NSX manager node shows repo_sync status as "Failed" or "in progress" during the upgrade.

Products

• VMware NSX

Issue/Introduction

• During the NSX Manager upgrade, the repo_sync status may show either "failed or "in progress" from NSX UI."

• Repo_sync status using the curl from manager shows "Collecting the information about files to synchronize"

# curl -k -H "Content-Type:application/json" -u admin -X GET https://localhost/api/v1/cluster/nodes/<manager-node-uuid>/repo_sync/status

{  "status" : "FAILED",

  "status_message" : "Collecting the information about files to synchronize",

  "failure_message" : "",

  "failure_code" : 0
  }

# curl -k -H "Content-Type:application/json" -u admin -X GET https://localhost/api/v1/cluster/nodes/<manager-node-uuid>/repo_sync/status

{  "status" : "in progress",

  "status_message" : "Collecting the information about files to synchronize",

  "failure_message" : "",

  "failure_code" : 0
  }

•    NSX Managers logs: /var/log/proton/nsxapi.log shows the repo sync failure occurs as reverse DNS alias #.#/#.#.#.#.in-addr.arpa fails to resolved ip address and connection timeout for repository url.  

2025-07-27T22:13:57.523Z  WARN DnsLookupProviderImpl - Fail to get IP address from FQDN #.#/#.#.#.#.in-addr.arpa  

2025-07-26T22:07:04.104Z  INFO RepoSyncFileHelper - curl_wrapper: (7) Connection timed out  URL: https://#.#/#.#.#.#.in-addr.arpa:443/repository/...  



• The /var/log/proton/nsxapi.log may also show the failed DNS within the repo sync logs. 

2025-12-18T12:52:14.001Z  INFO RepoSyncThread-1766062312863 RepoSyncFileHelper 4933 SYSTEM [nsx@6876 comp="nsx-manager" level="INFO" subcomp="manager"] Command to get server info for https://;; communications error to <DNS SERVER IP ADDRESS>#53: timed out:443/repository/4.2.1.52.0.24482522/Manager/ovf/nsx-unified-appliance.vmdk returned result CommandResultImpl [commandName=null, pid=0, status=FAILED, errorCode=7, errorMessage=curl_wrapper: (7) Failed to connect to ;; communications error to <DNS SERVER IP ADDRESS> port 443: [Errno -2] Name or service not known

 

Environment

VMware NSX

VMware NSX-T Datacenter

Cause

DNS reverse lookup configured with CNAME alias (#.#/#.#.#.#.in-addr.arpa), where CNAME alias failed to resolve ip-address.

This issue may also occur if there are multiple DNS entries configured on the NSX Managers but the primary is non responsive (as opposed to responding but not having a valid entry) then please see additional info.

Resolution

To fix the issue, ensure that forward and reverse DNS lookups are working properly for all three NSX Manager nodes.

Forward lookup:
dig <FQDN of Manager> +short
==> Should return the IP address of the Manager

Reverse lookup:
dig -x <IP of Manager> +short
==> Should return fully qualified domain name of the Manager

If reverse DNS is configured with CNAME alias instead of direct PTR record. Make sure forward lookup of alias resolve the ip-address.

dig -x <IP of Manager> +short
(#.#/#.#.#.#.in-addr.arpa  ← alias configured
<FQDN of Manager>

Forward lookup of alias:

dig <alias-name> +short
==> Should return the IP address

Additional Information

If this issue occurs even while a secondary DNS is configured then please see NSX management cluster DNS issues observed while secondary DNS is functional and present.