Erlang On Xen: Redefining the Cloud Software Stack
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This document discusses Erlang on Xen and two project ideas. Erlang on Xen runs Erlang code directly on the Xen hypervisor without an operating system for low latency. It was conceived in 2009 and is optimized for cloud deployments. The document also outlines seven principles for "Newsoftware" designed for the cloud, including not assuming an operating system, making software oblivious to physical boundaries, and avoiding administration. Two potential projects are described: building the Xen toolstack in Erlang and running web scripts in isolated Xen domains for increased security and performance.
Erlang On Xen: Redefining the Cloud Software Stack
- 1. Erlang on Xen: Redefining the cloud software stack erlangonxen.org Erlang Dnipro 2014 1 Monday, 17 February 14
- 2. Today’s agenda 7 commandments of Newsoftware + 2 project ideas 2 Monday, 17 February 14
- 3. Erlang on Xen 101 • A new Erlang runtime, runs w/o OS • Conceived in 2009 • Built from scratch, specifically to run on Xen • Optimised for low startup latency • Highly-compatible with Erlang/OTP • Not an open source (yet) • The public build service is free • EoX starts to exec Erlang code in 4-5 ms after the launch • Sustainable spawning rate = 10 instances/sec Monday, 17 February 14 3
- 4. 7 commandements of Newsoftware: 1) Do not assume the presence of OS underneath 2) Software must be oblivious to boundaries of physical nodes 3) All services must share the same auto-scalable fabric 4) Run computations near the data they process 5) Child nodes get configuration from the parent only 6) Avoid 'administration' at all costs 7) SMP is abomination of cloud computing Monday, 17 February 14
- 5. 1) Do not assume the presence of OS underneath -A full-featured kernel is an overkill for cloud instances -Linux is optimised for very reliable long-living servers -Unix-like access control does not help in the cloud -Virtual devices require much simpler drivers -Newsoftware will often run without a traditional OS Library OS – implement OS-level functions as a library – Mirage OS, OSv, rump kernels Language runtime OS – use high-level language for OS-level functions – Erlang on Xen 5 Monday, 17 February 14
- 6. 2) Software must be oblivious to boundaries of physical nodes -Cloud services make confines of a physical node less relevant -You can only scale so much vertically, horizontal is the true scaling -A user application should be ready to partition the computation onto many instances -Many services can be ephemeral – provisioned only when needed Current cloud stacks are not ready yet Cloud management should become an integral part of all standard libraries 6 Monday, 17 February 14
- 7. 3) All services must share the same auto-scalable fabric -Running cloud management stack isn’t different from other tasks. All animals tasks are equal. -Cloud services should be elastic too – it would be only too natural to implement them using the same auto-scalable infrastructure Packaging of cloud services as auto-scalable applications paves the way to autonomous clouds with far-reaching implications 7 Monday, 17 February 14
- 8. INTERMISSION: Zerg Demo See zerg.erlangonxen.org — instance-per-request proof of concept and check out the table at bottom of the page Monday, 17 February 14 8
- 9. 4) Run computations near data they process -“Scanning” database queries shovel all data through the network -Especially unpleasant when joining -The cloud storage hides the real topology too well -I/O traffic could congest datacenter’s networks Storage nodes should be able to run lightweight data processing instances Xen provides the proper isolation for safe local data processing Monday, 17 February 14 9
- 10. 5) Child nodes get configuration from the parent only -Apps are really big nowadays, and are difficult to understand -Configuration is a mess of config files, scripts, and Chef recipes -Introducing proper hierarchy and order should help -Erlang uses supervisor-workers scheme that works and keeps things simple and understandable The final destination is no manual configuration at all 10 Monday, 17 February 14
- 11. 6) Avoid “administration” at all costs -Human beings can react to once-per-hour events, not on the second (or millisecond) timescale -Human admins do not scale well -Apps should discover services they need and make scaling decisions -Traditional admin tasks go away due to simpler Newsoftware stack The final destination is no configuration at all Many administration tasks can and should be automated 11 Monday, 17 February 14
- 12. 7) SMP is abomination of cloud computing -SMP hinders VM migration -Datacenter is the computer for the Newsoftware -No shared memory - use message passing -Passing messages between VMs on a local host is as fast as shared memory/locking -Respawn smaller VMs are much faster Services built from single-core VMs are much more elastic and robust 12 Monday, 17 February 14
- 13. 2 project ideas: 1) Dom0 based on Erlang on Xen 2) Javascript in a Xen bottle Monday, 17 February 14
- 14. 1) Dom0 based on Erlang on Xen “Implement Xen toolstack in Erlang, remove Linux from Dom0” -Dom0 toolstack reminds strongly of Erlang – events, pattern matching, multiple processes, etc -xl is fast, yet not fast enough for on-demand instance provisioning -Use Linux inside unprivileged driver domains Current status: A prototype instance spawning interface developed – in C and Erlang (zerg.erlangonxen.org) 14 Monday, 17 February 14
- 15. 2) Javascript in a Xen bottle “Evaluate all web scripts inside a separate Xen domain” -Increase security of web browsing -Use languages other than Javascript -Run web scripts faster – native speed 15 Monday, 17 February 14
- 16. 2) Javascript in a Xen bottle “Evaluate all web scripts inside a separate Xen domain” -Increase security of web browsing -Use languages other than Javascript -Run web scripts faster – native speed API calls Browser domain Callbacks Engine domain Spidermonkey 16 Monday, 17 February 14
- 17. Thank you. Questions? 17 Monday, 17 February 14