A rootless Alloy shipped zero lines: the journal files are
root:systemd-journal 0640 (other::---) and a rootless container carries no
supplementary groups, so sd_journal_open sees an empty view silently; the
rootless quadlet container logs also live in user-1000.journal, not the
ctr.log paths the old config tailed.
As root, one loki.source.journal reads system.journal + user-*.journal
and carries both. Network=host because Loki publishes 127.0.0.1:3100 and
no bridge container can reach the host loopback; the UI binds loopback
directly (no PublishPort). The /etc/machine-id mount is load-bearing —
sd_journal finds the journal dir by the local machine id; without it the
source reads 0 lines, health green.
deploy_alloy routes around the rootless loop: build rootless, mirror the
image into the root store (a root build fails on DNS in the build
container), retire the old rootless alloy unit, install to
/etc/containers/systemd. Validated with a throwaway root probe: 31,825
lines read, 26,966 pushed to Loki in 20s, zero drops.