3 files changed, 29 insertions, 6 deletions
diff --git a/src/Propellor/Property/Chroot.hs b/src/Propellor/Property/Chroot.hs
index ecac1115..771c4b99 100644
--- a/src/Propellor/Property/Chroot.hs
+++ b/src/Propellor/Property/Chroot.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE FlexibleContexts, GADTs #-}
+{-# LANGUAGE FlexibleContexts, GADTs, DeriveDataTypeable #-}
 
 module Propellor.Property.Chroot (
 	debootstrapped,
@@ -8,6 +8,7 @@ module Propellor.Property.Chroot (
 	ChrootBootstrapper(..),
 	Debootstrapped(..),
 	ChrootTarball(..),
+	inChroot,
 	-- * Internal use
 	provisioned',
 	propagateChrootInfo,
@@ -207,7 +208,7 @@ chain hostlist (ChrootChain hn loc systemdonly onconsole) =
 		changeWorkingDirectory localdir
 		when onconsole forceConsole
 		onlyProcess (provisioningLock loc) $ do
-			r <- runPropellor h $ ensureProperties $
+			r <- runPropellor (setInChroot h) $ ensureProperties $
 				if systemdonly
 					then [Systemd.installed]
 					else map ignoreInfo $
@@ -243,3 +244,18 @@ mungeloc = replace "/" "_"
 
 chrootDesc :: Chroot -> String -> String
 chrootDesc (Chroot loc _ _) desc = "chroot " ++ loc ++ " " ++ desc
+
+-- | Check if propellor is currently running within a chroot.
+--
+-- This allows properties to check and avoid performing actions that
+-- should not be done in a chroot.
+inChroot :: Propellor Bool
+inChroot = extract . fromMaybe (InChroot False) . fromInfoVal <$> askInfo
+  where
+	extract (InChroot b) = b
+
+setInChroot :: Host -> Host
+setInChroot h = h { hostInfo = hostInfo h `addInfo` InfoVal (InChroot True) }
+
+newtype InChroot = InChroot Bool
+	deriving (Typeable, Show)
diff --git a/src/Propellor/Property/Hostname.hs b/src/Propellor/Property/Hostname.hs
index 78ec872f..8033bef8 100644
--- a/src/Propellor/Property/Hostname.hs
+++ b/src/Propellor/Property/Hostname.hs
@@ -2,13 +2,17 @@ module Propellor.Property.Hostname where
 
 import Propellor.Base
 import qualified Propellor.Property.File as File
+import Propellor.Property.Chroot (inChroot)
 
 import Data.List
 import Data.List.Utils
 
--- | Ensures that the hostname is set using best practices.
+-- | Ensures that the hostname is set using best practices, to whatever
+-- name the `Host` has.
 --
--- Configures </etc/hostname> and the current hostname.
+-- Configures both </etc/hostname> and the current hostname.
+-- (However, if used inside a chroot, avoids setting the current hostname
+-- as that would impact the system outside the chroot.)
 --
 -- Configures </etc/mailname> with the domain part of the hostname.
 --
@@ -25,6 +29,8 @@ sane' :: ExtractDomain -> Property NoInfo
 sane' extractdomain = property ("sane hostname") $
 	ensureProperty . setTo' extractdomain =<< asks hostName
 
+-- Like `sane`, but you can specify the hostname to use, instead
+-- of the default hostname of the `Host`.
 setTo :: HostName -> Property NoInfo
 setTo = setTo' extractDomain
 
@@ -41,7 +47,8 @@ setTo' extractdomain hn = combineProperties desc go
 			then Nothing 
 			else Just $ trivial $ hostsline "127.0.1.1" [hn, basehost]
 		, Just $ trivial $ hostsline "127.0.0.1" ["localhost"]
-		, Just $ trivial $ cmdProperty "hostname" [basehost]
+		, Just $ trivial $ check (not <$> inChroot) $
+			cmdProperty "hostname" [basehost]
 		, Just $ "/etc/mailname" `File.hasContent`
 			[if null domain then hn else domain]
 		]
diff --git a/src/Propellor/Property/Systemd.hs b/src/Propellor/Property/Systemd.hs
index 700bc350..8761d842 100644
--- a/src/Propellor/Property/Systemd.hs
+++ b/src/Propellor/Property/Systemd.hs
@@ -217,7 +217,7 @@ nspawned c@(Container name (Chroot.Chroot loc builder _) h) =
 
 	-- 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 provisions.
+	-- installed, but does not handle the other properties.
 	chrootprovisioned = Chroot.provisioned' (Chroot.propagateChrootInfo chroot) chroot True
 
 	-- Use nsenter to enter container and and run propellor to