MGN agentless stalled on "authenticate with service"

Question

Hi,

I'm testing MGN service with agentless method. I've configured the service in an onpremise VM, discovery runs OK, but when I start a replication, I get stalled at "Failed to authenticate with service".

For what I was able to troubleshoot, I think the problem is that the replication server cannot download the agent from the s3 bucket.

I've configured an s3 interface endpoint on my VPC, is there a way to make MGN use it? editing the vcenter-client.config and adding the proper s3 url endpoint?

Regards,

fmtrasan-Kd · Answer

A similar problem regarding private endpoints happen with the agent installation:

```
 [user@host tmp]# python3 aws-replication-installer-init.py --region us-east-2 --aws-access-key-id MY_KEY --aws-secret-access-key MY_SECRET --endpoint MY_MGN_PRIVATE_ENDPOINT_URL --s3-endpoint MY_S3_PRIVATE_ENDPOINT_URL
The installation of the AWS Replication Agent has started.
Downloading of 'https://aws-application-migration-service-us-east-2.s3.us-east-2.amazonaws.com/latest/linux/aws-replication-installer-64bit' from S3 Endpoint MY_S3_PRIVATE_ENDPOINT_URL failed.
This is usually caused by lack of routing to AWS, firewall configuration that block the connection (local or in a firewall appliance) or an incorrect web proxy configuration on this server.
Resolve the connectivity issue and run the installer again.
Learn more about connectivity issues in our documentation at https://docs.aws.amazon.com/mgn/latest/ug/Troubleshooting-Agent-Issues.html#Error-Installation-Failed
Error details: 
```

But if I try to download the agent manually using the private endpoint, it works ok:

```
[user@host tmp]# curl https://aws-application-migration-service-us-east-2.MY_S3_PRIVATE_ENDPOINT/latest/linux/aws-replication-installer-64bit -o latest_installer
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 19.7M  100 19.7M    0     0  1026k      0  0:00:19  0:00:19 --:--:-- 1136k
[user@host tmp]# ls -l latest_installer 
-rw-r--r--. 1 root root 20665936 Aug 26 13:12 latest_installer
```

Does anyone know what I'm doing wrong??

Regards,

fmtrasan-Kd · Answer

For it to work, I had to switch to a public subnet with public IP enabled for the replication instance to work properly. So, I guess there is something that I misconfigured or MGN doesn't work with private endpoints.

celso · Answer

For future reference, I've managed to overcome this issue by hardcoding the DNS in the source server HOSTS file.

Next I would try to create an inbound Route53 endpoint and point my servers resolv.conf to that so that the private endpoints dns entries resolve to the correct IP's inside the private subnet.

MGN agentless stalled on "authenticate with service"

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