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overnode-org / overnode

Predictable container deployment and management on top of automated multi-host docker-compose
https://overnode.org/
MIT License
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Docs: Service Discovery #23

Open jtagcat opened 4 years ago

jtagcat commented 4 years ago

https://overnode.org/docs/service-discovery

First of all, service discovery says 'the nodes find each other within a lan' to me.

avkonst commented 4 years ago

sorry, not sure what you mean... what do you want to change?

jtagcat commented 4 years ago

The page's title and maybe something about on how it gets the domain.

avkonst commented 4 years ago

Service Discovery is commonly used term in the container orchestration space. Everybody uses in k8s, swarm, etc... I do not think it is a good idea to change the page's title.

Also, I am not sure what you mean by "maybe something about on how it gets the domain" ? what domain? .weave.local?

jtagcat commented 4 years ago

https://en.wikipedia.org/wiki/Service_discovery

hmmm

Every node has got a set of configurable target nodes. A node proactively initiates a connection with the target nodes on start up and after a connection is lost. All other (non-target) nodes are discovered eventually via gossips and also inter-connected with each other. Connections are initiated to ports 6783 and 6784 via TCP and UDP protocols, so it should be allowed on a host / networking / firewall level. Selection of target nodes for each node is a decision you will have to make depending on an application, networking constraints, etc. As a safe default option, aim for each node to have every other node added as a target node.

I would describe the action like so:

Service Discovery is when a node discovers a non-target node through its list of target nodes, and treating the discovered node as equals, without user interaction, and ignoring the id 1-4 thing.

avkonst commented 4 years ago

I see where the confusion is coming from. This page https://overnode.org/docs/service-discovery is talking about discovery of containers' IP addresses, but not discovery of the IP addresses or peer nodes. These are 2 separate things.

The first is "nodes need to discover it's peers"

The second is "a container within a cluster needs to discover it's lower layer services, which it depends on" - the page is about this one.

So your proposed definition: "Service Discovery is when a node discovers a non-target node through its list of target nodes, and treating the discovered node as equals, without user interaction, and ignoring the id 1-4 thing." is for the first point, but not about the second. Container orchestration tools reserve the term "Service Discovery" for the second purpose, and I strongly believe Overnode should keep it and be aligned.

The wording for the first point should be improved to make sure it does not build the wrong association with the second.

Makes sense?