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Curl command error when configuring the load-balancing solution on a dedicated UCP node using Interlock + NGINX/NGINX+

Overview

When configuring the load-balancing solution on a dedicated UCP node using Interlock + NGINX/NGINX+, incorrect curl syntax will cause errors similar to the following: 

curl: (6) Couldn't resolve host '='
curl: (6) Couldn't resolve host ''
curl: (6) Couldn't resolve host 'dockerURL'
curl: (6) Couldn't resolve host '='
curl: (1) Protocol "tcp" not supported or disabled in libcurl

Diagnostic Steps

Proper syntax can be found in Reference Architecture: Service Discovery and Load-Balancing with Docker Universal Control Plane (UCP)

For example, in this instance, the closing single quote for the value should be placed at the end, not after listenAddr:

 value='listenAddr' = ":8080" dockerURL = "tcp://1.2.3.4.example.com:2376" \
  {"action":"set","node":
  {"key":"/interlock/v1/config","value":"listenAddr","modifiedIndex":194110,"createdIndex":194110},"prevNode":
  {"key":"/interlock/v1/config","value":"","modifiedIndex":194099,"createdIndex":194099}}

The correct syntax would be:

value='listenAddr = ":8080" dockerURL = "tcp://slx‐dockermaster01.uncg.edu:2376" \
  {"action":"set","node":
  {"key":"/interlock/v1/config","value":"listenAddr","modifiedIndex":194110,"createdIndex":194110},"prevNode":
  {"key":"/interlock/v1/config","value":"","modifiedIndex":194099,"createdIndex":194099}}'

Resolution

Fix the syntax, and rerun the curl command. If further errors or different errors persist review the syntax again.

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