Containers that run on two hosts can communicate?

Nomad
1

Hi,
I looked to many places, but could not see a clear answer to my this question:

If I create a job with multiple task groups, so that different groups run on different nodes/hosts, can those containers share same network? So, can they communicate with each other? My target is to run a mysql cluster in Nomad, but to place containers in different nodes, to be able to achive high availability.

In documentations and all help articles, I could not see such a scenario. There is even no “mysql cluster HA” example.

If you need more info, let me know.

I am trying to find this myself by installing Nomad on two nodes, but there are lots of unknowns for me. There is even no simple step by step guide to install a multi-node Nomad cluster… That is a little bit discouraging…

Thanks.

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Hi @support3,

If I create a job with multiple task groups, so that different groups run on different nodes/hosts, can those containers share same network? So, can they communicate with each other?

Yes, with the caveat that it depends on the underlying network topology and firewall rules allowing the traffic between the two instances. The service discovery Learn guides and the consul integration Learn guides provide good examples of how to register and discover services, so that you do not need to use hardcoded port values. The network job specification page is also a good reference in this topic area.

In documentations and all help articles, I could not see such a scenario.

The Nomad team have been working on improvements to our networking documentation; this is currently under review. PR #15358 has the work, and can provide a useful reference for additional learning.

simple step by step guide to install a multi-node Nomad cluster.

The Nomad Learn track has this guide on setting up a mulit-node cluster on AWS and this Terraform GCP project walks through setting up a multi-node cluster on GCP among other resources. If you have feedback about any areas in which these can be improved, that would be wonderful and much appreciated.

Thanks,
jrasell and the Nomad team

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