copyright 2014 1 Docker, DevOps, Security Chris Swan, CTO @cpswan Cloud native networking
Docker Chicago Meetup - July 2014
Jul 16, 2015
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copyright 2014 1
Docker, DevOps, Security
Chris Swan, CTO
@cpswan
Cloud native networking
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TL;DR
Dockerfile is awesomely productive
Great for DevOps
Containers don’t contain
At least not yet
Images have a manifest problem
Keep track of your stuff
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Why me?
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Let’s start with a demo
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Containers don’t contain
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With thanks to Dan Walsh @rhatdan
Watch his DockerCon 2014 presentation at http://is.gd/dcrhdw
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Shocker
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The issue
The response
http://stealth.openwall.net/xSports/shocker.c
https://news.ycombinator.com/item?id=7910117
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Because containers aren’t VMs
and this has yet to come:
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Possible to have our cake and eat it?
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cgroups
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namespaces
mnt mount points, filesystems
pid processes
net network
ipc inter process communication
uts hostname
device devices
user UIDs 12
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capabilities
Fine grained control over ‘root’ privileges:
• deny all "mount" operations;
• deny access to raw sockets (to prevent packet
spoofing);
• deny access to some filesystem operations, like
creating new device nodes, changing the owner of files,
or altering attributes (including the immutable flag);
• deny module loading;
• etc.
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Mandatory Access Control (MAC):
AppArmor and SELinux
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Containers will contain
• Use of namespaces, capabilities and MAC will
improve • Might be a game of ‘whack a mole’
• Hard to tell when we’re done (is @solomonstre’s word going to
be enough?)
• Libcontainer can drive other mechanisms • More secure options might come
• Hardware support might come • Existing rings 1 & 2 aren’t used much, but aren’t really suitable
• VT-x introduced ring -1, do we need a ring 0.5?
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The manifest problem
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My Dockerfile from earlier
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Each active line creates a layer
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Base OS
Sources
Update repos
Install nginx
Mod nginx.conf
Mod index.html
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An image binds layers together
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Base OS
Sources
Update repos
Install nginx
Mod nginx.conf
Mod index.html
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Nginx example
The image is the unit of deployment
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Nginx example
What version of nginx is that?
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Nginx example
What version of OpenSSL installed?
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?
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Problem 1 – non determinism
Whilst we want this to be cached in the short term:
apt-get install nginx
We perhaps don’t want it cached in the long term
What are those durations?
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2 – the manifest problem
When I run
apt-get install nginx
I don’t know which version of nginx I just got
Should I?
nginx –v > some_log.txt
Or maybe?
apt-cache policy nginx > some_log.txt
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TL;DR
Dockerfile is awesomely productive
Great for DevOps
Containers don’t contain
At least not yet
Images have a manifest problem
Keep track of your stuff
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Please give me feedback:
http://is.gd/chdmsf
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