I just tried using smaller value of subbuf size, and it works fine. I have 16GB of memory in my host, so I should have more than enough memory. The same size works fine in my host machine. My Docker container does not have any resource constraint. Do you know what could be the reason of the failure?

Thanks.

---

From: jeremie.galarneau@gmail.com <jeremie.galarneau@gmail.com> on behalf of Jérémie Galarneau <jeremie.galarneau@efficios.com>
Sent: Monday, April 10, 2017 12:26 PM

To: Jeffrey Chen
Cc: lttng-dev@lists.lttng.org
Subject: Re: [lttng-dev] LTTng on Docker

 

On 10 April 2017 at 14:06, Jeffrey Chen <cpthk@live.com> wrote:

I have attached the logs from the lttng daemon. I could see errors like below.

Error: Error creating UST channel "channel0" on the consumer daemon

My commands to create a session are:

lttng create test
lttng enable-channel --session test --userspace --tracefile-size 8388608 --subbuf-size 8388608 channel0
lttng enable-event --channel channel0 --userspace "service:*"
lttng add-context -u -t vtid
lttng add-context -u -t vpid
lttng start

Thanks for the info. Can you try to create the channel with the default values and see if it works?

$ lttng enable-channel --session test --userspace channel0

 

Also, can you re-capture the session daemon logs launching it with the "-vvv --verbose-consumer" option since the problem appears to occur on the consumer's end.

Thanks,

Jérémie

Installed:
apt-get -y install lttng-tools lttng-modules-dkms liblttng-ust0 liblttng-ust-dev

Thanks.

---

From: jeremie.galarneau@gmail.com <jeremie.galarneau@gmail.com> on behalf of Jérémie Galarneau <jeremie.galarneau@efficios.com>
Sent: Sunday, April 9, 2017 2:06 PM
To: Jeffrey Chen
Cc: lttng-dev@lists.lttng.org
Subject: Re: [lttng-dev] LTTng on Docker

 

On 7 April 2017 at 18:35, Jeffrey Chen <cpthk@live.com> wrote:
> Hi:
>
>
> I am trying to have LTTng UST tracing inside a docker container. I wasn't
> able to get the UST tracing working. LTTng would not write any UST trace
> files in the directory, even though it printed it would. Has it been tested
> before? Is there any known problem?

Tracing inside a container (not Docker), where the LTTng daemons and
the applications are running in the same container, is known to work
as this is how most of the LTTng CI works.

As far as Docker is concerned, I tested it a number of times and it
worked. Can you provide the versions of LTTng and Docker you're using
and the session daemon's logs (launching it with the -vvv option)?

Thanks,
Jérémie

>
>
> $ lttng enable-channel --session test --userspace channel0
>
> Error: Channel channel0: UST create channel failed (session ServiceFabric_0)
> Error: Command error
>
>
> Thanks.
>
>
>
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--
Jérémie Galarneau
EfficiOS Inc.
http://www.efficios.com

EfficiOS www.efficios.com At EfficiOS, our main goal is diminishing the amount of time our clients spend identifying faults. We also enable our clients' applications to scale on massive multi ...

--

Jérémie Galarneau
EfficiOS Inc.
http://www.efficios.com