[Promtail 3.6.0 docker] Journal target was configured but support for reading the systemd journal is not compiled into this build of promtail!

[chennin]

Describe the bug
Promtail docker image 3.6.0 does send journald logs, 3.5.8 worked

To Reproduce

docker run --rm -it -v ./promtail-config.yaml:/etc/promtail/config.yml index.docker.io/grafana/promtail:3.6.0

Expected behavior
Promtail works with journald

Environment:

• Infrastructure: Ubuntu 24.04

Screenshots, Promtail config, or terminal output

server:
  http_listen_port: 9080
  grpc_listen_port: 0
  log_level: debug

positions:
  filename: /tmp/positions.yaml

clients:
  - url: http://loki:3000/loki/api/v1/push

scrape_configs:
  - job_name: journal
    journal:
      json: false
      max_age: '12h'
      path: /run/log/journal
      labels:
        job: systemd-journal
    relabel_configs:
      - source_labels: ['__journal__systemd_unit']
        regex: 'agave.service'
        action: keep
      - source_labels: ['__journal__systemd_unit']
        target_label: 'unit'
      - source_labels: ['__journal_syslog_identifier']
        target_label: 'syslog_identifier'

3.5.8 (expected fatal error for this repro)

# docker run --rm -it -v ./promtail-config.yaml:/etc/promtail/config.yml index.docker.io/grafana/promtail:3.5.8
level=debug ts=2025-11-18T14:37:24.822501102Z caller=promtail.go:126 msg="Reloading configuration file"
level=info ts=2025-11-18T14:37:24.823348323Z caller=promtail.go:135 msg="Reloading configuration file" sha3sum=99bc8bcb8901e5d0e86819f2c299b63a6df0f96b3921918582bb993aedf3d419
level=error ts=2025-11-18T14:37:24.839994374Z caller=main.go:169 msg="error creating promtail" error="failed to make journal target manager: creating journal reader: failed to open journal in directory \"/run/log/journal\": no such file or directory"

3.6.0 (journald warning, startup continues, journals are not sent)

# docker run --rm -it -v ./promtail-config.yaml:/etc/promtail/config.yml index.docker.io/grafana/promtail:3.6.0
level=debug ts=2025-11-18T14:37:37.577308602Z caller=promtail.go:126 msg="Reloading configuration file"
level=info ts=2025-11-18T14:37:37.579067058Z caller=promtail.go:135 msg="Reloading configuration file" sha3sum=c6ceca01b442cf423b9a5af427fb7b9785f8ab4da1b4be5644862307258e8b8d
level=warn ts=2025-11-18T14:37:37.579484067Z caller=journaltargetmanager.go:29 msg="WARNING!!! Journal target was configured but support for reading the systemd journal is not compiled into this build of promtail!"
level=info ts=2025-11-18T14:37:37.579998819Z caller=server.go:386 msg="server listening on addresses" http=[::]:9080 grpc=[::]:44211

[codingjerk]

Can confirm, looks like it's a regression of #16220

From the docs:

Requires a build of Promtail that has journal support enabled.
If using the AMD64 Docker image, this is enabled by default