It breaks something inside of influxdb2, which results in flurry of errors like these:
> ts=2021-12-21T18:19:35.513910Z lvl=info msg="Write failed" log_id=0YZYwvV0000 service=storage-engine service=write shard=50 error="[shard 50] unlinkat ./L1-00000055.tsi: read-only file system"
I believe this is somehow caused by a mount namespace that systemd creates for
the service, but I didn't investigate this deeper.
* It's IMHO a slight overkill to deploy an additional container even if
it's never supposed to be running. Also, the currently suggested
approach wouldn't use the default state-directory for the new version.
* Explain the structure of the state-directories and where the
version-numbers are actually coming from.
* Mention `./analyze_new_cluster.sh` & `./delete_old_cluster.sh`.
unfortunately we don't have a good way to represent defaults that
reference other values of the current submodule, so we just use the
relative path of the referenced value and assume that the submodule was
declared as `rec`.
instead of keeping a defaultConfig value around, set that value as the
default of the option and explicitly use the option default instead.
this also allows us to write a defaultText that makes sense and is in
proximity to the definition of the default.
adds defaultText for all options that use `cfg.*` values in their
defaults, but only for interpolations with no extra processing (other
than toString where necessary)
This fixes:
```
systemd[1]: Started VictoriaMetrics time series database.
victoria-metrics[379550]: 2021-08-04T19:33:39.833Z panic VictoriaMetrics/lib/storage/partition.go:954 FATAL: unrecoverable error when merging small parts in the partition "/var/lib/victoriametrics/data/small/2021_08": cannot open source part for merging: cannot open metaindex file in stream mode: cannot open file "/var/lib/victoriametrics/data/small/2021_08/1228_1228_20210804184120.712_20210804184121.899_16982E83CD7A763A/metaindex.bin": open /var/lib/victoriametrics/data/small/2021_08/1228_1228_20210804184120.712_20210804184121.899_16982E83CD7A763A/metaindex.bin: too many open files
victoria-metrics[379550]: panic: FATAL: unrecoverable error when merging small parts in the partition "/var/lib/victoriametrics/data/small/2021_08": cannot open source part for merging: cannot open metaindex file in stream mode: cannot open file "/var/lib/victoriametrics/data/small/2021_08/1228_1228_20210804184120.712_20210804184121.899_16982E83CD7A763A/metaindex.bin": open /var/lib/victoriametrics/data/small/2021_08/1228_1228_20210804184120.712_20210804184121.899_16982E83CD7A763A/metaindex.bin: too many open files
victoria-metrics[379550]: goroutine 629 [running]:
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/logger.logMessage(0xbb3ea1, 0x5, 0xc001113800, 0x1e7, 0x4)
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/logger/logger.go:270 +0xc69
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/logger.logLevelSkipframes(0x1, 0xbb3ea1, 0x5, 0xbe3f8b, 0x4b, 0xc000bb3f88, 0x2, 0x2)
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/logger/logger.go:138 +0xd1
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/logger.logLevel(...)
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/logger/logger.go:130
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/logger.Panicf(...)
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/logger/logger.go:126
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/storage.(*partition).smallPartsMerger(0xc0014d7980)
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/storage/partition.go:954 +0x145
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/storage.(*partition).startMergeWorkers.func1(0xc0014d7980)
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/storage/partition.go:933 +0x2b
victoria-metrics[379550]: created by github.com/VictoriaMetrics/VictoriaMetrics/lib/storage.(*partition).startMergeWorkers
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/storage/partition.go:932 +0x6c
systemd[1]: victoriametrics.service: Main process exited, code=exited, status=2/INVALIDARGUMENT
systemd[1]: victoriametrics.service: Failed with result 'exit-code'.
systemd[1]: victoriametrics.service: Consumed 587ms CPU time, received 6.5K IP traffic, sent 1.7K IP traffic.
systemd[1]: victoriametrics.service: Scheduled restart job, restart counter is at 2064.
systemd[1]: Stopped VictoriaMetrics time series database.
systemd[1]: victoriametrics.service: Consumed 587ms CPU time, received 6.5K IP traffic, sent 1.7K IP traffic.
systemd[1]: Starting VictoriaMetrics time series database...
```
As the only consequence of isSystemUser is that if the uid is null then
it's allocated below 500, if a user has uid = something below 500 then
we don't require isSystemUser to be set.
Motivation: https://github.com/NixOS/nixpkgs/issues/112647
Ivan Kozik