On Mon, Feb 12, 2018 at 8:25 PM, David Disseldorp <ddiss@xxxxxxx> wrote:
> Hi,
>
> I've been working on having Samba's smbd daemon register itself with the
> Ceph Cluster via rados_service_register(), and would appreciate some
> input on what to include in the instance and metadata descriptors.
>
> The attached patch implements basic Samba service registration
> functionality, but only uses a $hostname:smbd string for the instance
> and doesn't add any extra metadata (see [1] as a sample service dump).
Just as a heads up, after making tcmu-runner and rbd-mirror daemon
both register as service daemons, I found that using a hostname wasn't
the best technique since you really need to ensure a unique name or
else the last registered service daemon will clobber the previously
registered daemon. Since the initial implementation, I now include the
global instance id from RADOS in the service name to guarantee
uniqueness (especially since the hostname is already automatically
included in the metadata).
> I'd like to (at the very least) pack the CephFS backed share names and
> paths into the service registration. For this, I'm leaning towards
> adding the share name as an instance suffix (i.e.
> $hostname:smbd:$share), with a separate registration for each share.
> Each share could then include the CephFS path as instance specific
> metadata. That still leaves me with a few questions:
> - does it make sense to only register shares which are backed by CephFS?
> + consider a server with local and CephFS shares, or worse still,
> shared printers
> + what about a Samba service without any shares?
> - I'd be using a single RADOS cluster connection to register all
> shares. Can these services can be deregistered individually in case of
> share removal, or are separate cluster connections required?
Currently you can only register a single service per (mgr) connection.
When I added the hooks to tcmu-runner and rbd-mirror daemons, I just
used the service status [1] to populate any data that would be
dynamically changing.
> + a rados_service_deregister() hook would be useful
>
> Cheers, David
>
> 1. Sample Samba smbd service dump with shares ignored
>
>> ceph service dump
> {
> "epoch": 2,
> "modified": "2018-02-13 01:53:09.263133",
> "services": {
> "samba": {
> "daemons": {
> "summary": "",
> "rapido1:smbd": {
> "start_epoch": 2,
> "start_stamp": "2018-02-13 01:53:08.112102",
> "gid": 4131,
> "addr": "192.168.124.104:0/1984347853",
> "metadata": {
> "arch": "x86_64",
> "ceph_version": "ceph version 12.2.1-387-g313479ab90 (313479ab90915289fa4905822d1f4825d1bf1e7c) luminous (stable)",
> "cpu": "QEMU Virtual CPU version 2.5+",
> "distro": "dracut",
> "distro_description": "openSUSE Leap 42.3 dracut-044-29.1 (Initramfs)",
> "distro_version": "044-29.1",
> "hostname": "rapido1",
> "kernel_description": "#21 SMP Tue Feb 13 01:05:27 CET 2018",
> "kernel_version": "4.4.115+",
> "mem_swap_kb": "0",
> "mem_total_kb": "1022828",
> "os": "Linux"
> }
> }
> }
> }
> }
> }
>
[1] https://github.com/ceph/ceph/blob/master/src/tools/rbd_mirror/ServiceDaemon.cc#L241
--
Jason
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