Can Fabio to prefer one ethernet interface for proxy_addr?

[protocol6]

Hi,

I'm running a cluster where the worker nodes run Nomad and Consul.
Each node (on Digitalocean) has a public IP on eth0 and a private IP on eth1.
I schedule fabio onto this cluster via nomad jobspec like so,

  group "fabio" {
      task "fabio" {
      driver = "exec"
      config {
        command = "fabio-1.5.14-go1.15-linux_amd64"
        args = ["-proxy.addr", ":9999", "-ui.addr", ":9998"]
      }

Unfortunately the above stanza results in fabio proxy_addr binding to my public IPs and not the private ones, which results in an⋅
empty/non-working routing table on private:9998/routes.⋅

Based on issue #653 I tried the following argument format, but it causes the allocated job to fail.

args = ["-proxy.addr", "{{ GetInterfaceIP 'eth1' }}:9999", "-ui.addr", "{{ GetInterfaceIP 'eth1' }}:9998"]

Based on issue #283 I tried the following, but these too causes the fabio job to fail and/or to violate jobspec syntax..

args = ["-proxy.addr", "eth1:9999", "-ui.addr", "eth1:9998"]

and

`args = ["-proxy.addr", "${ifconfig eth1 | grep 'inet' | awk '{print $2}' | cut -d: -f2}:9999", "-ui.addr", "${ifconfig eth1 | grep 'inet' | awk '{print

Question: is there a working mechanism in Fabio that lets you prefer one ethernet interface over another (eth1 for me)
and which is compatible with job submission via Nomad jobspec?

[nathanejohnson]

So several questions:

1. what does your nomad job spec look like?
2. are you sure there is an eth1 available?
3. what is nature of the nomad failure?

The first example you gave should more or less work, assuming eth1 exists and is available when fabio is launched

[protocol6]

Hi nathanejohnson,

Thanks for responding so quickly and sorry for my radio-silence.

I think I may have solved my issue with the following pattern. It seems to reliably bind fabio to the private IP, but I can't guarantee that it will always work in very circumstance.

group "fabio" {
      task "fabio" {
      driver = "exec"
      config {
        command = "fabio-1.5.15-go1.15.5-linux_amd64"
        args = ["-proxy.addr", "$${attr.unique.network.ip-address}:9999", "-registry.consul.addr", "$${attr.unique.network.ip-address}:8500", "-ui.addr", "$${attr.unique.network.ip-address}:9998"]
      }

      artifact {
        source = "https://github.com/fabiolb/fabio/releases/download/v1.5.15/fabio-1.5.15-go1.15.5-linux_amd64"
      }

The key to making this work for me was the use $$ instead of just $. Apparently this provides a necessary shell escape at least when using the Nomad provider in Terraform.

I would call this issue solved.

Thanks again for your attention.

:-)