Is there a way to set the backlog in listener?

[rodericliu]

STORY DESCRIPTION WRITING IS IN PROGRESS

Background

The backlog parameter of the NGINX listen directive can be used to increase the backlog (maximum length for the queue of pending connections), which is by default 511 for Linux. This can be helpful if as an admin you have a high rate of incoming connections and you are getting uneven levels of performance (for example some connections appear to be stalling).

References:

• NGINX listen directive – https://nginx.org/en/docs/http/ngx_http_core_module.html#listen
• NGINX tuning for high performance – https://nginx.org/en/docs/http/ngx_http_core_module.html#listen
• See also https://learning.oreilly.com/library/view/tcp-ip-illustrated-volume/9780132808200/ch13.xhtml 13.7.4. Incoming Connection Queue

Note: If you have multiple servers in NGINX for the same IP:port combination (like *:8001 below), you only need to set the backlog once.

server {<br/> listen 8001 backlog=1024;<br/> server_name a.com;<br/> return 200 "$server_name\n";<br/>}<br/>server {<br/> listen 8001;<br/> server_name b.com;<br/> return 200 "$server_name\n";<br/>}

Use Cases

• As an admin, I would like to fine tune the backlog parameter of NGINX listeners for VirtualServer ports 80 and 443.

Functional Requirements

Configuration

Normal Functioning

Edge Cases

Out of Scope

• Backlog for NGINX stream module (TransportServer resources).

Acceptance Criteria

• Functional requirements are implemented
• Test automation is written and covers normal functioning and edge cases
• Documentation is written (we need to add an entry in the table here https://docs.nginx.com/nginx-ingress-controller/configuration/global-configuration/configmap-resource/#listeners )

Aha! Link: https://nginx.aha.io/features/IC-175

[github-actions[bot]]

Hi @rodericliu thanks for reporting!

Be sure to check out the docs while you wait for a human to take a look at this 🙂

Cheers!

[vepatel]

Hi @rodericliu,

If you're using ingress resource, you can set if using annotations:

name: my-ingress
  annotations:
    nginx.org/server-snippets: |
      listen 80 backlog=1024;

[rodericliu]

hi @vepatel,

Yes, it added a listen backlog in ingress nginx server block, but nginx complained a duplicate listener on 80.

How did you solve it?

Roderic Liu

[vepatel]

Hi @rodericliu,

In that case we'd recommend you to use custom-template for ingress in your configmap: https://github.com/nginxinc/kubernetes-ingress/tree/v1.12.0/examples/custom-templates#example you'll have to pass your whole ingress config there as we don't have a configmap key parameter for backlog.
eg:

 ingress-template: |
    listen 80  backlog=1024;

[rodericliu]

Hi @rodericliu,

In that case we'd recommend you to use custom-template for ingress in your configmap: https://github.com/nginxinc/kubernetes-ingress/tree/v1.12.0/examples/custom-templates#example you'll have to pass your whole ingress config there as we don't have a configmap key parameter for backlog.
eg:

 ingress-template: |
    listen 80  backlog=1024;

Hi @vepatel,

Thanks for your help. I managed to fix it by the solution provided by you!

Roderic Liu

[bkannadassan]

@rodericliu Is there a way to specify the backlog in the latest builds ? or is it still via the custom template ?. If its via custom template then how does this co-exist with the streams ?. What I meant is those added via Transport CRD how can I get backlog added to the same ?