Linux server audit · single command · zero dependencies

Answers the two questions that actually matter at 3am.

Is anything on this server about to break — and did last night's backup actually run? Not "is the server up". Both of those failures are quiet, and most monitoring doesn't look for them.

$ vaultcheck audit

Vaultcheck audit — web-01 — overall: CRIT
generated 2026-10-31T02:04:11+00:00

CRIT  backup    newest artifact is 22d 4h old (threshold 26h)
WARN  disk      /var at 87% (5.2 GB free)
OK    inodes    max 31% (/)
OK    memory    1.4 GB / 8.0 GB used
OK    load      0.42 / 0.31 / 0.28
CRIT  systemd   backup@daily.service failed
OK    cron      crontab present, 6 jobs
WARN  clock     not synchronised (drift ~184s)
OK    logs      log growth within limits
WARN  updates   14 pending, reboot required

summary: 5 ok, 3 warn, 2 crit, 0 skipped
Buy now — $19.00 one-time

🔒 Secure checkout by Creem. 14-day money-back guarantee.

See what it checks

One-time payment. No subscription, no account, no telemetry. Linux only.

Ten read-only checks, one report

Vaultcheck reads. It never writes to your configuration, never installs an agent, and nothing runs between invocations. You can prove that by running a single check and watching it: vaultcheck audit --only disk.

CheckWhat it actually looks for
backupAge of the newest artefact in your backup target, compared against a threshold you set. This is the one that catches a job which exits 0 and writes nothing.
diskVolume usage and time-to-full, not just a percentage.
inodesInode exhaustion. A filesystem at 40% used with 100% inodes cannot be written to.
memoryMemory and swap pressure.
loadLoad average relative to core count.
systemdUnits in a failed state — the failure that can sit unnoticed for months.
cronThat your scheduled jobs still exist and are enabled, rather than having been dropped by an upgrade.
clockNTP synchronisation and drift. Bad clocks break TLS, cron timing and log correlation.
logsAbnormal log volume growth.
updatesPending package updates and whether a reboot is required.

Standard library only

No pip install, no virtualenv, no compiled extensions. A single 38 KB .pyz you can copy to a server and run.

No agent, no daemon

There is no background process and no state to corrupt. It runs, prints, exits.

Built for automation

--fail-on warn|crit returns a non-zero exit code so cron, systemd timers or a heartbeat service can page you.

Machine-readable output

Text for humans, JSON to diff day against day, HTML to attach to a ticket.

How it works

Requires Python 3.8 or newer. Nothing else.

1 · Get the file

After checkout you receive a download containing vaultcheck.pyz, a .whl package, a README, a licence text and a quickstart, plus a licence key.

2 · Activate once per machine

vaultcheck license activate --key YOUR-KEY

3 · Run the audit

python3 vaultcheck.pyz audit                 # full text report
python3 vaultcheck.pyz audit --format json   # for pipelines
python3 vaultcheck.pyz audit --format html -o report.html
python3 vaultcheck.pyz audit --fail-on crit  # exit non-zero on critical
python3 vaultcheck.pyz audit --only backup disk

Try before you buy

Without a licence the audit command still runs and prints the overall verdict and a per-severity count, so you can confirm it detects what you expect on your own server. Per-check detail, JSON and HTML output require an activated licence.

Network disclosure: Vaultcheck makes exactly one outbound connection — when you activate or validate a licence, it contacts our licence endpoint with your licence key and the hostname of the machine. The audit itself performs no network calls and reports nothing back. There is no analytics, no telemetry and no tracking in the tool.

Who builds this

Renhua Wei

Hi, I'm Renhua. I'm a solo developer based in Sichuan. I build simple, practical CLI tools to solve real operational problems like silent backup failures and data extraction. If you run into any issues or have questions, just reply to this email and I'll get back to you personally.
renhua.wei@zohomail.com

Pricing

$19.00 one-time payment · per licence · no subscription

You get the tool, one licence key, and updates within the 1.x series. No account to create, no recurring charge.

Buy now — $19.00

Secure checkout handled by Creem, who act as the merchant of record.
14-day money-back guarantee — see Terms.

Not sure it fits? Run the free preview on one of your servers first — it needs no licence and no signup. If it doesn't find anything useful, don't buy it.

FAQ

What exactly is it not?

Not a replacement for Prometheus, Zabbix or Netdata — there is no time-series database, no graphing and no long-term storage. Not cross-platform: Linux only. Not open source. If you already run a mature observability stack with alerting on backup freshness, you probably don't need this.

Does it replace my monitoring?

No. Vaultcheck is a point-in-time audit you run on demand or from cron. Monitoring tells you continuously whether things are up; this tells you whether the things you assume are happening actually are.

Does it send my server data anywhere?

No. The audit runs locally and reads local system state. The only network call is licence activation/validation, which sends your licence key and hostname. No report content, no hostnames from your infrastructure listings, no telemetry.

Is it safe to run on production?

It is read-only: it inspects filesystem usage, unit state, load, clock and similar signals. It does not modify configuration, restart services or write outside a state directory used to store your licence.

How many machines can I use one key on?

One licence is intended for one machine. Activation binds the key to a hostname; you can deactivate and move the licence to another machine using vaultcheck license deactivate.

Which Python versions are supported?

Python 3.8 and newer, on Linux. It uses only the standard library.

Can I get a refund?

Yes — within 14 days of purchase, no reason required. Email renhua.wei@zohomail.com with your order number and we will refund it.

Do you offer support?

Email renhua.wei@zohomail.com. This is a small, independently developed tool, so replies are usually within two business days.