Fleet is a distributed init system and service manager built on CoreOS. It allows deploying Docker containers across a cluster of machines and re-scheduling them if a machine fails. Fleet uses systemd unit files and properties to define services and leverage etcd for distributed coordination. It provides commands like fleetctl to manage services centrally and view cluster state. While Fleet makes container deployment easy with CoreOS, it provides limited options for server balancing and lacks a GUI.

1. Launching Containers with fleet
Docker Seoul Meetup #3 / Feb 14, 2014
by @subicura (김충섭)

2. deployment

3. container

6. image를
배포하고
container를
stop/start만 하면 되는데..

7. fleet

8. a distributed init system

9. fleet = systemd + etcd

10. fleet = systemd + etcd
System and Service Manager
CoreOS default init system
Fedora, Gentoo, Arch 사용중 / RedHat, Debian, Ubuntu 곧

11. fleet = systemd + etcd

12. [Unit]
Description=My Service
Requires=docker.service
After=docker.service
[Service]
ExecStart=/usr/bin/docker run --rm --name my_service busybox
/bin/sh -c "while true; do echo Hello World; sleep 1; done"
ExecStop=/usr/bin/docker kill my_service
systemd service file sample

13. systemd command
시작 - systemctl start [service]
종료 - systemctl stop [service]
강제종료 - systemctl kill [service]
상태보기 - systemctl status [service]
로그보기 - journalctl -u [service]

14. [Unit]
Description=My Service
Requires=docker.service
After=docker.service
[Service]
ExecStart=/usr/bin/docker run --rm --name my_service busybox
/bin/sh -c "while true; do echo Hello World; sleep 1; done"
ExecStop=/usr/bin/docker kill my_service
[X-Fleet]
MachineMetadata=type=app
Conflicts=%p@*.service
fleet unit file sample

15. fleet-specific properties
MachineID - 해당하는 machine에서 실행
MachineOf - 특정 서비스가 수행중인 machine에서 실행
MachineMetadata - metadata를 가진 machine에서 실행
Conflicts - 해당 서비스가 수행중인 machine을 피해서 실행
Global - 전체 machines에서 실행

16. fleetctl command
서버리스트 - fleetctl list-machines
유닛리스트 - fleetctl list-units
등록 - fleetctl submit [service]
시작 - fleetctl start [service]
종료 - fleetctl stop [service]
제거 - fleetctl destroy [service]
상태보기 - fleetctl status [service]
로그보기 - fleetctl journal [service]

17. fleet list-machines

18. fleet list-units

19. fleet start nginx-confd.service

20. DEMO

23. summary
easy (with coreos) - systemd + etcd + fleetd
Deploy docker containers on arbitrary hosts in a cluster
re-scheduling on machine failure
Automatically SSH into the machine running a job
difficult server balance - no check cpu/memory/hdd/network
Lack of option
Lack of GUI Tool