Confused by network behaviour

[ashic]

Hi,
I'm trying out singularity, and so far it looks good. I'm trying to sort out networking, but it's baffling me:

• I've created a single instance service that's not load balanced. In deploy, I specify docker: tutum/hello-world , bridge network with the following:

Container port type: Literal, 80
Host port type: Literal, 31010

When I do this, I get a response back from hostname:80, but not from hostname:31010. I should add that --resources=ports:[8000-8050,31000-32000] is specified when launching the slave.

• I'd really like to be able to hit a service endpoint instead of slave machines. I see that if I select "load balanced" when creating the request, I get a service base path (e.g. /singularity/api/v2) option when deploying. However, I've not been able to get this to work. Do I need something else set up for this to work? I don't have mesos-dns setup. Will that help? Will https://github.com/CiscoCloud/mesos-consul be useful for this as well?
• When selecting Bridge Network and adding a Docker Port Mapping, I see that using

Container Port Type: Literal, 80
Host Port Type: From Offer
Container Port: 0
Protocol: tcp

gives me the following error:

There was a problem: Index of port resource for hostPort must be between 0 and -1 (inclusive)

Is this expected? Is there some documentation as to how docker networking relates to Singularity?

Thanks,
Ashic.

[ashic]

Just solved the third bit: needed to ask for 1 port to be able to do From Offer[0]. First two points are still confusing me though. Tried the following:

"containerInfo": {
            "type": "DOCKER",
            "docker": {
                "image": "tutum/hello-world",
                "privileged": false,
                "network": "BRIDGE",
                "portMappings": [
                    {
                        "containerPortType": "LITERAL",
                        "containerPort": 80,
                        "hostPortType": "LITERAL",
                        "hostPort": 8050,
                        "protocol": "tcp"
                    }
                ]
            }
        },

Yet still, curl localhost:8050 fails, while curl localhost:80 succeeds. [curl call made from host, not container. container hosts a web page on port 80]. Any ideas?

[ssalinas]

To speak to your first point, there are a number of options for load balancing services run in mesos. We use Singularity with Baragon and nginx, which allows each load balanced service running in mesos to be available at a certain path (via nginx) and Baragon keeps the host:port of the running services in sync with Singularity. Docs for that can be found here and here

I am still investigating your second question. It seems that you have it correct and I will let you know if I find anything

[ssalinas]

Issues addressed here should be fixed by #837