Allocation Rules

The platform uses allocation rules to control the scheduling of resources in datacenters, although your virtualization technology must manage the use of the resources. For details of the allocation process, see the Virtual Machine Allocation section. 

There are two types of allocation rules: Global rules apply to all datacenters and Datacenter rules apply to the selected datacenter. 

The platform uses allocation rules to control the scheduling of resources in datacenters, although your virtualization technology must manage the use of the resources. For details of the allocation process, see the Virtual Machine Allocation section. 

You can create the following types of load balance rules:

• PERFORMANCE:  select the machine with the most available resources. If more than one physical machine has the same resources available, use a round-robin algorithm to allocate each VM to a different physical machine.
• PROGRESSIVE:  select the same physical machine until it is full, then change to another one. Begin with the machine with the most available resources. Default rule

To create a global load balance rule:

1. Go to Infrastructure → Private → select a datacenter
2. If you are in Map view or Statistics view, click the Server symbol in top right-hand corner to go to Servers view
3. Go to Allocation rules
4. On the Global panel, click the + add button
5. As the Rule type select "Load balance"

6. Select the Load balance type

If a tenant does not want to deploy on the same physical machine as another tenant, use enterprise exclusion rules, which are called Restrict shared server rules. There is no limit on the amount of these rules you can create.

To create a restrict shared server rule:

1. Go to Infrastructure --> Private → select Datacenter → Allocation rules → Global
2. Click the + add button
3. Select Restrict shared server rule 
4. Select the two enterprises that must not share a physical server. The cloud admin must configure the rules properly to customize VM deployments. 
   

Note that you can also restrict servers by editing an enterprise in Users view. 

The platform uses allocation rules to control the scheduling of resources in datacenters, although your virtualization technology must manage the use of the resources. For details of the allocation process, see the Virtual Machine Allocation section. 

You can create the following types of load balance rules:

• PERFORMANCE:  select the machine with the most available resources. If more than one physical machine has the same resources available, use a round-robin algorithm to allocate each VM to a different physical machine.
• PROGRESSIVE:  select the same physical machine until it is full, then change to another one. Begin with the machine with the most available resources. Default rule

A datacenter load balance rule will have priority over a global load balance rule.

To create a datacenter load balance rule:

1. Go to Infrastructure → Private → select datacenter
2. If you are in Map view or Statistics view, click the server symbol in top right-hand corner to go to Servers view
3. Go to Allocation rules
4. On the Datacenter panel, click the + add  button
5. Select Load balance as the rule type
6. Select the load balance type 

To specify the CPU and RAM load on machines, use compute load level rules. The scheduler will use these rules to help determine if a physical machine is a candidate to hold a VM. 

You can create load level rules for the following elements:

• a datacenter (all racks)
• a rack (all servers on the selected rack)
• a cluster (for supported hypervisors)
• a specific server 

You can only add one rule for an element at each level, but more than one rule may apply.

The priority order of rules is any cluster rule first (if it is present), then the other rules from the most specific rule to the least specific rule. A cluster rule affects all hosts in a cluster irrespective of their state, for example, it applies to hosts that are powered off.

To create a load level compute rule:

1. Go to Infrastructure → Private → select a datacenter
2. If you are in Map view or Statistics view, click the Server symbol in top right-hand corner to go to Servers view
3. Go to Allocation rules
4. On the Global panel, click the Add   button
5. Select the "Load level compute" rule type

6. Complete the dialog
   

   For more details see GUI Add a new rule load level compute

To specify the storage load on machine datastores, use storage load level rules. The scheduler will use these rules to help determine if a physical machine is a candidate to hold a VM. 

You can create rules for the following elements:

• A datacenter (all datastore tiers)
• A tier (all datastores in a tier)
• A specific datastore.

If there is more than one rule that applies to a datastore, the most specific rule takes precedence over more general rules.

To create a load level storage rule:

1. Go to Infrastructure → Private → select a datacenter
2. If you are in Map view or Statistics view, click the Server symbol in top right-hand corner to go to Servers view
3. Go to Allocation rules
4. On the Global panel, click the Add   button
5. Select the "Load level storage" rule type

6. Complete the dialog
   

   For more details see GUI Add a new rule load level storage

   
   

You can use allocation rules to redirect deployments. Here are some examples:

• To gradually migrate users to a new empty hypervisor, set load balance rules to performance. This will ensure that new deployments will go to the new machine. 
• To stop VMs from deploying to a specific physical machine, set load level rules to 1% for RAM and CPU. This will ensure that users cannot deploy more VMs to this physical machine. However, it is also important to consider that users will not be able to reconfigure the VMs that were already deployed there.