Creating a resource group by host name

Follow these steps to create a static resource group using hosts by explicitly specifying the host names.

1. From the cluster management console, select Resources > Resource Planning (Slot) > Resource Groups.
2. Click Global Actions > Create a Resource Group.
3. Specify a resource group name. The name must adhere to the following naming rules:
   • The resource group name must be unique.
   • The resource group name must not use the same name as the resource plan name.
   • The resource group name can only contain the following characters: 0 to 9, lowercase letters, uppercase letters, hyphens (-), or underscores (_). It cannot contain the these characters: \ / : * ? \ " < > | '
   • The resource group name can be a maximum of 64 characters.
4. Optional: Include a description of the resource group, up to a maximum of 200 characters. This is optional (by default, it is empty).
5. Specify how many slots per host you would like to have the system count.

   Select the following expression to allocate, as a starting point, one slot per CPU for each service instance: Number of slots per host is equal to Number of CPUs * 1.

   The maximum number of slots per host is 9999.

6. For the Resource Selection Method, select Static (List of Names).

   Static resource selection means that you are selecting specific hosts to belong to this resource group.

7. Under Filter display of member hosts > Hosts to Show in List, select how you would like to filter your host list.
   • All hosts gives you a list of all hosts that belong to your cluster. You cannot specify any resource requirements.
   • Hosts filtered by resource requirement lets you filter your hosts and display a list of candidates for your resource group based on a set of resource requirements. For example, you can specify all hosts that are Linux®.
8. If you chose to filter hosts by resource requirement, specify the resource requirement you want.

   For example, select(LINUX86).

   Notes:

   1. The expression you enter is evaluated against each host in the cluster. If a host is found to satisfy the stated resource requirement (if it returns true/ non-zero), then the host is added to the host group.
   2. Use the syntax from the select string to specify your resource requirements. You do not need to use XML equivalents in the cluster management console.

      Table 1. Selection strings for specifying resource requirements

      Resource Requirement	Description	Example
      maxmem	The maximum RAM available	select(maxmem>400)
      maxswp	The maximum swap space	select(maxswp>600)
      maxtmp	The maximum temporary space	select(maxtmp>100)
      ncpus	The number of CPUs	select(ncpus==1)
      type	The type of host	select(LINUX86)
      ndisks	Number of disks	select(ndisks>1)
      docker	Docker-enabled hosts	select(docker_enabled)

   3. Ensure that you enter a resource requirement expression that relates to the host and that can be used during evaluation (for example, maximum memory requirement or maximum swap space).

   Tip: Use the command egoconfig addresourceattr to add a custom tag to any hosts and then specify that tag when creating a resource group. See egoconfig.
9. If you have specified a resource requirement or modified one, click Refresh Host List to get an accurate list of hosts.
10. Expand the Member hosts section if necessary and review the hosts found.
    • If you selected to filter hosts by All hosts, the list of hosts provided is all the hosts in your cluster.
    • If you selected Hosts filtered by resource requirement, a list of hosts that currently fulfill the requirements you specified in the resource requirement string section display.
11. Review your member hosts and select the hosts you want using the check boxes.

    If your host list is long, it may go on for several pages. You can select hosts and click Create at any time and then add more hosts from other pages. Make sure you save before navigating to another page.

    Once you have selected a member host, filter the list again with a different resource requirement. The hosts highlighted and check marked are your member hosts.

    By default, if you select no member hosts, all hosts in your cluster are added to this resource group when you create it. Further, if you do not select a host, the resource group type switches from Static to Dynamic.

12. Click Check for overlaps.

    Hosts must not overlap resource groups. Resource groups are used to plan resource distribution in your resource plan. Having overlaps causes the hosts to be double-counted (or more) in the resource plan, resulting in recurring under-allocation of some consumers.

    If any hosts overlap, remove them from this resource group or remove them from the overlapping resource group. The exception is with hosts listed in InternalResourceGroup. Although all hosts in the cluster are listed here, they are not “double-counted” in the resource plan.

13. Click Create.