after write multipath.conf, reconfigure or reload is not working.

[HHHSong]

Hi:
I used function write_to_multipathd_conf() to update the multipath.conf. and then use 'multipathd -k'reconfigure'' or 'multipathd -k'reload'' update the multipathd, but the multipath.conf is not immediately working.
so I sleep 2s after write_to_multipatd_config() , the multipath.conf is working . is this a problem?

I think
def write_to_multipathd_conf(self, value, filepath=DEFAULT_CONF_FILE): """ save configuration to multipathd.conf file in order for the configuration to take affect, call reload() """ from ..config import Configuration assert isinstance(value, Configuration) with open(filepath, 'w') as fd: fd.write(value.to_multipathd_conf())

  After write, only write the data to the kernel buffer, but not to the disk.  so  we need  flush the kernel buffer to the disk .  used  fd.flush()  after write,  is that ok?

[wiggin15]

Since we're using "with open ..." in write_to_multipathd_conf, the file is closed after writing so it should already be flushed there. I don't think adding another "flush" will have any effect. I'm not aware of a problem where the configuration doesn't take effect fast enough that "sleep" should fix. Maybe something else can explain what you're experiencing?

[HHHSong]

Sorry， I was wrong , the function write_to_multipathd_conf() is no problem, it can write to multipath.conf immediately, the problem is used ' multipathd reconfigure ' is not working , It seems that 'multipathd reconfigure' need time to take affect. I used function rescan() can use to reload, is that right?

[wiggin15]

Hi @HHHSong . From what we remember, the refresh could be asynchronous and take time to take effect - it might depends on the operating system and version of multipath-tools. We don't remember for sure.

What we do when we want to detect specific changes in the storage stack, is use infi.storagemodel to do a full rescan of the stack, and write a "predicate" that makes sure the changes are applied. The predicate is a class that you can write to detect the changes you expect (e.g. a new multipath device appears). The rescan function will retry the rescan until the predicate returns True, or until a certain timeout expires.
See function rescan_and_wait_for: https://github.com/Infinidat/infi.storagemodel/blob/develop/src/infi/storagemodel/base/__init__.py#L83
and examples of predicates:
https://github.com/Infinidat/infi.storagemodel/blob/develop/src/infi/storagemodel/predicates/__init__.py

I hope this helps.