This doesn't match the actual API, which uses an array of net.IPNet for DefaultAddrPool, and a separate SubnetSize field for the size.

Swagger describes the API specification, so should not mention "flag".

"subnet size" is a separate option; you can mention it in the description here, but the default should probably be described as part of the description for SubnetSize.

Would be good to have an example value in the swagger spec as well, so that it's clear how what format is expected.

The change I proposed wouldn't change that logic; the only difference is that it would scope the b variable to the if (and it being a more idiomatic code-style); it's just a nit though, so not a blocker

Although I suggested to use IPNet for as internal type (mainly for the CLI-side); for the over-the-wire format for this is rather awkward; the string representation (without converting individual entries to a string when marshalling);

For example, the request now needs to look like;

{"DefaultAddrPool":[{"IP":"192.0.2.0","Mask":"////AA=="}]}

Whereas individually encoding IPNet to a string would look like

{"DefaultAddrPool":["192.0.2.0/24"]}

Completely agree with @thaJeztah, we shouldn't leak implementation detail in our API and have our own type here (if we need something complex). Here it seems just a slice of string would work.

Completely agree with @thaJeztah, we shouldn't leak implementation detail in our API and have our own type here (if we need something complex). Here it seems just a slice of string would work.

We are adding into slice only if b is not null.

Wrong, you're adding it to the slice only if err == nil, there is no check on b. I do agree with @thaJeztah and the proposed change 👼

I don't think this is required… We should update the NewSwarm function instead, with a WithInitOption operation.

Same as above, we could update StartAndSwarmInit to take *operationswith one forInitRequest`

func (d *Daemon) StartAndSwarmInit(t testingT, ops ...func(*swarm.InitRequest{})) {
    initRequest := &swarm.InitRequest{}
    for _, op := range ops { op(initRequest) }
    // …
    d.SwarmInit(t, *initRequest)
}

I would suggest updating to the latest which is cfa742c @selansen

will update now.

This should be "array" with "string" as type for the items, e.g. similar to

DefaultAddrPool is an array, so this should be something like;

DefaultAddrPool: ["10.10.0.0/16", "20.20.0.0/16"]

Ideally, we'd fix the int / uint32 on swarmkit side as well before GA (for a follow-up before GA)

yes. I am planning to refactor swarmkit code as Anshul wanted to move around code a bit

Could be done in a follow-up, but; I see other validation steps are done in newNodeRunner(); we should consider moving those all to a single place, not partly here, and partly there. We can also return parsing errors there.