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unix:virtualization:techniques [2022/05/08 17:17]
rodolico
unix:virtualization:techniques [2022/05/08 17:52] (current)
rodolico
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 ==== Live Migration ==== ==== Live Migration ====
  
-Live Migration rapidly migrates a running vm from source to target, in many caseswith no downtime detectable by the end user.+Live Migration rapidly migrates a running vm from source to target, in many cases with no downtime detectable by the end user.
  
-This generally has some limitations imposed, for example, migrating a running Xen machine must have Xen on both //source// and //target//, and the version of Xen must be very close on both machines. Same with KVM and virtlib. The CPU's on both machines should be similar also.+This generally has some limitations imposed. For example, migrating a running Xen machine must have Xen on both //source// and //target//, and the version of Xen must be very close on both machines. Same with KVM and virtlib. The CPU's on both machines should be similar also.
  
-Limitations+But, if you have compatible systems, you can migrate machines with little or no impact on end users, either as precursor to maintenance,​ or simply to manually load balance your hypervisors. 
 + 
 +=== Limitations ​===
  
   * Both hypervisors must be running compatible hypervisors.   * Both hypervisors must be running compatible hypervisors.
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   * //source// root user must have ssh access to //target//   * //source// root user must have ssh access to //target//
     * It is preferred if //​source//​.root can log into //​target//​.root without password.     * It is preferred if //​source//​.root can log into //​target//​.root without password.
 +
 +=== Procedure ===
 +
 +  - Ensure root access from //source// to //target// (required for Xen, preferred for all others)
 +    - **Xen** <code bash>ssh target '​ls'</​code>​ should give you a listing of all files in /root on //target//
 +    - **virtlib** issue the command <code bash>​virsh -c qemu+ssh:​%%//​%%target/​system list</​code>​ should return a list of running virtuals on //target//
 +  - Verify compatibility
 +    - Ensure hypervisor compatibility between //source// and //target//
 +    - Ensure network bridges with same name on //source// and //target//
 +    - Ensure path to block devices same on //source// and //target//
 +  - Issue command for migration from //source//. **Note** you can use the running virtual number instead of it's actual name in many cases
 +    - **Xen** - <code bash>xl migrate vm targetmachine</​code>​
 +    - **KVM** - unknown
 +    - **virtlib** - <code bash>​virsh migrate --live //vm// qemu+ssh://​target/​system</​code>​
 +
  
 ===== Move VirtualBox images to KVM/Xen ===== ===== Move VirtualBox images to KVM/Xen =====
unix/virtualization/techniques.txt · Last modified: 2022/05/08 17:52 by rodolico