Docker 101Russ Taylor

Containers vs. VMs

What are these ‘container’ things?

https://www.flickr.com/photos/jaxport/

Less Overhead

https://www.flickr.com/photos/whatmeworry/

Isolated(Mostly)

https://www.flickr.com/photos/143903271@N02/

No Dedicated Resources

https://www.flickr.com/photos/dahlstroms/

No Resource Limits

Containers: A History

2000:

2001:

2004:(Containers)

2005:

2006: Process Containers ➡ cgroups

2008:

2013: lmctfy(let me contain that for you)

2013:

Why Containers?

Super Minimal

root@00fcf1ae4e67:/# ps -A PID TTY TIME CMD 1 ? 00:00:00 bash 11 ? 00:00:00 ps

802 ? 00:00:00 xfsalloc 803 ? 00:00:00 xfs_mru_cache 805 ? 00:00:00 glock_workqueue 806 ? 00:00:00 delete_workqueu 811 ? 00:00:00 gfs_recovery 908 ? 00:00:00 acpi_thermal_pm 1565 ? 00:00:00 bioset 1566 ? 00:00:00 drbd-reissue 1567 ? 00:00:00 rbd 1569 ? 00:00:00 scsi_eh_0 1570 ? 00:00:00 scsi_tmf_0 1573 ? 00:00:00 bioset 1580 ? 00:00:00 bioset 1839 ? 00:00:00 scsi_eh_1 1844 ? 00:00:00 kworker/u2:3 1854 ? 00:00:00 scsi_tmf_1 1855 ? 00:00:00 scsi_eh_2 1857 ? 00:00:00 kworker/u2:4 1860 ? 00:00:00 scsi_tmf_2 1863 ? 00:00:00 kworker/u2:5 1878 ? 00:00:00 kworker/u2:6 1890 ? 00:00:00 raid5wq 1896 ? 00:00:00 dm_bufio_cache 1919 ? 00:00:00 ipv6_addrconf 1933 ? 00:00:00 kworker/0:2 1936 ? 00:00:00 ceph-msgr 1959 ? 00:00:00 bioset 1976 ? 00:00:00 bioset 1983 ? 00:00:00 bioset 1987 ? 00:00:00 kworker/0:1H 1988 ? 00:00:00 jbd2/sda-8 1989 ? 00:00:00 ext4-rsv-conver 2009 ? 00:00:00 systemd-journal 2011 ? 00:00:00 kworker/0:3 2016 ? 00:00:00 kworker/0:4 2019 ? 00:00:00 kworker/0:5 2020 ? 00:00:00 kauditd 2023 ? 00:00:00 systemd-udevd 2029 ? 00:00:00 kworker/0:6 2159 ? 00:00:00 systemd-timesyn 3416 ? 00:00:00 rsyslogd 3418 ? 00:00:00 dbus-daemon 3423 ? 00:00:00 cron 3425 ? 00:00:00 accounts-daemon 3428 ? 00:00:00 systemd-logind 3471 ttyS0 00:00:00 agetty 3473 tty1 00:00:00 agetty 3475 ? 00:00:00 ondemand 3489 ? 00:00:00 sleep 3653 ? 00:00:00 sshd 3717 ? 00:00:00 sshd 3719 ? 00:00:00 systemd 3760 ? 00:00:00 (sd-pam)

VM ➡

https://www.flickr.com/photos/onascht/

Usually Ephemeral

https://www.flickr.com/photos/tristantaussac/

Mostly Immutable

https://www.flickr.com/photos/soldiersmediacenter/

Portable

Hold Code, Not Data

Running Docker

LinuxWindows*

MacOS*

*Really, mostly for development.

https://www.docker.com/community-edition

Docker Registry

https://hub.docker.com/

Dockerfiles# From any image & tag (default tag is 'latest')FROM node:7.8.0

MAINTAINER Bend Hackers <bhg@bendhackers.com>

# Set environment variablesENV APP_PATH /var/app

# Copy folders/files into the imageCOPY src $APP_PATH

# Set the work directoryWORKDIR $APP_PATH

# Run arbitrary commandsRUN npm install

# Run when the container startsCMD ["node", "app.js"]

Demo Time!https://github.com/russtaylor/docker-101

Resources

● https://docs.docker.com

● https://docs.docker.com/compose/

● https://docs.docker.com/engine/reference/commandline/docker/

● http://shop.oreilly.com/product/0636920035671.do (Using Docker, O’Reilly)

Thanks!

russ@russt.me