diff --git a/CHANGELOG b/CHANGELOG
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,36 @@
+propellor (4.0.0) unstable; urgency=medium
+
+  * Added Monoid instances for Property and RevertableProperty.
+  * Removed applyToList. Instead, use mconcat. (API change)
+    If you had:  applyToList accountFor [User "joey", User "root"]
+    use instead: mconcat (map accountFor [User "joey", User "root"])
+  * Makefile: Removed "run" target which was default target.
+    "make" now only builds propellor, does not run it.
+    Note that propellor 1.0.0 and earlier relied on this target for
+    the Cron.runPropellor property's cronjob to work, so upgrading
+    directly from 1.0.0 to 4.0.0 would break that cron job.
+  * Remove make from propellor's dependency list; it's not used by
+    propellor any longer.
+  * Implemented hostChroot, as originally seen in my slides at
+    Linux.Conf.Au 2017 in January. Now that it's not vaporware, it allows
+    one Host to build a disk image that has all the properties of another
+    Host.
+  * DiskImage building properties used to propagate DNS info out from
+    the chroot used to build the disk image to the Host. That is no longer
+    done, since that chroot only exists as a side effect of the disk image
+    creation and servers will not be running in it.
+  * The IsInfo types class's propagateInfo function changed to use a
+    PropagateInfo data type. (API change)
+  * The action used to satisfy a property changed to Maybe (Propellor Result).
+    When it is Nothing, propellor knows it can skip displaying the
+    description of that property. This is mostly useful in the
+    implementation of mempty. (API change)
+  * The doNothing property is now simply mempty. The name was retained
+    because it can be clearer than mempty in some contexts.
+  * Added Apache.confEnabled.
+
+ -- Joey Hess <id@joeyh.name>  Wed, 15 Mar 2017 15:46:42 -0400
+
 propellor (3.4.1) unstable; urgency=medium
 
   * Fixed https url to propellor git repository.
diff --git a/Makefile b/Makefile
--- a/Makefile
+++ b/Makefile
@@ -1,11 +1,6 @@
 CABAL?=cabal
 DATE := $(shell dpkg-parsechangelog 2>/dev/null | grep Date | cut -d " " -f2-)
 
-# this target is provided (and is first) to keep old versions of the
-# propellor cron job working, and will eventually be removed
-run: build
-	./propellor
-
 build: tags propellor.1 dist/setup-config
 	$(CABAL) build
 	ln -sf dist/build/propellor-config/propellor-config propellor
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -12,8 +12,8 @@
 [components](http://propellor.branchable.com/components/)
 for details.
 
-Properties are defined using Haskell. Edit `~/.propellor/config.hs`
-to get started. There is fairly complete 
+Properties are defined using Haskell in the file `~/.propellor/config.hs`.
+There is fairly complete 
 [API documentation](http://hackage.haskell.org/package/propellor/),
 which includes many built-in Properties for dealing with
 [Apt](http://hackage.haskell.org/package/propellor/docs/Propellor-Property-Apt.html)
diff --git a/debian/changelog b/debian/changelog
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,36 @@
+propellor (4.0.0) unstable; urgency=medium
+
+  * Added Monoid instances for Property and RevertableProperty.
+  * Removed applyToList. Instead, use mconcat. (API change)
+    If you had:  applyToList accountFor [User "joey", User "root"]
+    use instead: mconcat (map accountFor [User "joey", User "root"])
+  * Makefile: Removed "run" target which was default target.
+    "make" now only builds propellor, does not run it.
+    Note that propellor 1.0.0 and earlier relied on this target for
+    the Cron.runPropellor property's cronjob to work, so upgrading
+    directly from 1.0.0 to 4.0.0 would break that cron job.
+  * Remove make from propellor's dependency list; it's not used by
+    propellor any longer.
+  * Implemented hostChroot, as originally seen in my slides at
+    Linux.Conf.Au 2017 in January. Now that it's not vaporware, it allows
+    one Host to build a disk image that has all the properties of another
+    Host.
+  * DiskImage building properties used to propagate DNS info out from
+    the chroot used to build the disk image to the Host. That is no longer
+    done, since that chroot only exists as a side effect of the disk image
+    creation and servers will not be running in it.
+  * The IsInfo types class's propagateInfo function changed to use a
+    PropagateInfo data type. (API change)
+  * The action used to satisfy a property changed to Maybe (Propellor Result).
+    When it is Nothing, propellor knows it can skip displaying the
+    description of that property. This is mostly useful in the
+    implementation of mempty. (API change)
+  * The doNothing property is now simply mempty. The name was retained
+    because it can be clearer than mempty in some contexts.
+  * Added Apache.confEnabled.
+
+ -- Joey Hess <id@joeyh.name>  Wed, 15 Mar 2017 15:46:42 -0400
+
 propellor (3.4.1) unstable; urgency=medium
 
   * Fixed https url to propellor git repository.
diff --git a/debian/control b/debian/control
--- a/debian/control
+++ b/debian/control
@@ -44,7 +44,6 @@
 	libghc-text-dev,
 	libghc-concurrent-output-dev,
 	git,
-	make,
 Description: property-based host configuration management in haskell
  Propellor ensures that the system it's run in satisfies a list of
  properties, taking action as necessary when a property is not yet met.
diff --git a/doc/README.mdwn b/doc/README.mdwn
--- a/doc/README.mdwn
+++ b/doc/README.mdwn
@@ -12,8 +12,8 @@
 [components](http://propellor.branchable.com/components/)
 for details.
 
-Properties are defined using Haskell. Edit `~/.propellor/config.hs`
-to get started. There is fairly complete 
+Properties are defined using Haskell in the file `~/.propellor/config.hs`.
+There is fairly complete 
 [API documentation](http://hackage.haskell.org/package/propellor/),
 which includes many built-in Properties for dealing with
 [Apt](http://hackage.haskell.org/package/propellor/docs/Propellor-Property-Apt.html)
diff --git a/joeyconfig.hs b/joeyconfig.hs
--- a/joeyconfig.hs
+++ b/joeyconfig.hs
@@ -164,7 +164,7 @@
 oyster = host "oyster.kitenet.net" $ props
 	& standardSystem Unstable X86_64
 		[ "Unreliable server. Anything here may be lost at any time!" ]
-	& ipv4 "64.137.221.146"
+	& ipv4 "45.62.245.55"
 
 	& CloudAtCost.decruft
 	& Ssh.hostKeys hostContext
@@ -249,14 +249,17 @@
 	-- No hardware clock.
 	& Apt.serviceInstalledRunning "ntp"
 
+	-- Runs only on weekdays.
 	& Systemd.nspawned (GitAnnexBuilder.autoBuilderContainer
 		GitAnnexBuilder.armAutoBuilder
-		Unstable ARMEL Nothing 
-		(Cron.Times "15 6 * * *") "22h")
+		Unstable ARMEL Nothing weekends "23h")
+	-- Runs only on weekends.
 	& Systemd.nspawned (GitAnnexBuilder.autoBuilderContainer
 		GitAnnexBuilder.stackAutoBuilder
-		(Stable "jessie") ARMEL (Just "ancient")
-		(Cron.Times "15 18 * * *") "22h")
+		(Stable "jessie") ARMEL (Just "ancient") weekdays "23h")
+  where
+	weekdays = Cron.Times "15 6 * * 2-5"
+	weekends = Cron.Times "15 6 * * 6-7"
 
 -- This is not a complete description of kite, since it's a
 -- multiuser system with eg, user passwords that are not deployed
diff --git a/propellor.cabal b/propellor.cabal
--- a/propellor.cabal
+++ b/propellor.cabal
@@ -1,5 +1,5 @@
 Name: propellor
-Version: 3.4.1
+Version: 4.0.0
 Cabal-Version: >= 1.8
 License: BSD2
 Maintainer: Joey Hess <id@joeyh.name>
diff --git a/src/Propellor/Bootstrap.hs b/src/Propellor/Bootstrap.hs
--- a/src/Propellor/Bootstrap.hs
+++ b/src/Propellor/Bootstrap.hs
@@ -94,7 +94,6 @@
 		, "libghc-exceptions-dev"
 		, "libghc-stm-dev"
 		, "libghc-text-dev"
-		, "make"
 		]
 	fbsddeps =
 		[ "gnupg"
@@ -112,7 +111,6 @@
 		, "hs-exceptions"
 		, "hs-stm"
 		, "hs-text"
-		, "gmake"
 		]
 	archlinuxdeps =
 		[ "gnupg"
@@ -131,7 +129,6 @@
 		, "haskell-exceptions"
 		, "haskell-stm"
 		, "haskell-text"
-		, "make"
 		]
 
 installGitCommand :: Maybe System -> ShellCommand
diff --git a/src/Propellor/Container.hs b/src/Propellor/Container.hs
--- a/src/Propellor/Container.hs
+++ b/src/Propellor/Container.hs
@@ -51,15 +51,30 @@
 		)
 	=> String
 	-> c
+	-> (PropagateInfo -> Bool)
 	-> Property metatypes
 	-> Property metatypes
-propagateContainer containername c prop = prop
+propagateContainer containername c wanted prop = prop
 	`addChildren` map convert (containerProperties c)
   where
 	convert p = 
-		let n = property (getDesc p) (getSatisfy p) :: Property UnixLike
+		let n = property'' (getDesc p) (getSatisfy p) :: Property UnixLike
 		    n' = n
 		    	`setInfoProperty` mapInfo (forceHostContext containername)
-				(propagatableInfo (getInfo p))
+				(propagatableInfo wanted (getInfo p))
 		   	`addChildren` map convert (getChildren p)
 		in toChildProperty n'
+
+-- | Filters out parts of the Info that should not propagate out of a
+-- container.
+propagatableInfo :: (PropagateInfo -> Bool) -> Info -> Info
+propagatableInfo wanted (Info l) = Info $
+	filter (\(InfoEntry a) -> wanted (propagateInfo a)) l
+
+normalContainerInfo :: PropagateInfo -> Bool
+normalContainerInfo PropagatePrivData = True
+normalContainerInfo (PropagateInfo b) = b
+
+onlyPrivData :: PropagateInfo -> Bool
+onlyPrivData PropagatePrivData = True
+onlyPrivData (PropagateInfo _) = False
diff --git a/src/Propellor/Engine.hs b/src/Propellor/Engine.hs
--- a/src/Propellor/Engine.hs
+++ b/src/Propellor/Engine.hs
@@ -66,7 +66,9 @@
 	ensure [] rs = return rs
 	ensure (p:ls) rs = do
 		hn <- asks hostName
-		r <- actionMessageOn hn (getDesc p) (catchPropellor $ getSatisfy p)
+		r <- maybe (pure NoChange)
+			(actionMessageOn hn (getDesc p) . catchPropellor)
+			(getSatisfy p)
 		ensure ls (r <> rs)
 
 -- | Lifts an action into the context of a different host.
diff --git a/src/Propellor/EnsureProperty.hs b/src/Propellor/EnsureProperty.hs
--- a/src/Propellor/EnsureProperty.hs
+++ b/src/Propellor/EnsureProperty.hs
@@ -46,7 +46,7 @@
 	=> OuterMetaTypesWitness outer
 	-> Property (MetaTypes inner)
 	-> Propellor Result
-ensureProperty _ = catchPropellor . getSatisfy
+ensureProperty _ = maybe (pure NoChange) catchPropellor . getSatisfy
 
 -- The name of this was chosen to make type errors a bit more understandable.
 type family Cannot_ensureProperty_WithInfo (l :: [a]) :: Bool
@@ -62,7 +62,7 @@
 	-> (OuterMetaTypesWitness metatypes -> Propellor Result)
 	-> Property (MetaTypes metatypes)
 property' d a =
-	let p = Property sing d (a (outerMetaTypesWitness p)) mempty mempty
+	let p = Property sing d (Just (a (outerMetaTypesWitness p))) mempty mempty
 	in p
 
 -- | Used to provide the metatypes of a Property to calls to 
diff --git a/src/Propellor/PrivData.hs b/src/Propellor/PrivData.hs
--- a/src/Propellor/PrivData.hs
+++ b/src/Propellor/PrivData.hs
@@ -281,10 +281,10 @@
 	{ fromPrivInfo :: S.Set (PrivDataField, Maybe PrivDataSourceDesc, HostContext) }
 	deriving (Eq, Ord, Show, Typeable, Monoid)
 
--- PrivInfo is propagated out of containers, so that propellor can see which
--- hosts need it.
+-- PrivInfo always propagates out of containers, so that propellor
+-- can see which hosts need it.
 instance IsInfo PrivInfo where
-	propagateInfo _ = True
+	propagateInfo _ = PropagatePrivData
 
 -- | Sets the context of any privdata that uses HostContext to the
 -- provided name.
diff --git a/src/Propellor/Property.hs b/src/Propellor/Property.hs
--- a/src/Propellor/Property.hs
+++ b/src/Propellor/Property.hs
@@ -16,7 +16,6 @@
 	, check
 	, fallback
 	, revert
-	, applyToList
 	-- * Property descriptions
 	, describe
 	, (==>)
@@ -54,7 +53,6 @@
 import qualified Data.Hash.MD5 as MD5
 import Data.List
 import Control.Applicative
-import Data.Foldable hiding (and, elem)
 import Prelude
 
 import Propellor.Types
@@ -120,13 +118,15 @@
         -> CombinedType x y
 onChange = combineWith combiner revertcombiner
   where
-	combiner p hook = do
+	combiner (Just p) (Just hook) = Just $ do
 		r <- p
 		case r of
 			MadeChange -> do
 				r' <- hook
 				return $ r <> r'
 			_ -> return r
+	combiner (Just p) Nothing = Just p
+	combiner Nothing _ = Nothing
 	revertcombiner = (<>)
 
 -- | Same as `onChange` except that if property y fails, a flag file
@@ -144,24 +144,30 @@
         -> CombinedType x y
 onChangeFlagOnFail flagfile = combineWith combiner revertcombiner
   where
-	combiner s1 s2 = do
+	combiner (Just s1) s2 = Just $ do
 		r1 <- s1
 		case r1 of
 			MadeChange -> flagFailed s2
 			_ -> ifM (liftIO $ doesFileExist flagfile)
-				(flagFailed s2
+				( flagFailed s2
 				, return r1
 				)
+	combiner Nothing _ = Nothing
+
 	revertcombiner = (<>)
-	flagFailed s = do
+
+	flagFailed (Just s) = do
 		r <- s
 		liftIO $ case r of
 			FailedChange -> createFlagFile
 			_ -> removeFlagFile
 		return r
+	flagFailed Nothing = return NoChange
+
 	createFlagFile = unlessM (doesFileExist flagfile) $ do
 		createDirectoryIfMissing True (takeDirectory flagfile)
 		writeFile flagfile ""
+	
 	removeFlagFile = whenM (doesFileExist flagfile) $ removeFile flagfile
 
 -- | Changes the description of a property.
@@ -178,11 +184,13 @@
 fallback :: (Combines p1 p2) => p1 -> p2 -> CombinedType p1 p2
 fallback = combineWith combiner revertcombiner
   where
-	combiner a1 a2 = do
+	combiner (Just a1) (Just a2) = Just $ do
 		r <- a1
 		if r == FailedChange
 			then a2
 			else return r
+	combiner (Just a1) Nothing = Just a1
+	combiner Nothing _ = Nothing
 	revertcombiner = (<>)
 
 -- | Indicates that a Property may change a particular file. When the file
@@ -292,9 +300,9 @@
 	-- are added as children, so their info will propigate.
 	c = withOS (getDesc a) $ \_ o ->
 		if matching o a
-			then getSatisfy a
+			then maybe (pure NoChange) id (getSatisfy a)
 			else if matching o b
-				then getSatisfy b
+				then maybe (pure NoChange) id (getSatisfy b)
 				else unsupportedOS'
 	matching Nothing _ = False
 	matching (Just o) p =
@@ -343,14 +351,6 @@
 revert :: RevertableProperty setup undo -> RevertableProperty undo setup
 revert (RevertableProperty p1 p2) = RevertableProperty p2 p1
 
--- | Apply a property to each element of a list.
-applyToList
-	:: (Foldable t, Functor t, Combines p p, p ~ CombinedType p p)
-	=> (b -> p)
-	-> t b
-	-> p
-prop `applyToList` xs = Data.Foldable.foldr1 before $ prop <$> xs
-
 makeChange :: IO () -> Propellor Result
 makeChange a = liftIO a >> return MadeChange
 
@@ -358,7 +358,7 @@
 noChange = return NoChange
 
 doNothing :: SingI t => Property (MetaTypes t)
-doNothing = property "noop property" noChange
+doNothing = mempty
 
 -- | Registers an action that should be run at the very end, after
 -- propellor has checks all the properties of a host.
diff --git a/src/Propellor/Property/Apache.hs b/src/Propellor/Property/Apache.hs
--- a/src/Propellor/Property/Apache.hs
+++ b/src/Propellor/Property/Apache.hs
@@ -64,6 +64,24 @@
 			`onChange` reloaded
 	isenabled = boolSystem "a2query" [Param "-q", Param "-m", Param modname]
 
+-- | Control whether an apache configuration file is enabled. 
+--
+-- The String is the base name of the configuration, eg "charset" or "gitweb".
+confEnabled :: String -> RevertableProperty DebianLike DebianLike
+confEnabled confname = enable <!> disable
+  where
+	enable = check (not <$> isenabled)
+		(cmdProperty "a2enconf" ["--quiet", confname])
+			`describe` ("apache configuration enabled " ++ confname)
+			`requires` installed
+			`onChange` reloaded
+	disable = check isenabled
+		(cmdProperty "a2disconf" ["--quiet", confname])
+			`describe` ("apache configuration disabled " ++ confname)
+			`requires` installed
+			`onChange` reloaded
+	isenabled = boolSystem "a2query" [Param "-q", Param "-c", Param confname]
+
 -- | Make apache listen on the specified ports.
 --
 -- Note that ports are also specified inside a site's config file,
diff --git a/src/Propellor/Property/Apt.hs b/src/Propellor/Property/Apt.hs
--- a/src/Propellor/Property/Apt.hs
+++ b/src/Propellor/Property/Apt.hs
@@ -265,7 +265,7 @@
 	:: [AptPackagePref]
 	-> [(DebianSuite, PinPriority)]
 	-> RevertableProperty Debian Debian
-pinnedTo ps pins = (\p -> pinnedTo' p pins) `applyToList` ps
+pinnedTo ps pins = mconcat (map (\p -> pinnedTo' p pins) ps)
 	`describe` unwords (("pinned to " ++ showSuites):ps)
   where
 	showSuites = intercalate "," $ showSuite . fst <$> pins
diff --git a/src/Propellor/Property/Chroot.hs b/src/Propellor/Property/Chroot.hs
--- a/src/Propellor/Property/Chroot.hs
+++ b/src/Propellor/Property/Chroot.hs
@@ -4,6 +4,7 @@
 	debootstrapped,
 	bootstrapped,
 	provisioned,
+	hostChroot,
 	Chroot(..),
 	ChrootBootstrapper(..),
 	Debootstrapped(..),
@@ -40,18 +41,18 @@
 -- | Specification of a chroot. Normally you'll use `debootstrapped` or
 -- `bootstrapped` to construct a Chroot value.
 data Chroot where
-	Chroot :: ChrootBootstrapper b => FilePath -> b -> Host -> Chroot
+	Chroot :: ChrootBootstrapper b => FilePath -> b -> InfoPropagator -> Host -> Chroot
 
 instance IsContainer Chroot where
-	containerProperties (Chroot _ _ h) = containerProperties h
-	containerInfo (Chroot _ _ h) = containerInfo h
-	setContainerProperties (Chroot loc b h) ps = Chroot loc b (setContainerProperties h ps)
+	containerProperties (Chroot _ _ _ h) = containerProperties h
+	containerInfo (Chroot _ _ _ h) = containerInfo h
+	setContainerProperties (Chroot loc b p h) ps = Chroot loc b p (setContainerProperties h ps)
 
 chrootSystem :: Chroot -> Maybe System
 chrootSystem = fromInfoVal . fromInfo . containerInfo
 
 instance Show Chroot where
-	show c@(Chroot loc _ _) = "Chroot " ++ loc ++ " " ++ show (chrootSystem c)
+	show c@(Chroot loc _ _ _) = "Chroot " ++ loc ++ " " ++ show (chrootSystem c)
 
 -- | Class of things that can do initial bootstrapping of an operating
 -- System in a chroot.
@@ -115,7 +116,9 @@
 -- | Defines a Chroot at the given location, bootstrapped with the
 -- specified ChrootBootstrapper.
 bootstrapped :: ChrootBootstrapper b => b -> FilePath -> Props metatypes -> Chroot
-bootstrapped bootstrapper location ps = Chroot location bootstrapper (host location ps)
+bootstrapped bootstrapper location ps = c
+  where
+	c = Chroot location bootstrapper (propagateChrootInfo c) (host location ps)
 
 -- | Ensures that the chroot exists and is provisioned according to its
 -- properties.
@@ -124,15 +127,14 @@
 -- is first unmounted. Note that it does not ensure that any processes
 -- that might be running inside the chroot are stopped.
 provisioned :: Chroot -> RevertableProperty (HasInfo + Linux) Linux
-provisioned c = provisioned' (propagateChrootInfo c) c False
+provisioned c = provisioned' c False
 
 provisioned'
-	:: (Property Linux -> Property (HasInfo + Linux))
-	-> Chroot
+	:: Chroot
 	-> Bool
 	-> RevertableProperty (HasInfo + Linux) Linux
-provisioned' propigator c@(Chroot loc bootstrapper _) systemdonly =
-	(propigator $ setup `describe` chrootDesc c "exists")
+provisioned' c@(Chroot loc bootstrapper infopropigator _) systemdonly =
+	(infopropigator normalContainerInfo $ setup `describe` chrootDesc c "exists")
 		<!>
 	(teardown `describe` chrootDesc c "removed")
   where
@@ -151,17 +153,20 @@
 		property ("removed " ++ loc) $
 			makeChange (removeChroot loc)
 
-propagateChrootInfo :: Chroot -> Property Linux -> Property (HasInfo + Linux)
-propagateChrootInfo c@(Chroot location _ _) p = propagateContainer location c $
-	p `setInfoProperty` chrootInfo c
+type InfoPropagator = (PropagateInfo -> Bool) -> Property Linux -> Property (HasInfo + Linux)
 
+propagateChrootInfo :: Chroot -> InfoPropagator
+propagateChrootInfo c@(Chroot location _ _ _) pinfo p =
+	propagateContainer location c pinfo $
+		p `setInfoProperty` chrootInfo c
+
 chrootInfo :: Chroot -> Info
-chrootInfo (Chroot loc _ h) = mempty `addInfo`
+chrootInfo (Chroot loc _ _ h) = mempty `addInfo`
 	mempty { _chroots = M.singleton loc h }
 
 -- | Propellor is run inside the chroot to provision it.
 propellChroot :: Chroot -> ([String] -> IO (CreateProcess, IO ())) -> Bool -> Property UnixLike
-propellChroot c@(Chroot loc _ _) mkproc systemdonly = property (chrootDesc c "provisioned") $ do
+propellChroot c@(Chroot loc _ _ _) mkproc systemdonly = property (chrootDesc c "provisioned") $ do
 	let d = localdir </> shimdir c
 	let me = localdir </> "propellor"
 	shim <- liftIO $ ifM (doesDirectoryExist d)
@@ -200,7 +205,7 @@
 		return r
 
 toChain :: HostName -> Chroot -> Bool -> IO CmdLine
-toChain parenthost (Chroot loc _ _) systemdonly = do
+toChain parenthost (Chroot loc _ _ _) systemdonly = do
 	onconsole <- isConsole <$> getMessageHandle
 	return $ ChrootChain parenthost loc systemdonly onconsole
 
@@ -225,7 +230,7 @@
 chain _ _ = errorMessage "bad chain command"
 
 inChrootProcess :: Bool -> Chroot -> [String] -> IO (CreateProcess, IO ())
-inChrootProcess keepprocmounted (Chroot loc _ _) cmd = do
+inChrootProcess keepprocmounted (Chroot loc _ _ _) cmd = do
 	mountproc
 	return (proc "chroot" (loc:cmd), cleanup)
   where
@@ -245,13 +250,13 @@
 provisioningLock containerloc = "chroot" </> mungeloc containerloc ++ ".lock"
 
 shimdir :: Chroot -> FilePath
-shimdir (Chroot loc _ _) = "chroot" </> mungeloc loc ++ ".shim"
+shimdir (Chroot loc _ _ _) = "chroot" </> mungeloc loc ++ ".shim"
 
 mungeloc :: FilePath -> String
 mungeloc = replace "/" "_"
 
 chrootDesc :: Chroot -> String -> String
-chrootDesc (Chroot loc _ _) desc = "chroot " ++ loc ++ " " ++ desc
+chrootDesc (Chroot loc _ _ _) desc = "chroot " ++ loc ++ " " ++ desc
 
 -- | Adding this property to a chroot prevents daemons and other services
 -- from being started, which is often something you want to prevent when
@@ -287,3 +292,22 @@
 
 newtype InChroot = InChroot Bool
 	deriving (Typeable, Show)
+
+-- | Generates a Chroot that has all the properties of a Host.
+-- 
+-- Note that it's possible to create loops using this, where a host
+-- contains a Chroot containing itself etc. Such loops will be detected at
+-- runtime.
+hostChroot :: ChrootBootstrapper bootstrapper => Host -> bootstrapper -> FilePath -> Chroot
+hostChroot h bootstrapper d = chroot
+  where
+	chroot = Chroot d bootstrapper pinfo h
+	pinfo = propagateHostChrootInfo h chroot
+
+-- This is different than propagateChrootInfo in that Info using
+-- HostContext is not made to use the name of the chroot as its context,
+-- but instead uses the hostname of the Host.
+propagateHostChrootInfo :: Host -> Chroot -> InfoPropagator
+propagateHostChrootInfo h c pinfo p =
+	propagateContainer (hostName h) c pinfo $
+		p `setInfoProperty` chrootInfo c
diff --git a/src/Propellor/Property/Concurrent.hs b/src/Propellor/Property/Concurrent.hs
--- a/src/Propellor/Property/Concurrent.hs
+++ b/src/Propellor/Property/Concurrent.hs
@@ -64,10 +64,13 @@
 	-- Increase the number of capabilities right up to the number of
 	-- processors, so that A `concurrently` B `concurrently` C
 	-- runs all 3 properties on different processors when possible.
-	go a1 a2 = do
+	go (Just a1) (Just a2) = Just $ do
 		n <- liftIO getNumProcessors
 		withCapabilities n $
 			concurrentSatisfy a1 a2
+	go (Just a1) Nothing = Just a1
+	go Nothing (Just a2) = Just a2
+	go Nothing Nothing = Nothing
 
 -- | Ensures all the properties in the list, with a specified amount of
 -- concurrency.
@@ -101,9 +104,9 @@
 			Nothing -> return r
 			Just p -> do
 				hn <- asks hostName
-				r' <- actionMessageOn hn
-					(getDesc p)
-					(getSatisfy p)
+				r' <- case getSatisfy p of
+					Nothing -> return NoChange
+					Just a -> actionMessageOn hn (getDesc p) a
 				worker q (r <> r')
 
 -- | Run an action with the number of capabiities increased as necessary to
diff --git a/src/Propellor/Property/Conductor.hs b/src/Propellor/Property/Conductor.hs
--- a/src/Propellor/Property/Conductor.hs
+++ b/src/Propellor/Property/Conductor.hs
@@ -323,15 +323,15 @@
 	show (NotConductorFor l) = "NotConductorFor " ++ show (map hostName l)
 
 instance IsInfo ConductorFor where
-	propagateInfo _ = False
+	propagateInfo _ = PropagateInfo False
 instance IsInfo NotConductorFor where
-	propagateInfo _ = False
+	propagateInfo _ = PropagateInfo False
 
 -- Added to Info when a host has been orchestrated.
 newtype Orchestrated = Orchestrated Any
 	deriving (Typeable, Monoid, Show)
 instance IsInfo Orchestrated where
-	propagateInfo _ = False
+	propagateInfo _ = PropagateInfo False
 
 isOrchestrated :: Orchestrated -> Bool
 isOrchestrated (Orchestrated v) = getAny v
diff --git a/src/Propellor/Property/DiskImage.hs b/src/Propellor/Property/DiskImage.hs
--- a/src/Propellor/Property/DiskImage.hs
+++ b/src/Propellor/Property/DiskImage.hs
@@ -50,29 +50,7 @@
 --
 -- Then, the disk image is set up, and the chroot is copied into the
 -- appropriate partition(s) of it.
---
--- Example use:
---
--- > import Propellor.Property.DiskImage
---
--- > let chroot d = Chroot.debootstrapped mempty d
--- >	& osDebian Unstable X86_64
--- >	& Apt.installed ["linux-image-amd64"]
--- >	& User.hasPassword (User "root")
--- >	& User.accountFor (User "demo")
--- > 	& User.hasPassword (User "demo")
--- >	& User.hasDesktopGroups (User "demo")
--- > 	& ...
--- > in imageBuilt "/srv/images/foo.img" chroot
--- >	MSDOS (grubBooted PC)
--- >	[ partition EXT2 `mountedAt` "/boot"
--- >		`setFlag` BootFlag
--- >	, partition EXT4 `mountedAt` "/"
--- >		`addFreeSpace` MegaBytes 100
--- >		`mountOpt` errorReadonly
--- >	, swapPartition (MegaBytes 256)
--- >	]
---
+-- 
 -- Note that the disk image file is reused if it already exists,
 -- to avoid expensive IO to generate a new one. And, it's updated in-place,
 -- so its contents are undefined during the build process.
@@ -81,6 +59,52 @@
 -- chroot while the disk image is being built, which should prevent any
 -- daemons that are included from being started on the system that is
 -- building the disk image.
+--
+-- Example use:
+--
+-- > import Propellor.Property.DiskImage
+-- > import Propellor.Property.Chroot
+-- > 
+-- > foo = host "foo.example.com" $ props
+-- > 	& imageBuilt "/srv/diskimages/disk.img" mychroot
+-- >		MSDOS (grubBooted PC)
+-- >		[ partition EXT2 `mountedAt` "/boot"
+-- >			`setFlag` BootFlag
+-- >		, partition EXT4 `mountedAt` "/"
+-- >			`addFreeSpace` MegaBytes 100
+-- >			`mountOpt` errorReadonly
+-- >		, swapPartition (MegaBytes 256)
+-- >		]
+-- >  where
+-- >	mychroot d = debootstrapped mempty d $ props
+-- >		& osDebian Unstable X86_64
+-- >		& Apt.installed ["linux-image-amd64"]
+-- >		& User.hasPassword (User "root")
+-- >		& User.accountFor (User "demo")
+-- > 		& User.hasPassword (User "demo")
+-- >		& User.hasDesktopGroups (User "demo")
+-- > 		& ...
+--
+-- This can also be used with `Chroot.hostChroot` to build a disk image
+-- that has all the properties of a Host. For example:
+--
+-- > foo :: Host
+-- > foo = host "foo.example.com" $ props
+-- >	& imageBuilt "/srv/diskimages/bar-disk.img"
+-- >		(hostChroot bar (Debootstrapped mempty))
+-- >		MSDOS (grubBooted PC)
+-- >		[ partition EXT2 `mountedAt` "/boot"
+-- >			`setFlag` BootFlag
+-- >		, partition EXT4 `mountedAt` "/"
+-- >			`addFreeSpace` MegaBytes 5000
+-- >		, swapPartition (MegaBytes 256)
+-- >		]
+-- >
+-- > bar :: Host
+-- > bar = host "bar.example.com" $ props
+-- >	& osDebian Unstable X86_64
+-- >	& Apt.installed ["linux-image-amd64"]
+-- >	& hasPassword (User "root")
 imageBuilt :: DiskImage -> (FilePath -> Chroot) -> TableType -> Finalization -> [PartSpec] -> RevertableProperty (HasInfo + DebianLike) Linux
 imageBuilt = imageBuilt' False
 
@@ -106,7 +130,7 @@
 		| otherwise = doNothing
 	chrootdir = img ++ ".chroot"
 	chroot =
-		let c = mkchroot chrootdir
+		let c = propprivdataonly $ mkchroot chrootdir
 		in setContainerProps c $ containerProps c
 			-- Before ensuring any other properties of the chroot,
 			-- avoid starting services. Reverted by imageFinalized.
@@ -114,6 +138,9 @@
 			-- First stage finalization.
 			& fst final
 			& cachesCleaned
+	-- Only propagate privdata Info from this chroot, nothing else.
+	propprivdataonly (Chroot.Chroot d b ip h) =
+		Chroot.Chroot d b (const $ ip onlyPrivData) h
 
 -- | This property is automatically added to the chroot when building a
 -- disk image. It cleans any caches of information that can be omitted;
diff --git a/src/Propellor/Property/Docker.hs b/src/Propellor/Property/Docker.hs
--- a/src/Propellor/Property/Docker.hs
+++ b/src/Propellor/Property/Docker.hs
@@ -184,8 +184,9 @@
 	image = getImageName ctr
 
 propagateContainerInfo :: Container -> Property (HasInfo + Linux) -> Property (HasInfo + Linux)
-propagateContainerInfo ctr@(Container _ h) p = propagateContainer cn ctr $
-	p `addInfoProperty` dockerinfo
+propagateContainerInfo ctr@(Container _ h) p = 
+	propagateContainer cn ctr normalContainerInfo $
+		p `addInfoProperty` dockerinfo
   where
 	dockerinfo = dockerInfo $
 		mempty { _dockerContainers = M.singleton cn h }
diff --git a/src/Propellor/Property/Firejail.hs b/src/Propellor/Property/Firejail.hs
--- a/src/Propellor/Property/Firejail.hs
+++ b/src/Propellor/Property/Firejail.hs
@@ -22,7 +22,7 @@
 --
 -- See "DESKTOP INTEGRATION" in firejail(1).
 jailed :: [String] -> Property DebianLike
-jailed ps = (jailed' `applyToList` ps)
+jailed ps = mconcat (map jailed' ps)
 	`requires` installed
 	`describe` unwords ("firejail jailed":ps)
 
diff --git a/src/Propellor/Property/FreeBSD/Pkg.hs b/src/Propellor/Property/FreeBSD/Pkg.hs
--- a/src/Propellor/Property/FreeBSD/Pkg.hs
+++ b/src/Propellor/Property/FreeBSD/Pkg.hs
@@ -39,7 +39,7 @@
 newtype PkgUpdate = PkgUpdate String
 	deriving (Typeable, Monoid, Show)
 instance IsInfo PkgUpdate where
-	propagateInfo _ = False
+	propagateInfo _ = PropagateInfo False
 
 pkgUpdated :: PkgUpdate -> Bool
 pkgUpdated (PkgUpdate _) = True
@@ -55,8 +55,9 @@
 
 newtype PkgUpgrade = PkgUpgrade String
 	deriving (Typeable, Monoid, Show)
+
 instance IsInfo PkgUpgrade where
-	propagateInfo _ = False
+	propagateInfo _ = PropagateInfo False
 
 pkgUpgraded :: PkgUpgrade -> Bool
 pkgUpgraded (PkgUpgrade _) = True
diff --git a/src/Propellor/Property/FreeBSD/Poudriere.hs b/src/Propellor/Property/FreeBSD/Poudriere.hs
--- a/src/Propellor/Property/FreeBSD/Poudriere.hs
+++ b/src/Propellor/Property/FreeBSD/Poudriere.hs
@@ -21,7 +21,7 @@
 	deriving (Typeable, Monoid, Show)
 
 instance IsInfo PoudriereConfigured where
-	propagateInfo _ = False
+	propagateInfo _ = PropagateInfo False
 
 poudriereConfigured :: PoudriereConfigured -> Bool
 poudriereConfigured (PoudriereConfigured _) = True
diff --git a/src/Propellor/Property/List.hs b/src/Propellor/Property/List.hs
--- a/src/Propellor/Property/List.hs
+++ b/src/Propellor/Property/List.hs
@@ -53,7 +53,7 @@
 combineSatisfy :: [ChildProperty] -> Result -> Propellor Result
 combineSatisfy [] rs = return rs
 combineSatisfy (p:ps) rs = do
-	r <- catchPropellor $ getSatisfy p
+	r <- maybe (pure NoChange) catchPropellor (getSatisfy p)
 	case r of
 		FailedChange -> return FailedChange
 		_ -> combineSatisfy ps (r <> rs)
diff --git a/src/Propellor/Property/SiteSpecific/JoeySites.hs b/src/Propellor/Property/SiteSpecific/JoeySites.hs
--- a/src/Propellor/Property/SiteSpecific/JoeySites.hs
+++ b/src/Propellor/Property/SiteSpecific/JoeySites.hs
@@ -228,23 +228,29 @@
 		`requires` Ssh.knownHost hosts "usw-s002.rsync.net" (User "root")
 		`requires` Ssh.authorizedKeys (User "family") (Context "git.kitenet.net")
 		`requires` User.accountFor (User "family")
-	& Apt.installed ["git", "rsync", "gitweb"]
+	& Apt.installed ["git", "rsync", "cgit"]
 	& Apt.installed ["git-annex"]
 	& Apt.installed ["kgb-client"]
 	& File.hasPrivContentExposed "/etc/kgb-bot/kgb-client.conf" anyContext
 		`requires` File.dirExists "/etc/kgb-bot/"
 	& Git.daemonRunning "/srv/git"
-	& "/etc/gitweb.conf" `File.containsLines`
-		[ "$projectroot = '/srv/git';"
-		, "@git_base_url_list = ('git://git.kitenet.net', 'http://git.kitenet.net/git', 'https://git.kitenet.net/git', 'ssh://git.kitenet.net/srv/git');"
-		, "# disable snapshot download; overloads server"
-		, "$feature{'snapshot'}{'default'} = [];"
+	& "/etc/cgitrc" `File.hasContent`
+		[ "clone-url=https://git.joeyh.name/git/$CGIT_REPO_URL git://git.joeyh.name/$CGIT_REPO_URL"
+		, "css=/cgit-css/cgit.css"
+		, "logo=/cgit-css/cgit.png"
+		, "enable-http-clone=1"
+		, "root-title=Joey's git repositories"
+		, "root-desc="
+		, "enable-index-owner=0"
+		, "snapshots=tar.gz"
+		, "enable-git-config=1"
+		, "scan-path=/srv/git"
 		]
-		`describe` "gitweb configured"
-	-- Repos push on to github.
-	& Ssh.knownHost hosts "github.com" (User "joey")
-	-- I keep the website used for gitweb checked into git..
+		`describe` "cgit configured"
+	-- I keep the website used for git.kitenet.net/git.joeyh.name checked into git..
 	& Git.cloned (User "root") "/srv/git/joey/git.kitenet.net.git" "/srv/web/git.kitenet.net" Nothing
+	-- Don't need global apache configuration for cgit.
+	! Apache.confEnabled "cgit"
 	& website "git.kitenet.net"
 	& website "git.joeyh.name"
 	& Apache.modEnabled "cgi"
diff --git a/src/Propellor/Property/Ssh.hs b/src/Propellor/Property/Ssh.hs
--- a/src/Propellor/Property/Ssh.hs
+++ b/src/Propellor/Property/Ssh.hs
@@ -227,7 +227,7 @@
 	deriving (Eq, Ord, Typeable, Show)
 
 instance IsInfo HostKeyInfo where
-	propagateInfo _ = False
+	propagateInfo _ = PropagateInfo False
 
 instance Monoid HostKeyInfo where
 	mempty = HostKeyInfo M.empty
@@ -248,7 +248,7 @@
 	deriving (Eq, Ord, Typeable, Show)
 
 instance IsInfo UserKeyInfo where
-	propagateInfo _ = False
+	propagateInfo _ = PropagateInfo False
 
 instance Monoid UserKeyInfo where
 	mempty = UserKeyInfo M.empty
diff --git a/src/Propellor/Property/Systemd.hs b/src/Propellor/Property/Systemd.hs
--- a/src/Propellor/Property/Systemd.hs
+++ b/src/Propellor/Property/Systemd.hs
@@ -259,7 +259,7 @@
 -- Reverting this property stops the container, removes the systemd unit,
 -- and deletes the chroot and all its contents.
 nspawned :: Container -> RevertableProperty (HasInfo + Linux) Linux
-nspawned c@(Container name (Chroot.Chroot loc builder _) h) =
+nspawned c@(Container name (Chroot.Chroot loc builder _ _) h) =
 	p `describe` ("nspawned " ++ name)
   where
 	p :: RevertableProperty (HasInfo + Linux) Linux
@@ -271,7 +271,7 @@
 	-- Chroot provisioning is run in systemd-only mode,
 	-- which sets up the chroot and ensures systemd and dbus are
 	-- installed, but does not handle the other properties.
-	chrootprovisioned = Chroot.provisioned' (Chroot.propagateChrootInfo chroot) chroot True
+	chrootprovisioned = Chroot.provisioned' chroot True
 
 	-- Use nsenter to enter container and and run propellor to
 	-- finish provisioning.
@@ -281,7 +281,7 @@
 			<!>
 		doNothing
 
-	chroot = Chroot.Chroot loc builder h
+	chroot = Chroot.Chroot loc builder (Chroot.propagateChrootInfo chroot) h
 
 -- | Sets up the service file for the container, and then starts
 -- it running.
diff --git a/src/Propellor/Types.hs b/src/Propellor/Types.hs
--- a/src/Propellor/Types.hs
+++ b/src/Propellor/Types.hs
@@ -12,6 +12,7 @@
 	  Host(..)
 	, Property(..)
 	, property
+	, property''
 	, Desc
 	, RevertableProperty(..)
 	, (<!>)
@@ -56,7 +57,6 @@
 -- | The core data type of Propellor, this represents a property
 -- that the system should have, with a descrition, and an action to ensure
 -- it has the property.
--- that have the property.
 --
 -- There are different types of properties that target different OS's,
 -- and so have different metatypes. 
@@ -67,7 +67,7 @@
 --
 -- There are many associated type families, which are mostly used
 -- internally, so you needn't worry about them.
-data Property metatypes = Property metatypes Desc (Propellor Result) Info [ChildProperty]
+data Property metatypes = Property metatypes Desc (Maybe (Propellor Result)) Info [ChildProperty]
 
 instance Show (Property metatypes) where
 	show p = "property " ++ show (getDesc p)
@@ -90,11 +90,18 @@
 	=> Desc
 	-> Propellor Result
 	-> Property (MetaTypes metatypes)
-property d a = Property sing d a mempty mempty
+property d a = Property sing d (Just a) mempty mempty
 
+property''
+	:: SingI metatypes
+	=> Desc
+	-> Maybe (Propellor Result)
+	-> Property (MetaTypes metatypes)
+property'' d a = Property sing d a mempty mempty
+
 -- | Changes the action that is performed to satisfy a property.
 adjustPropertySatisfy :: Property metatypes -> (Propellor Result -> Propellor Result) -> Property metatypes
-adjustPropertySatisfy (Property t d s i c) f = Property t d (f s) i c
+adjustPropertySatisfy (Property t d s i c) f = Property t d (f <$> s) i c
 
 -- | A property that can be reverted. The first Property is run
 -- normally and the second is run when it's reverted.
@@ -148,7 +155,7 @@
 type instance CombinedType (RevertableProperty (MetaTypes x) (MetaTypes x')) (Property (MetaTypes y)) = Property (MetaTypes (Combine x y))
 type instance CombinedType (Property (MetaTypes x)) (RevertableProperty (MetaTypes y) (MetaTypes y')) = Property (MetaTypes (Combine x y))
 
-type ResultCombiner = Propellor Result -> Propellor Result -> Propellor Result
+type ResultCombiner = Maybe (Propellor Result) -> Maybe (Propellor Result) -> Maybe (Propellor Result)
 
 class Combines x y where
 	-- | Combines together two properties, yielding a property that
@@ -198,3 +205,35 @@
 
 instance TightenTargets Property where
 	tightenTargets (Property _ d a i c) = Property sing d a i c
+
+-- | Any type of Property is a monoid. When properties x and y are
+-- appended together, the resulting property has a description like
+-- "x and y". Note that when x fails to be ensured, it will not
+-- try to ensure y.
+instance SingI metatypes => Monoid (Property (MetaTypes metatypes))
+  where
+	mempty = Property sing "noop property" Nothing mempty mempty
+	mappend (Property _ d1 a1 i1 c1) (Property _ d2 a2 i2 c2) =
+	  	Property sing d (a1 <> a2) (i1 <> i2) (c1 <> c2)
+	  where
+		-- Avoid including "noop property" in description
+		-- when using eg mconcat.
+		d = case (a1, a2) of
+			(Just _, Just _) -> d1 <> " and " <> d2
+			(Just _, Nothing) -> d1
+			(Nothing, Just _) -> d2
+			(Nothing, Nothing) -> d1
+
+-- | Any type of RevertableProperty is a monoid. When revertable 
+-- properties x and y are appended together, the resulting revertable
+-- property has a description like "x and y".
+-- Note that when x fails to be ensured, it will not try to ensure y.
+instance
+	( Monoid (Property setupmetatypes)
+	, Monoid (Property undometatypes)
+	)
+	=> Monoid (RevertableProperty setupmetatypes undometatypes)
+  where
+	mempty = RevertableProperty mempty mempty
+	mappend (RevertableProperty s1 u1) (RevertableProperty s2 u2) =
+		RevertableProperty (s1 <> s2) (u2 <> u1)
diff --git a/src/Propellor/Types/Chroot.hs b/src/Propellor/Types/Chroot.hs
--- a/src/Propellor/Types/Chroot.hs
+++ b/src/Propellor/Types/Chroot.hs
@@ -16,7 +16,7 @@
 	deriving (Show, Typeable)
 
 instance IsInfo ChrootInfo where
-	propagateInfo _ = False
+	propagateInfo _ = PropagateInfo False
 
 instance Monoid ChrootInfo where
 	mempty = ChrootInfo mempty mempty
diff --git a/src/Propellor/Types/Core.hs b/src/Propellor/Types/Core.hs
--- a/src/Propellor/Types/Core.hs
+++ b/src/Propellor/Types/Core.hs
@@ -48,9 +48,10 @@
 instance LiftPropellor IO where
 	liftPropellor = liftIO
 
+-- | When two actions are appended together, the second action
+-- is only run if the first action does not fail.
 instance Monoid (Propellor Result) where
 	mempty = return NoChange
-	-- | The second action is only run if the first action does not fail.
 	mappend x y = do
 		rx <- x
 		case rx of
@@ -71,7 +72,7 @@
 
 -- | Since there are many different types of Properties, they cannot be put
 -- into a list. The simplified ChildProperty can be put into a list.
-data ChildProperty = ChildProperty Desc (Propellor Result) Info [ChildProperty]
+data ChildProperty = ChildProperty Desc (Maybe (Propellor Result)) Info [ChildProperty]
   
 instance Show ChildProperty where
 	show p = "property " ++ show (getDesc p)
@@ -92,7 +93,7 @@
 	-- | Gets the action that can be run to satisfy a Property.
 	-- You should never run this action directly. Use
 	-- 'Propellor.EnsureProperty.ensureProperty` instead.
-	getSatisfy :: p -> Propellor Result
+	getSatisfy :: p -> Maybe (Propellor Result)
 
 instance IsProp ChildProperty where
 	setDesc (ChildProperty _ a i c) d = ChildProperty d a i c
diff --git a/src/Propellor/Types/Dns.hs b/src/Propellor/Types/Dns.hs
--- a/src/Propellor/Types/Dns.hs
+++ b/src/Propellor/Types/Dns.hs
@@ -28,7 +28,7 @@
 	deriving (Show, Eq, Ord, Monoid, Typeable)
 
 instance IsInfo AliasesInfo where
-	propagateInfo _ = False
+	propagateInfo _ = PropagateInfo False
 
 toAliasesInfo :: [HostName] -> AliasesInfo
 toAliasesInfo l = AliasesInfo (S.fromList l)
@@ -45,7 +45,7 @@
 -- | DNS Info is propagated, so that eg, aliases of a container
 -- are reflected in the dns for the host where it runs.
 instance IsInfo DnsInfo where
-	propagateInfo _ = True
+	propagateInfo _ = PropagateInfo True
 
 -- | Represents a bind 9 named.conf file.
 data NamedConf = NamedConf
@@ -157,7 +157,7 @@
 	deriving (Eq, Ord, Show, Typeable)
 
 instance IsInfo NamedConfMap where
-	propagateInfo _ = False
+	propagateInfo _ = PropagateInfo False
 
 -- | Adding a Master NamedConf stanza for a particulr domain always
 -- overrides an existing Secondary stanza for that domain, while a
diff --git a/src/Propellor/Types/Docker.hs b/src/Propellor/Types/Docker.hs
--- a/src/Propellor/Types/Docker.hs
+++ b/src/Propellor/Types/Docker.hs
@@ -16,7 +16,7 @@
 	deriving (Show, Typeable)
 
 instance IsInfo DockerInfo where
-	propagateInfo _ = False
+	propagateInfo _ = PropagateInfo False
 
 instance Monoid DockerInfo where
 	mempty = DockerInfo mempty mempty
diff --git a/src/Propellor/Types/Info.hs b/src/Propellor/Types/Info.hs
--- a/src/Propellor/Types/Info.hs
+++ b/src/Propellor/Types/Info.hs
@@ -1,13 +1,14 @@
 {-# LANGUAGE GADTs, DeriveDataTypeable, GeneralizedNewtypeDeriving #-}
 
 module Propellor.Types.Info (
-	Info,
+	Info(..),
+	InfoEntry(..),
 	IsInfo(..),
+	PropagateInfo(..),
 	addInfo,
 	toInfo,
 	fromInfo,
 	mapInfo,
-	propagatableInfo,
 	InfoVal(..),
 	fromInfoVal,
 	Typeable,
@@ -44,8 +45,14 @@
 class (Typeable v, Monoid v, Show v) => IsInfo v where
 	-- | Should info of this type be propagated out of a
 	-- container to its Host?
-	propagateInfo :: v -> Bool
+	propagateInfo :: v -> PropagateInfo
 
+data PropagateInfo
+	= PropagateInfo Bool
+	| PropagatePrivData
+	-- ^ Info about PrivData generally will be propigated even in cases
+	-- where other Info is not, so it treated specially.
+
 -- | Any value in the `IsInfo` type class can be added to an Info.
 addInfo :: IsInfo v => Info -> v -> Info
 addInfo (Info l) v = Info (InfoEntry v:l)
@@ -68,11 +75,6 @@
 		Nothing -> i
 		Just v -> InfoEntry (f v)
 
--- | Filters out parts of the Info that should not propagate out of a
--- container.
-propagatableInfo :: Info -> Info
-propagatableInfo (Info l) = Info (filter (\(InfoEntry a) -> propagateInfo a) l)
-
 -- | Use this to put a value in Info that is not a monoid.
 -- The last value set will be used. This info does not propagate
 -- out of a container.
@@ -85,7 +87,7 @@
 	mappend v NoInfoVal = v
 
 instance (Typeable v, Show v) => IsInfo (InfoVal v) where
-	propagateInfo _ = False
+	propagateInfo _ = PropagateInfo False
 
 fromInfoVal :: InfoVal v -> Maybe v
 fromInfoVal NoInfoVal = Nothing