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Problem with an overlay network on UCP


(Campbech) #1

Hi All,

I am working on setting up UCP for production and have run into issues when getting a multi host application using overlay networking set up. What I have done so far.

  1. Setup UCP
  2. Created an overlay network
  3. Create three containers and add them to the network created in step 2.
  4. Exec into the ubuntu container and perform an nslookup to resolve the other containers IP.

The containers are allocated to my nodes as follows.


  • Ubuntu
  • Nginx1


  • Nginx2

Now here is the issue. When I curl Nginx1 the request succeeds, but when I curl Nginx2 the request fails with curl: (7) Failed to connect to web port 80: No route to host

So to summarize.

  1. I can create a docker overlay network
  2. I can add containers to the network
  3. Containers on the same host can reach each other
  4. Containers on different hosts can not reach each other.

Any help or insight that the community might have would be greatly appreciated.

Thank you,

(Vivek Saraswat) #2

Hi Chris,

How did you go about setting up the overlay network and adding the containers to it? Can you show the commands?

(Campbech) #3

Hi Vivek,

Sorry for the slow reply. The solution ended up being that I was blocking ports that are used for overlay networking.

port 4789(udp) and 7946(tcp and udp)