See #7593. Use connection_max to stop connections in rabbitmq

[SimonUnge]

Proposed Changes

Closes #7593

Use connection_max to limit connections per node, from rabbitmq code, instead of ranch.

Add ranch_connection_max setting for setting ranch connection max.

Types of Changes

What types of changes does your code introduce to this project?
Put an x in the boxes that apply

• Bug fix (non-breaking change which fixes issue #NNNN)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause an observable behavior change in existing systems)
• Documentation improvements (corrections, new content, etc)
• Cosmetic change (whitespace, formatting, etc)
• Build system and/or CI

Checklist

Put an x in the boxes that apply.
You can also fill these out after creating the PR.
If you're unsure about any of them, don't hesitate to ask on the mailing list.
We're here to help!
This is simply a reminder of what we are going to look for before merging your code.

• I have read the CONTRIBUTING.md document
• I have signed the CA (see https://cla.pivotal.io/sign/rabbitmq)
• I have added tests that prove my fix is effective or that my feature works
• All tests pass locally with my changes
• If relevant, I have added necessary documentation to https://github.com/rabbitmq/rabbitmq-website
• If relevant, I have added this change to the first version(s) in release-notes that I expect to introduce it

Further Comments

N/A

[lhoguin]

Nevermind the previous comment I understand now. Looks good to me, thanks!

[michaelklishin]

We don't have a lot of details but in #7787 this new function runs into an exception when a client connects.

[michaelklishin]

Here are various config files

[michaelklishin]

RABBITMQ_NODENAME=rabbit@primary
RABBITMQ_LOG_BASE=/var/log/kolla/rabbitmq
RABBITMQ_DIST_PORT=25672
RABBITMQ_PID_FILE=/var/lib/rabbitmq/mnesia/rabbitmq.pid
RABBITMQ_SERVER_ADDITIONAL_ERL_ARGS="-kernel inetrc '/etc/rabbitmq/erl_inetrc' +S 2:2 +sbwt none +sbwtdcpu none +sbwtdio none"
RABBITMQ_CTL_ERL_ARGS=""

export ERL_EPMD_ADDRESS=192.0.2.1
export ERL_EPMD_PORT=4369
export ERL_INETRC=/etc/rabbitmq/erl_inetrc

[
  {kernel, [
    {inet_dist_use_interface, {192,0,2,1}},
    {inet_dist_listen_min, 25672},
    {inet_dist_listen_max, 25672}
  ]}
].

[michaelklishin]

A follow-up that will go into 3.11.13 #7788