We ended up implementing a solution where we did the pre/post steps as
separate mesos tasks and adding logic to our scheduler to ensure they were
run on the same machine. If anybody knows of a standard / openly available
DockerExecutor like what is described below, my team would be greatly
interested.
On Fri, Aug 7, 2015 at 4:01 AM, Kapil Malik kma...@adobe.com wrote:
Hi,
We have a similar usecase while running multi-user workloads on mesos.
Users provide docker images encapsulating application logic, which we (we =
say some “Central API”) schedule on Chronos / Marathon. However, we need to
run some standard pre / post steps for every docker submitted by users. We
have following options –
1. Ask every user to embed their logic inside a pre-defined docker
template which will perform pre/post steps.
è This is error prone, makes us dependent on whether the users followed
template, and not very popular with users either.
2. Extend every user docker (FROM ) and find a way to add
pre-post steps in our docker. Refer this docker when scheduling on chronos
/ marathon.
è Building new dockers does not scale as users and applications grow
3. Write a custom executor which will perform the pre-post steps
and manage the user docker lifetime.
è Deals with user docker lifetime and is obviously complex.
Is there a standard / openly available DockerExecutor which manages the
docker lifetime and which I can extend to build my custom executor? This
way I will be concerned only with my custom logic (pre/post steps) and
still get benefits of a standard way to manage docker containers.
Btw, thanks for the meaningful discussion below, it is very helpful.
Thanks and regards,
Kapil Malik | kma...@adobe.com | 33430 / 8800836581
*From:* James DeFelice [mailto:james.defel...@gmail.com]
*Sent:* 09 April 2015 18:12
*To:* user@mesos.apache.org
*Subject:* Re: Custom python executor with Docker
If you can run the pre/post steps in a container then I'd recommend
building a Docker image that includes your pre/post step scripting + your
algorithm and launching it using the built-in mesos Docker containerizer.
It's much simpler than managing the lifetime of the Docker container
yourself.
On Thu, Apr 9, 2015 at 8:29 AM, Tom Fordon tom.for...@gmail.com wrote:
Thanks for all the responses, I really appreciate the help. Let me try to
state my problem more clearly
Our project is performing file-based data processing. I would like to
keep the actual algorithm as contained as possible since we are in an RD
setting and will be getting untested code. We have some pre/post steps
that need to be run on the same box as the actual algorithm:
downloading/uploading files and database calls.
We can run the pre/post steps and algorithm within the same container.
The algorithm will be a little less contained, but it will work.
Docker letting you specify a cgroup parent is really exciting. If I
invoke a docker container with the executor as the cgroup-parent are there
any other steps I need to perform? Would I need to do anything special to
make mesos aware of the resource usage, or is that handled since the docker
process would be in the executors cgroup?
Thanks again,
Tom
On Tue, Apr 7, 2015 at 8:10 PM, Timothy Chen tnac...@gmail.com wrote:
Hi Tom(s),
Tom Arnfeld is right, if you want to launch your own docker container
in your custom executor you will have to handle all the issues
yourself and not able to use the Docker containerizer at all.
Alternatively, you can actually launch your custom executor in a
Docker container by Mesos, by specifying the ContainerInfo in the
ExecutorInfo.
What this means is that your custom executor is already running in a
docker container, and you can do your custom logic afterwards. This
does means you can simply just launch multiple containers in the
executor anymore.
If there is something you want to do and doesnt' fit these let us know
what you're trying to achieve and we can see what we can do.
Tim
On Tue, Apr 7, 2015 at 4:15 PM, Tom Arnfeld t...@duedil.com wrote:
It's not possible to invoke the docker containerizer from outside of
Mesos,
as far as I know.
If you persue this route, you can run into issues with orphaned
containers
as your executor may die for some unknown reason, and the container is
still
running. Recovering from this can be tricky business, so it's better if
you
can adapt your framework design to fit within the Mesos Task/Executor
pattern.
--
Tom Arnfeld
Developer // DueDil
(+44) 7525940046
25 Christopher Street, London, EC2A 2BS
On Mon, Apr 6, 2015 at 7:00 PM, Vinod Kone vinodk...@apache.org wrote:
Tim, do you want answer this?
On Wed, Apr 1, 2015 at 7:27 AM, Tom Fordon tom.for...@gmail.com
wrote:
Hi. I'm trying to understand using docker within a custom executor.
For
each of my tasks, I would like
