feat(control): allow specifying max_namespaces on subsystem creation

[rahullepakshi]

This PR gives user a flexibility to specify maximum number of namespaces in a subsystem

Fixes #146

[trociny]

I assume you have tried it and it works as expected?

I just was surprised to see the current behaviour you reported in #146 (i.e. max_ namespaces=32 by default). Because just glancing through the spdk code it seemed to me that if the param was not specified the default would be 0, i.e. unlimited.

[rahullepakshi]

I assume you have tried it and it works as expected?

I just was surprised to see the current behaviour you reported in #146 (i.e. max_ namespaces=32 by default). Because just glancing through the spdk code it seemed to me that if the param was not specified the default would be 0, i.e. unlimited.

Yes I did try, few observations below

From GW CLI,
`
python3 -m control.cli create_subsystem -n nqn.2016-06.io.spdk:cnode15 -s SPDK15 -m 500
INFO:main:Created subsystem nqn.2016-06.io.spdk:cnode15: True

[ubuntu@clara011 ceph-nvmeof]$ python3 -m control.cli get_subsystems
INFO:main:Get subsystems:
[
{
"nqn": "nqn.2014-08.org.nvmexpress.discovery",
"subtype": "Discovery",
"listen_addresses": [],
"allow_any_host": true,
"hosts": []
},
{
"nqn": "nqn.2016-06.io.spdk:cnode8",
"subtype": "NVMe",
"listen_addresses": [],
"allow_any_host": false,
"hosts": [],
.......
......
{
"nqn": "nqn.2016-06.io.spdk:cnode15",
"subtype": "NVMe",
"listen_addresses": [],
"allow_any_host": false,
"hosts": [],
"serial_number": "SPDK15",
"model_number": "SPDK bdev Controller",
"max_namespaces": 500,
"min_cntlid": 1,
"max_cntlid": 65519,
"namespaces": []
}
]
`

From GW server,
`INFO:control.grpc:Received request to create subsystem nqn.2016-06.io.spdk:cnode15

INFO:control.grpc:create_subsystem nqn.2016-06.io.spdk:cnode15: True

DEBUG:control.state:omap_key generated: subsystem_nqn.2016-06.io.spdk:cnode15`

[idryomov]

Need to change the title of the commit to follow Conventional Commits syntax as per https://github.com/ceph/ceph-nvmeof/blob/devel/CONTRIBUTING.md#commit-format.

[idryomov]

Need to change the title of the commit to follow Conventional Commits syntax as per https://github.com/ceph/ceph-nvmeof/blob/devel/CONTRIBUTING.md#commit-format.

@rahullepakshi I see it changed but still not in accordance with https://www.conventionalcommits.org/en/v1.0.0/#summary. I have changed the title of the PR for you, please update the title of the commit to match it.

[rahullepakshi]

Need to change the title of the commit to follow Conventional Commits syntax as per https://github.com/ceph/ceph-nvmeof/blob/devel/CONTRIBUTING.md#commit-format.

@rahullepakshi I see it changed but still not in accordance with https://www.conventionalcommits.org/en/v1.0.0/#summary. I have changed the title of the PR for you, please update the title of the commit to match it.

@idryomov changed to match it. Will keep this updated going forward