Nagios Support Forum

hsmith wrote:I'm pretty unfamiliar with third party load balancers. To the best of my understanding, NLS does a pretty good job balancing its own load when you have multiple instances, I'm not sure what the interaction would be like if you were to add another one on top of that.

What exactly is being load balanced by NLS? At what point does one need to worry about introducing external load balancers when using NLS minimum and recommended specs?

NLS has essentially one component that does real load-balancing, and that's the Elasticsearch component. In this regard it load-balances the burden of storing and querying logs, in the sense that:

• Each node in the cluster will hold a subset of the logs as well as potentially a backup of logs it does not have (there are primaries and replicas of the logs, basically)
• When a query is performed, the CPU and memory of each node in the cluster is able to simultaneously be used to handle the request

There is also the Logstash component to consider, which itself is not particularly load-balanced - any node in the cluster can accept logs and send them to the cluster to be stored, but typically only one actual node in the cluster is defined by the remote machines to be the recipient.

So as far as true load-balancing, I wouldn't say a lot needs to be done externally, but you might want to look into round-robin DNS or something similar so that remote machiens sending in logs don't have to worry about the receiving node going down.