Journalctl should be runnable from inside the Docker container

[pbhavsar211]

Trying to run cadvisor on mac using boot2docker. mentioned issues is found while identifying docker logs cadvisor

[vmarmol]

Does cAdvisor exit? That should be a recoverable error and should only degrade what information we provide.

Is the system a systemd system btw?

[pbhavsar211]

no cAdvisor is still running. can you please explain "Is the system a systemd system?"

[vmarmol]

I guess I'm asking if you're running Systemd as your init system (I am not super familiar with what boot2docker runs). The error is benign, although we should try to get to the bottom of it and get OOM support on your specified platform.

[furlongm]

Also getting this issue on Centos 7 (with systemd on the main system, and journalctl available on the main system).

The error message is from within the cadvisor docker container and it is the only message returned by docker logs cadvisor.

Should journalctl be installed in the docker container?

[vmarmol]

Yes, although we'll need to test how systemd access works within a container. Will change the issue's title to reflect that.

[amos6224]

Also getting this issue on boot2docker even after i upgrade.

[radcheb]

+1
Getting same issue on Ubuntu 14.04 with no boot2docker.

[cgswong]

I'm on CoreOS 647.2.0 and getting the error below when running cAdvisor (Google Docker image) in a fleet/systemd unit:

Jun 09 13:55:41 stluengtst03.monsanto.com docker[22924]: I0609 13:55:41.040406 00001 manager.go:151] Version: {KernelVersion:4.0.1 ContainerOsVersion:Buildroot 2014.02 DockerVersion:1.5.0 CadvisorVersion:0.14.0}
Jun 09 13:55:41 stluengtst03.monsanto.com docker[22924]: I0609 13:55:41.137500 00001 factory.go:220] System is using systemd
Jun 09 13:55:41 stluengtst03.monsanto.com docker[22924]: I0609 13:55:41.140705 00001 factory.go:228] Registering Docker factory
Jun 09 13:55:41 stluengtst03.monsanto.com docker[22924]: I0609 13:55:41.143247 00001 factory.go:64] Registering Raw factory
Jun 09 13:55:41 stluengtst03.monsanto.com docker[22924]: I0609 13:55:41.348053 00001 manager.go:930] Started watching for new ooms in manager
Jun 09 13:55:41 stluengtst03.monsanto.com docker[22924]: E0609 13:55:41.348260 00001 manager.go:217] Failed to start OOM watcher, will not get OOM events: exec: "journalctl": executable file not found in $PATH
Jun 09 13:55:41 stluengtst03.monsanto.com docker[22924]: I0609 13:55:41.348930 00001 manager.go:230] Starting recovery of all containers
Jun 09 13:55:41 stluengtst03.monsanto.com docker[22924]: I0609 13:55:41.456439 00001 manager.go:235] Recovery completed
Jun 09 13:55:41 stluengtst03.monsanto.com docker[22924]: I0609 13:55:41.510994 00001 cadvisor.go:90] Starting cAdvisor version: "0.14.0" on port 8080

cAdvisor remains up and running.

[vmarmol]

cAdvisor degrades its OOM support in these cases (it does not record OOMs), but should otherwise function as expected.

Not sure what the right answer is here, we probably don't want to include our own journalctl in the Docker image. We may end up mounting it from the host.

[trinitronx]

Just a hint: It's probably good to gracefully degrade here, and not require journalctl because older distro versions (e.g.: CentOS / RHEL 6) do not have systemd or journalctl.

[vmarmol]

We do today, although we always assume that if systemd is present so will
journalctl. Let us know if that's not the case :)
On Jun 9, 2015 9:22 AM, "James Cuzella" notifications@github.com wrote:

Just a hint: It's probably good to gracefully degrade here, and not
require journalctl because older distro versions (e.g.: CentOS / RHEL 6)
do not have systemd or journalctl.

—
Reply to this email directly or view it on GitHub
#645 (comment).

[trinitronx]

@vmarmol: To answer your question earlier in the thread. boot2docker does not have systemd or journalctl installed. boot2docker is based on Tiny Core Linux. A quick look at this wiki page tells me that it's using the tried and true inittab / /etc/init.d / SysV-style init process. So no systemd there.

[trinitronx]

My thoughts are that this is "not a bug"... It appears that @pbhavsar211 just may have not understood that boot2docker is not using systemd as it's init system. It also is good to know that the message:

Failed to start OOM watcher, will not get OOM events: exec: "journalctl": executable file not found in $PATH

Is really just a warning and that cAdvisor gracefully degrades.

Perhaps really there is a hidden desire for a feature request here to add OOM-watcher support for old SysV-style init systems?

[rjnagal]

I think the message should not say "Failed to..." and not be an error :)

The message should make clear that we are degraded gracefully. I'll add a
fix.

On Tue, Jun 9, 2015 at 9:35 AM, James Cuzella notifications@github.com
wrote:

My thoughts are that this is "not a bug"... It appears that @pbhavsar211
https://github.com/pbhavsar211 just may have not understood that
boot2docker is not using systemd as it's init system. It also is good to
know that the message:

Failed to start OOM watcher, will not get OOM events: exec: "journalctl":
executable file not found in $PATH

Is really just a warning and that cAdvisor gracefully degrades.

Perhaps really there is a hidden desire for a feature request here to add
OOM-watcher support for old SysV-style init systems?

—
Reply to this email directly or view it on GitHub
#645 (comment).