X-Git-Url: https://git.proxmox.com/?a=blobdiff_plain;f=qm.adoc;h=ae9c74a78d35b7efe82773ebfd226a32f3d1e73b;hb=709194114f8c48bacbaec00334fd78f987ce3187;hp=b9b7ca160fb8bf9eada37ccd1377cca31bc0045b;hpb=4dbeb548bf90537388b52d3d52bda4783d8d5e0f;p=pve-docs.git diff --git a/qm.adoc b/qm.adoc index b9b7ca1..ae9c74a 100644 --- a/qm.adoc +++ b/qm.adoc @@ -484,6 +484,107 @@ start after those where the parameter is set, and this parameter only makes sense between the machines running locally on a host, and not cluster-wide. + +[[qm_migration]] +Migration +--------- + +[thumbnail="gui-qemu-migrate.png"] + +If you have a cluster, you can migrate your VM to another host with + + qm migrate + +When your VM is running and it has no local resources defined (such as disks +on local storage, passed through devices, etc.) you can initiate a live +migration with the -online flag. + +If you have local resources, you can still offline migrate your VMs, +as long as all disk are on storages, which are defined on both hosts. +Then the migration will copy the disk over the network to the target host. + + +VM Templates, Copies and Clones +------------------------------- + +[thumbnail="gui-qemu-full-clone.png"] + +VM installation is usually done using an installation media (CD-ROM) +from the operation system vendor. Depending on the OS, this can be a +time consuming task one might want to avoid. + +An easy way to deploy many VMs of the same type is to copy an existing +VM. We use the term 'clone' for such copies, and distinguish between +'linked' and 'full' clones. + +Full Clone:: + +The result of such copy is an independent VM. The +new VM does not share any storage resources with the original. ++ + +It is possible to select a *Target Storage*, so one can use this to +migrate a VM to a totally different storage. You can also change the +disk image *Format* if the storage driver supports several formats. ++ + +NOTE: A full clone need to read and copy all VM image data. This is +usually much slower than creating a linked clone. ++ + +Some storage types allows to copy a specific *Snapshot*, which +defaults to the 'current' VM data. This also means that the final copy +never includes any additional snapshots from the original VM. + + +Linked Clone:: + +Modern storage drivers supports a way to generate fast linked +clones. Such a clone is a writable copy whose initial contents are the +same as the original data. Creating a linked clone is nearly +instantaneous, and initially consumes no additional space. ++ + +They are called 'linked' because the new image still refers to the +original. Unmodified data blocks are read from the original image, but +modification are written (and afterwards read) from a new +location. This technique is called 'Copy-on-write'. ++ + +This requires that the original volume is read-only. With {pve} one +can convert any VM into a read-only <>). Such +templates can later be used to create linked clones efficiently. ++ + +NOTE: You cannot delete the original template while linked clones +exists. ++ + +It is not possible to change the *Target storage* for linked clones, +because this is a storage internal feature. + + +The *Target node* option allows you to create the new VM on a +different node. The only restriction is that the VM is on shared +storage, and that storage is also available on the target node. + +To avoid resource conflicts, all network interface MAC addresses gets +randomized, and we generate a new 'UUID' for the VM BIOS (smbios1) +setting. + + +[[qm_templates]] +Virtual Machine Templates +------------------------- + +One can convert a VM into a Template. Such templates are read-only, +and you can use them to create linked clones. + +NOTE: It is not possible to start templates, because this would modify +the disk images. If you want to change the template, create a linked +clone and modify that. + + Managing Virtual Machines with `qm` ------------------------------------