[[inputs.system]] /var/run/utmp: no such file... when using Alpine as base Image
Closed this issue · 5 comments
some informations to #5283 and the older issue #5031: and as asked by @danielnelson
here the Issue
Relevant telegraf.conf:
used the standard, did no changes. just ran the two commands provided in the readme of Dockerhub:
$ docker run -d --name influxdb -p 8083:8083 -p 8086:8086 influxdb
$ docker run --net=container:influxdb telegraf:alpine
System info:
Host MacOs, Docker Version 2.0.0.2
[Include Telegraf version, operating system name, and other relevant details]
DockerEnvironment$ docker run --net=container:influxdb telegraf:alpine
2019-02-08T21:54:40Z I! Starting Telegraf 1.9.4
2019-02-08T21:54:40Z I! Using config file: /etc/telegraf/telegraf.conf
2019-02-08T21:54:40Z I! Loaded inputs: inputs.mem inputs.processes inputs.swap inputs.system inputs.cpu inputs.disk inputs.diskio inpu
ts.kernel
2019-02-08T21:54:40Z I! Loaded aggregators:
2019-02-08T21:54:40Z I! Loaded processors:
2019-02-08T21:54:40Z I! Loaded outputs: influxdb
2019-02-08T21:54:40Z I! Tags enabled: host=9ab66945f415
2019-02-08T21:54:40Z I! [agent] Config: Interval:10s, Quiet:false, Hostname:"9ab66945f415", Flush Interval:10s
2019-02-08T21:54:50Z E! [inputs.system]: Error in plugin: open /var/run/utmp: no such file or directory
...
...
Steps to reproduce:
- ...
$ docker run -d --name influxdb -p 8083:8083 -p 8086:8086 influxdb - ...
$ docker run --net=container:influxdb telegraf:alpine
watch the command line output.
Expected behavior:
run without errors
Actual behavior:
2019-02-08T21:54:50Z E! [inputs.system]: Error in plugin: open /var/run/utmp: no such file or directory
Additional info:
I did dig deeper in this problem.
Alpine as being such a minimal image somehow does not provide the file, that [[inputs.system]] is looking for.
The command uptime is working.
bash-4.4# uptime
22:11:56 up 6:36, 0 users, load average: 0.44, 0.43, 0.30
I did not find a solution how to load the utmp corresponding program via apk.
So the workaround provided in other bugs #5031 has some deeper issue behind.
In my specific case I would like to use the container with alpine, without having to bind anything to the host. this behavior makes the container somehow dependent, what I would like to avoid.
[Include gist of relevant config, logs, etc.]
Based on running strace uptime, I believe uptime is using /proc/uptime and /proc/loadavg on alpine. However I cannot see how it is retrieving the users value, perhaps it is always hardcoded to 0?
The version of uptime on alpine:
# uptime -V
uptime from procps-ng UNKNOWN
I believe this is the source code:
https://gitlab.com/procps-ng/procps/blob/master/proc/whattime.c
There are 23 issues relating around this and i'm just wondering if anybody else is interested in this just having a flag to turn off "uptime" collection. Would maintainers take a merge that put in a config flag for that?
Made the PR for both n_users (which is what actually requires utmp http://man7.org/linux/man-pages/man5/utmp.5.html) and for uptime. Both of which i feel are not useful enough to keep fighting with this.
Also @evanphx the docs do say to mount /var/run/utmp:/var/run/utmp however this wont work on the mac and the latest docker CE.
Closed in #5742