This document provides steps to solve “DNS lookup failure” issue after one of the Fabric deleted from the cluster.

Users might get this error when we delete one of the fabric nodes from UI and add the new one to the fabric, sometimes entries related to the old node are still present in the database or the file system of Junos Space.

Space platform GUI shows the below error:

Proxy Error

The proxy server received an invalid response from an upstream server.

The proxy server could not handle the request

Reason: DNS lookup failure for: space-005056a9c077

Following the steps below will help to disable/stop deleted node proxy connections, which cause “DNS lookup failure” error.
 

Step 1: Login to Space CLI using admin user and select Debug shell.

Step 2: Edit the below files:

/etc/httpd/conf.d/webConf/webProxyCertAuth.conf

/etc/httpd/conf.d/webConf/webProxy.conf

Uncomment (just remove #) ModClusterManager configuration as mentioned below:

Example:
Before

# If you want to monitor the status of all the workers, please uncomment ModClusterManager
# <Location /mod_cluster_manager>
# SetHandler mod_cluster-manager
# Order allow,deny
# Allow from all 
# </Location>
 

After

# If you want to monitor the status of all the workers, please uncomment ModClusterManager
<Location /mod_cluster_manager>
SetHandler mod_cluster-manager
Order allow,deny
Allow from all 
</Location>

Step 2: Then save the changes and restart “httpd” service

# systemctl restart httpd

Step 4: Open Browser enter URL https://<VIP>/mod_cluster_manager

Step 4.1: Identify the deleted Node by Hostname

Step 4.2: Click Disable Context / Stop Context. This will stop the deleted node proxy connection from being used.

Step 4 (Optional): Revert the configuration changes perform in Step 2 by commenting on the uncommented lines on both the files "webProxy.conf" "webProxyCertAuth.conf".

Step 5: Login to Junos Space GUI, it should allow a user to login.

 

2024-02-28 : Article Created

2025-11-06: changed the visibility