Wiki errors - "Troubleshooting a multicast"

  • Senior Developer

    @3mu Thanks, updated the wiki.

  • Moderator

    @3mu said in Wiki errors - "Troubleshooting a multicast":

    I’m not saying this is the issue, but I would remove any special characters out of the file name. While the dot is a legal characters for both http and linux, I would still remove that out of the name. The simplest way is to go into the linux console on the fog server and use the mv command something like mv /images/T500Linux19.10desktopclean /images/T500Linux19-10desktopclean then go into the web ui and image definition and update it there.

    How many systems are you going to image at one time? A single subnet is good. That eliminates a lot of the issues. Its possible that unmanaged switch will cause us a problem (not being fast enough to send the data out to multiple ports at the same time). We can do some debugging by putting the target computer into debug mode then load udp-receiver and then issue the udp-sender command from the fog server.

    I also noticed that you need to FIX your interface settings in the fog configuration->FOG Settings page. Your interface is dev that’s not right. You need to get the network name of the ethernet interface. You can get the interface name with ip addr show.

    # This is wrong >> dev <<
    /usr/local/sbin/udp-sender --interface >> dev << --min-receivers 2 --max-wait 600 --portbase 60328

    Depending on the network adapter it should be something like ens192 or eth0 You will find this under FOG Configuration->FOG Settings->Multicast Settings->UDPCAST INTERFACE

  • @george1421 - I only have a single unmanaged switch and a basic broadband router, so any multicast traffic will be treated as a broadcast (I’m planning to use FOG to maintain PCs for Scouts, Guides and the other groups that I’m involved with, so this is being done as cheap as possible). All machines are on the same L2 network.

    I have successfully completed the “Testing 1 client” and “Testing 2 client” tests, and started a multicast session a few minutes ago with two computers joining, but I don’t think that the image is actually being deployed. All that I get in the log is

    [04-06-20 11:52:39 pm] | Task ID: 6 Name: Multi-Cast Task - Multicast t500 image file found, file: /images/T500Linux19.10desktopclean
    [04-06-20 11:52:39 pm] | Task ID: 6 Name: Multi-Cast Task - Multicast t500 2 clients found
    [04-06-20 11:52:39 pm] | Task ID: 6 Name: Multi-Cast Task - Multicast t500 sending on base port 60328
    [04-06-20 11:52:39 pm] | Command: /usr/local/sbin/udp-sender --interface dev --min-receivers 2 --max-wait 600 --portbase 60328 --full-duplex --ttl 32 --nokbd --nopointopoint --file /images/T500Linux19.10desktopclean/d1p1.img;
    [04-06-20 11:52:39 pm] | Task ID: 6 Name: Multi-Cast Task - Multicast t500 has started

    every 10 seconds. I’m too tired to continue now, so will have another crack tomorrow and post in the technical section - this post was just to save some time for anyone else who needs to troubleshoot.


  • Another helpful addition - the “Something else to try” section has

    gunzip -c "/images/anyimagename/file"

    The -S switch is helpful here, as the default extension for image files isn’t the .gz that gunzip expects:

    gunzip  -S ".img" -c "/images/anyimagename/file"

  • Moderator

    Multicasting is a beast upon its own. With that said, 50% of the issues are related to network infrastructure and the rest with FOG.

    So for your network, do you have igmp snooping turned on for the VLAN(S) where your FOG server is as well as target computers?

    Is the FOG server and target computers on the same subnet?

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