Add maximum replicas per node support to stack version 3.8

[olljanat]

- What I did
Added support for maximum replicas per node to docker stack deploy

Fourth step to be able solve:

• Add --max-replicas-per-node for docker service create moby/moby#26259

- How I did it
Added new schema 3.8 version including max_replicas_per_node setting

- How to verify it

Use stack like this:

version: "3.8"
services:
  test:
    image: nginx
    networks:
      - test
    deploy:
      mode: replicated
      replicas: 2
      placement:
        max_replicas_per_node: 1

networks:
  test:
    driver: overlay

NOTE! Max replicas value from stack file does not work yet. More details in below.

- Description for the changelog

• Split empty compose version 3.8 own commit.
• Split non-stack version of implementation to Add support for maximum replicas per node without stack #1612

TODO:

• Make sure that max_replicas_per_node setting works correctly on stack file.
• Create another PR to describe max_replicas_per_node on https://github.com/docker/docker.github.io/blob/master/compose/compose-file/index.md

[codecov-io]

Codecov Report

Merging #1410 into master will decrease coverage by 0.79%.
The diff coverage is 100%.

@@            Coverage Diff            @@
##           master    #1410     +/-   ##
=========================================
- Coverage   56.12%   55.32%   -0.8%     
=========================================
  Files         306      283     -23     
  Lines       20964    19331   -1633     
=========================================
- Hits        11766    10695   -1071     
+ Misses       8345     7939    -406     
+ Partials      853      697    -156

[GordonTheTurtle]

Please sign your commits following these rules:
https://github.com/moby/moby/blob/master/CONTRIBUTING.md#sign-your-work
The easiest way to do this is to amend the last commit:

$ git clone -b "replicas-max-per-node" git@github.com:olljanat/cli.git somewhere
$ cd somewhere
$ git rebase -i HEAD~842354053072
editor opens
change each 'pick' to 'edit'
save the file and quit
$ git commit --amend -s --no-edit
$ git rebase --continue # and repeat the amend for each commit
$ git push -f

Amending updates the existing PR. You DO NOT need to open a new one.

[olljanat]

@vdemeester @thaJeztah Rebased to latest state of master. I think that it would be nice to have first review round and I really would have use to good ideas why max replicas value is not read from stack file.

[thaJeztah]

left some comment, but I'll have to dig into the compose issue as well

ping @vdemeester any clues?

[thaJeztah]

Oh, sorry, I probably didn't describe #1410 (comment) properly ☺️ 😓 😅

What I meant is; include the new schema in this PR, but split it in two; similar to;

1. 787e30d (adding the new schema, which is a copy of the previous version with only the version changed)
2. followed by 47cf2ea (which adds the new feature/field to the schema)

Both of the above are part of the same PR (#426), but having 2. separate makes it a) easier to review what exactly changed in the schema, and b) allows finding the PR that added the new feature (using "git blame")

[olljanat]

@thaJeztah ahaa. No worries. Updated 😉

[olljanat]

Now this works correctly.
@silvin-lubecki @thaJeztah PTAL

[silvin-lubecki]

LGTM thank you @olljanat and sorry for the delay!

[thaJeztah]

LGTM, thanks!

did a quick check if the latest schema changes in the 3.7 schema (#1657) were copied to the 3.8 format, and all looks well;

--- cli/compose/schema/data/config_schema_v3.7.json	2019-02-20 13:09:49.000000000 +0100
+++ cli/compose/schema/data/config_schema_v3.8.json	2019-02-20 13:09:49.000000000 +0100
@@ -1,6 +1,6 @@
 {
   "$schema": "http://json-schema.org/draft-04/schema#",
-  "id": "config_schema_v3.7.json",
+  "id": "config_schema_v3.8.json",
   "type": "object",
   "required": ["version"],
 
@@ -424,7 +424,8 @@
                 },
                 "additionalProperties": false
               }
-            }
+            },
+            "max_replicas_per_node": {"type": "integer"}
           },
           "additionalProperties": false
         }

[thaJeztah]

So what's remaining after this;

• update documentation https://github.com/docker/docker.github.io/blob/master/compose/compose-file/index.md
• update compose-file changelog https://github.com/docker/docker.github.io/blob/master/compose/compose-file/compose-versioning.md#version-37
• update docker-compose to accept the 3.8 schema(?) @ulyssessouza @chris-crone

[zcaudate]

Which version of docker should I be using to have this supported?

Currently I'm using the following version but it's not working for me

Version:           19.03.8
API version:       1.40
Docker Compose:  1.25.5

[olljanat]

@zcaudate because you are listing docker compose version here it sounds that you are understood something wrong. This feature works only with docker stack deploy command on Swarm mode. Not with docker-compose.

[zcaudate]

I might be missing something but docker stack deploy takes a docker-compose file doesn’t it? I included the version just to make sure that there wasn’t a compatibility issue with swarm and docker compose.

…

On 24-May-2020, at 4:11 PM, Olli Janatuinen ***@***.***> wrote: @zcaudate because you are listing docker compose version here it sounds that you are understood something wrong. This feature works only with docker stack deploy command on Swarm mode. Not with docker-compose. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub, or unsubscribe.

[olljanat]

@zcaudate Yea syntax which stack deploy uses have is based docker-compose but those works differently (for example docker-compose totally ignores deploy section from file).. However, if you do not get it working then please create new issue to https://github.com/moby/moby/issues with all asked details.