404 After Test Connection Succeeds

Problem : You receive a 404 after "test-connection" was successful

This situation happens when the Dashboard cannot resolve the domain names returned by the API endpoint api/v8/manager/cluster/topology

For example:

{
  "payloadType": "ClusterTopologyPayload",
  "payloadVersion": "1",
  "payload": {
      "topology": "CLUSTERED_PRIMARY",
      "name": "oulu",
      "datasources": [
          {
              "name": "db21",
              /* the value of "host" must be resolvable by Dashboard's dns */
              "host": "db21", 
              "role": "master"
          },
          {
              "name": "db22",
              /* the value of "host" must be resolvable by Dashboard's dns */
              "host": "db22",
              "role": "slave"
          },
          {
              "name": "db23",
              /* the value of "host" must be resolvable by Dashboard's dns */
              "host": "db23",
              "role": "witness"
          }
      ],
      "routers": [...]
  }
}

If the Dashboard cannot obtain an IP address for the node name located above, the load balancing functionality breaks down. To resolve the issue:

1. Identify all hostnames returned by the REST API endpoint api/v8/manager/cluster/topology

2. SSH to the Dashboard container

3. Install the DNS Tools to get access to the dig command:

   shell> apt upgrade;
   shell> apt install dnsutils;

4. Test the hostname resolution for each hostname you collected in step 1. If successful you will get ';; ANSWER SECTION:'

   shell> dig db21;
   "
   ; <<>> DiG 9.18.30-0ubuntu0.24.04.2-Ubuntu <<>> db21
   ;; global options: +cmd
   ;; Got answer:
   ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 30152
   ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
   
   ;; OPT PSEUDOSECTION:
   ; EDNS: version: 0, flags:; udp: 1232
   ; COOKIE: ab4ead051ab4fa5d (echoed)
   ;; QUESTION SECTION:
   ;db21.        IN  A
   
   ;; ANSWER SECTION:
   db21.     5 IN  A XX.XXX.XX.XXX" # <---- note valid ip in the answer.
   "
   
   ;; Query time: 4 msec
   ;; SERVER: XX.XX.X.XXX#53(XX.XX.X.XX) (UDP)
   ;; WHEN: Wed Apr 09 12:13:03 UTC 2025
   ;; MSG SIZE  rcvd: 65
   "

   Example of a failed dns resolution:

   shell> dig db20;
   "
   ; <<>> DiG 9.18.30-0ubuntu0.24.04.2-Ubuntu <<>> db20
   ;; global options: +cmd
   ;; Got answer:
   ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 12636
   ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
   
   ;; OPT PSEUDOSECTION:
   ; EDNS: version: 0, flags:; udp: 1232
   ; COOKIE: ad741d4ba38cc0a7 (echoed)
   ;; QUESTION SECTION:
   ;db20.        IN  A"

   Note how the dig never got a valid IP address in the ';; ANSWER SECTION:' like in the success example.

Make sure that all of the hosts returned by the API topology endpoint can be resolved before proceeding further. Once all hostnames are resolvable, re-add the cluster to the Dashboard or reload the topology using the reload action or by making a small change to it, such as changing the first host.