Add explicit (separate) "docker-swarm" and "triton" docker-compose files

[tianon]

Since Triton does not yet support docker network, this is the best solution for making sure this repository can function appropriately in both environments (uses docker network for Swarm and --link for Triton).

Without this, Swarm will see --link and co-schedule all the containers, which defeats the whole purpose of the demonstration.

[tianon]

Any particular reason we don't just embed CONTAINERBUDDY=file:///etc/containerbuddy.json directly in the image itself?

[misterbisson]

You're right to ask. That's what we've started doing since this one. Example: https://github.com/autopilotpattern/couchbase/blob/master/Dockerfile#L12

[tianon]

cc @misterbisson

[misterbisson]

@tianon if this repo implemented the DNS discovery of Consul as it's demonstrated in https://github.com/autopilotpattern/jenkins and https://github.com/autopilotpattern/couchbase (and discussed in #10), how would that change this PR?

Related: I just ticketed the task of adding setup and demo scripts, #12 and explained it in more detail in autopilotpattern/wordpress#1 (comment)

[misterbisson]

Ideally we'd eliminate the common-compose.yml entirely. We dropped it in our more recent blueprints because eliminating the use of --link for Consul meant that the main docker-compose.yml could be the common parent. https://github.com/autopilotpattern/couchbase is a good example.

[misterbisson]

FYI, I've started work on fixing up this repo in #14

[tianon]

I think some of the Triton vs Swarm issues might make more sense in the context of a diff between the two:

diff --git a/docker-swarm/docker-compose.yml b/triton/docker-compose.yml
index d282c07..89130e7 100644
--- a/docker-swarm/docker-compose.yml
+++ b/triton/docker-compose.yml
@@ -6,8 +6,12 @@ services:
         extends:
             file: ../common-compose.yml
             service: mysql
+        network_mode: bridge
+        links:
+            - consul:consul

     consul:
         extends:
             file: ../common-compose.yml
             service: consul
+        network_mode: bridge

The addition of links is to combat the fact that Triton doesn't have DNS (which could use CNS given #11, but I'm honestly not convinced that's actually simpler since now my _env needs even more account-specific information in it that it didn't need before), and the addition of network_mode is to stop docker-compose from trying to create an overlay network (which fails outright on Triton).

Even with that other approach, I don't see a simple way to get back to a single docker-compose.yml that works for both unless Triton implements some bits of the new Docker networking features. 😞

[tianon]

(If you'd rather, I'm happy to move the discussion of --links over to #12, but it sounds like the goal of doing so is to remove the need for two docker-compose.yml files, which won't actually be doable AFAICT 😢)

[tianon]

Just verified -- with a version 1 docker-compose.yml, docker-compose does not create an overlay network, and thus doesn't give us DNS to access consul for free. 😞 (which is the reason we had to move to version 2 in the first place)

[misterbisson]

I don't see a simple way to get back to a single docker-compose.yml that works for both unless Triton implements some bits of the new Docker networking features

We've got good news on that coming. So, it'll be two files for now, but one in the future. At the same time, we're also looking at moving the local development to Swarm environments to make it easier to test multi-host environments on our laptops.

My biggest concern isn't really about this PR, but with how much we've learned about other things that I'd want to implement here before we enshrine the historical practice. Thanks for your patience and insight as we try to work through both problems at once.

[misterbisson]

Triton doesn't have DNS

Say more about what you're expecting that isn't covered by https://www.joyent.com/blog/introducing-triton-container-name-service? Is it just that the search domain isn't automatically set?

[misterbisson]

FYI, I've started work on fixing up this repo in #14

[tianon]

Is it just that the search domain isn't automatically set?

That's the one! 😄 👍

Happy to have helped spur so much interesting discussion. 😄

[misterbisson]

Regarding Triton support for Docker Compose file format v2 and Docker network syntax, I should share the following tickets:

• https://smartos.org/bugview/DOCKER-585: Leverage network driver in docker run for specifying networks
• https://smartos.org/bugview/DOCKER-723: support docker network create
• https://smartos.org/bugview/DOCKER-724: support docker network connect|disconnect
• https://smartos.org/bugview/DOCKER-725: support docker network ls
• https://github.com/joyent/rfd/blob/master/rfd/0018/README.md is not the approach we're taking for specifying networks

[tianon]

Re: DOCKER-585, I can't seem to find a --publish-service flag, but the flag Compose uses is --net-alias, which does allow multiple aliases, so seems like an OK candidate for TCNS (just tested myself with --net-alias a --net-alias b --net-alias c, which was successful).

$ docker run -dit --name test --net-alias a --net-alias b --net-alias c --net some-network debian:sid
...
$ docker inspect test
...
            "Networks": {
                "some-network": {
                    "IPAMConfig": null,
                    "Links": null,
                    "Aliases": [
                        "a",
                        "b",
                        "c"
                    ],
                    "NetworkID": "e76b7deb5c688dcf4829acc02ffff84bdbde9e3ba2fe98b3dc1068c7fb1e98a7",
                    "EndpointID": "6592a9634170458ac9ce98b23f0db8c01dba016281bf9bf1707fd408a4b41705",
                    "Gateway": "172.19.0.1",
                    "IPAddress": "172.19.0.3",
                    "IPPrefixLen": 16,
                    "IPv6Gateway": "",
                    "GlobalIPv6Address": "",
                    "GlobalIPv6PrefixLen": 0,
                    "MacAddress": "02:42:ac:13:00:03"
                }
            }
...

(but worth pointing out that the aliases are network-specific)

[tianon]

(is there any way I could subscribe to these bugs without doing something hacky like page2rss?)

[misterbisson]

I can't seem to find a --publish-service flag

Right. That was from an earlier, proposed Docker syntax back in 2015. I need to add a note there about --net-alias. Thank you for highlighting it.

is there any way I could subscribe to these bugs without doing something hacky like page2rss?

That's my goal, but I'm not aware of a better plan today.

[tianon]

Rock on, thanks! 👍 🤘

[misterbisson]

@tianon I've added #19 with what I think is a plan to integrate what you've shown us here in to the rest of the repo. Does that make sense?

[tgross]

I think we can finally close this one because of the work done in #79 for #19