Re: [Gluster-devel] Network Block device (NBD) on top of glusterfs

[Xiubo Li <xiubli@xxxxxxxxxx>]

On 2019/3/21 18:09, Prasanna Kalever wrote:

On Thu, Mar 21, 2019 at 9:00 AM Xiubo Li <xiubli@xxxxxxxxxx> wrote:

All,

I am one of the contributor for gluster-block[1] project, and also I contribute to linux kernel and open-iscsi project.[2]

NBD was around for some time, but in recent time, linux kernel’s Network Block Device (NBD) is enhanced and made to work with more devices and also the option to integrate with netlink is added. So, I tried to provide a glusterfs client based NBD driver recently. Please refer github issue #633[3], and good news is I have a working code, with most basic things @ nbd-runner project[4].

While this email is about announcing the project, and asking for more collaboration, I would also like to discuss more about the placement of the project itself. Currently nbd-runner project is expected to be shared by our friends at Ceph project too, to provide NBD driver for Ceph. I have personally worked with some of them closely while contributing to open-iSCSI project, and we would like to take this project to great success.

Now few questions:

1. Can I continue to use http://github.com/gluster/nbd-runner as home for this project, even if its shared by other filesystem projects?

• I personally am fine with this.

2. Should there be a separate organization for this repo?

• While it may make sense in future, for now, I am not planning to start any new thing?

It would be great if we have some consensus on this soon as nbd-runner is a new repository. If there are no concerns, I will continue to contribute to the existing repository.

Thanks Xiubo Li, for finally sending this email out. Since this email is out on gluster mailing list, I would like to take a stand from gluster community point of view *only* and share my views.

My honest answer is "If we want to maintain this within gluster org, then 80% of the effort is common/duplicate of what we did all these days with gluster-block",

The great idea came from Mike Christie days ago and the nbd-runner project's framework is initially emulated from tcmu-runner. This is why I name this project as nbd-runner, which will work for all the other Distributed Storages, such as Gluster/Ceph/Azure, as discussed with Mike before.

nbd-runner(NBD proto) and tcmu-runner(iSCSI proto) are almost the same and both are working as lower IO(READ/WRITE/...) stuff, not the management layer like ceph-iscsi-gateway and gluster-block currently do.

Currently since I only implemented the Gluster handler and also using the RPC like glusterfs and gluster-block, most of the other code (about 70%) in nbd-runner are for the NBD proto and these are very different from tcmu-runner/glusterfs/gluster-block projects, and there are many new features in NBD module that not yet supported and then there will be more different in future.

The framework coding has been done and the nbd-runner project is already stable and could already work well for me now.

like:

* rpc/socket code

* cli/daemon parser/helper logics

* gfapi util functions

* logger framework

* inotify & dyn-config threads

Yeah, these features were initially from tcmu-runner project, Mike and I coded two years ago. Currently nbd-runner also has copied them from tcmu-runner.

Very appreciated for you great ideas here Prasanna and hope nbd-runner could be more generically and successfully used in future.

BRs

Xiubo Li

* configure/Makefile/specfiles

* docsAboutGluster and etc ..

The repository gluster-block is actually a home for all the block related stuff within gluster and its designed to accommodate alike functionalities, if I was you I would have simply copied nbd-runner.c into https://github.com/gluster/gluster-block/tree/master/daemon/ just like ceph plays it here https://github.com/ceph/ceph/blob/master/src/tools/rbd_nbd/rbd-nbd.cc and be done.

Advantages of keeping nbd client within gluster-block:

-> No worry about maintenance code burdon

-> No worry about monitoring a new component

-> shipping packages to fedora/centos/rhel is handled

-> This helps improve and stabilize the current gluster-block framework

-> We can build a common CI

-> We can use reuse common test framework and etc ..

If you have an impression that gluster-block is for management, then I would really want to correct you at this point.

Some of my near future plans for gluster-block:

* Allow exporting blocks with FUSE access via fileIO backstore to improve large-file workloads, draft:  https://github.com/gluster/gluster-block/pull/58

* Accommodate kernel loopback handling for local only applications

* The same way we can accommodate nbd app/client, and IMHO this effort shouldn't take 1 or 2 days to get it merged with in gluster-block and ready for a go release.

Hope that clarifies it.

Best Regards,

--

Prasanna

 

Regards,
Xiubo Li (@lxbsz)

[1] - https://github.com/gluster/gluster-block
[2] - https://github.com/open-iscsi
[3] - https://github.com/gluster/glusterfs/issues/633
[4] - https://github.com/gluster/nbd-runner

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