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[BUGFIX] Let syslog-ng take the messages of the services on Alpine - #623
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Kanti merged 1 commit intoNov 15, 2026
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syslog-ng listened on /dev/log as a stream socket. syslog() of musl, and so cron, Postfix and logger on Alpine, sends datagrams only, so their messages were lost: they reached neither the container log nor the file of LOG_STDOUT. A datagram socket takes them; glibc tries datagrams first too, so nothing changes on Debian and Ubuntu. The image tests send a message with logger and check that it arrives, and that cron logs a job at the level of SERVICE_CRON_OPTS.
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Kanti
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November 15, 2026 15:28
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Summary
syslog-ng listened on
/dev/logas a stream socket.syslog()of musl sends datagrams only, so on Alpine the messages of cron, Postfix andloggerwere lost: they reached neither the container log nor the file ofLOG_STDOUT. syslog-ng now listens on a datagram socket. glibc tries datagrams first, so Debian and Ubuntu behave as before.Related issues: none found.
Changes
provisioning/base/general/etc/syslog-ng/syslog-ng.conf:unix-dgram("/dev/log")instead ofunix-stream;make generate.testSyslogMessagesReachTheFileFromTheEnvironment: a message sent withloggerarrives in the file ofLOG_STDOUT. syslog-ng is started where the image does not start it.testCronRunsJobsInTheTimeZoneFromTheEnvironment: cron also logs the job at the level ofSERVICE_CRON_OPTS(-L 15on Debian logs its end,-l 0on Alpine its start). This replaces the check intestServiceOptionsFromTheEnvironment, which only looked for the option in the command line of cron.docs/environment-variables.mdare removed.How it was verified
php-nginx:8.5-alpineloggermessage are missingbase:alpineloggermessage is missingphp-nginx-dev:8.5(Debian)"With the fix" is the published image with the new
syslog-ng.confin place of the old one. The two files differ only in the/dev/logline.The runs of
base:alpineandphp-nginx-dev:8.5are from before the rebase onto the current master; the change and its tests are the same. GrumPHP passes, andci/console generatechanges nothing.Not verified: a full build of the images, a GitHub Actions run, arm64.