If a cluster can process current traffic without fully utilizing its resources, you can scale in the cluster to cut costs.
Scaling in a Logstash cluster means to randomly remove some of its nodes, so that it is less costly to keep it running.
Scale-in process: Random remove cluster nodes and modify the cluster configuration.
Impact on Billing
For a pay-per-use cluster, you can see its new price when confirming the scale-in on the console. After the scale-out or scale-up is complete, the new price will apply. For pricing details, see .
Constraints
- To reduce the impact on services, you are advised to perform scale-in during off-peak hours.
- In a cross-AZ cluster, the difference between the numbers of the same-type nodes in different AZs cannot exceed 1.
Change Impact
Before the change, learn about possible impacts and operation suggestions, and develop a plan to minimize these impacts.
- Impact on cluster throughput
Taking Logstash nodes offline usually does not interrupt services. However, jobs that are running on these will be stopped, causing the cluster throughput to decrease.
- Characteristics of this process
Once started, a scaling task cannot be stopped until it succeeds or fails.
Scale-in Duration
The following formula can be used to estimate how long a scale-in operation will take:
Scale-in duration (min) = 5 (min) x Number of nodes to be removed
where, 5 minutes is the duration per node. It is an empirical value.
Prerequisites
The cluster status is Available, and there are no ongoing tasks.
Reducing the Nodes of a Logstash Cluster
- Log in to the CSS management console.
- In the navigation pane on the left, choose Clusters > Logstash.
- In the cluster list, find the target cluster, and choose More > Modify Configuration in the Operation column. The Modify Configuration page is displayed.
- Select the Scale Cluster tab and click Scale in to set parameters.
Table 1 Removing nodes randomly Parameter
Description
Action
Select Scale in.
Resources
Quantities of resources reduced.
Nodes
Reduce the number of nodes in the Nodes column.
- Click Next.
- Confirm the information and click Submit.
- Click Back to Cluster List to go back to the Clusters page. Task Status is Scaling in. When Cluster Status changes to Available, the cluster has been successfully scaled in.
Related Documents
To optimize costs, you may also reduce the capacity of a Logstash cluster by downgrading node specifications. For details, see Changing the Node Specifications of a Logstash Cluster.