moby: Swarm does not consider health checks while updating

Hi,

Im playing around with docker 1.12 and the HEALTHCHECK directive in dockerfiles. What I do is:

docker swarm init

Dockerfile

FROM nginx:latest

RUN touch /marker

ADD ./check_running.sh /check_running.sh
RUN chmod +x /check_running.sh

HEALTHCHECK --interval=5s --timeout=3s CMD ./check_running.sh

check_running.sh

#!/usr/bin/env bash

if [[ -e /marker ]]; then
    rm /marker
    exit 2
else
    exit 0
fi

Build some images from this Dockerfile:

$ docker build -t mynginx:1 .
$ docker build -t mynginx:2 .

Start a service with 5 replicas

$ docker service create --name web --replicas=5 -p 8080:80 mynginx:1

Wait some time (5s) until all replicas are healthy. Now I want to update the image to v2. The update procedure should be rolling with a parallelism of 1. So I run:

$ docker service update --image mynginx:2 --update-parallelism 1 web

From my understanding swarm should execute the update based on this algorithm:

1. swarm stops one container
2. swarm starts a container with mynginx:2 and waits as long as it becomes healthy again (not starting)
3. go to 1)

But what I get is:

$ docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED                  STATUS                                     PORTS               NAMES
eee2b1b184ac        mynginx:2           "nginx -g 'daemon off"   Less than a second ago   Up Less than a second (health: starting)   80/tcp, 443/tcp     web.3.6kn82dul8gnyvzgz6cje2byfj
b3797cdb5e05        mynginx:2           "nginx -g 'daemon off"   3 seconds ago            Up 2 seconds (health: starting)            80/tcp, 443/tcp     web.5.46ll6b2lhrhr98utowuifccei
0c85128b031e        mynginx:2           "nginx -g 'daemon off"   6 seconds ago            Up 5 seconds (health: starting)            80/tcp, 443/tcp     web.1.apenirwkjp96xiyhhspx134wx
9dcec24ae32a        mynginx:2           "nginx -g 'daemon off"   9 seconds ago            Up 8 seconds (health: starting)            80/tcp, 443/tcp     web.2.5oi6fk1c6u25s3rpqbal39i3b
f37332162d40        mynginx:2           "nginx -g 'daemon off"   12 seconds ago           Up 11 seconds (healthy)                    80/tcp, 443/tcp     web.4.7mgs62e6s78iijcqwv4cose11

Sometimes all replicas are in starting state which results in a downtime of this service. My expectation was that I can obtain “native” zero downtime deployment with HEALTHCHECK and rolling updates on my swarm cluster 😃

Whats wrong with my attempt?

Thanks!

Update: Sorry for closing/opening this issue. My mobile is somehow broken today 😕