Files
Aleksei Sviridkin 527d4ea00f test(e2e): measure tenant worker CPU as a rate, and the sandbox nodes under it
Two instruments for the node-join failure the kubernetes-* suites keep
hitting. Neither changes what the suites assert.

The worker CPU capture now reads container_cpu_usage_seconds_total
beside the CFS counters, and reads them twice a fixed interval apart
instead of once. The throttled counters say a container met its ceiling
and cannot say how much CPU it got, which are the two candidate
explanations for a stalled worker: a guest held at a one-core ceiling,
and a guest whose vCPU thread is rarely scheduled at all. Both leave
throttled periods behind. Every counter involved accumulates from
container start, so a single reading is an average over the whole uptime
and no rate at all, and the profile under investigation is a guest that
freezes for tens of seconds and then runs flat out: the average comes
out low, the instantaneous figure comes out at the cap, and only the
second separates it from a guest that is simply capped.

The sandbox nodes are a new subject. The worker captures describe a
cgroup, so a guest that is runnable and never scheduled looks from there
like a guest that asked for nothing. Whether the sandbox node itself was
given its turn is recorded only in the steal column of its own
/proc/stat: no kubelet endpoint carries it, and crust-gather cannot
reach it because PodSecurity refuses its node-shell Pod here, so the
read goes over the Talos API, which is already how the report reaches
those nodes for dmesg. The rows are captured verbatim with their column
legend beside them rather than reduced to a percentage, because
/proc/stat has no header, steal and guest sit next to each other, and
guest is large on a node running VMs and already counted inside user.

Both subjects are read on either side of one shared wait, so the pair
pays it once. The wait is not the interval either subject's counters
span, though: each pass walks its own nodes and the other subject's pass
falls between a subject's two readings, and on the run this exists for
those passes are the slow part. Each capture therefore stamps both ends
of its read, so a rate comes from subtracting stamps rather than from
assuming the knob, and the width of those brackets is the uncertainty.
That wait is a measurement interval rather than a stand-in for a
condition nobody wrote a wait for, so the e2e conventions carve it out
by name instead of marking it as a fixed timeout to be replaced.

The pair is gated below the serial console rather than above it. Its
ceiling is sixteen bounded reads plus the interval, which is most of the
phase budget, and admission gates only when a collector may start, so
above the console a run that hit those bounds would leave the console
never started rather than merely cut short. The console is the only
capture that survives a worker which never reached apid, which is the
shape this failure usually takes. That overrun is inside the term the
budget derivation already allows for one late admission, and a guard
holds the pair's ceiling against it.

No collector here may leave an empty directory, since an empty directory
reads as a healthy node: a missing binary, a missing talosconfig, a
listing that never answered, a node with no address and a read that was
cut off each land as a named note or a COLLECTION-FAILED.txt.

Assisted-By: Claude <noreply@anthropic.com>
Signed-off-by: Aleksei Sviridkin <3811295@gmail.com>
2026-08-15 10:19:19 +03:00
..
2026-08-05 10:04:43 +00:00