To configure a trigger for the automatic horizontal scaling, follow the steps below.
When a single certified application server (not a custom Docker container) is scaled out on environment without load balancers
, the NGINX balancer is added automatically. Herewith, if you require a different one for your application, it should be added manually before the first scaling event.
1. Click the Settings
button for the required environment.
2. In the opened tab, navigate to the Monitoring > Auto Horizontal Scaling
section, where you can see a list of scaling triggers configured for the current environment (if any).
Use the buttons at the tools panel to manage auto horizontal scaling for the environment:
Click Add to proceed.
3. Select the required environment layer from the drop-down list and choose the resource type to monitor via one of the appropriate tabs (CPU
, Disk I/O
, Disk IOPS
- the initial (master) node can be used as a storage server for sharing data within the whole layer, including nodes added through automatic horizontal scaling
- the CPU and Memory limits are calculated based on the amount of the allocated cloudlets (a special Jelastic resource unit, which represents 400 MHz CPU and 128 MiB RAM simultaneously)
4. The graph to the right shows the statistics on the selected resource consumption. You can choose the required period for displayed data (up to one week) using the appropriate drop-down list. Herewith, if needed, you can enable/disable the statistics’ Auto Refresh
Also, you can hover over the graph to see the exact amount of used resources for a particular moment. Use this information to set up proper conditions for your triggers.
5. Each trigger has Add
and Remove Nodes
conditions, which can be enabled with the corresponding check-boxes right before the title.
Both of them are configured similarly:
When configuring a trigger, we recommend taking into consideration the scaling mode of the layer. For example, you should set lower loading percent in the Add Nodes trigger for the stateful mode, as content cloning requires some time (especially for containers with a lot of data) and you can reach resources limit before a new node is created.
6. You automatically receive an email notification on the configured auto horizontal scaling trigger activity by default; however, if needed, you can disable it with the appropriate Send Email Notifications
7. At the bottom of the form you have the following buttons:
- Undo Changes - returns to the previous state (for editing only)
- Close - exits the dialog without changes
- Apply (Add) - confirms changes for the trigger
the required option to finish trigger creation (adjustment).