What is an autoscaler and what are the consequences of its enabling (also in the context of a container)
Posted by on 05.09.2012 09:52
Due to a unique mechanism to observe the behaviour of instances and their groups, Oktawave autoscaler can dynamically change the parameters of the instance (reserving RAM, CPU - vertical autoscaling ) and change the number of instances in the container that supports the specified service (horizontal autoscaling). In conjunction with the load balancing service it ensures a smooth, stable operation of your services no matter the circumstances.
Enabled Oktawave autoscaler constantly monitors the load on the instances and their containers. If in the past 20 minutes the load is maintained at over 80%, the response taken depends on the chosen settings.
Autoscaler mechanism settingscan be found in the panel in each instance tab. Autoscaler configuration for containers is described later in this text.
For each newly created instance autoscaler is disabled by default. Turning it ON enables the system to change OCI instances class up and down without confirmation (requires instance restart), as well as to adjust the allocated memory (without restart). This method is the best way to optimize the cost of the instance and its performance.
You can choose from many autoscaler settings.
After changing the settings, click Apply.
To edit the settings of the autoscaler of a container of an instance, click its name (subpage Oktawave | Services | Containers). A list of containers can be found in the Dashboard. The container panel includes Autoscaling tab.
Mechanism is disabled by default. Editing settings of the container autoscaler is more complex than of a single instance. This allows for scaling of raising the class of machines or their number.
If you choose the scaling method Changes the number of machines, you must select its type. Cloning involves creating and attaching instances to the container of such a configuration, as chosen by you for the master machine (Select OCI instance).
The option Add existing involves increasing the existing power of the container by attaching to it an OCI instances created earlier. After clicking Free OCI instances you will see a list of machines that were not assigned to any container. Select the ones you want to be used by the autoscaler if it detects a need for increased computing power.
The last thing you need to specify is the maximum and minimum number of OCI in the container. The lower limit is intended to ensure that even at low load, a number of instances will work and your service will not be surprised by a sudden increase in traffic.
The upper limit protects you e.g. from the exhaustion of the budget due to an unexpected load increase.
Autoscaler features are complemented by Schedulers, the tools for the automatic implementation of planned actions on instances and containers. To create a new scheduler, enter the appropriate tab in the container panel and click Add Scheduler.
After naming the scheduler you must determine whether it should performa one-time action or cyclical, and when it is to be carried out for the first time. If you decide on cyclical actions, you still must select how often they should be performed (the number of days / weeks).
Then, in the fields you choose what action is to be carried out. You can choose from several options, including Parki the machine, Turn in on, Remove, Add to a container. Depending on the action selected you will see a window with its specific settings. When you finish creating the scheduler, click Save
How to use schedulers for an even more effective scaling of the Oktawave services and IT cost optimization? Note that autoscaler monitors the load and if in the past 15 minutes the load was maintained at over 80%, this mechanism increases the efficiency by one step, and repeats the monitoring of the situation for the next fifteen minutes.
In the case of a significant increase in load the ultimate efficiency adaptation might take a few dozens of minutes. While automatic adding or removing machines by the scheduler is instantaneous. So if for example, you are responsible for a system that is used by most employees between 8 am and 5 pm, you can create a scheduler, which will add additional machines before 8:00 am, and will remove them immediately after 5:00 pm.