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computing:virtmanagerhell [2022/08/08 06:41] – oemb1905computing:virtmanagerhell [2022/08/08 20:13] – oemb1905
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-Alright, I am completely re-writing this as the old notes were just out of date and incomplete.  The title of this is virt-manager hell because virt-manager used to be a pain in the ass for me, but I now love it.  Regardless, the name is staying the same.  At any rate, this tutorial is for Debian based users who have physical hosts using an external IP (either self-hosted or VPS/data center), and want to allocate some other external IPs in their block to public-facing VMs.  Every step except for one is command-line based, for ease, stability, and understanding - and I am not using network-manager or dhcpd at all.  In my case, I am using a SuperMicro host which has 5 ethernet ports, including two which have IPMI functionality.  In my case, I decided to allocate two external IPs to the physical host so in case I tinker with bridge settings (on the other interface), then I don't lose shell access to the box or have to hassle the Data Center for KVM egcy connection, etc.  On ent8s0g0 I configured the base connection, and on ent8s0g1 I configured the bridge as follows: +This is all very old fyi and not current or helpful; might delete it soon. Resize an .img with virt-manager, for example, expanding a 64GB disk to a 124GB disk.  Start by installing the optional tools for this:
- +
-  sudo nano /etc/network/interfaces +
- +
-That file should look like this (adjust to your use-case, ofc): +
-   +
-  #eth0 (alt name ent8s0g) physical host base-connection +
-  auto ent8s0g0 +
-  iface ent8s0f0 inet static +
-        address 8.25.76.160 +
-        netmask 255.255.255.0 +
-        gateway 8.25.76.1 +
-        nameserver 8.8.8.8 +
-  #eth1 (alt name enp8s0g1) interface for bridge +
-  auto enp8s0g1 +
-  iface enp8s0g1 inet manual +
-  auto br0 +
-  iface br0 inet static +
-        address 8.25.76.159 +
-        netmask 255.255.255.0 +
-        gateway 8.25.76.1 +
-        bridge_ports enp8s0g1 +
-        nameserver 8.8.8.8 +
- +
-Once that's done, run ''ip a'' to make sure your primary interface connects upstream to the Data Center, and also make sure that the interface ''br0'' appears at the bottom and that the secondary interface shows it as bound to the bridge in its output.  Sometimes, I find that nameservers don't properly populate to resolv.conf, so I do the following so that my ''resolv.conf'' configurations stick and I don't lose upstream DNS. (Note: I do this because Debian - rightfully - still supports manual over-writing of /etc/resolv.conf.) +
- +
-  echo nameserver 8.8.8.8 > /etc/resolv.conf +
-   +
-Reboot the host and ping 8.8.8.8 and google.com to ensure you have link and upstream DNS.  Next up, it is time to configure the guest / VM machine.  I saw a lot of good tutorials online, but most of them got sloppy at this stage as far as interfaces and bridging was concerned, so I'll try to be clear where they were not.  When you set up the new VM (not covered here), instead of relying on the NAT-based default network, change the option to "Bridge" (this is in the virt-manager GUI) and enter the name of the bridge, in my case ''br0''.  (You can also use ''virsh'' for this step, but why lol - I just use X forwarding and open the GUI.)  This step connects the hypervisor NIC to the virtual switch of the bridge on the physical host.  Once that's done, spin up the VM and open up the Terminal (the one **inside** the VM).  In the VM's Terminal, configure the NIC interface as follows: +
- +
-  sudo nano /etc/network/interfaces +
- +
-This file should look like this (adjust to your use-case - and again, this is **inside the VM** Terminal, and __not__ on the Terminal of the physical host): +
- +
-  auto epr1 +
-  iface epr1 inet static +
-    address 8.25.76.158 +
-    netmask 255.255.255.0 +
-    gateway 8.25.76.1 +
-    nameservers 8.8.8.8 +
- +
-The VM interface is listed inside the guest/VM as epr1 - but remember, that's connected to the virtual switch and bridge through the previous steps, so don't worry.  After this step, restart the networking service and check to see if your IP address is assigned.  Also, in my use-case my VM is Ubuntu which does not allow manual over-writing of resolv.conf, so I also add upstream DNS as follows: +
- +
-  sudo service networking restart +
-  ip a +
-  sudo apt install resolvconf +
-  sudo nano /etc/resolvconf/resolv.conf.d/tail +
-   +
-Enter the name server as follows: +
-   +
-  nameserver 8.8.8.8 +
- +
-At this point, I would probably reboot and then from within the VM, ping 8.8.8.8, and then ping google.com to ensure you have link and upstream DNS.  Everything should be rosy ;>.  Some folks might be concerned about ARP and such, but virt-manager handles that with the gateway entry combined with the bridge, so no need to alter proc and pass traffic, etc.  Of course, replace Google's DNS if you so choose, but I had reliability problems with Level 3 during testing myself (sad). +
- +
--- Below, are notes from when I shrunk an .img file / expanded an .img file (cannot remember lol) -- +
- +
-Resize an .img with virt-manager, for example, expanding a 64GB disk to a 124GB disk.  Start by installing the optional tools for this:+
      
   sudo apt install libguestfs-tools   sudo apt install libguestfs-tools
computing/virtmanagerhell.txt · Last modified: 2023/01/15 17:47 by oemb1905

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