Multitasking - Not All Clients Start Tasking

[Tom Elliott]

Are you on the working branch? Can you show us the /var/log/fog/multicast.log file?

[Joe Gill]

@tom-elliott
Yes I am on the working branch. I’ll post the log file here shortly.

[Joe Gill]

@Tom-Elliott

The last line repeats until it finished.

If you would like the entire log file I can post it.

[Tom Elliott]

@joe-gill So you’re saying some machines work fine, not all of them though?

[Tom Elliott]

Sorry for reasking the questions you’ve already answered, just trying to understand the whole situation.

[Tom Elliott]

I’m assuming, for the log you posted, there were only 27 hosts in that group that needed the tasking?

[Joe Gill]

@tom-elliott

That is correct.

Some machines start multitasking like normal and others sit on the Partclone screen. All of them make it to the Partclone screen at the same time.

[Tom Elliott]

So chatting with @Joe-Gill We narrowed down what the problem.

First, the backstory.

So Multicast tasks would work for some machines, but not all. And, to add to that, it was always the same machines that failed to work. If the machines that failed were subsequently put into their own group, they would multicast without issue.

This lead me to ask if the machines that would fail were on a different switch from the rest of the machines, and indeed @Joe-Gill found out that this was the case. They are using Meraki switches and they replaced a few of them. Those that were replaced do not work fluidly with the older switches in place.

@Joe-Gill keep me truthful here, but this is the gist of this information.

[george1421]

@tom-elliott Also be aware in another thread we had to make some changes to the www.conf file (adding the memory limit of 256MB). He also had 3 versions of php and php-fpm installed. When I left the session (a few days ago) he had no more than 6 active php-fpm worker threads for 24 hosts in a multicast. Memory and CPU usage looked good, but understand I was only focused on why php-fpm was behaving so badly on his system.

@Joe-Gill Check to see if igmp snooping is turned on, for your network switches. That will allow the switches to handle multicast traffic a bit more intelligently.

[Joe Gill]

@tom-elliott

That is excactly correct. I am reaching out to our vendor to find out if their are any known issues here. I will post back for others to know.

For the record we are using Meraki MS225-48FP and Meraki MS42P.

Thanks for helping be troubleshoot this @Tom-Elliott .

[Joe Gill]

@george1421 Thanks! I’ll check it out.

[Joe Gill]

@george1421
IGMP snooping is enabled.

[george1421]

@joe-gill said in Multitasking - Not All Clients Start Tasking:

@george1421
IGMP snooping is enabled.

For all switches (even meraki), on the vlan where the machines are multicasting?

[Joe Gill]

@george1421
It is set like that for the default stack.

[Joe Gill]

@george1421
The only switches we have on campus now are Meraki or dumb switches. Most things are on Meraki’s. The vendor turned “port flooding” off. I’m going to check but I believe I’ll still have the issue. I do not think that’s it. I’ll post back as soon as I know.

[Joe Gill]

@george1421
@Tom-Elliott

To update this issue… I had a network engineer look at this issue. He determined that we had our multicast setting set to flood all ports. So far disabling this has fixed the majority of our multicasting issues.

One thing we did notice is that we had one old switch going to one of our labs that seems to fail on multicast and not unicast. Multicast works everywhere else with that image. We will be replacing that switch at some point but I believe that switch is the culprit. It’s an older 10/100 “dumb” HP switch (commercial grade).

So far I have not experienced any other issues with that version of FOG.

Thanks again for all the help!

[george1421]

@joe-gill Well in a way I’m glad this issue was a FOG specific one, but rather an infrastructure. I can say multicasting is a bit of a fickle beast no matter what imaging technology you are using. When it works, its great.

It sounds like your network was configured for dense mode multicasting where it would just send the mutlicast stream to all ports even if there were no multicast subscribers.

Thank you for providing solid feedback and sticking with this issue until it is resolved.