module Propellor.Property.Systemd ( installed, started, stopped, enabled, persistentJournal, Container, container, nspawned, ) where import Propellor import qualified Propellor.Property.Chroot as Chroot import qualified Propellor.Property.Apt as Apt import qualified Propellor.Property.File as File import Utility.SafeCommand import Utility.FileMode import Data.List.Utils type ServiceName = String type MachineName = String type NspawnParam = CommandParam data Container = Container MachineName System [CommandParam] Host instance Hostlike Container where (Container n s ps h) & p = Container n s ps (h & p) (Container n s ps h) &^ p = Container n s ps (h &^ p) getHost (Container _ _ _ h) = h -- dbus is only a Recommends of systemd, but is needed for communication -- from the systemd inside a container to the one outside, so make sure it -- gets installed. installed :: Property installed = Apt.installed ["systemd", "dbus"] -- | Starts a systemd service. started :: ServiceName -> Property started n = trivial $ cmdProperty "systemctl" ["start", n] `describe` ("service " ++ n ++ " started") -- | Stops a systemd service. stopped :: ServiceName -> Property stopped n = trivial $ cmdProperty "systemctl" ["stop", n] `describe` ("service " ++ n ++ " stopped") -- | Enables a systemd service. enabled :: ServiceName -> Property enabled n = trivial $ cmdProperty "systemctl" ["enable", n] `describe` ("service " ++ n ++ " enabled") -- | Enables persistent storage of the journal. persistentJournal :: Property persistentJournal = check (not <$> doesDirectoryExist dir) $ combineProperties "persistent systemd journal" [ cmdProperty "install" ["-d", "-g", "systemd-journal", dir] , cmdProperty "setfacl" ["-R", "-nm", "g:adm:rx,d:g:adm:rx", dir] , started "systemd-journal-flush" ] `requires` Apt.installed ["acl"] where dir = "/var/log/journal" -- | Defines a container with a given machine name, containing the specified -- System. Properties can be added to configure the Container. -- -- > container "webserver" (System (Debian Unstable) "amd64") [] container :: MachineName -> System -> [NspawnParam] -> Container container name system ps = Container name system ps (Host name [] mempty) -- | Runs a container using systemd-nspawn. -- -- A systemd unit is set up for the container, so it will automatically -- be started on boot. -- -- Systemd is automatically installed inside the container, and will -- communicate with the host's systemd. This allows systemctl to be used to -- examine the status of services running inside the container. -- -- When the host system has persistentJournal enabled, journactl can be -- used to examine logs forwarded from the container. -- -- Reverting this property stops the container, removes the systemd unit, -- and deletes the chroot and all its contents. nspawned :: Container -> RevertableProperty nspawned c@(Container name system _ h) = RevertableProperty setup teardown where setup = propertyList ("nspawned " ++ name) (map toProp steps) teardown = propertyList ("not nspawned " ++ name) (map (toProp . revert) (reverse steps)) steps = [ enterScript c , chrootprovisioned , nspawnService c ] -- When provisioning the chroot, pass a version of the Host -- that only has the Property of systemd being installed. -- This is to avoid starting any daemons in the chroot, -- which would not run in the container's namespace. chrootprovisioned = Chroot.provisioned $ mkChroot $ h { hostProperties = [installed] } -- Use nsenter to enter container and and run propellor to -- finish provisioning. containerprovisioned = Chroot.propellChroot (mkChroot h) (enterContainerProcess c) mkChroot = Chroot.Chroot (containerDir name) system nspawnService :: Container -> RevertableProperty nspawnService (Container name _ ps _) = RevertableProperty setup teardown where service = nspawnServiceName name servicefile = "/etc/systemd/system/multi-user.target.wants" service setup = check (not <$> doesFileExist servicefile) $ started service `requires` enabled service -- TODO ^ adjust execStart line to reflect ps teardown = undefined -- | Installs a "enter-machinename" script that root can use to run a -- command inside the container. -- -- This uses nsenter to enter the container, by looking up the pid of the -- container's init process and using its namespace. enterScript :: Container -> RevertableProperty enterScript c@(Container name _ _ _) = RevertableProperty setup teardown where setup = combineProperties ("generated " ++ enterScriptFile c) [ scriptfile `File.hasContent` [ "#!/bin/sh" , "# Generated by propellor" , "pid=\"$(machinectl show " ++ shellEscape name ++ " -p Leader | cut -d= -f2)\" || true" , "if [ -n \"$pid\" ]; then" , "\tnsenter -p -u -n -i -m -t \"$pid\"" , "else" , "\texit 1" , "fi" ] , scriptfile `File.mode` combineModes (readModes ++ executeModes) ] teardown = File.notPresent scriptfile scriptfile = enterScriptFile c enterScriptFile :: Container -> FilePath enterScriptFile (Container name _ _ _ ) = "enter-" ++ mungename name enterContainerProcess :: Container -> [String] -> CreateProcess enterContainerProcess = proc . enterScriptFile nspawnServiceName :: MachineName -> ServiceName nspawnServiceName name = "systemd-nspawn@" ++ name ++ ".service" containerDir :: MachineName -> FilePath containerDir name = "/var/lib/container" mungename name mungename :: MachineName -> String mungename = replace "/" "_"