Set default network scheduler to fight bufferbloat.

fgci-org / fgci-ansible

:microscope: Collection of the Finnish Grid and Cloud Infrastructure Ansible playbooks

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Set default network scheduler to fight bufferbloat. #158

Closed jabl closed 8 years ago

jabl commented 8 years ago

Set the default network scheduler to "fq". On routers (NAT gateways) it's recommended to override this and set network_scheduler="fq_codel".

martbhell commented 8 years ago

From examples it seems that admin,grid,login and install all have NAT iptables rules. Probably only login and install are needed (install is during initial install of the cluster).
There is an ansible-system-limits which we could add to the install node to. It's already used with login and compute nodes to set ulimits so should not cause any issues. That role doesn't use the sysctl module for some reason.

Can we use the system-limits instead?

jabl commented 8 years ago

I didn't use system-limits as I thought it would be nicer to have networking sysctl's together with other networking configs.

Also, as you say, system-limits doesn't use the sysctl module.

But I have no particularly huge feelings either way on this.

jabl commented 8 years ago

PING? Is this Ok to pull, or do you want me to do some further work?

(I'd like to have this in before we roll over our kernels, as this setting only takes effect after an interface is brought down + up again, so we'd like to doing it at the same time we're doing a rolling reboot)

martbhell commented 8 years ago

Sorry for the delay. We had some internal discussion.