Monitoring Application and Scale¶
Monitoring Applications instances¶
- When deployment finishes all noded turn green
- On the instance list the application is shown as “DEPLOYED”.
- Monitoring metrics are presented for each one of the application nodes
Application Elasticity¶
- From the application instance list, the user must select the “Elasticity Policies” option for the deployed application, in order to configure how the application scales.
- By selecting the appropriate function, user can to aggregate the monitoring results in various ways.
- For the monitored parameter we select the metric and it’s dimension from appropriate lists.
- An operand shall be added to the policy and the threshold that the policy shall confirm to.
- The period field is used to set the size of the time window that the metric values are collected and aggregated for the policy enforcement.
- On the scaling action we can select the component to scale in or scale out, and the number of workers to scale.
- After a scaling action is performed, some time is needed for having the component workers deployed. For this reason we should ensure that for this period we don’t fire additional scaling actions.
- This is done through the “Inertia” field that is used to define the time in minutes that after a scaling action is done,no further action is performed.
- Multiple scaling actions can be added.
- The policy can be saved and will be enforced to the application within few seconds.
- In this example we had initially only one worker of the WordPress component.
- But due to the scaling rule, an additional node has been created.
- A load balancer had been already deployed from the initial deployment since we had defined that this component might need multiple workers.
- The scaling action is visible to the user through the logs and the number on workers in the “WordPress” node in the graphs.