chris swan at qcon 2014: using docker in cloud networks
TRANSCRIPT
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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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What do I mean by ‘DevOps’?
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John Boyd’s OODA loop
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Industrial design maturity - cars
Design for purpose
Design for manufacture
Design for operations
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Industrial design maturity - software
Design for purpose
Design for manufacture
Design for operations
DevOps is an artefact
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Containers and containment
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With thanks to Dan Walsh @rhatdanWatch 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
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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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<optimist>Containers will contain</optimist>
• 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 OSSources
Update reposInstall nginx
Mod nginx.confMod index.html
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An image binds layers together
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Base OSSources
Update reposInstall nginx
Mod nginx.confMod 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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Nginx example
and which bash?
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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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Again, Solomon promises to fix things
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There is another way
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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
