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DTR host parameter required

Hi, I have 2 CentOS7 machines. I installed UCP on node ucp.docker.ns and added node dtr.docker.ns as a worker. That works fine.
If I run the below command on the ucp node I get an error:
_INFO[0003] Validating UCP cert
_INFO[0003] Connecting to UCP
_INFO[0003] UCP cert validation successful
_INFO[0003] The UCP cluster contains the following nodes: dtr.docker.ns, ucp.docker.ns _
_INFO[0003] verifying [80 443] ports on dtr.docker.ns
_FATA[0000] DTR host parameter is required
_FATA[0008] Failed to execute phase 2: Phase 2 returned non-zero status: 1

docker run -it --rm docker/dtr install
–dtr-external-url https://
–ucp-node dtr.docker.ns
–ucp-username admin

Anyone an idea what I am missing/ doing wrong? Haven’t been able to find any related posts/ material about this error.

With kind regards,


Hi Bram,
Are you filling out the --dtr-external-url paramenter? It should be the external hostname of the node.

Hi Patrick,

No I left it blank. UCP gives the full command when choosing who and where to run the DTR and so I just assumed that would be the correct command. I thought the external URL is only necessary when using a load balanced in front of it?!

Will see if it makes a difference when I give a value along with that option.

With kind regards,


Hi Bram,

The external URL is used to tell the auth service how to connect, so if it’s not set then things will break. We are looking at relaxing that in an upcoming version, but for now you should put it in. If you’re not load balancing in front of DTR, just use whatever external hostname you would use to connect to the machine.

Let me know how it goes!

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