dettrace
testground
dettrace | testground | |
---|---|---|
2 | 2 | |
29 | 401 | |
- | 0.2% | |
2.6 | 1.6 | |
over 3 years ago | 7 months ago | |
C++ | Go | |
GNU General Public License v3.0 or later | GNU General Public License v3.0 or later |
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dettrace
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Deterministic Linux for Controlled Testing and Software Bug-Finding
Note that this is a follow-on project from the earlier Dettrace system, which was applied mainly to reproducible builds (as in the academic paper, https://dl.acm.org/doi/10.1145/3373376.3378519, and presented to the Debian Reproducible Builds summit):
- https://github.com/dettrace/dettrace
And one cool part of it is this Rust program instrumentation layer:
- https://github.com/facebookexperimental/reverie
It's good for building OS-emulator style projects or tracing tools.
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Shadow Simlulator โ run real applications over a simulated Internet topology
We've started looking into eBPF a bit - IIUC eBPF by itself doesn't give us the ability to service or arbitrarily manipulate the traced process's syscalls.
We have recently learned of an interesting technique that dettrace [1] uses of combining seccomp with an eBPF filter and ptrace. Instead of generating a ptrace-stop for every syscall (as we do now, using PTRACE_SYSEMU), they use a seccomp policy with an eBPF filter, s.t. a ptrace-stop is only generated for syscalls that violate the policy, allowing them to emulate the result of those syscalls. syscalls that don't violate the policy are allowed to execute natively, saving a lot of overhead.
[1]: https://github.com/dettrace/dettrace
This works great for them since they want to emulate a relatively small subset of syscalls. In our case we want to emulate most syscalls, so it's not as clear-cut of a win. We have found though that if we use an LD_PRELOAD'd shim in the target process to intercept syscalls and then service them via IPC, that's substantially faster than catching them with ptrace. That runs back into the problems with LD_PRELOAD in general of there being various ways of missing syscalls. but, we may be able to use that technique along with ptrace+seccomp+ebpf to intercept any syscalls that we'd otherwise miss. The seccomp technique would allow us to exempt the syscalls that our shim itself is making to do the IPC.
testground
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Testing Distributed Systems
They have their own solutions for these problems as well, see e.g. https://github.com/testground/testground, which comes from the IPFS/Filecoin folks to coordinate distributed state, network traffic shaping, etc. for testing distributed systems.
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Shadow Simlulator โ run real applications over a simulated Internet topology
related, but "higher level" project: project:https://github.com/testground/testground
What are some alternatives?
mininet - Emulator for rapid prototyping of Software Defined Networks
shadow - Shadow is a discrete-event network simulator that directly executes real application code, enabling you to simulate distributed systems with thousands of network-connected processes in realistic and scalable private network experiments using your laptop, desktop, or server running Linux.
core - Common Open Research Emulator
imunes - Integrated Multiprotocol Network Emulator/Simulator
shadow-plugin-tor - A Shadow plug-in that runs the Tor anonymity software
garden - Automation for Kubernetes development and testing. Spin up production-like environments for development, testing, and CI on demand. Use the same configuration and workflows at every step of the process. Speed up your builds and test runs via shared result caching
reverie - An ergonomic and safe syscall interception framework for Linux.