Unable to connect to Site Recovery Manager Server - java.net.UnknownHostException: Temporary failure in name resolution

Products

VMware Live Recovery

Issue/Introduction

Symptoms:

SRM UI display the below errors:

Unable to retrieve pairs from extension server at https://Servername:443/drserver/vcdr/vmomi/sdk. Unable to connect to Site Recovery Manager Server at https://Servername:443/drserver/vcdr/vmomi/sdk. Reason: java.net.UnknownHostException: DRSRM: Temporary failure in name resolution
Unable to connect to Site Recovery Manager Server at https://DRSRM:443/drserver/vcdr/vmomi/sdk. Reason: java.net.UnknownHostException: DRSRM: Temporary failure in name resolution
Operation ID: d3b05c76-6c97-48e2-b102-a398cf801775
8/3/20, 1:26:11 PM -0400

Unable to retrieve pairs from extension server at https://Servername:443/drserver/vcdr/vmomi/sdk.Unable to connect to Site Recovery Manager Server at https://Servername:443/drserver/vcdr/vmomi/sdk. Reason: java.net.UnknownHostException: HQSRM: Temporary failure in name resolution
SRM Server at HQ-SRM-01 is unreachable.
Unable to connect to Site Recovery Manager Server at https://Servername:443/drserver/vcdr/vmomi/sdk. Reason: java.net.UnknownHostException: HQSRM: Temporary failure in name resolution
Operation ID: 0acf80a1-a0a1-43b4-a9c2-8e58fab0245b
8/3/20, 1:26:17 PM -0400

SRM Server at DRSRM is unreachable.
SRM appliances successfully register to vCenter
You notice the same errors whether you register SRM using its FQDN or IP address
You are able to PING the SRM appliances using its IP address/FQDN (DNS records are fully resolvable)
No PSC SSL thumbprint mismatch OR duplicate cs.identity.sso entries are found
There are no internal or external firewalls blocking any ports and also you are able to connect to port # 443 by running the curl command
The below error is seen in "dr-client.log":

2020-08-03 16:13:03,184 [srm-reactive-thread-15] WARN com.vmware.srm.client.infrastructure.requestHandlers.navigation.SitePairHelper -5521004966068210375 593d3eb4-5c51-4157-b69a-6786fd8b3905 getDrSitePairs - Fail to get SRM sitePairData for SrmServerImpl {_guid = 7e366da4-4b7a-4365-ace0-e91317e0f197_url = https://Servername:443/drserver/vcdr/vmomi/sdk
}:
com.vmware.srm.client.topology.client.view.availability.ExtensionServer$GetPairFailedException: Unable to retrieve pairs from extension server at https://Servername:443/drserver/vcdr/vmomi/sdk.Unable to connect to Site Recovery Manager Server at https://Servername:443/drserver/vcdr/vmomi/sdk. Reason: java.net.UnknownHostException: DRSRM: Temporary failure in name resolution
at com.vmware.srm.client.topology.impl.view.availability.ExtensionServerImpl.complete(ExtensionServerImpl.java:51)
at com.vmware.srm.client.reactive.impl.PromiseImpl$ErrorCompletion.complete(PromiseImpl.java:178)
at com.vmware.srm.client.reactive.impl.PromiseImpl$Result.complete(PromiseImpl.java:41)
at com.vmware.srm.client.reactive.impl.PromiseImpl$Completion.lambda$null$8(PromiseImpl.java:71)
at com.vmware.srm.client.utilities.ThreadContext.lambda$wrap$12(ThreadContext.java:38)
at com.vmware.srm.client.utilities.ThreadContext.execute(ThreadContext.java:183)
at com.vmware.srm.client.utilities.ThreadContext.execute(ThreadContext.java:193)
at com.vmware.srm.client.utilities.ThreadContext.execute(ThreadContext.java:176)
at com.vmware.srm.client.utilities.ThreadContext.setupContext(ThreadContext.java:59)
at com.vmware.srm.client.utilities.ThreadContext.setupContext(ThreadContext.java:87)
at com.vmware.srm.client.reactive.impl.PromiseImpl$Completion.lambda$setResult$9(PromiseImpl.java:71)
at com.vmware.srm.client.utilities.AsyncConsumer$Worker.run(AsyncConsumer.java:37)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
Caused by: com.vmware.vim.vmomi.client.exception.ConnectionException: Unable to connect to Site Recovery Manager Server at https://Servername:443/drserver/vcdr/vmomi/sdk. Reason: java.net.UnknownHostException: DRSRM: Temporary failure in name resolution
at com.vmware.srm.client.topology.impl.vmomi.vlsi.VmomiServiceImpl.lambda$getVersionInternal$53(VmomiServiceImpl.java:400)
at com.vmware.srm.client.reactive.impl.PromiseImpl$ComposeCompletion.complete(PromiseImpl.java:207)
at com.vmware.srm.client.reactive.impl.PromiseImpl$Result.complete(PromiseImpl.java:39)
... 17 more
Caused by: java.net.UnknownHostException: DRSRM: Temporary failure in name resolution
at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method)
at java.net.InetAddress$2.lookupAllHostAddr(InetAddress.java:929)
at java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1324)
at java.net.InetAddress.getAllByName0(InetAddress.java:1277)
at java.net.InetAddress.getAllByName(InetAddress.java:1193)
at java.net.InetAddress.getAllByName(InetAddress.java:1127)
at org.apache.http.impl.conn.SystemDefaultDnsResolver.resolve(SystemDefaultDnsResolver.java:45)
at org.apache.http.impl.nio.conn.PoolingNHttpClientConnectionManager$InternalAddressResolver.resolveRemoteAddress(PoolingNHttpClientConnectionManager.java:637)
at org.apache.http.impl.nio.conn.PoolingNHttpClientConnectionManager$InternalAddressResolver.resolveRemoteAddress(PoolingNHttpClientConnectionManager.java:608)

Environment

VMware Site Recovery Manager 8.x

VMware vSphere Replication 8.x

VMware Site Recovery Manager 9.x

VMware vSphere Replication 9.x

Cause

The SRM and replication appliance has difficulty in resolving the FQDN names internally.

Resolution

The correct resolution is to resolve the issue with the name resolution

Workaround

Login to VCSA & SRM appliances using SSH
Edit and update the ‘hosts’ file to include vCenter and SRM IP & FQDN information of both the sites
Format is "IP FQDN Hostname"; Example: "xx.xx.xx.xx SRM01.domain.local SRM01"
Refresh the SRM browser tab

Additional Information

Editing files on an ESXi host using vi editor