Linux OS advice for building a SAM-SD
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@magicmarker said in Linux OS advice for building a SAM-SD:
@stacksofplates The way you are describing it, makes it feel more like a Type 2 Hypervisor. I was attempting to install Fedora as a minimal install and add the KVM role through the cli. I then was able to successfully launch Virt-Manager from a Windows box using Xming and Putty. I was having trouble on the Linux admin side understanding how to add a volumes for VM data storage and how to properly setup the networking within the Virt-Manager which is not documented well. My host has multiple nic's and I'm used to setting up a Virtual Switch.
it's all type 1, there is no type 2 for KVM. Default volume for guests is /var/lib/libvirt/images. You can literally just create a directory and use that as a volume. There is nothing special for ISOs or guest images at all. For multiple NICs you can just pick which one it should be using. So VM1 can use macvtap on em2 and VM2 can use macvtap on em3 (or whatever the NIC is called on your system).
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@scottalanmiller said in Linux OS advice for building a SAM-SD:
It what sense?
I'm sure it feels like type-2 in the same sense that everybody else gets confused about Hyper-V as a role. If you're installing something after the OS install, it feels like it's "on top"
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@scottalanmiller said in Linux OS advice for building a SAM-SD:
@magicmarker said in Linux OS advice for building a SAM-SD:
@stacksofplates The way you are describing it, makes it feel more like a Type 2 Hypervisor.
It what sense?
Installing the Linux Server OS with a desktop, then adding the KVM package. It reminds of installing Windows Server OS, and then adding the Hypervisor role. Maybe I'm making this harder on myself. I was doing a Fedora minimal install (no pretty GUI) and installing the KVM packages via the cli to keep the overhead to a minimum. If I were to install Fedora with a desktop package like Gnome I would probably have an easier time working with KVM.
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@magicmarker said in Linux OS advice for building a SAM-SD:
Installing the Linux Server OS with a desktop, then adding the KVM package. It reminds of installing Windows Server OS, and then adding the Hypervisor role.
Right, The Hyper-V process was modeled after the Xen process. All type-1 hypervisors installed this way (until recently ESXi changed and is the first to have a different process after a decade of doing it this way.) This is how type-1 has always been installed.
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Why the preference of Fedora over CentOS. It seems like you'd want the more stable release cycle for your dom0.
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@kelly Both @scottalanmiller and @JaredBusch recommended Fedora.
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@magicmarker said in Linux OS advice for building a SAM-SD:
@kelly Both @scottalanmiller and @JaredBusch recommended Fedora.
Yeah, that is why I have my question. I respect both of their opinions, but they have been wrong in the past.
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@kelly said in Linux OS advice for building a SAM-SD:
Why the preference of Fedora over CentOS. It seems like you'd want the more stable release cycle for your dom0.
That's one theory. I don't believe that CentOS is more stable. I've not seen that. Stability is certainly of concern, but does being "old" really constitute more stability? I think that it used to, long ago when technology was quite different, but I'm not convinced that it does today. CentOS is stable in terms of "package versions", but that's not the same as stable. Fedora gets more updates, more advances, more security, more quickly than CentOS does. All things that you want in your hypervisor.
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Fedora has a better upgrade path as well. Moving from CentOS X to CentOS Y tends to be high risk and relatively painful. Moving from Fedora X to Fedora Y happens many times more often, but tends to be painless and trivial.
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@scottalanmiller said in Linux OS advice for building a SAM-SD:
@kelly said in Linux OS advice for building a SAM-SD:
Why the preference of Fedora over CentOS. It seems like you'd want the more stable release cycle for your dom0.
That's one theory. I don't believe that CentOS is more stable. I've not seen that. Stability is certainly of concern, but does being "old" really constitute more stability? I think that it used to, long ago when technology was quite different, but I'm not convinced that it does today. CentOS is stable in terms of "package versions", but that's not the same as stable. Fedora gets more updates, more advances, more security, more quickly than CentOS does. All things that you want in your hypervisor.
I was using stability in the context of release cycles, not functionality. On the face of it, I would think you'd want to be running on something less likely to make significant changes. That is my inclination personally. Seeing people post about release changes on Fedora leaves me mistrustful of my ability to rely on it for a subsystem like a VM host.
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@magicmarker said in Linux OS advice for building a SAM-SD:
@scottalanmiller said in Linux OS advice for building a SAM-SD:
@magicmarker said in Linux OS advice for building a SAM-SD:
@stacksofplates The way you are describing it, makes it feel more like a Type 2 Hypervisor.
It what sense?
Installing the Linux Server OS with a desktop, then adding the KVM package. It reminds of installing Windows Server OS, and then adding the Hypervisor role. Maybe I'm making this harder on myself. I was doing a Fedora minimal install (no pretty GUI) and installing the KVM packages via the cli to keep the overhead to a minimum. If I were to install Fedora with a desktop package like Gnome I would probably have an easier time working with KVM.
You don't need a desktop unless it's on a workstation. Literally during the install instead of picking minimal pick hypervisor role. It's done, that's it. Then just use Virt-Manager to control it.
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@kelly said in Linux OS advice for building a SAM-SD:
@scottalanmiller said in Linux OS advice for building a SAM-SD:
@kelly said in Linux OS advice for building a SAM-SD:
Why the preference of Fedora over CentOS. It seems like you'd want the more stable release cycle for your dom0.
That's one theory. I don't believe that CentOS is more stable. I've not seen that. Stability is certainly of concern, but does being "old" really constitute more stability? I think that it used to, long ago when technology was quite different, but I'm not convinced that it does today. CentOS is stable in terms of "package versions", but that's not the same as stable. Fedora gets more updates, more advances, more security, more quickly than CentOS does. All things that you want in your hypervisor.
I was using stability in the context of release cycles, not functionality. On the face of it, I would think you'd want to be running on something less likely to make significant changes. That is my inclination personally. Seeing people post about release changes on Fedora leaves me mistrustful of my ability to rely on it for a subsystem like a VM host.
I saw the same thing about @scottalanmiller as he changes his tune on a solution every month or so. Look at the life of ML and the topic about the different Hypervisors. It was "omg XS is the only reasonable tool" then it went to Scale, and then to Hyper-V and then to KVM.
Stability is based around the support you get, investing in a platform needs to be carefully considered and not abandoned just because something else has a good feature.
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@stacksofplates said in Linux OS advice for building a SAM-SD:
@magicmarker said in Linux OS advice for building a SAM-SD:
@stacksofplates The way you are describing it, makes it feel more like a Type 2 Hypervisor. I was attempting to install Fedora as a minimal install and add the KVM role through the cli. I then was able to successfully launch Virt-Manager from a Windows box using Xming and Putty. I was having trouble on the Linux admin side understanding how to add a volumes for VM data storage and how to properly setup the networking within the Virt-Manager which is not documented well. My host has multiple nic's and I'm used to setting up a Virtual Switch.
it's all type 1, there is no type 2 for KVM. Default volume for guests is /var/lib/libvirt/images. You can literally just create a directory and use that as a volume. There is nothing special for ISOs or guest images at all. For multiple NICs you can just pick which one it should be using. So VM1 can use macvtap on em2 and VM2 can use macvtap on em3 (or whatever the NIC is called on your system).
Also Qemu/KVM User session default volume is /home/username/.local/share/libvirt/images
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@stacksofplates said in Linux OS advice for building a SAM-SD:
@magicmarker said in Linux OS advice for building a SAM-SD:
@scottalanmiller said in Linux OS advice for building a SAM-SD:
@magicmarker said in Linux OS advice for building a SAM-SD:
@stacksofplates The way you are describing it, makes it feel more like a Type 2 Hypervisor.
It what sense?
Installing the Linux Server OS with a desktop, then adding the KVM package. It reminds of installing Windows Server OS, and then adding the Hypervisor role. Maybe I'm making this harder on myself. I was doing a Fedora minimal install (no pretty GUI) and installing the KVM packages via the cli to keep the overhead to a minimum. If I were to install Fedora with a desktop package like Gnome I would probably have an easier time working with KVM.
You don't need a desktop unless it's on a workstation. Literally during the install instead of picking minimal pick hypervisor role. It's done, that's it. Then just use Virt-Manager to control it.
I don't remember that being an option with Fedora. That sounds like a good deal. What distro gives you that option?
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@magicmarker said in Linux OS advice for building a SAM-SD:
@stacksofplates said in Linux OS advice for building a SAM-SD:
@magicmarker said in Linux OS advice for building a SAM-SD:
@scottalanmiller said in Linux OS advice for building a SAM-SD:
@magicmarker said in Linux OS advice for building a SAM-SD:
@stacksofplates The way you are describing it, makes it feel more like a Type 2 Hypervisor.
It what sense?
Installing the Linux Server OS with a desktop, then adding the KVM package. It reminds of installing Windows Server OS, and then adding the Hypervisor role. Maybe I'm making this harder on myself. I was doing a Fedora minimal install (no pretty GUI) and installing the KVM packages via the cli to keep the overhead to a minimum. If I were to install Fedora with a desktop package like Gnome I would probably have an easier time working with KVM.
You don't need a desktop unless it's on a workstation. Literally during the install instead of picking minimal pick hypervisor role. It's done, that's it. Then just use Virt-Manager to control it.
I don't remember that being an option with Fedora. That sounds like a good deal. What distro gives you that option?
It's on CentOS but I was pretty sure Fedora had it also. I'm running CentOS hosts. Only Fedora hosts I have are workstations and it's set up by default on Fedora WS.
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@kelly said in Linux OS advice for building a SAM-SD:
Why the preference of Fedora over CentOS. It seems like you'd want the more stable release cycle for your dom0.
Minimal installs improves stability anyway.
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@kelly said in Linux OS advice for building a SAM-SD:
@scottalanmiller said in Linux OS advice for building a SAM-SD:
@kelly said in Linux OS advice for building a SAM-SD:
Why the preference of Fedora over CentOS. It seems like you'd want the more stable release cycle for your dom0.
That's one theory. I don't believe that CentOS is more stable. I've not seen that. Stability is certainly of concern, but does being "old" really constitute more stability? I think that it used to, long ago when technology was quite different, but I'm not convinced that it does today. CentOS is stable in terms of "package versions", but that's not the same as stable. Fedora gets more updates, more advances, more security, more quickly than CentOS does. All things that you want in your hypervisor.
I was using stability in the context of release cycles, not functionality. On the face of it, I would think you'd want to be running on something less likely to make significant changes. That is my inclination personally. Seeing people post about release changes on Fedora leaves me mistrustful of my ability to rely on it for a subsystem like a VM host.
I agree, if those changes affect things like the core system. And Fedora has been through some of those changes, but only as a precursor to them happening on CentOS, at least in theory. So while there is potential for more change on Fedora, in reality there is normally just "earlier change" on it. Exceptions will happen, but they are not common. Most of what people talk about is desktop apps and really high level things, not the core OS or hypervisor environments.
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@scottalanmiller said in Linux OS advice for building a SAM-SD:
Fedora has a better upgrade path as well. Moving from CentOS X to CentOS Y tends to be high risk and relatively painful. Moving from Fedora X to Fedora Y happens many times more often, but tends to be painless and trivial.
That is now changed as starting with CentOS 7 they have added the Fedora style release upgrades as a native function of the OS. Granted we have not seen it happen yet because there is not CentOS 8 yet, but it is designed to do it now.
Also, the CentOS 7 to CentOS 8 will be a larger upgrade than a say Fedora 25 to Fedora 26, but no less intrusive.
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@kelly said in Linux OS advice for building a SAM-SD:
@scottalanmiller said in Linux OS advice for building a SAM-SD:
@kelly said in Linux OS advice for building a SAM-SD:
Why the preference of Fedora over CentOS. It seems like you'd want the more stable release cycle for your dom0.
That's one theory. I don't believe that CentOS is more stable. I've not seen that. Stability is certainly of concern, but does being "old" really constitute more stability? I think that it used to, long ago when technology was quite different, but I'm not convinced that it does today. CentOS is stable in terms of "package versions", but that's not the same as stable. Fedora gets more updates, more advances, more security, more quickly than CentOS does. All things that you want in your hypervisor.
I was using stability in the context of release cycles, not functionality. On the face of it, I would think you'd want to be running on something less likely to make significant changes. That is my inclination personally. Seeing people post about release changes on Fedora leaves me mistrustful of my ability to rely on it for a subsystem like a VM host.
Prior to modern, commodity virtualization, I was firmly in the CentOS over Fedora camp.
But now, I don't care because I can snapshot and upgrade then roll back if needed.
When it comes to the hypervisor itself, it is similar. Backup or migrate the guests, then upgrade the host. If it fails, reinstall the host and restore the guests or move them back.
Though honestly, if you have enough capacity to migrate all the hosts, I would jsut nuke it and reinstall for a larger organization. I would upgrade for a smaller one that likely cannot easily reapply permissions, etc.
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@kelly said in Linux OS advice for building a SAM-SD:
Why the preference of Fedora over CentOS. It seems like you'd want the more stable release cycle for your dom0.
After using a lot of different distros, I'm totally hooked on Fedora. Everything about it, to me, makes the most logical sense. It flows the nicest, and imo manages the best.
