Add --read-only for service create and service update

This fix tries to address the issue raised in 29972 where
it was not possible to specify `--read-only` for `docker service create`
and `docker service update`, in order to have the container's root file
system to be read only.

This fix adds `--read-only` and update the `ReadonlyRootfs` in `HostConfig`
through `service create` and `service update`.

Related docs has been updated.

Integration test has been added.

This fix fixes 29972.

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

api/swagger.yaml

@@ -1884,6 +1884,9 @@ definitions:
           TTY:
             description: "Whether a pseudo-TTY should be allocated."
             type: "boolean"
+          ReadOnly:
+            description: "Mount the container's root filesystem as read only."
+            type: "boolean"
           Mounts:
             description: "Specification for mounts to be added to containers created as part of the service."
             type: "array"

api/types/swarm/container.go

@@ -34,6 +34,7 @@ type ContainerSpec struct {
 	Groups          []string                `json:",omitempty"`
 	TTY             bool                    `json:",omitempty"`
 	OpenStdin       bool                    `json:",omitempty"`
+	ReadOnly        bool                    `json:",omitempty"`
 	Mounts          []mount.Mount           `json:",omitempty"`
 	StopGracePeriod *time.Duration          `json:",omitempty"`
 	Healthcheck     *container.HealthConfig `json:",omitempty"`

cli/command/service/opts.go

@@ -303,6 +303,7 @@ type serviceOptions struct {
 	user            string
 	groups          opts.ListOpts
 	tty             bool
+	readOnly        bool
 	mounts          opts.MountOpt
 	dns             opts.ListOpts
 	dnsSearch       opts.ListOpts
@@ -384,6 +385,7 @@ func (opts *serviceOptions) ToService() (swarm.ServiceSpec, error) {
 				User:     opts.user,
 				Groups:   opts.groups.GetAll(),
 				TTY:      opts.tty,
+				ReadOnly: opts.readOnly,
 				Mounts:   opts.mounts.Value(),
 				DNSConfig: &swarm.DNSConfig{
 					Nameservers: opts.dns.GetAll(),
@@ -488,6 +490,9 @@ func addServiceFlags(cmd *cobra.Command, opts *serviceOptions) {
 
 	flags.BoolVarP(&opts.tty, flagTTY, "t", false, "Allocate a pseudo-TTY")
 	flags.SetAnnotation(flagTTY, "version", []string{"1.25"})
+
+	flags.BoolVar(&opts.readOnly, flagReadOnly, false, "Mount the container's root filesystem as read only")
+	flags.SetAnnotation(flagReadOnly, "version", []string{"1.26"})
 }
 
 const (
@@ -532,6 +537,7 @@ const (
 	flagPublish               = "publish"
 	flagPublishRemove         = "publish-rm"
 	flagPublishAdd            = "publish-add"
+	flagReadOnly              = "read-only"
 	flagReplicas              = "replicas"
 	flagReserveCPU            = "reserve-cpu"
 	flagReserveMemory         = "reserve-memory"

cli/command/service/update.go

@@ -341,6 +341,14 @@ func updateService(flags *pflag.FlagSet, spec *swarm.ServiceSpec) error {
 		cspec.TTY = tty
 	}
 
+	if flags.Changed(flagReadOnly) {
+		readOnly, err := flags.GetBool(flagReadOnly)
+		if err != nil {
+			return err
+		}
+		cspec.ReadOnly = readOnly
+	}
+
 	return nil
 }
 

cli/command/service/update_test.go

@@ -442,3 +442,25 @@ func TestUpdateSecretUpdateInPlace(t *testing.T) {
 	assert.Equal(t, updatedSecrets[0].SecretName, "foo")
 	assert.Equal(t, updatedSecrets[0].File.Name, "foo2")
 }
+
+func TestUpdateReadOnly(t *testing.T) {
+	spec := &swarm.ServiceSpec{}
+	cspec := &spec.TaskTemplate.ContainerSpec
+
+	// Update with --read-only=true, changed to true
+	flags := newUpdateCommand(nil).Flags()
+	flags.Set("read-only", "true")
+	updateService(flags, spec)
+	assert.Equal(t, cspec.ReadOnly, true)
+
+	// Update without --read-only, no change
+	flags = newUpdateCommand(nil).Flags()
+	updateService(flags, spec)
+	assert.Equal(t, cspec.ReadOnly, true)
+
+	// Update with --read-only=false, changed to false
+	flags = newUpdateCommand(nil).Flags()
+	flags.Set("read-only", "false")
+	updateService(flags, spec)
+	assert.Equal(t, cspec.ReadOnly, false)
+}

daemon/cluster/convert/container.go

@@ -25,6 +25,7 @@ func containerSpecFromGRPC(c *swarmapi.ContainerSpec) types.ContainerSpec {
 		Groups:    c.Groups,
 		TTY:       c.TTY,
 		OpenStdin: c.OpenStdin,
+		ReadOnly:  c.ReadOnly,
 		Hosts:     c.Hosts,
 		Secrets:   secretReferencesFromGRPC(c.Secrets),
 	}
@@ -146,6 +147,7 @@ func containerToGRPC(c types.ContainerSpec) (*swarmapi.ContainerSpec, error) {
 		Groups:    c.Groups,
 		TTY:       c.TTY,
 		OpenStdin: c.OpenStdin,
+		ReadOnly:  c.ReadOnly,
 		Hosts:     c.Hosts,
 		Secrets:   secretReferencesToGRPC(c.Secrets),
 	}

daemon/cluster/executor/container/container.go

@@ -339,6 +339,7 @@ func (c *containerConfig) hostConfig() *enginecontainer.HostConfig {
 		GroupAdd:       c.spec().Groups,
 		PortBindings:   c.portBindings(),
 		Mounts:         c.mounts(),
+		ReadonlyRootfs: c.spec().ReadOnly,
 	}
 
 	if c.spec().DNSConfig != nil {

docs/reference/commandline/service_create.md

@@ -48,6 +48,7 @@ Options:
       --network list                     Network attachments (default [])
       --no-healthcheck                   Disable any container-specified HEALTHCHECK
   -p, --publish port                     Publish a port as a node port
+      --read-only                        Mount the container's root filesystem as read only
       --replicas uint                    Number of tasks
       --reserve-cpu decimal              Reserve CPUs (default 0.000)
       --reserve-memory bytes             Reserve Memory (default 0 B)

docs/reference/commandline/service_update.md

@@ -58,6 +58,7 @@ Options:
       --no-healthcheck                   Disable any container-specified HEALTHCHECK
       --publish-add port                 Add or update a published port
       --publish-rm port                  Remove a published port by its target port
+      --read-only                        Mount the container's root filesystem as read only
       --replicas uint                    Number of tasks
       --reserve-cpu decimal              Reserve CPUs (default 0.000)
       --reserve-memory bytes             Reserve Memory (default 0 B)

integration-cli/docker_cli_swarm_test.go

@@ -1644,3 +1644,24 @@ func (s *DockerSwarmSuite) TestSwarmInitWithDrain(c *check.C) {
 	c.Assert(err, checker.IsNil)
 	c.Assert(out, checker.Contains, "Drain")
 }
+
+func (s *DockerSwarmSuite) TestSwarmReadonlyRootfs(c *check.C) {
+	testRequires(c, DaemonIsLinux, UserNamespaceROMount)
+
+	d := s.AddDaemon(c, true, true)
+
+	out, err := d.Cmd("service", "create", "--name", "top", "--read-only", "busybox", "top")
+	c.Assert(err, checker.IsNil, check.Commentf(out))
+
+	// make sure task has been deployed.
+	waitAndAssert(c, defaultReconciliationTimeout, d.CheckActiveContainerCount, checker.Equals, 1)
+
+	out, err = d.Cmd("service", "inspect", "--format", "{{ .Spec.TaskTemplate.ContainerSpec.ReadOnly }}", "top")
+	c.Assert(err, checker.IsNil, check.Commentf(out))
+	c.Assert(strings.TrimSpace(out), checker.Equals, "true")
+
+	containers := d.ActiveContainers()
+	out, err = d.Cmd("inspect", "--type", "container", "--format", "{{.HostConfig.ReadonlyRootfs}}", containers[0])
+	c.Assert(err, checker.IsNil, check.Commentf(out))
+	c.Assert(strings.TrimSpace(out), checker.Equals, "true")
+}