Multicast Issues

[LPS]

Hi all,

I am having trouble multicasting an image, I have looked through the forums and tried some previous advice like setting the rendezvous address and turning off IGMP snooping on my network, neither have worked. I can boot into the multicast, but it gets stop on the blue partclone screen and never serves the image. Thoughts?

[george1421]

@lps Is the target computers on the same subnet as the FOG server?

[LPS]

@george1421 The server resides over a vpn but the storage node is on the same network and subnet. Ive had it thought where the server was on the same subnet with the same results.

[george1421]

@lps Well you’ve run into a few technical issues with your current configuration.

1. FOG Multicasing uses “multicast packets”. Those are not typically forwarded between subnets or over wan links. You will need an igmp proxy to forward multicast packets from one subnet to another, as well as igmp snooping enabled.
2. Only a normal FOG server can multicast. Storage nodes don’t know how to do that.

Mutlicasting is a bit more complex than unicast imaging. But 98% of the issues are infrastructure related and not FOG specific when multicasting fails to work.

[LPS]

@george1421 Ok I will install a local copy of fog on my current subnet, but like i said before, i had it configured that way originally and it still did the same thing. I will report back once i have it completed and try it out.

[LPS]

@george1421 Ok so everything is on the local network now and im still getting the hangup on the partclone screen once its booted in. Thoughts?

[george1421]

@lps Same IP subnet for both fog server and target computers, or same site?

[LPS]

@george1421 So i have a /20 network, server is 100.185 computer was 104.xx because my subnet runs from 96.xx.xx to 111.xx.xx. Are you saying that the computer and server need to be in the same block of 255 ips?

[george1421]

@lps The fog server and target computers need to be on the same broadcast domain. So /20 network with the server on 100.xxx client was on 104.xxx they would be on the same IP subnet (with no router in between).

So if you create a multicast image on the server, pxe boot the target computer and select multicast. Can you connect to the stream? This would be before the minimum number of clients to connect. Once the minimum number of clients connect it should start imaging.

So for your rendezvous address in the fog server configuration you defined a valid class D (multicast) address?

[LPS]

@george1421 what i have in the rendezvous address is the server ip address which in this case is 10.200.100.185. Now if i specify 1 computer in the task setup to run as a test it should go correct? Also its not even registering my client if i view the task, even though the client is connected and at the blue partclone screen waiting for the image to be served. I cant figure out what is wrong here.

[george1421]

@lps The multicast stuff is a bit of black magic on how it works. I’m not 100% on multicast imaging because it just worked on my campus so I didn’t have to dig into how it was working. Also we don’t use multicast imaging except for rare special occasions.

Now with that said, I reviewed the FOG WIKI page on multicasting as well as a previous post I had on the subject. IMO There is some inaccurate text on the wiki page.

ref: https://wiki.fogproject.org/wiki/index.php/Multicasting
ref: https://forums.fogproject.org/topic/13707/multicast-off-of-bond/5

I setup a test and set these values in the multicast section of the FOG server configuration
MULTICAST ADDRESS: 192.168.23.61 (not the dev fog server IP)
MULTICAST RENDEZVOUS: 239.2.2.2

Looking at the processes running on the fog server you see how it impacts the udp-sender command.

/usr/local/sbin/udp-sender --interface ens192 --min-receivers 10 --max-wait 600 --mcast-data-address 192.168.23.61 --mcast-rdv-address 239.2.2.2 --portbase 63100 --full-duplex --ttl 32 --nokbd --nopointopoint --file /images/USNCYW10E/d1p1.img;
/usr/local/sbin/udp-sender --interface ens192 --min-receivers 10 --max-wait 10 --mcast-data-address 192.168.23.61 --mcast-rdv-address 239.2.2.2 --portbase 63100 --full-duplex --ttl 32 --nokbd --nopointopoint --file /images/USNCYW10E/d1p2.img;
/usr/local/sbin/udp-sender --interface ens192 --min-receivers 10 --max-wait 10 --mcast-data-
address 192.168.23.61 --mcast-rdv-address 239.2.2.2 --portbase 63100 --full-duplex --ttl 32 --nokbd --nopointopoint --file /images/USNCYW10E/d1p3.img;

If we look at the man page for udp-send it says the --mcast-rdv-address Uses a non-standard multicast address for the control connection So this ( MULTICAST RENDEZVOUS ) should not be the IP address of the FOG server, but either blank, where the address of 224.0.0.1 will be used or a valid Class D multicast address. Also unless you have a VERY unique situation you should not enter any value in MULTICAST ADDRESS because the FOG Server default will be used.

The RENDEZVOUS address is where the control communications happens (i.e. the target computers first meet up with the FOG server), and the MULTICAST ADDRESS is where the data is transferred from.

Finally you need to make sure that the name of the UDPCAST INTERFACE matched the actual interface name on the FOG server for the imaging network.

If you have this setup correctly then we will take the next steps.

[LPS]

@george1421 ok so i took that rendezvous address back out and then ran it and now it works! I also updated the kernel on the server to the newest one so not sure if that had anything to do with it. Thanks!

[LPS]

@george1421 Ok so next question, is there any place in the config to auto join a session i can add and change for larger deployments so i dont need to type the session name, I already eliminated the password prompt for now through the gui.

[george1421]

@lps I have not tested this out, but via some reverse engineering tricks I know I think this should get you pretty close. Just create a new FOG iPXE menu and add this in as the parameter.

chain -ar ${boot-url}/service/ipxe/boot.php?mac0=${net0/mac}&arch=${arch}&platform=${platform}&sessname=bob || goto MENU

You will need to replace bob with your session name for the multicast image push. That should join you right into the session with one pick on the fog menu.