coreos : 설치부터 컨테이너 배포까지

CoreOS를 이용한 도커 컨테이너 배포 Docker Seoul Meetup #1 / Aug 23, 2014

!by @subicura (김충섭)

도커로

모든 어플리케이션을컨테이너로 만든다면

MY APPRAILS NGINX

MONGODBMYSQL RABBITMQ

서버는

도커를 돌리기 위해

존재할 뿐..

Docker 구동에 최적화된

가볍고 최소화된 모던 OS

no package manager (apt/yum)

2013년 6월부터

Alex Polvi Brandon Philips

(rackspace) Michael Marineau

(google)

Chrome OS를 기반으로

몇가지 기능을 추가하고

서버로 사용할 수 있도록 커스터마이징

CoreOS 특징

A Minimal Operating System Painless Updating

Docker Containers Clustered By Default

CoreOS GUI

유료!!

CoreOS 핵심구성

etcd

systemd

fleet

+ cloud-init

install

coreos-cloudinit enables a user to customize CoreOS machines

cloud-config sample#cloud-config !coreos: etcd: discovery: https://discovery.etcd.io/<token> addr: $public_ipv4:4001 peer-addr: $public_ipv4:7001 fleet: public-ip: $public_ipv4 units: - name: etcd.service command: start - name: fleet.service command: start users: - name: core coreos-ssh-import-github: subicura

vagrant

$ git clone https://github.com/coreos/coreos-vagrant.git $ cd coreos-vagrant $ vi user-data # edit config $ vagrant up

*vagrant : Virtual Machine 자동 관리 툴

DEMO

etcd

A highly-available key value store

/services/app/app_1 {“ip”:”172.17.8.101”}

valuekey

directory

etcd

A highly-available key value store

Raft protocol

etcd

쉬운 API (HTTP + JSON)

SSL 보안

1000s of writes/s per instance

Watch (via HTTP long-polling)

Keys support TTL

Lock

DEMO

systemd나아진 init system

Fedora, Gentoo, Arch 사용중 / RedHat, Debian, Ubuntu 곧

deamonize

pid

logfile path

하기쉬움

start/stop hook, audo restart…

할 필요 없음

기억할 필요 없음

기억할 필요 없음

coordination

systemd

시작 - systemctl start [service]

종료 - systemctl stop [service]

강제종료 - systemctl kill [service]

상태보기 - systemctl status [service]

로그보기 - journalctl -u [service]

sample.service

[Unit] Description=My Service 1 Requires=docker.service After=docker.service ![Service] ExecStart=/usr/bin/docker run --rm --name app1 busybox \ /bin/sh -c "while true; do echo Hello World; sleep 1; done" ExecStop=/usr/bin/docker kill app1

ExecStartPre / ExecStart / ExecStartPost / ExecReload / ExecStop / ExecStopPost / RestartSec

DEMO

fleet

etcd를 backend로

systemd에 custom configuration을 추가하여

service와 machine을 추상화하고

High availability를 구현함

fleet서버리스트 - fleetctl list-machines

유닛리스트 - fleetctl list-units

시작 - fleetctl start [service]

종료 - fleetctl stop [service]

제거 - fleetctl destroy [service]

상태보기 - fleetctl status [service]

로그보기 - fleetctl journal [service]

remote ssh-add ~/.ssh/id_rsa export FLEETCTL_TUNNEL=172.17.8.101

sample.1.service

[Unit] Description=My Service 1 Requires=docker.service After=docker.service ![Service] ExecStart=/usr/bin/docker run --rm --name app1 busybox \ /bin/sh -c "while true; do echo Hello World; sleep 1; done" ExecStop=/usr/bin/docker kill app1 ![X-Fleet] X-Conflicts=sample.*.service

DEMO

service discovery

service discovery

database ip와 port는 뭘까?

service discovery

app의 ip와 port는 뭘까?

service discovery

Application은 자신의 IP와 PORT를 등록(registry)하고

Load Balancer는 IP와 PORT를 발견(discovery)하여

적용함

service discovery

etcd TTL 자동으로 삭제 되는 value > 서비스가 비정상적으로 종료되었을 경우에도 체크 가능함

WATCH value 변화를 감지 > 바로바로 즉시성으로 대응 가능함

APP NGINX! !APP ip/port APP ip/port

"XXX ip/port

"NGINX ip/port

service discoveryip port 등록

# #

/services/app/app_1 { “ip”: “172.17.8.101”, “port”: “8080” }

while true; do etcdctl set /services/app/app_1 “{xxx}” —-ttl 60; sleep 45; done

service discoveryip port 발견

$

/services/app/app_1 { “ip”: “172.17.8.101”, “port”: “8080” }

설정 적용upstream web_application { <% infos.each do |info| %> server <%= info["ip"] %>:<%= info["port"] %>; <% end %> }

서비스 재시작$ nginx -s reload

sidekick[Unit] Description=Announce web_1 BindsTo=web.1.service ![Service] ExecStart=/bin/sh -c “WEB_SERVICE_IP=$(…) && WEB_SERVICE_PORT=$(…) && while true; do etcdctl set /services/web/web_1 \"{ \\\"ip\\\": \\\"$WEB_SERVICE_IP\\\", \\\"port\\\": \\\"$WEB_SERVICE_PORT\\\" }\" --ttl 60; sleep 45; done" ExecStop=/usr/bin/etcdctl rm /services/web/web_1 ![X-Fleet] X-ConditionMachineOf=web.1.service

DEMO

THANK YOU !

QUESTION?