Requires=docker.service

After=docker.service

[Service]

TimeoutStartSec=0

ExecStartPre=-/usr/bin/docker kill busybox-%i

ExecStartPre=-/usr/bin/docker rm busybox-%i

ExecStartPre=/usr/bin/docker pull busybox

ExecStart=/usr/bin/docker run --name busybox-%i busybox /bin/sh -

c "while true; do echo Hello World; sleep 1; done"

ExecStop=/usr/bin/docker stop busybox-%i

[X-Fleet]

X-Conflicts=busybox@*.service

# 必要に応じてgcloud config set project <project_id>gcloud config set compute/zone asia-east1-agcloud config set compute/region asia-east1

# 3つのインスタンスを起動gcloud compute instances create core1 core2 core3 --image coreos \ --machine-type f1-micro --metadata-from-file user-data=cloud-config.yaml

# ログインgcloud compute ssh core1

# サービスの登録と起動fleetctl submit /tmp/busybox@.servicefleetctl start busybox@{1,2}.servicefleetctl list-units

# unitに割り当てのあるインスタンスを削除してみる

gcloud compute instances delete core2

gcloud compute ssh core1

# フェイルオーバーが行われることを確認

fleetctl list-units

UNIT DSTATE STATE MACHINE ACTIVE

busybox@.service inactive inactive - -

busybox@1.service launched launched ffc81480.../10.xxx.xxx.237 active

busybox@2.service launched launched 99f741a8.../10.xxx.xxx.150 active

UNIT DSTATE STATE MACHINE ACTIVE

busybox@.service inactive inactive - -

busybox@1.service launched launched ffc81480.../10.xxx.xxx.237 active

busybox@2.service launched launched 27c76d9a.../10.xxx.xxx.221 activa

ting