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    KVM Virtual Machine Boot Order

    IT Discussion
    virtualization kvm boot order
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    • DustinB3403D
      DustinB3403 @Obsolesce
      last edited by

      @obsolesce said in KVM Virtual Machine Boot Order:

      @dustinb3403 said in KVM Virtual Machine Boot Order:

      @obsolesce but it could be an issue if your DHCP server starts after other VM's. Or a database server that is dependant on other VM's being up and accessible first.

      There is truly a case for needing a startup priority here.

      I wonder what Amazon does. . .

      My point was that, Amazon doesn't have hosts with DB servers and DHCP servers and other apps that depend on them on the same hosts.

      And those companies who do are small enough to just do it manually with minimal effort.

      I have a host with 70 VMs on it, it takes seconds to start the AD and DHCP server first, then a few database servers.

      How are you starting the remaining 60 VM's?

      ObsolesceO 1 Reply Last reply Reply Quote 0
      • ObsolesceO
        Obsolesce @DustinB3403
        last edited by Obsolesce

        @dustinb3403 said in KVM Virtual Machine Boot Order:

        @obsolesce said in KVM Virtual Machine Boot Order:

        @dustinb3403 said in KVM Virtual Machine Boot Order:

        @obsolesce but it could be an issue if your DHCP server starts after other VM's. Or a database server that is dependant on other VM's being up and accessible first.

        There is truly a case for needing a startup priority here.

        I wonder what Amazon does. . .

        My point was that, Amazon doesn't have hosts with DB servers and DHCP servers and other apps that depend on them on the same hosts.

        And those companies who do are small enough to just do it manually with minimal effort.

        I have a host with 70 VMs on it, it takes seconds to start the AD and DHCP server first, then a few database servers.

        How are you starting the remaining 60 VM's?

        Select-all or shift+click, right-click on them, click start.

        Edit, this is on Hyper-V.

        DustinB3403D 1 Reply Last reply Reply Quote 1
        • DustinB3403D
          DustinB3403 @Obsolesce
          last edited by DustinB3403

          @obsolesce that's annoying. . .

          Edit: still annoying but doesn't Hyper-V have startup priority?

          ObsolesceO matteo nunziatiM 2 Replies Last reply Reply Quote 0
          • ObsolesceO
            Obsolesce @DustinB3403
            last edited by

            @dustinb3403 said in KVM Virtual Machine Boot Order:

            @obsolesce that's annoying. . .

            Not really, it's once a month at worst.

            1 Reply Last reply Reply Quote 0
            • matteo nunziatiM
              matteo nunziati @DustinB3403
              last edited by

              @dustinb3403 said in KVM Virtual Machine Boot Order:

              @obsolesce that's annoying. . .

              Edit: still annoying but doesn't Hyper-V have startup priority?

              No it hasnt until I checked 6 months ago. Only way is build a delay schema by hand and assign delays to VM batch start them in layers

              DustinB3403D ObsolesceO 2 Replies Last reply Reply Quote 1
              • DustinB3403D
                DustinB3403 @matteo nunziati
                last edited by

                @matteo-nunziati said in KVM Virtual Machine Boot Order:

                @dustinb3403 said in KVM Virtual Machine Boot Order:

                @obsolesce that's annoying. . .

                Edit: still annoying but doesn't Hyper-V have startup priority?

                No it hasnt until I checked 6 months ago. Only way is build a delay schema by hand and assign delays to VM batch start them in layers

                Well. . . that's just bad. . .

                1 Reply Last reply Reply Quote 0
                • matteo nunziatiM
                  matteo nunziati
                  last edited by

                  The only actual need I got was a vm expecting a postgres to be up. I delayed such a vm. But yes: complex dependency schemas are a PITA but also out of the smb standard scenario imho.

                  1 Reply Last reply Reply Quote 0
                  • matteo nunziatiM
                    matteo nunziati @black3dynamite
                    last edited by

                    @black3dynamite said in KVM Virtual Machine Boot Order:

                    Uncomment START_DELAY=0 in /etc/sysconfig/libvirt-guests file.

                    https://access.redhat.com/discussions/685243
                    0_1533138645107_8657357f-89b9-4565-a0ba-c6a64389a585-image.png

                    0_1533138783472_51e96b88-60ae-443b-8cbc-2c3ebac10574-image.png

                    This will kill parallel startup adding a delay between each vm boot

                    dafyreD 1 Reply Last reply Reply Quote 2
                    • dafyreD
                      dafyre @matteo nunziati
                      last edited by

                      @matteo-nunziati said in KVM Virtual Machine Boot Order:

                      @black3dynamite said in KVM Virtual Machine Boot Order:

                      Uncomment START_DELAY=0 in /etc/sysconfig/libvirt-guests file.

                      https://access.redhat.com/discussions/685243
                      0_1533138645107_8657357f-89b9-4565-a0ba-c6a64389a585-image.png

                      0_1533138783472_51e96b88-60ae-443b-8cbc-2c3ebac10574-image.png

                      This will kill parallel startup adding a delay between each vm boot

                      I think that's the point, though. Some of the VMs are starting before the other VMs that they need to work properly.

                      matteo nunziatiM 1 Reply Last reply Reply Quote 1
                      • matteo nunziatiM
                        matteo nunziati @dafyre
                        last edited by

                        @dafyre nope starting order is still 'random'

                        1 Reply Last reply Reply Quote 0
                        • DustinB3403D
                          DustinB3403
                          last edited by

                          I still find it odd that there isn't a start priority or weight setting to apply to each VM so the hypervisor could do this automatically. . .

                          1 Reply Last reply Reply Quote 2
                          • DustinB3403D
                            DustinB3403
                            last edited by

                            XenServer and XCP-ng both have this option to set for individual VM's under "Start options" under properties of each VM.

                            By default everything is "0" aka start immediately if configured for Autostart/HA. But it can be changed easily to 1, 2 3 etc and the VM's will boot in that order.

                            matteo nunziatiM 1 Reply Last reply Reply Quote 2
                            • ObsolesceO
                              Obsolesce @matteo nunziati
                              last edited by Obsolesce

                              @matteo-nunziati said in KVM Virtual Machine Boot Order:

                              @dustinb3403 said in KVM Virtual Machine Boot Order:

                              @obsolesce that's annoying. . .

                              Edit: still annoying but doesn't Hyper-V have startup priority?

                              No it hasnt until I checked 6 months ago. Only way is build a delay schema by hand and assign delays to VM batch start them in layers

                              Hyper-V had startup priority since 2012... fully configurable... startup action and startup delay.

                              matteo nunziatiM JaredBuschJ 2 Replies Last reply Reply Quote 0
                              • matteo nunziatiM
                                matteo nunziati @Obsolesce
                                last edited by

                                @obsolesce said in KVM Virtual Machine Boot Order:

                                @matteo-nunziati said in KVM Virtual Machine Boot Order:

                                @dustinb3403 said in KVM Virtual Machine Boot Order:

                                @obsolesce that's annoying. . .

                                Edit: still annoying but doesn't Hyper-V have startup priority?

                                No it hasnt until I checked 6 months ago. Only way is build a delay schema by hand and assign delays to VM batch start them in layers

                                Hyper-V had startup priority since 2012... fully configurable... startup action and startup delay.

                                You mean you can use action to wait for another vm to be up and running? If so I ignored it. Delay is mostly a workaround as no one really knows when a dependency will be ready!

                                1 Reply Last reply Reply Quote 1
                                • matteo nunziatiM
                                  matteo nunziati @DustinB3403
                                  last edited by

                                  @dustinb3403 but this will include "wait until vm A is operational/service B is available"?

                                  DustinB3403D 1 Reply Last reply Reply Quote 0
                                  • DustinB3403D
                                    DustinB3403 @matteo nunziati
                                    last edited by

                                    @matteo-nunziati said in KVM Virtual Machine Boot Order:

                                    @dustinb3403 but this will include "wait until vm A is operational/service B is available"?

                                    The hypervisor has no way of knowing what the VM does, so no. It just says start this VM first, then that one, and then that one etc.

                                    matteo nunziatiM 1 Reply Last reply Reply Quote 0
                                    • matteo nunziatiM
                                      matteo nunziati @DustinB3403
                                      last edited by

                                      @dustinb3403 said in KVM Virtual Machine Boot Order:

                                      @matteo-nunziati said in KVM Virtual Machine Boot Order:

                                      @dustinb3403 but this will include "wait until vm A is operational/service B is available"?

                                      The hypervisor has no way of knowing what the VM does, so no. It just says start this VM first, then that one, and then that one etc.

                                      At this level hyperv acts like xen. Anyway pre post hooks could be available...

                                      matteo nunziatiM 1 Reply Last reply Reply Quote 0
                                      • matteo nunziatiM
                                        matteo nunziati @matteo nunziati
                                        last edited by

                                        Now to be fair both mine and @dafyre cases could be solved with longer polling intervals, so they are a sysadmin issue not related to virtualization. Anyway hv agents are used for a lot of things, I don't see why they couldn't act as kubernates with containers. I suppose it is just a lack of demand.

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

                                          @obsolesce said in KVM Virtual Machine Boot Order:

                                          @matteo-nunziati said in KVM Virtual Machine Boot Order:

                                          @dustinb3403 said in KVM Virtual Machine Boot Order:

                                          @obsolesce that's annoying. . .

                                          Edit: still annoying but doesn't Hyper-V have startup priority?

                                          No it hasnt until I checked 6 months ago. Only way is build a delay schema by hand and assign delays to VM batch start them in layers

                                          Hyper-V had startup priority since 2012... fully configurable... startup action and startup delay.

                                          This is inaccurate. There is not a priority.

                                          Hyper has only ever had this.
                                          0_1533154098692_7bc8e1f1-b436-47db-8e4e-726f1555ebb1-image.png

                                          ObsolesceO 1 Reply Last reply Reply Quote 1
                                          • ObsolesceO
                                            Obsolesce @JaredBusch
                                            last edited by

                                            @jaredbusch said in KVM Virtual Machine Boot Order:

                                            @obsolesce said in KVM Virtual Machine Boot Order:

                                            @matteo-nunziati said in KVM Virtual Machine Boot Order:

                                            @dustinb3403 said in KVM Virtual Machine Boot Order:

                                            @obsolesce that's annoying. . .

                                            Edit: still annoying but doesn't Hyper-V have startup priority?

                                            No it hasnt until I checked 6 months ago. Only way is build a delay schema by hand and assign delays to VM batch start them in layers

                                            Hyper-V had startup priority since 2012... fully configurable... startup action and startup delay.

                                            This is inaccurate. There is not a priority.

                                            Hyper has only ever had this.
                                            0_1533154098692_7bc8e1f1-b436-47db-8e4e-726f1555ebb1-image.png

                                            Okay, technically incorrect.... I'll give you that.

                                            The point I was trying to make, was you can artificially set priority VM booting by adjusting the "startup delay" for each VM.

                                            1 Reply Last reply Reply Quote 0
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