We have multiple docker workers and few managers running in docker swarm.
After deployment of new applications, from time to time I have found that some of our micro services is having connections problems and the request are failing. Usually the problem is gone by scaling the service to 0 and to number of replicas.
In the latest case we had 3 replicas of service running on separate workers. After failing request we scaled to 1 and all the failing request were gone (on the monitoring), the we tried to scale up to 2, and the failing of request started again, so in this case scaling did not solve the issue.
I’m wondering what could be the issue? BUT also wondering how to dig deeper into issue, atm I cannot find anything from logs.
One thing could be updating the docker to latest, but before, I would like to know that this is really issue of docker swarm, and not something else…
Docker version is: Docker version 17.09.1-ce, build 19e2cf6
App: Spring boot java application