Create the SPDK socket under /var/run/ceph/<fsid> and not /var/tmp

[gbregman]

Fixes #216

Notice that this works for an SPDK run from within the gateway. If SPDK is run as a stand alone container (which we don't do), the socket file would still be created in /var/tmp/

[gbregman]

@caroav , once this change is merged there will be a little change to ceph-nvmeof.conf which you might want to update the Cephadm people about. The rpc_socket attribute was deleted two new attributes were added. They are commented out in the conf file so we just use the default values:

• rpc_socket_dir
• rpc_socket_name

These are only needed if we want to change the default behavior. In case the old "rpc_socket" is still in the conf file it will be used and not the new attributes. This will maintain backward compatibility with old conf file.

[barakda]

Is the next line (in file Dockerfile.spdk) should be updated as well?
CMD [ "-u", "-r", "/var/tmp/spdk.sock" ]

[gbregman]

@barakda I saw the reference in Dockerfile.spdk but I didn't see it made any difference. I'll have another look.

[gbregman]

@barakda Dockerfile.spdk is relevant only when we run SPDK as a container. We don't do that. We start SPDK from within the gateway. When we do it we already know the Ceph FSID and can use it for the directory. As this value is dynamic we can't use it Dockerfile.spdk. So, if somehow the SPDK would be started as a container the socket file will be created in the old place, /var/tmp.