Using AutoScaler in Fuse

Autoscaling is an easy repeatable way of spinning up fabric containers associated with the profiles . It can be particularly helpful while performing load tests and also to create the containers when new profiles are being deployed to the environment.

• Add the auto-scale profile to the root-container of the fabric (parent container ) not to the child containers.

Profile Requirements  can be defined  in two ways;from the web-console or the command line.

• Command Line : 
• fabric:require-profile-set command is used for defining the requirements for the instances that the profile is applied on 
• fabric:require-profile-set --minimum 1 --maximum 3 some-profile-id which then tells fabric that a minimum of one instance should always be associated with the profile in the fabric environment and also that a maximum of 3 instances can be associated at any given time.
• Web-Console
• Navigate to the Profiles page on the Hawt-io screen.
• Select the profile to which you want to add the requirements.
• Click the Add-Requirements link to the right of the screen.

• Provide the minimum and Maximum number of hosts to be associated with the profile.

Issues

Once the autoscaler is defined on the root container , the requirements on the profile will be auto-provisioned by the fabric environment . 

• But if for any reason the child containers are brought down , fabric will automatically create a new instance , this might prove to be a problem in case the child containers is being brought down for maintenance.
• If a container is down and is associated to a minimum requirements on a profile , the fabric will spin up a new container but will not attempt to start the shut-down container.