The Reconnaissance SSH: How a Single Command Uncovered the Deployment Landscape for cuzk's Memory Manager

Introduction

In the middle of a high-stakes deployment sequence, a single SSH command can reveal the entire topography of a production system. Message <msg id=2300> captures one such moment: an assistant, having just committed a comprehensive memory manager rewrite for the cuzk GPU proving engine, pauses to map out the remote machine's configuration landscape before deploying the new binary. The message is deceptively simple—a single bash tool invocation that runs a multi-part find and ls pipeline over SSH—but it represents a critical inflection point between development and deployment, between "it works on my machine" and "it works in production."

Context and Motivation: Why This Message Was Written

To understand why this message exists, one must trace the thread backward through the conversation. The assistant had just spent multiple sessions designing and implementing a unified budget-based memory manager for cuzk (see segments 14–17 of the conversation). The old system relied on a static partition_workers semaphore and preloaded SRS/PCE data, which led to fragile concurrency limits and OOM risks. The new system introduced MemoryBudget, MemoryReservation, PceCache with LRU eviction, and budget-aware SRS loading—a deep architectural change touching seven source files and adding over 2,600 lines of code.

The user's instruction in <msg id=2293> was clear: commit the changes, test them on a remote machine running Curio and cuzk, and verify that the memory constraints work correctly. The assistant had already committed the changes in <msg id=2296> with a detailed commit message, and had performed an initial reconnaissance of the remote machine in <msg id=2298>—checking free memory (755 GiB total, 528 GiB available), GPU (RTX 5090 with 32 GiB VRAM), CPU count (64 cores), and the presence of existing binaries at /usr/local/bin/cuzk and /usr/local/bin/cuzk-bench.

But <msg id=2298> also revealed a critical gap: while the binaries existed, the assistant had not yet located the configuration files. The systemctl status cuzk command returned nothing, and ps aux showed only a curio run process—no cuzk daemon was actively running. This raised an immediate question: where is the cuzk configuration stored, and what format does it use? Without answering this, deploying the new binary would be pointless—the new memory manager introduces new config fields (total_budget, safety_margin, eviction_min_idle) and deprecates old ones (partition_workers, srs.preload, pinned_budget). The old config would either be ignored (with warnings) or cause the daemon to misbehave.

Thus, <msg id=2300> was written to answer a single, essential question: where are the cuzk config files on this machine, and what is the current configuration state?

The Reconnaissance Strategy: How Decisions Were Made

The command itself reveals a careful, layered reconnaissance strategy. Rather than guessing at config locations, the assistant constructed a four-part SSH pipeline:

find / -name "cuzk.toml" -type f 2>/dev/null — A broad search for any file literally named cuzk.toml anywhere on the system. This is the most specific query: it targets the exact config filename the cuzk daemon expects by default.
find / -name "*.toml" -path "*cuzk*" 2>/dev/null — A broader search for any TOML file whose path contains "cuzk". This catches files like cuzk-run-config.toml or cuzk-bench-config.toml that don't use the exact default name but are clearly related.
ls -la /root/.config/cuzk/ 2>/dev/null || ls -la /etc/cuzk/ 2>/dev/null || true — A targeted check of two standard config directories: the XDG-compliant ~/.config/cuzk/ and the system-level /etc/cuzk/. The || true ensures the overall command doesn't fail if neither directory exists.
find / -maxdepth 4 -name "cuzk*" -type f 2>/dev/null | grep -v proc — A shallow (max 4 levels deep) search for any file starting with "cuzk", excluding /proc entries. This catches binaries, logs, and any other cuzk-related artifacts. The results painted a clear picture. The config files were not in standard locations: they lived at /tmp/cuzk-bench-config.toml and /tmp/cuzk-run-config.toml. The /etc/cuzk/ directory existed but was completely empty (only . and .. entries, created at 11:08 on March 13). The /root/.config/cuzk/ directory didn't exist at all. The remaining files were a mix of logs (/tmp/cuzk-daemon.log, /tmp/cuzk-bench-daemon.log, etc.) and the two binaries already known from the previous reconnaissance.

Assumptions and Their Implications

Every reconnaissance operation rests on assumptions, and this message reveals several. The assistant assumed that:

The config file would be named cuzk.toml or contain "cuzk" in its path. This is a reasonable default based on how most Unix daemons name their configs, but it could have missed a config with a completely unrelated name (e.g., config.toml in a cuzk-specific directory).
The config would be in a standard location like /etc/cuzk/ or ~/.config/cuzk/. This assumption proved partially correct—/etc/cuzk/ existed but was empty, suggesting someone had created the directory structure but never populated it, or that configs were managed through a different mechanism (perhaps environment variables or command-line flags).
The find commands would complete quickly and not hang on network filesystems or special devices. The -maxdepth 4 flag on the last search was a prudent guard against traversing deep directory trees, but the first two find commands had no depth limit, which could have been slow on a machine with many files.
The remote machine's filesystem layout was conventional. The assistant assumed that /root/.config/ and /etc/ were meaningful locations, which is true for standard Linux distributions but might not hold for containerized or heavily customized environments. These assumptions were validated by the results, but they also revealed something unexpected: the config files were in /tmp/. This is unusual for a production service—/tmp/ is typically ephemeral and may be cleared on reboot. It suggests that either the cuzk daemon was being run in a testing/benchmarking mode, or that the deployment was still in an experimental phase. This finding would directly influence the deployment strategy: if the config is in /tmp/, the assistant would need to either copy it to a persistent location or ensure the new config is also placed in /tmp/.

Input Knowledge Required

To fully understand this message, a reader needs knowledge of several domains:

Linux system administration: Understanding find syntax, ls -la, path wildcards, grep -v, and SSH command invocation is essential. The 2>/dev/null redirects and || true fallback are standard patterns for robust scripting.
cuzk architecture: Knowing that cuzk is a GPU proving engine, that it uses a TOML config file, and that the memory manager rewrite changed the config schema is necessary to grasp why locating the config matters.
The deployment context: The reader must know that this is a production machine running Curio (a Filecoin-related service) and that cuzk is being upgraded from a static partition-based memory model to a dynamic budget-based one.
TOML format: Understanding that cuzk uses TOML for configuration explains why the search targets .toml files specifically.

Output Knowledge Created

This message produced several concrete pieces of knowledge:

Config file locations: /tmp/cuzk-run-config.toml and /tmp/cuzk-bench-config.toml are the active configuration files. This is the single most important finding—without it, the assistant would have deployed a new binary with no way to configure it.
Config directory state: /etc/cuzk/ exists but is empty, suggesting it was created as a placeholder or by a package installation that never completed its setup.
File inventory: A complete list of cuzk-related files on the system, including logs from previous benchmark runs (cuzk-bench-daemon.log, cuzk-bench-warmup.log, etc.) and the two binaries.
Deployment readiness assessment: The fact that no cuzk daemon process was running (confirmed in the previous message) and that configs were in /tmp/ rather than a persistent location suggested that the machine was in a pre-production or testing state, which lowered the risk of deploying a new binary.

The Thinking Process Visible in the Command

The structure of the command itself reveals the assistant's reasoning. It's not a single find call but a carefully ordered pipeline of four distinct queries, each answering a different question:

Query 1 (exact filename match) asks: "Is there a config file using the standard name?"
Query 2 (path contains "cuzk") asks: "Is there a config file using a non-standard name but clearly related?"
Query 3 (standard directories) asks: "Is the config in a location I'd expect from convention?"
Query 4 (broad shallow search) asks: "What cuzk artifacts exist on this system at all?" This layered approach is a classic diagnostic pattern: start with the most specific, most likely hypothesis, then broaden the search if it fails. The || true on query 3 is a defensive measure—it prevents the entire pipeline from failing if neither directory exists, which would mask the results of query 4. The use of grep -v proc on the final search is another thoughtful touch. The /proc filesystem is a virtual filesystem that can contain references to running processes' file handles; excluding it prevents false positives and avoids potential hangs from traversing a pseudo-filesystem.

Broader Significance

While <msg id=2300> is a single command in a longer conversation, it exemplifies a crucial phase in any deployment workflow: the transition from "what changed" to "where does it go." The assistant had just completed a major architectural change to cuzk's memory management—a change that touched the config schema, the SRS loading path, the PCE caching strategy, and the engine's admission control. But all that work would be wasted if the new binary was deployed with an old config that didn't use the new fields.

This message is also a reminder that production deployment is not just about building the right binary—it's about understanding the target environment. The assistant didn't assume the config was in a standard location; it searched systematically. It didn't assume the daemon was running; it checked. It didn't assume the directory structure matched expectations; it verified. This systematic approach, embodied in a single well-crafted SSH command, is what separates a fragile deployment from a robust one.

The results—config files in /tmp/, an empty /etc/cuzk/ directory, and a collection of benchmark logs—told a story about how cuzk had been used on this machine. It had been tested and benchmarked, but never fully deployed as a production daemon. This context would shape everything the assistant did next: how to update the config, whether to restart a daemon or start one, and what level of risk was acceptable in the deployment.

Conclusion

Message <msg id=2300> is a masterclass in targeted reconnaissance. In a single SSH command, the assistant mapped the entire cuzk deployment on a remote machine, discovered the non-standard config location, assessed the deployment maturity, and gathered the information needed to proceed with confidence. It's a reminder that in complex systems engineering, the questions you ask are often more important than the answers you find—and that a well-constructed find pipeline can answer more than a dozen guesses ever could.