Switch as a Server - PuppetConf 2014 - Leslie Carr
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Leslie Carr is an operations engineer at Cumulus Networks, which develops Cumulus Linux, a Debian-based network operating system that allows network switches to be managed like servers. Cumulus Linux uses ONIE to boot and install the OS image over the network in a manner similar to how a server OS is installed using PXE. It supports zero-touch provisioning (ZTP) using scripts to automate configuration of networking services like Puppet. Ifupdown2 is Cumulus Linux's network interface manager that handles dependencies and allows incremental configuration changes with minimal disruption.
Switch as a Server - PuppetConf 2014 - Leslie Carr
- 1. v Switch as a Server Leslie Carr
- 2. Who is Leslie? § Operations Engineer § Google § Craigslist § Twitter § Wikimedia Foundation (Wikipedia)
- 3. Who is Leslie? § Cumulus Networks®
- 4. What is Cumulus Linux? § Cumulus® Linux® § Debian based distribution for Network switches Cumulus Philosophy § Manage your network switch as a server § Use existing linux tools to configure network switches § Current release — Based on Debian wheezy
- 5. Cumulus® Linux® Hardware Compatibility List cumulusnetworks.com 5
- 6. v Installation and Configuration
- 7. Traditional Network Gear Process § Comes preinstalled with (old) software § Telnet or serial into box § TFTP new image § Enable SSH (sometimes with passwords!) § Copy/paste configuration § Automation usually restricted to Perl, TCL, and expect scripts
- 8. Normal Server Installation § Reboot and bios with PXE automatically catches § TFTP boot image § New image pulled over via normal means (usually webserver, sometimes TFTP) § Pre/post installation scripts runs § Automation software manages configuration and administration
- 9. Network OS installer discovery and execution § Like a pre-installed BIOS, PXE, and kickstarter in one § Implemented through Linux kernel with BusyBox Donated to the Open Compute Project (OCP) http://www.onie.org ONIE
- 10. Cumulus Linux OS Installation with ONIE § Look for installer (“discover”) § Locally, e.g. USB if available § Over the network on eth0 • DHCP, IPv6 neighbor, TFTP § Search for file name and execute § onie-‐installer-‐* cumulusnetworks.com 10 1 2 Cumulus Linux OS image
- 11. During the DHCP process over eth0 (management interface), Cumulus Linux will request DHCP option 239. This option is used to specify the custom provisioning script. It will also send the following headers: Header Value Example -‐-‐-‐-‐-‐-‐ -‐-‐-‐-‐-‐ -‐-‐-‐-‐-‐-‐-‐ User-‐Agent CumulusLinux-‐AutoProvision/0.4 CUMULUS-‐ARCH CPU architecture powerpc CUMULUS-‐BUILD 1.5.1-‐5c6829a-‐201309251712-‐final CUMULUS-‐LICENSE-‐INSTALLED Either 0 or 1 1 CUMULUS-‐MANUFACTURER dni CUMULUS-‐PRODUCTNAME et-‐7448bf CUMULUS-‐SERIAL XYZ123004 CUMULUS-‐VERSION 1.5.1 CUMULUS-‐PROV-‐COUNT 0 CUMULUS-‐PROV-‐MAX 32 ZTP
- 12. ZTP Execution § Script must contain CUMULUS-‐AUTOPROVISIONING Can be in the following languages : § Perl § Python § Ruby § Shell
- 13. ZTP Example with Puppet 1 #!/bin/bash 2 3 function error() { 4 echo -‐e "e[0;33mERROR: Provisioning failed running $BASH_COMMAND at line $BASH_LINENO of $(basename $0) e[0m" >&2 5 exit 1 6 } 7 trap error ERR 8 # Allow Cumulus testing repo 9 sed -‐i /etc/apt/sources.list -‐e 's/^#s* (deb.*testing.*)$/1/g' 10 11 # Upgrade and install Puppet 12 apt-‐get update -‐y 13 apt-‐get upgrade -‐y 14 apt-‐get install puppet -‐y 15 16 echo "Configuring puppet" | wall -‐n 17 sed -‐i /etc/default/puppet -‐e 's/ START=no/START=yes/' 18 19 service puppet restart 20 21 # CUMULUS-‐AUTOPROVISIONING 22 23 exit 0
- 14. Comparison Similar to installing a server OS using PXE app app app Server OS BIOS and PXE bare metal server app app app Network OS Boot Loader and ONIE bare metal switch ONIE looks for and installs network OS image boot into Network OS boot into Boot Loader and ONIE Boot Loader and ONIE
- 15. Video
- 16. § Because Debian based, we can do everything via puppet § users § interface configuration § routing software (Quagga) configuration Puppet
- 17. Video!
- 18. Make Life Even Better How can we make your life better?
- 19. Interim Puppet Server! Warning - small hard drive and limited processing power -- not recommended for long term Scenario - installing new rack with limited connectivity * make switch puppetmaster
- 20. Example Topology leaf 1 leaf 2 swp1 - 4 swp1 - 4 Puppetmaster
- 21. Video
- 22. Transition
- 23. Existing Network Interface Managers § Optimized for desktop and hypervisor environments § Complexity increases with interface configuration scale § Burden of network interface configuration dependency ordering is on the user § Lack of support for incremental changes to network interfaces: minimal disruption § Lack of tools to query and validate running interface configuration
- 24. Linux Networking § Switch networking characteristics: § Large number of interfaces § Switch ports, bridges, bonds, vlans § Large number of interface attributes § Addresses, bridge stp, mstp and igmp attributes § Mostly static configuration
- 25. ifupdown § Benefits § Pluggable architecture § Uses native Linux tools, enabling faster development § Good user documentation, well known tool § Challenges § No knowledge of interface configuration dependency (burden on the user) § Large scale configuration results in large files or too many files § No support for incremental configurations § No support to query/validate running interface configuration § literate program § Bugs
- 26. ifupdown2 § New implementation of ifupdown in Python § Backward compatible with ifupdown interfaces format and commands § Continues to use existing Linux native tools to configure network interfaces. § Large number of interface attributes § Pluggable architecture add-on python modules for interface configuration § Meets some shortcomings seen with existing network interface managers on network switches § ifreload acts like HUP instead of restart
- 27. ifupdown2 compare cli? ifupdown auto swp19 iface swp19 inet manual up link set $IFACE up down link set $IFACE down pre-‐up /sbin/ethtool -‐s $IFACE speed 1000 auto swp19.100 iface swp19.100 inet manual up link set $IFACE up down link set $IFACE down auto vlan100 iface vlan100 inet manual bridge_ports swp19.100 mstpctl_stp on ifupdown2 auto swp19 iface swp19 link-‐speed 1000 auto vlan100 iface vlan100 bridge-‐ports swp19.100 bridge-‐stp on
- 28. Network Interface Dependency ▪ Handles network interface dependency using dependency graphs ▪ Uses topological sort to order network interface configurations ▪ Provides options and tools to query and execute interface configuration in dependency order ▪ Built-in devices support ifupdown2 implicitly recognizes vlan and physical interfaces that appear as dependents and does the required minimal configuration to get them up: No need to specify `iface swp1.1000` in the example cumulusnetworks.com
- 29. ifupdown2 - Mako Templates ## Note that the "range" ends with '4' ## But will iterate only from 1 to 3 ## See Python range() for more details % for i in range(1, 4): auto swp${i} iface swp${i} % endfor <%def name="interface_defaults()"> mtu 9000 link-‐speed 10000 link-‐duplex full link-‐autoneg off </%def> % for i in range(3,7): auto swp${i} iface swp${i} ${interface_defaults()} % endfor auto default_bridge iface default_bridge bridge_ports glob swp3-‐6 bridge-‐stp on
- 30. Find out more! § Ifupdown2 § https://github.com/CumulusNetworks/ifupdown2 § PTM § https://github.com/CumulusNetworks/ptm Example Code § https://github.com/LeslieCarr/puppet-presentation Cumulus Open Source § http://oss.cumulusnetworks.com Twitter § @lesliegeek
- 31. Bringing the Linux Revolution to Networking § Thank You! © 2014 Cumulus Networks. Cumulus Networks, the Cumulus Networks Logo, and Cumulus Linux are trademarks or registered trademarks of Cumulus Networks, Inc. or its affiliates in the U.S. and other countries. Other names may be trademarks of their respective owners. The registered trademark Linux® is used pursuant to a sublicense from LMI, the exclusive licensee of Linus Torvalds, owner of the mark on a world-wide basis. cumulusnetworks.com