Allow hostname to be updated on service.

Signed-off-by: Daniel Nephin <dnephin@docker.com>

cli/command/service/create.go

@@ -33,7 +33,6 @@ func newCreateCommand(dockerCli *command.DockerCli) *cobra.Command {
 
 	flags.VarP(&opts.labels, flagLabel, "l", "Service labels")
 	flags.Var(&opts.containerLabels, flagContainerLabel, "Container labels")
-	flags.StringVar(&opts.hostname, flagHostname, "", "Container hostname")
 	flags.VarP(&opts.env, flagEnv, "e", "Set environment variables")
 	flags.Var(&opts.envFile, flagEnvFile, "Read in a file of environment variables")
 	flags.Var(&opts.mounts, flagMount, "Attach a filesystem mount to the service")

cli/command/service/opts.go

@@ -570,6 +570,7 @@ func addServiceFlags(cmd *cobra.Command, opts *serviceOptions) {
 
 	flags.StringVarP(&opts.workdir, flagWorkdir, "w", "", "Working directory inside the container")
 	flags.StringVarP(&opts.user, flagUser, "u", "", "Username or UID (format: <name|uid>[:<group|gid>])")
+	flags.StringVar(&opts.hostname, flagHostname, "", "Container hostname")
 
 	flags.Var(&opts.resources.limitCPU, flagLimitCPU, "Limit CPUs")
 	flags.Var(&opts.resources.limitMemBytes, flagLimitMemory, "Limit Memory")

cli/command/service/update.go

@@ -208,6 +208,7 @@ func updateService(flags *pflag.FlagSet, spec *swarm.ServiceSpec) error {
 	updateEnvironment(flags, &cspec.Env)
 	updateString(flagWorkdir, &cspec.Dir)
 	updateString(flagUser, &cspec.User)
+	updateString(flagHostname, &cspec.Hostname)
 	if err := updateMounts(flags, &cspec.Mounts); err != nil {
 		return err
 	}

docs/reference/commandline/service_update.md

@@ -45,6 +45,7 @@ Options:
       --help                             Print usage
       --host-add list                    Add or update a custom host-to-IP mapping (host:ip) (default [])
       --host-rm list                     Remove a custom host-to-IP mapping (host:ip) (default [])
+      --hostname string                  Container hostname
       --image string                     Service image tag
       --label-add list                   Add or update a service label (default [])
       --label-rm list                    Remove a label by its key (default [])