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.