Re: Packaging CF app as bosh-release


Paul Bakare
 

Thanks Dmitriy,

Just for clarity, are you saying multiple instances of a VM cannot share a
single shared filesystem?

On Wed, Sep 16, 2015 at 6:59 PM, Dmitriy Kalinin <dkalinin(a)pivotal.io>
wrote:

BOSH allocates a persistent disk per instance. It never shares persistent
disks between multiple instances at the same time.

If you need a shared file system, you will have to use some kind of a
release for it. It's not any different from what people do with nfs
server/client.

On Wed, Sep 16, 2015 at 7:09 AM, Amit Gupta <agupta(a)pivotal.io> wrote:

The shared file system aspect is an interesting wrinkle to the problem.
Unless you use some network layer to how you write to the shared file
system, e.g. SSHFS, I think apps will not work because they get isolated to
run in a container, they're given a chroot "jail" for their file system,
and it gets blown away whenever the app is stopped or restarted (which will
commonly happen, e.g. during a rolling deploy of the container-runner VMs).

Do you have something that currently works? How do your VMs currently
access this shared FS? I'm not sure BOSH has the abstractions for choosing
a shared, already-existing "persistent disk" to be attached to multiple
VMs. I also don't know what happens when you scale your VMs down, because
BOSH would generally destroy the associated persistent disk, but you don't
want to destroy the shared data.

Dmitriy, any idea how BOSH can work with a shared filesystem (e.g. HDFS)?

Amit

On Wed, Sep 16, 2015 at 6:54 AM, Kayode Odeyemi <dreyemi(a)gmail.com>
wrote:


On Wed, Sep 16, 2015 at 3:44 PM, Amit Gupta <agupta(a)pivotal.io> wrote:

Are the spark jobs tasks that you expect to end, or apps that you
expect to run forever?
They are tasks that run forever. The jobs are subscribers to RabbitMQ
queues that process
messages in batches.


Do your jobs need to write to the file system, or do they access a
shared/distributed file system somehow?
The jobs write to shared filesystem.


Do you need things like a static IP allocated to your jobs?
No.


Are your spark jobs serving any web traffic?
No.



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