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Herding Cats

Herding Cats. Managing a mobile Unix platform in the enterprise. Who are we?. IT department of Cisco TAC Sun Solaris servers/desktops, HA environment 5600 active accounts, 1200 workstations, 5 major sites globally 18 people Mail us:. maarten wout. @cisco.com @cisco.com.

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Herding Cats

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  1. Herding Cats Managing a mobile Unix platform in the enterprise

  2. Who are we? • IT department of Cisco TAC • Sun Solaris servers/desktops, HA environment • 5600 active accounts, 1200 workstations, 5 major sites globally • 18 people • Mail us: maarten wout @cisco.com @cisco.com

  3. This presentation • Desktop replacement plan 1. Choose Platform & Tools 2. ??? 3. Profit !!! • Desktop analysis and source code available • http://radmind.org/contrib/LISA05

  4. Choose platform • Find out what’s important to you, attach weights • For every platform, give a score for each attribute • sum(), total() • Important in our case: • Unix networking and engineering tools • Only one platform • Supportability • Laptop experience: hotplugging, battery life, … • Security

  5. Herding Cats • Managing laptops is like herding cats • Always know where your cats are • They’re off the network before you know it • Perform hourly client-side update checks with fast tools • Use asset tracking to know IP address and current system state

  6. This is a personal laptop!

  7. Herding Cats • Keep your cats healthy & happy • Feed them regular software updates • Stroke their ego by giving them control over the update process • File system checking makes sure there are no invading organisms • With backups, your users can have nine lives too!

  8. Tools and tricks These apply not just to OS X !

  9. How • Manage file system: rpm, tripwire? • Asset database: ethers? • Uniquely identify systems: SSL/PGP cert? • Naming service: LDAP? • Secure data: FileVault? • Business continuity: Backups?

  10. Managing the file system • Our rules: • Keep full control over the client systems • No root access for the user • One image to rule them all • Identical problems/solutions • Fast system replacement • No need to back up system image • Enforce known-good state on client • Install what we want there • Remove what we don’t want there • Do it without bothering the sysadmins

  11. Which toolkit? • Apple’s OS X package system is lacking • No consistent uninstall • No dependency tracking • Most package tools can’t manage OS X • They assume they’re alone on the system • Resource forks / extended attributes • File system is case insensitive

  12. So… radmind • We chose RAdminD • Large installed base of radmind on OS X • http://radmind.org • Thanks, UMich!

  13. Why … radmind? • Can repair broken systems without re-imaging • Bit flips, rootkits, user with sudo rights⇒ repair automatically! • Can handle OS upgrades • Server can run on any platform • re-use existing infrastructure • KISS, easily extensible, Unix philosophy

  14. How radmind works

  15. System state p base-system-10.3.4.T n os-negative.T p omnigraffle.T • Command file determines the overloads that make up the system • Positive transcripts add files, negative ignore files d /Users 0755 0 0 d /private/tmp 1777 0 0 os-negative.T command.K d /Applications/OmniGraffle.app 0755 0 80 f /Applications/OmniGraffle.app/.DS_Store 0755 0 0 1096985459 6148 WCf1IuqHcXrNGZDUiX+Buucs83Q= d /Applications/OmniGraffle.app/Contents 0755 0 80 … omnigraffle.T

  16. User experience • Updates run while user is working • User gets prompted before downloading

  17. Radmind conclusion • 1 mechanism • Fixes all problems • Introduces new ones • Solved by client side trigger scripts • Normally used in lab setting at reboot time • Normally not used while user is working • But it works really well for us

  18. Our radmind setup • Global DNS service points to nearest, available radmind server • Produces a scalable, highly available setup • SSL certs should contain DNS alias • 3 ports for 3 trees: stable, testing, staging • Reduces operator error • Shared file tree for disk space optimization • Master host to maintain trees • Push changes downstream using rsync • Script checks correctness and dependencies before pushing (dist-it)

  19. Distributed setup

  20. Multi-release setup • The file storage is shared between releases • Stable, testing and staging are the source dirs for 3 radmind daemons on 3 ports • Symlinks allow fast switching

  21. AssetInterface • Asset tracking software tracks: • Owner of machine (set on first login) • IP addresses • Logins • Etc • Saves data locally until machine can reach the server • Precompiled SQL • Once system leaves us, we don’t see it again until it breaks ⇒ Margaritas @ the beach!

  22. RegServ • Radmind differentiates systems based on IP or certificate name • We encode system info in the certificate name • e.g. ppc7450.PowerBook5,4.W842219KQW3.mthibaut • Wildcards allow matching any of the parts • RegServ uses generic client certificate installed on base image to securely provide a machine specific certificate • Secure as long as client base image is secure • Based on radmind code

  23. How - LDAP • We used our existing LDAP servers • OS X can cache the credentials • Lots of policy enforcement possible • provide default or forced custom settings for any Cocoa application, lots more • Sounds simple, but we had quite a bit of trouble • “MCX” keywords are undocumented • Trial and error • Final solution: use same LDAP layout as OS X server in a subtree, allows using Apple’s GUI tools • Overall it works, could be better

  24. How - FileVault • Secures user data using AES-128 encryption • Data is stored in a resizing disk image • Master certificate allows password recovery by admin • Deemed mandatory in our organization • We had to hack things a bit • A script runs at login time and verifies existence • Creates FileVault if not there • Works reasonably well, fast (2-3 MiB/s)

  25. Backups • KISS • We already back up our home directories on Solaris • So we wrote a GUI for rsync over SSH • Works fine, even though resource forks not copied

  26. Wrapping up

  27. Mac OS X vs Solaris In our experience: • Better application availability/installation • Little need to manually compile tools (e.g. fink) • GUI/usability is not an afterthought • User mountable filesystems • User installable programs • It Just Works • We can concentrate on our users

  28. Giving back • All our programs, utilities and scripts for this project have been published • http://radmind.org/contrib/LISA05/ • We apologize for the inconvenience • Hard coded paths • No installation scripts • Little documentation • Choose your license, but don’t call Cisco TAC about these!

  29. Questions?

  30. Backup Slides Because we didn’t tell you everything :)

  31. Desktop replacement

  32. Why • Laptops are becoming standard • Telecommuting • Lab work • Customer visits • One system for everything • One computer per employee • Our users need/want Unix

  33. Why • Needed a supportable platform • Experiments with Linux failed • OS X was the only viable Unix for portable systems • It Just Works

  34. Why … not Linux? • No vendor hardware support • No drivers for recent hardware • Missing UI for common laptop tasks • Networking setup • Mounting network file systems • Hotplugging disks, audio, video, …

  35. Why … choose OS X? • Unix! • X-Windows capability • Well designed, e.g. fixing long-time Unix issues (launchd, directory services, …) • Everything is integrated • Applescript • User preference system • Server side preference setting overrides • Naming services • Etc (very extensive)

  36. Why … choose OS X? • Security • Admin access hardly needed • User installs, network setup, USB drives, audio devices, … • FileVault • Secure screen lock • Good software support from Apple • Reasonable software availability for platform

  37. Why … choose Apple? • One vendor for hardware and software • Perfect platform support for OS X • Quality hardware • Supportability: • Firewire target mode for disk rescue • One disk image for all system types • Except for brand-new systems

  38. Why … not OS X? • Politics (MS centric world) • Apple not geared towards enterprise • HW release schedule forces use of buggy OS releases • Undocumentation & secrecy • No on-site or phone support as with Sun • Support costs $$ per admin rather than $$ per machine

  39. Why … not OS X? • LDAP caching • System always contacts LDAP server when cached data expires and name lookup occurs • Where can we change expiry timers? • Can’t this be done asynchronously? • Have to learn “the Apple Way” • Sometimes there is no other way • Using X-Windows is a pain

  40. FileVault architecture • Sparse disk image • Encrypted by long key stored with disk image • Key is encrypted with 2 keys, each can unlock it: • User password • Master FileVault certificate • Master FileVault certificate is encrypted with an admin password

  41. What is radmind? • Command files + overloads • Describe system state, files + checksums • ktcheck • Download wanted system state • fsdiff • Compare file system with wanted state • lapply • Repair changes found by fsdiff • All done using encryption and authentication

  42. Our overload layout

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