Runner fails to register agent to server instance w/ token

[jlee3227]

An IBMer was trying to register the runner to a GitLab server instance. The server is running on-prem and within a private network.

gitlab-runner register --url http://gitlab.dat.ibm.com/ --token <TOKEN>
Runtime platform                                    arch=s390x os=zos pid=50399008 revision=HEAD version=development version
Running in system-mode.
WARNING: You need to manually start builds processing:
WARNING: $ gitlab-runner run

Enter the GitLab instance URL (for example, https://gitlab.com/):
[http://gitlab.dat.ibm.com/]:
ERROR: Verifying runner... failed                   runner=UWwzpnFLw status=couldn't execute POST against http://gitlab.dat.ibm.com/api/v4/runners/verify: Post "http://gitlab.dat.ibm.com/api/v4/runners/verify": dial tcp 104.168.92.213:80: connect: EDC8128I Connection refused.
PANIC: Failed to verify the runner.

We don't know why runner is trying to connect to 104.168.92.213 and it is not a machine that the IBMer knows about. This error does look somewhat similar to a test failure for runner that involved a bad TLS cert, but I doubt it's the same.

A workaround that seems to work is to supply the IP address of the machine hosting the server instance for the --url flag:

gitlab-runner register --url http://<IP>/ --token <TOKEN>
Runtime platform                                    arch=s390x os=zos pid=67176009 revision=HEAD version=development version
Running in system-mode.
WARNING: You need to manually start builds processing:
WARNING: $ gitlab-runner run

Enter the GitLab instance URL (for example, https://gitlab.com/):
[http://<IP>/ ]:
Verifying runner... is valid                        runner=fnNfxoS9o
Enter a name for the runner. This is stored only in the local config.toml file:
[ZT01]:
Enter an executor: docker+machine, docker-autoscaler, virtualbox, docker-windows, ssh, parallels, docker, kubernetes, instance, custom, shell:
shell
Runner registered successfully. Feel free to start it, but if it's running already the config should be automatically reloaded!

Configuration (with the authentication token) was saved in "/etc/gitlab-runner/config.toml"

I vaguely remember that the Go on z/OS team ran into some problems resolving URLs, it could be related.

[v1gnesh]

When I registered to the GitLab site itself, it worked ok.
sudo gitlab-runner register --url https://gitlab.com/ --registration-token blabla