Enabling/Disabling AWS Load Balancer Target Nodes for Maintenance

Question

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

Justin_B · 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](https://docs.aws.amazon.com/elasticloadbalancing/latest/network/load-balancer-target-groups.html#target-group-attributes).

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!

Enabling/Disabling AWS Load Balancer Target Nodes for Maintenance

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