Enabling/Disabling AWS Load Balancer Target Nodes for Maintenance


Question: Is there any way to temporarily disable/re-enable Network Load Balancer Target Group nodes for maintenance like we usually do with other load balancers?

Background: We have a distributed replicated LDAP service that serves our enterprise. It is based in multiple datacenters of various architectures. We have several representative LDAP nodes in AWS under a Network Load Balancer to provide service to our AWS-based applications. These LDAP nodes each hold a replicated copy of the entire directory, which consists of 1.8 million accounts plus attendant groups and other structures. The service is more akin to a database and loading the data can take a few hours, so the nodes aren't so amenable to auto-scaling processes. These nodes run RHEL7 and 389 Directory Server.

Attempted Solution: I've tried draining/re-registering each node for maintenance but it didn't work particularly well as the connections don’t seem to get killed reliably when drained and the whole drain/re-register operation takes a long time. I also don't want to have to rebuild my target group every time I do maintenance on the nodes

Thanks a lot

asked a year ago2235 views
1 Answer

A set of target group options you could look in to improve the drain and deregistration time of your NLB targets would be the Deregistration Delay and Connection Termination on Deregistration.

The Deregistration Delay can be modified from the default value of 300 seconds to decrease the time ELB will wait before changing the state of a target from "draining" to "unused". As well, modifying "Connection termination on deregistration" to "true" is a recommended option that will cause NLB to terminate any remaining active connections to that target once the Deregistration Delay time is reached, bringing it to a fully deregistered state.

Hope this helps!

answered a year ago

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