OSv - A Modern Semi-POSIX LibraryOS
Glauber Costa, Lead Engineer [email protected] Typical Cloud Stack
Application Runtime Protection Operating System and Hypervisor abstraction Hardware Containers
Application Application ● high simplicity ● high resource efficiency ● high performance Runtime Runtime Operating System Hardware “Library OS”
Application Application ● high simplicity ● high resource efficiency ● high performance Runtime + OS Runtime + OS ● high isolation Hypervisor Hardware Architecture
● Only one application / many threads ● Single address space ● Network channels ● Written in C++11 ● User API - REST ● BSD licenced ● ZFS filesystem Not the only one out there
● Other examples: Erlang-on-Xen, Mirage, ClickOS.
● But runs on wide range of Hypervisors ○ Xen, KVM/Qemu, VMWare, VirtualBox. ● Supports a quasi-POSIX API. ○ no fork(), no exec(), ○ largely Linux compatible. ● Less than 1s boot time. ○ as fast as needed, not as fast as possible. quasi-POSIX
● Allow unmodified applications to work, ● and modified applications to shine. Performance
● System calls are free ○ context switches are really cheap ( x 4 Fedora) ● Network performance significantly faster ○ around 20 % with netperf over Fedora Linux ○ more than 50 % for some UDP workloads ● I will show you concrete results at the end What do people think?
Roman Shaposhnik, Bigtop/Hadoop
"Mark my words, GridGain [...] and OSv [...] are going to be excitingly disruptive in the next few years. […] And, by the way, if, after reading this blog, you are not dropping everything and porting your cloud application to OSv, I don’t know what’s wrong with you."
http://blog.gopivotal.com/pivotal/features/pivotal-debuts-at-apachecon-north-america-2014-thanks-for-having-us The Xen Situation
● We like HVM because it brings greater flexibility ○ Xen's HVM boot is really slow ○ Other than that, all other goodies are there ■ interrupt injection, pv devices, etc. ● PVH is viable, but no one looking at the moment. ○ We take patches! ● PV out of question ○ too complex, ○ technically not possible. The Xen Situation - cont
Stack
Current Frame
128-byte Red Zone The Xen Hypervisor does NOT region respect that! Will my application be fast?
● short answer: ○ yes ● short answer 2: ○ no ● Similar to Ahmdal's law, in the context of parallelism ○ no gains for 95 % CPU hungry userspace applications ● POSIX APIs poses a limitation. Fresh from the Oven
● Cassandra NoSQL ● OSv vs CentOS 7 ● up to 25 % faster reads ○ 1 VCPU only redis
● up to 80 % faster than Ubuntu 14.04 ○ 10 Gb networking ○ No specialized interfaces ○ we do have some problems, though ○ check our blog about it, details at http://osv.io/blog/ memcached
● unmodified, ○ brings a juicy improvement out of the box. ● modified: ○ that showcases the real performance opportunity behind OSv. That's already ~20 % more at http://osv.io/benchmarks/ To know more
http://osv.io https://github.com/cloudius-systems/osv
@CloudiusSystems