coreos

Nikolay Ryzhikov

Linux for Massive Server Deployments

Кластер (Гроздь)

Объединение однородных элементов, которое может рассматриваться как единое целое...

• os: chromeos fork
• coordination: etcd
• packages and services: docker
• init system: fleet on systemd
• overlay network: flannel

Alex Polivi

Mozzila sysadmin

core OS

• fork of chromeos--
• atomic updates (fast patch)
• read-only partition for root
• fast boot time
• cloud-config

locksmith

locksmith is a reboot manager

Updates

Alpha->Betta->Stable

cloud-config (yaml)

    #cloud-config

    coreos:
      units:
        - name: etcd.service
          command: start
    users:
    - name: core
      passwd: $1$allJZawX$00S5T756I5PGdQga5qhqv1

    write_files:
      - path: /etc/resolv.conf
        content: |
          nameserver 192.0.2.2
          nameserver 192.0.2.3

    coreos-cloudinit -validate -from-file=cfg.yaml
    

distributed, consistent key value store

   etcdctl set /foo/bar "Hello world" --ttl 60

   etcdctl get /foo/bar

   etcdctl watch /foo/bar --forever

   etcdctl exec-watch /foo/bar -- sh -c "env | grep ETCD"

   etcdctl ls --recursive -p

   etcdctl rm /path/to/dir --recursive

   curl -L http://etcd.com:4001/v2/keys/mykey -XPUT -d value="this is awesome"
    

raft - consensus algorythm

Leader election

Log eplication

Safety

fleet

---

systemd + etcd

distributed init system

systemd

[Unit]
Description=My Advanced Service
After=etcd.service
After=docker.service

[Service]
TimeoutStartSec=0
ExecStartPre=-/usr/bin/docker kill apache1
ExecStartPre=-/usr/bin/docker rm apache1
ExecStartPre=/usr/bin/docker pull coreos/apache
ExecStart=/usr/bin/docker run --name apache1 -p 80:80 coreos/apache /usr/sbin/apache2ctl -D FOREGROUND
ExecStartPost=/usr/bin/etcdctl set /domains/example.com/10.10.10.123:8081 running
ExecStop=/usr/bin/docker stop apache1
ExecStopPost=/usr/bin/etcdctl rm /domains/example.com/10.10.10.123:8081

[Install]
WantedBy=multi-user.target
  

fleetctl

alias f=fleetctl
f list-machines
f list-units
f list-unit-files

f submit/destroy examples/hello.service

f cat hello.service

f load/unload hello.service

f start/stop goodbye.service

f journal hello.service
  

MachineID, MachineOf, MachineMetadata, Conflicts, Global

docker

appc spec

• Composable
• Secure
• Decentralized
• Open
• read more

flannel

fleetctl

#cloud-conf
...
coreos:
 units:
   - name: flanneld.service
     drop-ins:
       - name: 50-network-config.conf
         content: |
           [Service]
           ExecStartPre=/usr/bin/etcdctl set /coreos.com/network/config \
              '{ "Network": "10.1.0.0/16" }'
     command: start
  

What next?

kubernetes.io

deis.io

demo?