KVM Snapshot/Backup Script
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@Romo said in KVM Snapshot/Backup Script:
@stacksofplates said in KVM Snapshot/Backup Script:
I create the template, and run virt-sysprep on it. Then I can update the disk with virt-sysprep --update. It automatically spins up a temp VM that updates all of the packages in the disk. But if you do this, you need to run virt-sysprep --selinux-relabel so it relabels the disk on the next clone. If not, labels can get screwed up;
Is this is only available for RHEL guests or can it be used with other distros?
You should be able to sysprep Ubuntu also. Not sure about any others.
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@stacksofplates said in KVM Snapshot/Backup Script:
@Romo said in KVM Snapshot/Backup Script:
@stacksofplates said in KVM Snapshot/Backup Script:
@Romo said in KVM Snapshot/Backup Script:
@stacksofplates said in KVM Snapshot/Backup Script:
@Romo said in KVM Snapshot/Backup Script:
Are you using external snapshots to thin provision any vms? Is there a performance hit on doing this?
No. I have a template that uses a qcow2 disk. It's only a 15GB disk, but since it's thin provisioned it's only around 1.5GB. I can clone it in about 1-2 seconds so I haven't bothered with doing externals for that.
My clones take 30-40 seconds, how do you thin provision? Using virt-sparsify on an image?
No, qcow2 is thin by default. But all of my templates are RHEL systems. So the OS doesn't use hardly any space. Are you cloning Windows machines?
No, no windows
Hmm, I don't have anything special. Some 300G 10K SAS drives in RAID 10.
Here's a video I did for Dash:
Youtube VideoAnd another of a script I wrote that names the VM and spins up how many instances you tell it:
Youtube VideoI want that speed!! I am on 4 500GB 7200 SATA in RAID 10
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@Romo said in KVM Snapshot/Backup Script:
@stacksofplates said in KVM Snapshot/Backup Script:
@Romo said in KVM Snapshot/Backup Script:
@stacksofplates said in KVM Snapshot/Backup Script:
@Romo said in KVM Snapshot/Backup Script:
@stacksofplates said in KVM Snapshot/Backup Script:
@Romo said in KVM Snapshot/Backup Script:
Are you using external snapshots to thin provision any vms? Is there a performance hit on doing this?
No. I have a template that uses a qcow2 disk. It's only a 15GB disk, but since it's thin provisioned it's only around 1.5GB. I can clone it in about 1-2 seconds so I haven't bothered with doing externals for that.
My clones take 30-40 seconds, how do you thin provision? Using virt-sparsify on an image?
No, qcow2 is thin by default. But all of my templates are RHEL systems. So the OS doesn't use hardly any space. Are you cloning Windows machines?
No, no windows
Hmm, I don't have anything special. Some 300G 10K SAS drives in RAID 10.
Here's a video I did for Dash:
Youtube VideoAnd another of a script I wrote that names the VM and spins up how many instances you tell it:
Youtube VideoI want that speed!! I am on 4 500GB 7200 SATA in RAID 10
How big is your template?
2.0G -rw-------. 1 root root 16G Feb 13 03:37 template.qcow2That's what I have.
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Also it's not virt-sysprep --update it's virt-customize --update. I didn't think that was right, so I just went back and looked.
I have a daily cron job that runs this
/bin/virt-customize --update --selinux-relabel -a /data/VMs/template.qcow2 -
@stacksofplates said in KVM Snapshot/Backup Script:
@Romo said in KVM Snapshot/Backup Script:
@stacksofplates said in KVM Snapshot/Backup Script:
@Romo said in KVM Snapshot/Backup Script:
@stacksofplates said in KVM Snapshot/Backup Script:
@Romo said in KVM Snapshot/Backup Script:
@stacksofplates said in KVM Snapshot/Backup Script:
@Romo said in KVM Snapshot/Backup Script:
Are you using external snapshots to thin provision any vms? Is there a performance hit on doing this?
No. I have a template that uses a qcow2 disk. It's only a 15GB disk, but since it's thin provisioned it's only around 1.5GB. I can clone it in about 1-2 seconds so I haven't bothered with doing externals for that.
My clones take 30-40 seconds, how do you thin provision? Using virt-sparsify on an image?
No, qcow2 is thin by default. But all of my templates are RHEL systems. So the OS doesn't use hardly any space. Are you cloning Windows machines?
No, no windows
Hmm, I don't have anything special. Some 300G 10K SAS drives in RAID 10.
Here's a video I did for Dash:
Youtube VideoAnd another of a script I wrote that names the VM and spins up how many instances you tell it:
Youtube VideoI want that speed!! I am on 4 500GB 7200 SATA in RAID 10
How big is your template?
2.0G -rw-------. 1 root root 16G Feb 13 03:37 template.qcow2That's what I have.
Way bigger, apparently its not thing provisioned at all
1 root root 2.9G Oct 26 17:39 centos7-clone.qcow2 1 root root 26G Feb 8 15:35 centos-7.qcow2 -
I use this to create my image and the use virt-manager to finish the install
qemu-img create -f qcow2 -o preallocation=metadata centos-7.qcow2 25G -
@Romo said in KVM Snapshot/Backup Script:
@stacksofplates said in KVM Snapshot/Backup Script:
@Romo said in KVM Snapshot/Backup Script:
@stacksofplates said in KVM Snapshot/Backup Script:
@Romo said in KVM Snapshot/Backup Script:
@stacksofplates said in KVM Snapshot/Backup Script:
@Romo said in KVM Snapshot/Backup Script:
@stacksofplates said in KVM Snapshot/Backup Script:
@Romo said in KVM Snapshot/Backup Script:
Are you using external snapshots to thin provision any vms? Is there a performance hit on doing this?
No. I have a template that uses a qcow2 disk. It's only a 15GB disk, but since it's thin provisioned it's only around 1.5GB. I can clone it in about 1-2 seconds so I haven't bothered with doing externals for that.
My clones take 30-40 seconds, how do you thin provision? Using virt-sparsify on an image?
No, qcow2 is thin by default. But all of my templates are RHEL systems. So the OS doesn't use hardly any space. Are you cloning Windows machines?
No, no windows
Hmm, I don't have anything special. Some 300G 10K SAS drives in RAID 10.
Here's a video I did for Dash:
Youtube VideoAnd another of a script I wrote that names the VM and spins up how many instances you tell it:
Youtube VideoI want that speed!! I am on 4 500GB 7200 SATA in RAID 10
How big is your template?
2.0G -rw-------. 1 root root 16G Feb 13 03:37 template.qcow2That's what I have.
Way bigger, apparently its not thing provisioned at all
1 root root 2.9G Oct 26 17:39 centos7-clone.qcow2 1 root root 26G Feb 8 15:35 centos-7.qcow2was that with ls -lsh? It should give you the actual size on the left before the permissions.
I use a minimal image by default, then just add what I need after the clone.
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@stacksofplates I only did a ls -lh
output of ls -lsh
2.9G -rw-r--r--. 1 root root 2.9G Oct 26 17:39 centos7-clone.qcow2 1.1G -rw-r--r--. 1 root root 26G Feb 8 15:35 centos-7.qcow2 -
@Romo said in KVM Snapshot/Backup Script:
I use this to create my image and the use virt-manager to finish the install
qemu-img create -f qcow2 -o preallocation=metadata centos-7.qcow2 25GI preallocated the original template, and then when I clone with Virt-Manager or cli I don't usually change it after. I did some tests and didn't see any difference between running the preallocation on the clone and not. I'm not sure if it copies the preallocation flag when you clone, but like I said, I haven't seen much of a read/write difference.
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@Romo said in KVM Snapshot/Backup Script:
@stacksofplates I only did a ls -lh
output of ls -lsh
2.9G -rw-r--r--. 1 root root 2.9G Oct 26 17:39 centos7-clone.qcow2 1.1G -rw-r--r--. 1 root root 26G Feb 8 15:35 centos-7.qcow2Ya so it's thin provisioned. I wonder why it's taking so long. I don't think the disk speeds would make that much of a difference.
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What's your host specs? Mine is a DL380 G6. Dual 4 core Xeons and 96GB RAM. Don't think the RAM would have much to do with it. I had 24 originally and I'm pretty sure it cloned at the same speed.
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@stacksofplates said in KVM Snapshot/Backup Script:
What's your host specs? Mine is a DL380 G6. Dual 4 core Xeons and 96GB RAM. Don't think the RAM would have much to do with it. I had 24 originally and I'm pretty sure it cloned at the same speed.
Its tiny
ML110 G7 8GB RAM , Single 4 core Xeon
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@Romo said in KVM Snapshot/Backup Script:
@stacksofplates said in KVM Snapshot/Backup Script:
What's your host specs? Mine is a DL380 G6. Dual 4 core Xeons and 96GB RAM. Don't think the RAM would have much to do with it. I had 24 originally and I'm pretty sure it cloned at the same speed.
Its tiny
ML110 G7 8GB RAM , Single 4 core Xeon
Hmm. Do you have anything else running while you clone? You would think 4 cores would be enough as long as you're not way over provisioned.
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@stacksofplates said in KVM Snapshot/Backup Script:
@Romo said in KVM Snapshot/Backup Script:
@stacksofplates said in KVM Snapshot/Backup Script:
What's your host specs? Mine is a DL380 G6. Dual 4 core Xeons and 96GB RAM. Don't think the RAM would have much to do with it. I had 24 originally and I'm pretty sure it cloned at the same speed.
Its tiny
ML110 G7 8GB RAM , Single 4 core Xeon
Hmm. Do you have anything else running while you clone? You would think 4 cores would be enough as long as you're not way over provisioned.
3 vms
virsh # list Id Name State ---------------------------------------------------- 111 FreePBX running 144 rocket-chat running 160 ubt-ans-ininja runningThis is a clone on the centos image.
[root@kvm2 ~]# virt-clone -o centos-7 -n clone-test -f /vmrepo/clone-test.qcow2 Allocating 'clone-test.qcow2' | 25 GB 00:00:33 Clone 'clone-test' created successfully. -
@Romo said in KVM Snapshot/Backup Script:
@stacksofplates said in KVM Snapshot/Backup Script:
@Romo said in KVM Snapshot/Backup Script:
@stacksofplates said in KVM Snapshot/Backup Script:
What's your host specs? Mine is a DL380 G6. Dual 4 core Xeons and 96GB RAM. Don't think the RAM would have much to do with it. I had 24 originally and I'm pretty sure it cloned at the same speed.
Its tiny
ML110 G7 8GB RAM , Single 4 core Xeon
Hmm. Do you have anything else running while you clone? You would think 4 cores would be enough as long as you're not way over provisioned.
3 vms
virsh # list Id Name State ---------------------------------------------------- 111 FreePBX running 144 rocket-chat running 160 ubt-ans-ininja runningThis is a clone on the centos image.
[root@kvm2 ~]# virt-clone -o centos-7 -n clone-test -f /vmrepo/clone-test.qcow2 Allocating 'clone-test.qcow2' | 25 GB 00:00:33 Clone 'clone-test' created successfully.Maybe it is hw limitations. I'm not sure. Still, 33 seconds is much faster than building by hand
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@stacksofplates yeah it must be my hardware, and indeed it is way faster than building by hand. I will still be jealous of your cloning times =).
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@Romo said in KVM Snapshot/Backup Script:
@stacksofplates yeah it must be my hardware, and indeed it is way faster than building by hand. I will still be jealous of your cloning times =).
Oh mine is nothing. Google can spin up thousands with Kubernetes in seconds. That's something to be jealous of.
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@stacksofplates said in KVM Snapshot/Backup Script:
@Romo said in KVM Snapshot/Backup Script:
@stacksofplates yeah it must be my hardware, and indeed it is way faster than building by hand. I will still be jealous of your cloning times =).
Oh mine is nothing. Google can spin up thousands with Kubernetes in seconds. That's something to be jealous of.
But they spin up containers don't they.
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@Romo said in KVM Snapshot/Backup Script:
@stacksofplates said in KVM Snapshot/Backup Script:
@Romo said in KVM Snapshot/Backup Script:
@stacksofplates yeah it must be my hardware, and indeed it is way faster than building by hand. I will still be jealous of your cloning times =).
Oh mine is nothing. Google can spin up thousands with Kubernetes in seconds. That's something to be jealous of.
But they spin up containers don't they.
True, good point but I would think it's relative. For example I could probably only spin up a handful in a few seconds. With their equipment they have to be able to spin up a ton of full VMs pretty quickly.
Plus there are the really trimmed down cloud versions of these OSs that spin up even faster.
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Thanks.
