VMmanager 5 OVZ: Administrator guide
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Policy settings

Policies define the rules that the control panel applies in different situations. To set up the policy rules, navigate to Cluster settings→ Policy.

There are several policy groups:

  • main;
  • network;
  • SWAP;
  • container compression.

Main

The main policy rules that are applied to the cluster nodes and virtual machines. 



  • Synchronize parameters of containers - containers' parameters will be synchronized once a day at midnight. The following parameters will be synchronized: the amount of RAM, HDD, CPU, number of CPU. Containers' statuses will be synchronized as well once in 15 minutes.
  • Allow overselling - select the checkbox to check available resources while creating a new container.  VMmanager allows for RAM and HDD overselling;
  • RAM overselling - the percentage of RAM that virtual machines will be allowed to use (50% is the minimum value, 1000% is the maximum value).
  • CPU overselling - provide the percentage of CPU that virtual machines will be allowed to use (50% - 1000%);
  • HDD reserve - hard drive size in %% reserved for system needs;  
  • Units of measure — units of measure for the reserved space: 
    • Percent;
    • MiB;
    • GiB.
  • CPU limit for containers:
    • Unlimited mode - unlimited CPU frequency; 
    • Limited mode - the maximum CPU is limited by container parameters;  
    • Adaptive mode - VMmanager OVZ dynamically changes CPU frequency; 
  • Migration method:
    • Standard migration - (vzmigrate) live migration is supported;
    • VMmanager OVZ migration algorithm - the internal algorithm is used, live migration is not supported
  • Decrease disk size on suspended VM — disable a virtual machine when decreasing its size;
  • Delayed deletion of VM (in hours) — Yyou can configure the container's deletion cleanup to happen later (in hours), after it is deleted in the control panel. Possible values 0-48. 0 - deletion will happen immediately. When deleting a virtual machine from the panel, the container's directory will be renamed into '.ID.to.delete.XXXX', where ID - is the container id. The 'at' utility creates the cron job to delete that directory in a specified period in hours. Normally, container contents are located in /vz/private;
  • Recipe - select a recipe that will be executed on a virtual machine. For more information please refer to the article Recipe management;
  • Allow users to edit recipes - select the check box to allow users to edit recipes;

Overselling allows offering resources to virtual machines in excess of actual supply. 

Example: overselling amount - 200%, total RAM on the server - 8 Gb. Virtual machines will be allocated 16 Gb of RAM.

The NodeReservedMemPercent parameter in the VMmanager configuration file allows setting the amount of reserved RAM on cluster nodes, in %. The default value is 0. If NodeReservedMemPercent equals 10%, when creating a virtual machine (with 512 Mb of RAM) the amount of RAM on the server should be 512 Mb + 10% from the total RAM.

The control panel saves a recipe name.  Several recipes can have similar internal names, but different tags. During OS installation the first recipe with the selected name compatible with a template is selected. Therefore, you can set different recipes for different operating systems. 

Network

  • Traffic shaping — set traffic shaping for every container;  
  • Unique IP check — the system will check that the  IP address of a newly created virtual machine is unique. 

Swap

  • Individual swap limits — select this check box to limit the swap file for every container; 
  • Swap/Ram ratio — specify the ratio between swap and RAM in %. The default value is 200%.
  • Apply to existing — select the check box to apply the "Swap/Ram ratio" parameter to all existing containers.

Containers compression 

  • Period — period to start compression of all ploop-containers on the cluster node
    • do not perform;
    • weekly;
    • monthly.
  • Execution day — the day of week/month. This field is available only if you selected Weekly or Monthly;
  • Execution time — hours and minutes to start the operation. This field is available only if you selected Weekly or Monthly. 
The article was last updated on 11.27.2018. The article was prepared by technical writers of ISPsystem.