Text of Herding Cats Managing a mobile Unix platform in the enterprise
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
This presentation Desktop replacement plan Desktop analysis and source code available http://radmind.org/contrib/LISA05 1. Choose Platform & Tools 2. ??? 3. Profit !!!
Choose platform Find out whats 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
Herding Cats Managing laptops is like herding cats Always know where your cats are Theyre 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
This is a personal laptop!
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!
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 dont want there Do it without bothering the sysadmins
Which toolkit? Apples OS X package system is lacking No consistent uninstall No dependency tracking Most package tools cant manage OS X They assume theyre alone on the system Resource forks / extended attributes File system is case insensitive
So radmind We chose RAdminD Large installed base of radmind on OS X http://radmind.org Thanks, UMich!
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
How radmind works
System state Command file determines the overloads that make up the system Positive transcripts add files, negative ignore files p base-system-10.3.4.T n os-negative.T p omnigraffle.T 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 d /Users 0755 0 0 d /private/tmp 1777 0 0 os-negative.T command.K omnigraffle.T
User experience Updates run while user is working User gets prompted before downloading
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
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)
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
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 dont see it again until it breaks Margaritas @ the beach!
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
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 Apples GUI tools Overall it works, could be better
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)
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
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
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 dont call Cisco TAC about these!
Backup Slides Because we didnt tell you everything :)
Why Laptops are becoming standard Telecommuting Lab work Customer visits One system for everything One computer per employee Our users need/want Unix
Why Needed a supportable platform Experiments with Linux failed OS X was the only viable Unix for portable systems It Just Works
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,
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)
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
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
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
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? Cant this be done asynchronously? Have to learn the Apple Way Sometimes there is no other way Using X-Windows is a pain
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
What is radmind? Command files + overloads Describe system state, files