Windows container failed to start with error, “failed to create endpoint on network nat: HNS failed with error : Failed to create endpoint.”

Question

I have been trying Windows Containers on windows server 2016 TP5. Suddenly I started getting error while running a container with port maping option -p 80:80

Answer 1

After searching around I stunbled upon this issue on github. This seemed to be a known issue with Windows containers on Windows server TP5.

Then thanks to this forum, I found the solution You can check active static port mapping with below command

C:\>powershell
PS C:\>Get-NetNatStaticMapping


StaticMappingID               : 3
NatName                       : Hda6caca4-06ec-4251-8a98-1fe0b4c5af88
Protocol                      : TCP
RemoteExternalIPAddressPrefix : 0.0.0.0/0
ExternalIPAddress             : 0.0.0.0
ExternalPort                  : 80
InternalIPAddress             : 172.31.181.4
InternalPort                  : 80
InternalRoutingDomainId       : {00000000-0000-0000-0000-000000000000}
Active                        : True

From above output it seemed that even though container was removed the static port mapping was not removed and was still active.

But I removed it with below command.

PS C:\> Get-NetNatStaticMapping | ? ExternalPort -eq 80 | Remove-NetNatStaticMapping

Then simply rebooted the system and the error was gone.