diff --git a/README.md b/README.md index 7993e3c..e450887 100644 --- a/README.md +++ b/README.md @@ -57,6 +57,7 @@ You can configure the stock `ubuntu` image yourself from your Dockerfile, so why * [Environment variable dumps](#envvar_dumps) * [Modifying environment variables](#modifying_envvars) * [Security](#envvar_security) + * [System logging](#logging) * [Upgrading the operating system inside the container](#upgrading_os) * [Container administration](#container_administration) * [Running a one-shot command in a new container](#oneshot) @@ -303,6 +304,14 @@ If you are sure that your environment variables don't contain sensitive data, th RUN chmod 755 /etc/container_environment RUN chmod 644 /etc/container_environment.sh /etc/container_environment.json + +### System logging + +Baseimage-docker uses syslog-ng to provide a syslog facility to the container. Syslog-ng is not managed as an runit service (see below). Syslog messages are forwarded to the console via the service at /etc/service/syslog-forwarder. + +#### Log startup/shutdown sequence +In order to ensure that all application log messages are captured by syslog-ng, syslog-ng is started separately before the runit supervisor process, and shutdown after runit exits. This uses the [startup script facility](#running_startup_scripts) provided by this image. This avoids a race condition which would exist if syslog-ng were managed as an runit service, where runit kills syslog-ng in parallel with the container's other services, causing log messages to be dropped during a graceful shutdown if syslog-ng exits while logs are still being produced by other services. + ### Upgrading the operating system inside the container diff --git a/image/services/syslog-ng/syslog-ng.init b/image/services/syslog-ng/syslog-ng.init new file mode 100755 index 0000000..04f526b --- /dev/null +++ b/image/services/syslog-ng/syslog-ng.init @@ -0,0 +1,34 @@ +#!/bin/bash +set -e + +# If /dev/log is either a named pipe or it was placed there accidentally, +# e.g. because of the issue documented at https://github.com/phusion/baseimage-docker/pull/25, +# then we remove it. +if [ ! -S /dev/log ]; then rm -f /dev/log; fi +if [ ! -S /var/lib/syslog-ng/syslog-ng.ctl ]; then rm -f /var/lib/syslog-ng/syslog-ng.ctl; fi + +PIDFILE="/var/run/syslog-ng.pid" +SYSLOGNG_OPTS="" + +[ -r /etc/default/syslog-ng ] && . /etc/default/syslog-ng + +syslogng_wait() { + if [ "$2" -ne 0 ]; then + return 1 + fi + + RET=1 + for i in $(seq 1 30); do + status=0 + syslog-ng-ctl stats >/dev/null 2>&1 || status=$? + if [ "$status" != "$1" ]; then + RET=0 + break + fi + sleep 1s + done + return $RET +} + +/usr/sbin/syslog-ng --pidfile "$PIDFILE" -F $SYSLOGNG_OPTS & +syslogng_wait 1 $? diff --git a/image/services/syslog-ng/syslog-ng.runit b/image/services/syslog-ng/syslog-ng.runit deleted file mode 100755 index 7045d26..0000000 --- a/image/services/syslog-ng/syslog-ng.runit +++ /dev/null @@ -1,32 +0,0 @@ -#!/bin/sh -set -e - -# If /dev/log is either a named pipe or it was placed there accidentally, -# e.g. because of the issue documented at https://github.com/phusion/baseimage-docker/pull/25, -# then we remove it. -if [ ! -S /dev/log ]; then rm -f /dev/log; fi -if [ ! -S /var/lib/syslog-ng/syslog-ng.ctl ]; then rm -f /var/lib/syslog-ng/syslog-ng.ctl; fi - -SYSLOGNG_OPTS="" - -[ -r /etc/default/syslog-ng ] && . /etc/default/syslog-ng - -case "x$CONSOLE_LOG_LEVEL" in - x[1-8]) - dmesg -n $CONSOLE_LOG_LEVEL - ;; - x) - ;; - *) - echo "CONSOLE_LOG_LEVEL is of unaccepted value." - ;; -esac - -if [ ! -e /dev/xconsole ] -then - mknod -m 640 /dev/xconsole p - chown root:adm /dev/xconsole - [ -x /sbin/restorecon ] && /sbin/restorecon $XCONSOLE -fi - -exec syslog-ng -F -p /var/run/syslog-ng.pid $SYSLOGNG_OPTS diff --git a/image/services/syslog-ng/syslog-ng.sh b/image/services/syslog-ng/syslog-ng.sh index 5c25e9d..610d80c 100755 --- a/image/services/syslog-ng/syslog-ng.sh +++ b/image/services/syslog-ng/syslog-ng.sh @@ -7,8 +7,8 @@ SYSLOG_NG_BUILD_PATH=/bd_build/services/syslog-ng ## Install a syslog daemon. $minimal_apt_get_install syslog-ng-core -mkdir /etc/service/syslog-ng -cp $SYSLOG_NG_BUILD_PATH/syslog-ng.runit /etc/service/syslog-ng/run +cp $SYSLOG_NG_BUILD_PATH/syslog-ng.init /etc/my_init.d/10_syslog-ng.init +cp $SYSLOG_NG_BUILD_PATH/syslog-ng.shutdown /etc/my_init.post_shutdown.d/10_syslog-ng.shutdown mkdir -p /var/lib/syslog-ng cp $SYSLOG_NG_BUILD_PATH/syslog_ng_default /etc/default/syslog-ng touch /var/log/syslog diff --git a/image/services/syslog-ng/syslog-ng.shutdown b/image/services/syslog-ng/syslog-ng.shutdown new file mode 100755 index 0000000..0288004 --- /dev/null +++ b/image/services/syslog-ng/syslog-ng.shutdown @@ -0,0 +1,24 @@ +#!/bin/bash + +PIDFILE="/var/run/syslog-ng.pid" + +syslogng_wait() { + if [ "$2" -ne 0 ]; then + return 1 + fi + + RET=1 + for i in $(seq 1 30); do + status=0 + syslog-ng-ctl stats >/dev/null 2>&1 || status=$? + if [ "$status" != "$1" ]; then + RET=0 + break + fi + sleep 1s + done + return $RET +} + +kill $(cat "$PIDFILE") +syslogng_wait 0 $?