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    Help me understand KVM Networking

    Scheduled Pinned Locked Moved Unsolved IT Discussion
    kvmnetworkingsetuphelpfedorafedora 27cockpit
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    • JaredBuschJ
      JaredBusch @black3dynamite
      last edited by

      @black3dynamite said in Help me understand KVM Networking:

      Have you already check out this site about bridge?
      https://fedoramagazine.org/build-network-bridge-fedora/

      I do not have any issues creating a bridge. CLI or Cockpit GUI. I am trying to use it

      1 Reply Last reply Reply Quote 0
      • JaredBuschJ
        JaredBusch
        last edited by

        When I delete the bridge, and then select this configuration:

        0_1514477363096_123a560f-667f-4b25-b980-e1b45c97951b-image.png

        The VM immediately pulls an IP.
        0_1514489366662_96a03896-e698-4602-adbe-fc1adde999fe-image.png

        1 Reply Last reply Reply Quote 0
        • stacksofplatesS
          stacksofplates
          last edited by

          I’ve never done it through Cockpit. I’ve always used either nmcli or nmtui to create everything. What do your ifcfg files look like for those interfaces?

          JaredBuschJ 1 Reply Last reply Reply Quote 1
          • stacksofplatesS
            stacksofplates
            last edited by

            I also usually just use macvtap. If I need host to guest communication I just set up a private network for them to communicate on.

            JaredBuschJ 2 Replies Last reply Reply Quote 1
            • JaredBuschJ
              JaredBusch @stacksofplates
              last edited by

              @stacksofplates said in Help me understand KVM Networking:

              I also usually just use macvtap. If I need host to guest communication I just set up a private network for them to communicate on.

              Well, I cannot think of a reason to require host to guest communication, except that I may want to connect from a guest to the host to update the ISO store I use occasionally.

              stacksofplatesS 1 Reply Last reply Reply Quote 1
              • JaredBuschJ
                JaredBusch @stacksofplates
                last edited by

                @stacksofplates said in Help me understand KVM Networking:

                I’ve never done it through Cockpit. I’ve always used either nmcli or nmtui to create everything. What do your ifcfg files look like for those interfaces?

                As I had removed it to test the macvtap, i had to recreate it. I did it with nmcli this time.

                jbusch@dt-jared ~]$ ssh 10.254.103.5
                Last login: Thu Dec 28 00:05:54 2017 from 10.254.103.200
                [jbusch@kvm ~]$ su -
                Password: 
                [root@kvm ~]# nmcli connection add ifname bridge0 type bridge con-name bridge0
                Connection 'bridge0' (0febbbde-8d06-475a-a21b-a88ebdf006d8) successfully added.
                [root@kvm ~]# nmcli connection add type bridge-slave ifname team0 master bridge0
                Connection 'bridge-slave-team0' (d44dd210-92d7-4337-b4dd-66afbd048370) successfully added.
                [root@kvm ~]# nmcli connection modify bridge0 bridge.stp no
                [root@kvm ~]# 
                
                1 Reply Last reply Reply Quote 0
                • stacksofplatesS
                  stacksofplates
                  last edited by

                  Do the guests have network access if you give them a static address?

                  JaredBuschJ 1 Reply Last reply Reply Quote 1
                  • stacksofplatesS
                    stacksofplates @JaredBusch
                    last edited by

                    @jaredbusch said in Help me understand KVM Networking:

                    @stacksofplates said in Help me understand KVM Networking:

                    I also usually just use macvtap. If I need host to guest communication I just set up a private network for them to communicate on.

                    Well, I cannot think of a reason to require host to guest communication, except that I may want to connect from a guest to the host to update the ISO store I use occasionally.

                    Ya that's really the only advantage to a full bridge.

                    JaredBuschJ 1 Reply Last reply Reply Quote 1
                    • JaredBuschJ
                      JaredBusch @stacksofplates
                      last edited by JaredBusch

                      @stacksofplates said in Help me understand KVM Networking:

                      @jaredbusch said in Help me understand KVM Networking:

                      @stacksofplates said in Help me understand KVM Networking:

                      I also usually just use macvtap. If I need host to guest communication I just set up a private network for them to communicate on.

                      Well, I cannot think of a reason to require host to guest communication, except that I may want to connect from a guest to the host to update the ISO store I use occasionally.

                      Ya that's really the only advantage to a full bridge.

                      And for my lab, colo, and most clients, I do not see that ever being an issue.

                      But I do have one specific client that will have a stand alone RHEL 7 box running KVM on a remote site. It will be running a single VM. I will have easy access to the VM, but not the host, because of "reasons" that have nothing to do with IT.

                      stacksofplatesS ObsolesceO 2 Replies Last reply Reply Quote 1
                      • JaredBuschJ
                        JaredBusch
                        last edited by

                        [root@kvm ~]# nmcli connection show
                        NAME                UUID                                  TYPE            DEVICE   
                        Wired connection 1  5371d5ee-0c26-3e5a-ae0d-6d3683d7d584  802-3-ethernet  enp1s0f0 
                        Wired connection 2  a2977c44-7e0a-3f9d-8ecc-74e222e150a9  802-3-ethernet  enp1s0f1 
                        bridge0             0febbbde-8d06-475a-a21b-a88ebdf006d8  bridge          bridge0  
                        eno1                3a2e709f-49c8-3ac8-aa99-aab4d616e650  802-3-ethernet  eno1     
                        team0               74aa71fe-e149-49e9-94ce-ab4a22a319e4  team            team0    
                        virbr0              0df1e6b8-e9e2-4538-a581-0f1c727495c4  bridge          virbr0   
                        bridge-slave-team0  d44dd210-92d7-4337-b4dd-66afbd048370  802-3-ethernet  --       
                        [root@kvm ~]# 
                        
                        1 Reply Last reply Reply Quote 0
                        • JaredBuschJ
                          JaredBusch @stacksofplates
                          last edited by

                          @stacksofplates said in Help me understand KVM Networking:

                          Do the guests have network access if you give them a static address?

                          I will try that.

                          1 Reply Last reply Reply Quote 0
                          • stacksofplatesS
                            stacksofplates @JaredBusch
                            last edited by stacksofplates

                            @jaredbusch said in Help me understand KVM Networking:

                            @stacksofplates said in Help me understand KVM Networking:

                            @jaredbusch said in Help me understand KVM Networking:

                            @stacksofplates said in Help me understand KVM Networking:

                            I also usually just use macvtap. If I need host to guest communication I just set up a private network for them to communicate on.

                            Well, I cannot think of a reason to require host to guest communication, except that I may want to connect from a guest to the host to update the ISO store I use occasionally.

                            Ya that's really the only advantage to a full bridge.

                            And for my lab, colo, and most clients, I do not see that ever being an issue.

                            But I do have one specific client that will have a stand alone RHEL 7 box running KVM on a remote site. It will be running a single VM. I will have easy access to the VM, but not the host, because of "reasons" that have nothing to do with IT.

                            Ah ic. I really wish there was an easy way to get ovs installed on RHEL 7/CentOS 7.

                            1 Reply Last reply Reply Quote 0
                            • JaredBuschJ
                              JaredBusch
                              last edited by

                              So working, but lots of packet loss for a while.

                              0_1514491104806_d57c0e5a-bcbf-4512-8d41-507781e19336-image.png

                              It seems solid now.
                              0_1514491185933_152af0bb-9c5e-4e27-bc15-f61046d98734-image.png

                              Nevermind.. while it was trying to communicate out to get the base repo info, the pings failed. Once that timed out, the pings worked. Just tried it a couple times...

                              1 Reply Last reply Reply Quote 0
                              • JaredBuschJ
                                JaredBusch @stacksofplates
                                last edited by

                                @stacksofplates said in Help me understand KVM Networking:

                                I also usually just use macvtap. If I need host to guest communication I just set up a private network for them to communicate on.

                                So how do you setup a private connection?

                                I have no issues with using macvtap on the team.

                                stacksofplatesS 1 Reply Last reply Reply Quote 0
                                • stacksofplatesS
                                  stacksofplates @JaredBusch
                                  last edited by

                                  @jaredbusch said in Help me understand KVM Networking:

                                  @stacksofplates said in Help me understand KVM Networking:

                                  I also usually just use macvtap. If I need host to guest communication I just set up a private network for them to communicate on.

                                  So how do you setup a private connection?

                                  I have no issues with using macvtap on the team.

                                  You can just create it in Virt-Manager. I'll jump on my laptop and take a screenshot.

                                  1 Reply Last reply Reply Quote 0
                                  • stacksofplatesS
                                    stacksofplates
                                    last edited by stacksofplates

                                    Just click on your connection and go to edit -> connection details and click on the Virtual Networks tab.

                                    Click the plus

                                    0_1514491907472_createprivate.png

                                    Then run through the wizard.

                                    0_1514491928279_name.png

                                    0_1514491934772_ipv4 settings.png

                                    0_1514491943423_last.png

                                    If you choose NAT instead it will still work but is kind of pointless since you will already have an address through the macvtap.

                                    You can do this through virsh as well. The host uses dnsmasq to configure everything so you can also add reservations and all of the other goodies as well. For reservations you can just add it in after the range line:

                                        <host mac='de:ad:be:ef:ca:fe' name='test-vm' ip='192.168.30.50'/>
                                    

                                    0_1514492370729_virsh.png

                                    1 Reply Last reply Reply Quote 2
                                    • JaredBuschJ
                                      JaredBusch
                                      last edited by

                                      Works perfectly.

                                      1 Reply Last reply Reply Quote 3
                                      • stacksofplatesS
                                        stacksofplates
                                        last edited by

                                        Too bad ovs isnt in the repos for RHEL/CentOS. You can set up these private networks and connect them through a VXLAN with ovs. That way you can have something like a separate dev network on the same hosts and they can communicate between hosts.

                                        black3dynamiteB 1 Reply Last reply Reply Quote 0
                                        • black3dynamiteB
                                          black3dynamite @stacksofplates
                                          last edited by

                                          @stacksofplates said in Help me understand KVM Networking:

                                          Too bad ovs isnt in the repos for RHEL/CentOS. You can set up these private networks and connect them through a VXLAN with ovs. That way you can have something like a separate dev network on the same hosts and they can communicate between hosts.

                                          Not available in the epel repo?

                                          wirestyle22W 1 Reply Last reply Reply Quote 0
                                          • wirestyle22W
                                            wirestyle22 @black3dynamite
                                            last edited by

                                            @black3dynamite said in Help me understand KVM Networking:

                                            @stacksofplates said in Help me understand KVM Networking:

                                            Too bad ovs isnt in the repos for RHEL/CentOS. You can set up these private networks and connect them through a VXLAN with ovs. That way you can have something like a separate dev network on the same hosts and they can communicate between hosts.

                                            Not available in the epel repo?

                                            That is apparently the case unless my google--fu isn't up to snuff

                                            stacksofplatesS 1 Reply Last reply Reply Quote 0
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