Description

Description

ErrConflictHostNetwork was added in #17476.

Confusingly, the same error message is used for two different errors.

1. When attempting to change the network mode of a running container from a different mode to host.
   

   moby/daemon/container_operations.go

   Lines 175 to 177 in c90cbc8

   	if !ctr.HostConfig.NetworkMode.IsHost() && containertypes.NetworkMode(n.Type()).IsHost() {
   	return runconfig.ErrConflictHostNetwork
   	}

2. When the network mode of a running container is already host and attempting to disconnect from host.
   

   moby/daemon/container_operations.go

   Lines 1055 to 1057 in c90cbc8

   	if ctr.HostConfig.NetworkMode.IsHost() && containertypes.NetworkMode(n.Type()).IsHost() {
   	return runconfig.ErrConflictHostNetwork
   	}

Using the same error message for these two errors makes troubleshooting difficult.

Suggestions

Split the ErrConflictHostNetwork error into two distinct errors:

1. ErrConflictConnectToHostNetwork when attempting to change the network mode of a running container from a different mode to host
2. ErrConflictDisconnectFromHostNetwork when the network mode of a running container is host and attempting to disconnect from host

Related

• Fix connect to host and prevent disconnect from host for host network #17476
• daemon/container_operations.go
• runconfig/errors.go