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Myriad provides the capability for fine-grained or coarse-grained scaling via the Myriad user interface (UI) or the Myriad REST API. Scaling is done by using the flexup and flexdown feature. Flexup expands the cluster and flexdown shrinks the cluster. While doing so, the number of instances and size of the scale are specified.  The number of instances that you can scale are bound only by the number of nodes in the cluster. The instance size is a profile parameter that is a predefined value of zero, small, medium, and large. During initial startup, the default profile is zero.  These predefined values are specified in the Myriad configuration file (myriad-config-default.yml).

Note

During initial startup, Myriad launches one NodeManager instance with a profile of medium through the parameter, nmInstances, which is specified in the myriad-config-default.yml file.

"nmInstances": {
    "medium": 1
  },

Profile Defaults

Code Block
  "profiles": {
    "zero": {
      "cpu": "0",
      "mem": "0"
    },
    "small": {
      "cpu": "12",
      "mem": "11002048"
    },
    "medium": {
      "cpu": "24",
      "mem": "20484096"
    },
    "large": {
      "cpu": "410",
      "mem": "409612288"
    }
  },


User Interface

The myriad Myriad button is the main console which shows the API code for the flexup and flexdown feature. The Flex button directs you to the Flex panel where you can flexup and flex down instances. The Config button directs you to the Config panel where the Myriad configuration defaults display.

To flexup and flexdown instances via the Myriad UI, go to the Flex button on the top navigation bar.

 

Flex panel:

 

REST API

To scale a cluster up or down, use the Myriad Cluster API. The Cluster API provides flexup and flexdown capability that changes the size of one or more instances in a cluster. These predefined values are specified in the Myriad configuration file (myriad-config-default.yml). To retrieve the Myriad configuration and the Myriad Scheduler state, use the Configuration API and State API.

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