HELP Problem DHCP - Ubuntu 18.04


  • Olá,

    Meu Servidor FOG está anunciando DHCP na rede, causando problemas em alguns computadores.

    Tentei desabilitar o serviço de DHCP no ubuntu (Servidor FOG) e não consegui mais encontrar o servidor via boot PXE !

    é possível fazer algo sem a necessidade de reinstalar o FOG?


  • @george1421
    Boa Noite,

    Eu olhei o link que você enviou e acredito que entendi a teoria, você tem ou conhece algum tutorial ou vídeo explicativo em funcionamento ?

  • Moderator

    @ultralivre said in HELP Problem DHCP - Ubuntu 18.04:

    Muito bem, você consegue me dar um exemplo de como utilizar o cliente multicast ?

    https://wiki.fogproject.org/wiki/index.php/Multicasting


  • @george1421
    Muito bem, você consegue me dar um exemplo de como utilizar o cliente multicast ?

  • Moderator

    @ultralivre I’ve never really looked at ram usage during a single unicast deployment to know how many you can send at one time for a limit.

    I have done testing with how many unicast images can I send at one time without impacting performance of the 1GbE network connection. The answer is 3. Above 3 you can saturate a 1GbE network connection.

    How much ram do you have in your fog server?

    There is another method to deploy many computers at one time with FOG its called multicast imaging. This method configures the target computer with a receiver program and then FOG server sends out a single image to all computers running the receiver program. This method you can image 25 computers using no more fog server resources than a single unicast image. The multicast deployments require more configuration on the network side and all target computers must be on the same IP subnet as the FOG server.


  • @george1421

    Bom dia,

    Perfeito 😃

    Vou aproveitar o contato e perguntar:

    Tenho muitos computadores e pouca memória ram no meu servidor fog, porém gostaria de colocar todos ao mesmo tempo mas que o servidor fog fosse administrando a clonagem, de 5 em 5 ou de 4 em 4, para não sobrecarregar o meu servidor físico. É possível ?

    Obrigado 😃

  • Moderator

    @ultralivre Yes you are still running on the old FOS linux kernel and that is causing the error message you see.

    When you select the buttons for 5.15.71 (or whatever version) it should download and install in FOG.

    If the auto update is not working for you, then you can get the kernels from here: https://github.com/FOGProject/fos/releases

    They need to be renamed as bzImage and bzImage32 and placed in the following directory on the fog server. /var/www/html/fog/service/ipxe directory. You can also run this command to verify the version of the kernel from the FOG server’s linux command prompt file bzImage it will print the kernel version.


  • @george1421
    Bom dia,
    Executei a atualização do kernel, porém fiquei na duvida se: a atualização precisar aparecer no fog?

    fog04.png
    fog01.png

    Como pode ver eu atualizei mas continua aparecendo a versão 4.19.145

    Esta certo?

  • Moderator

    @ultralivre If you make a new FOG server then be sure to update the FOS Linux kernel to 5.15.x version. FOG Web UI -> FOG Configuration -> Kernel update.


  • @george1421
    Boa noite !

    Recentemente recebi uma quantidade grande de equipamentos da Dell optplex 5000 e ao tentar utilizar o servidor FOG recebi a seguinte mensagem:

    photo_2022-09-14_21-40-08.jpg

  • Moderator

    @ultralivre said in HELP Problem DHCP - Ubuntu 18.04:

    Você consegue mostrar o que são estes metadados?

    Anything stored in the FOG database. From the web ui you can export and import this metadata.

    image_export.png


  • @george1421

    Você consegue mostrar o que são estes metadados?

  • Moderator

    @ultralivre Yes its possible.

    There are two parts

    1. Raw data stored in /images/<image_name> directory
    2. Meta data that is stored in the database. You can export this info using the web ui

    Move the /images files to your new server
    Export the metadata from old server then import into new server all using the web ui.


  • @george1421

    Boa tarde,

    Trocando de assunto !

    É possível movimentar imagens criadas em diferentes servidores FOG ?

  • Moderator

    @ultralivre FOG doesn’t use or interact with dhcp directly. The PXE booting client computer uses dhcp to get its IP address and the hint how to find the FOG server. This is via dhcp options 66 and 67. The client computer then connects to the fog server using the tftp protocol to download the network boot loader (iPXE). That is where the FOG server firsts connects to the workflow.


  • @george1421 Boa noite !
    A aplicação FOG funciona na rede através do protocolo DHCP?
    cliente vs servidor trocam informações primeiramente com DHCP?

    Estou tentando procurar a documentação para descobrir como o FOG funciona.

    Obrigado.

  • Moderator

    @ultralivre I’m not sure I understand 100% of what you said. I can tell you that FOG will image correctly on a fully routable network with vlans. For DNSMASQ to work across VLANs, you need to update your subnet router and put the FOG’s IP address as the last server in the dhcp-helper/dhcp-relay service on your router. Then you can image across the subnets.

    Now there are reasons to turn this option on and reasons to keep fog imaging isolated. You make the settings that work best for your company.


  • @george1421

    Boa noite !!

    Servidor FOG a todo vapor por aqui 😃
    Uma duvida, Criando uma Vlan roteavel isolada somente para o FOG o servidor PXE irá funcionar?

    A duvida é por que vao estar em dominios de broadcast diferentes !

  • Moderator

    @ultralivre How it works, easy and hard to explain.

    DNSMASQ in this configuration is setup to function as proxydhcp configuration. It will not give out IP address only pxe booting information. If you put a computer with wireshark on same subnet as fog server (to watch the communications). Set the capture filter to port 67 or port 68 or port 4011 You will see what is called the DORA process for dhcp (DISCOVER, OFFER, REQUEST, ACK == DORA)

    PXE booting computer sends out DISCOVER packet. Every DHCP server that hears the DISCOVER will then send an OFFER. Wireshark will show two offers with dnsmasq is running. One will be from your main dhcp server and second from dnsmasq with dhcp option 60 set. This is a flag for a proxydhcp OFFER. PXE client knows to ask for IP address from real dhcp server then asks proxydhcp (dnsmasq) for pxe boot info after the ACK packet.

    OK your version of dnsmasq is good. The configuration will support both bios and uefi computers pxe booting.


  • @george1421

    gnuuser@gnuuser:~$ sudo dnsmasq -v
    Dnsmasq version 2.79  Copyright (c) 2000-2018 Simon Kelley
    Compile time options: IPv6 GNU-getopt DBus i18n IDN DHCP DHCPv6 no-Lua TFTP conntrack ipset auth nettlehash DNSSEC loop-detect inotify
    
    This software comes with ABSOLUTELY NO WARRANTY.
    Dnsmasq is free software, and you are welcome to redistribute it
    under the terms of the GNU General Public License, version 2 or 3.
    gnuuser@gnuuser:~$
    
    

    Fiz toda configuração do dnsmasq conforme o seu artigo, reiniciei meu server FOG tudo certo ! vou aguardar mais alguns testes, a principio tudo funcionando 😃

    Você poderia explicar um pouco mais detalhado o que faz o dnsmasq nesse caso ?

    Obrigado !

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