{-# LANGUAGE BangPatterns #-} -- | Docker support for propellor -- -- The existance of a docker container is just another Property of a system, -- which propellor can set up. See config.hs for an example. module Propellor.Property.Docker ( -- * Host properties installed, configured, container, docked, memoryLimited, garbageCollected, Image, ContainerName, -- * Container configuration dns, hostname, name, publish, expose, user, volume, volumes_from, workdir, memory, cpuShares, link, ContainerAlias, -- * Internal use chain, ) where import Propellor import Propellor.SimpleSh import Propellor.Types.Info import qualified Propellor.Property.File as File import qualified Propellor.Property.Apt as Apt import qualified Propellor.Property.Docker.Shim as Shim import Utility.SafeCommand import Utility.Path import Control.Concurrent.Async hiding (link) import System.Posix.Directory import System.Posix.Process import Data.List import Data.List.Utils import qualified Data.Set as S installed :: Property installed = Apt.installed ["docker.io"] -- | Configures docker with an authentication file, so that images can be -- pushed to index.docker.io. Optional. configured :: Property configured = property "docker configured" go `requires` installed where go = withPrivData DockerAuthentication $ \cfg -> ensureProperty $ "/root/.dockercfg" `File.hasContent` (lines cfg) -- | A short descriptive name for a container. -- Should not contain whitespace or other unusual characters, -- only [a-zA-Z0-9_-] are allowed type ContainerName = String -- | Starts accumulating the properties of a Docker container. -- -- > container "web-server" "debian" -- > & publish "80:80" -- > & Apt.installed {"apache2"] -- > & ... container :: ContainerName -> Image -> Host container cn image = Host hn [] info where info = dockerInfo $ mempty { _dockerImage = Val image } hn = cn2hn cn cn2hn :: ContainerName -> HostName cn2hn cn = cn ++ ".docker" -- | Ensures that a docker container is set up and running, finding -- its configuration in the passed list of hosts. -- -- The container has its own Properties which are handled by running -- propellor inside the container. -- -- Additionally, the container can have DNS info, such as a CNAME. -- These become info of the host(s) it's docked in. -- -- Reverting this property ensures that the container is stopped and -- removed. docked :: [Host] -> ContainerName -> RevertableProperty docked hosts cn = RevertableProperty ((maybe id exposeDnsInfos mhost) (go "docked" setup)) (go "undocked" teardown) where go desc a = property (desc ++ " " ++ cn) $ do hn <- asks hostName let cid = ContainerId hn cn ensureProperties [findContainer mhost cid cn $ a cid] mhost = findHost hosts (cn2hn cn) setup cid (Container image runparams) = provisionContainer cid `requires` runningContainer cid image runparams `requires` installed teardown cid (Container image _runparams) = combineProperties ("undocked " ++ fromContainerId cid) [ stoppedContainer cid , property ("cleaned up " ++ fromContainerId cid) $ liftIO $ report <$> mapM id [ removeContainer cid , removeImage image ] ] exposeDnsInfos :: Host -> Property -> Property exposeDnsInfos (Host _ _ containerinfo) p = combineProperties (propertyDesc p) $ p : map addDNS (S.toList $ _dns containerinfo) findContainer :: Maybe Host -> ContainerId -> ContainerName -> (Container -> Property) -> Property findContainer mhost cid cn mk = case mhost of Nothing -> cantfind Just h -> maybe cantfind mk (mkContainer cid h) where cantfind = containerDesc cid $ property "" $ do liftIO $ warningMessage $ "missing definition for docker container \"" ++ cn2hn cn return FailedChange mkContainer :: ContainerId -> Host -> Maybe Container mkContainer cid@(ContainerId hn _cn) h = Container <$> fromVal (_dockerImage info) <*> pure (map (\a -> a hn) (_dockerRunParams info)) where info = _dockerinfo $ hostInfo h' h' = h -- expose propellor directory inside the container & volume (localdir++":"++localdir) -- name the container in a predictable way so we -- and the user can easily find it later & name (fromContainerId cid) -- | Causes *any* docker images that are not in use by running containers to -- be deleted. And deletes any containers that propellor has set up -- before that are not currently running. Does not delete any containers -- that were not set up using propellor. -- -- Generally, should come after the properties for the desired containers. garbageCollected :: Property garbageCollected = propertyList "docker garbage collected" [ gccontainers , gcimages ] where gccontainers = property "docker containers garbage collected" $ liftIO $ report <$> (mapM removeContainer =<< listContainers AllContainers) gcimages = property "docker images garbage collected" $ do liftIO $ report <$> (mapM removeImage =<< listImages) -- | Configures the kernel to respect docker memory limits. -- -- This assumes the system boots using grub 2. And that you don't need any -- other GRUB_CMDLINE_LINUX_DEFAULT settings. -- -- Only takes effect after reboot. (Not automated.) memoryLimited :: Property memoryLimited = "/etc/default/grub" `File.containsLine` cfg `describe` "docker memory limited" `onChange` cmdProperty "update-grub" [] where cmdline = "cgroup_enable=memory swapaccount=1" cfg = "GRUB_CMDLINE_LINUX_DEFAULT=\""++cmdline++"\"" data Container = Container Image [RunParam] -- | Parameters to pass to `docker run` when creating a container. type RunParam = String -- | A docker image, that can be used to run a container. type Image = String -- | Set custom dns server for container. dns :: String -> Property dns = runProp "dns" -- | Set container host name. hostname :: String -> Property hostname = runProp "hostname" -- | Set name for container. (Normally done automatically.) name :: String -> Property name = runProp "name" -- | Publish a container's port to the host -- (format: ip:hostPort:containerPort | ip::containerPort | hostPort:containerPort) publish :: String -> Property publish = runProp "publish" -- | Expose a container's port without publishing it. expose :: String -> Property expose = runProp "expose" -- | Username or UID for container. user :: String -> Property user = runProp "user" -- | Mount a volume -- Create a bind mount with: [host-dir]:[container-dir]:[rw|ro] -- With just a directory, creates a volume in the container. volume :: String -> Property volume = runProp "volume" -- | Mount a volume from the specified container into the current -- container. volumes_from :: ContainerName -> Property volumes_from cn = genProp "volumes-from" $ \hn -> fromContainerId (ContainerId hn cn) -- | Work dir inside the container. workdir :: String -> Property workdir = runProp "workdir" -- | Memory limit for container. -- Format: , where unit = b, k, m or g -- -- Note: Only takes effect when the host has the memoryLimited property -- enabled. memory :: String -> Property memory = runProp "memory" -- | CPU shares (relative weight). -- -- By default, all containers run at the same priority, but you can tell -- the kernel to give more CPU time to a container using this property. cpuShares :: Int -> Property cpuShares = runProp "cpu-shares" . show -- | Link with another container on the same host. link :: ContainerName -> ContainerAlias -> Property link linkwith calias = genProp "link" $ \hn -> fromContainerId (ContainerId hn linkwith) ++ ":" ++ calias -- | A short alias for a linked container. -- Each container has its own alias namespace. type ContainerAlias = String -- | A container is identified by its name, and the host -- on which it's deployed. data ContainerId = ContainerId HostName ContainerName deriving (Eq, Read, Show) -- | Two containers with the same ContainerIdent were started from -- the same base image (possibly a different version though), and -- with the same RunParams. data ContainerIdent = ContainerIdent Image HostName ContainerName [RunParam] deriving (Read, Show, Eq) toContainerId :: String -> Maybe ContainerId toContainerId s | myContainerSuffix `isSuffixOf` s = case separate (== '.') (desuffix s) of (cn, hn) | null hn || null cn -> Nothing | otherwise -> Just $ ContainerId hn cn | otherwise = Nothing where desuffix = reverse . drop len . reverse len = length myContainerSuffix fromContainerId :: ContainerId -> String fromContainerId (ContainerId hn cn) = cn++"."++hn++myContainerSuffix containerHostName :: ContainerId -> HostName containerHostName (ContainerId _ cn) = cn2hn cn myContainerSuffix :: String myContainerSuffix = ".propellor" containerDesc :: ContainerId -> Property -> Property containerDesc cid p = p `describe` desc where desc = "[" ++ fromContainerId cid ++ "] " ++ propertyDesc p runningContainer :: ContainerId -> Image -> [RunParam] -> Property runningContainer cid@(ContainerId hn cn) image runps = containerDesc cid $ property "running" $ do l <- liftIO $ listContainers RunningContainers if cid `elem` l then do -- Check if the ident has changed; if so the -- parameters of the container differ and it must -- be restarted. runningident <- liftIO $ getrunningident if runningident == Just ident then noChange else do void $ liftIO $ stopContainer cid restartcontainer else ifM (liftIO $ elem cid <$> listContainers AllContainers) ( restartcontainer , go image ) where ident = ContainerIdent image hn cn runps restartcontainer = do oldimage <- liftIO $ fromMaybe image <$> commitContainer cid void $ liftIO $ removeContainer cid go oldimage getrunningident :: IO (Maybe ContainerIdent) getrunningident = simpleShClient (namedPipe cid) "cat" [propellorIdent] $ \rs -> do let !v = extractident rs return v extractident :: [Resp] -> Maybe ContainerIdent extractident = headMaybe . catMaybes . map readish . catMaybes . map getStdout go img = do liftIO $ do clearProvisionedFlag cid createDirectoryIfMissing True (takeDirectory $ identFile cid) shim <- liftIO $ Shim.setup (localdir "propellor") (localdir shimdir cid) liftIO $ writeFile (identFile cid) (show ident) ensureProperty $ boolProperty "run" $ runContainer img (runps ++ ["-i", "-d", "-t"]) [shim, "--docker", fromContainerId cid] -- | Called when propellor is running inside a docker container. -- The string should be the container's ContainerId. -- -- This process is effectively init inside the container. -- It even needs to wait on zombie processes! -- -- Fork a thread to run the SimpleSh server in the background. -- In the foreground, run an interactive bash (or sh) shell, -- so that the user can interact with it when attached to the container. -- -- When the system reboots, docker restarts the container, and this is run -- again. So, to make the necessary services get started on boot, this needs -- to provision the container then. However, if the container is already -- being provisioned by the calling propellor, it would be redundant and -- problimatic to also provisoon it here. -- -- The solution is a flag file. If the flag file exists, then the container -- was already provisioned. So, it must be a reboot, and time to provision -- again. If the flag file doesn't exist, don't provision here. chain :: String -> IO () chain s = case toContainerId s of Nothing -> error $ "Invalid ContainerId: " ++ s Just cid -> do changeWorkingDirectory localdir writeFile propellorIdent . show =<< readIdentFile cid -- Run boot provisioning before starting simpleSh, -- to avoid ever provisioning twice at the same time. whenM (checkProvisionedFlag cid) $ do let shim = Shim.file (localdir "propellor") (localdir shimdir cid) unlessM (boolSystem shim [Param "--continue", Param $ show $ Chain $ containerHostName cid]) $ warningMessage "Boot provision failed!" void $ async $ job reapzombies void $ async $ job $ simpleSh $ namedPipe cid job $ do void $ tryIO $ ifM (inPath "bash") ( boolSystem "bash" [Param "-l"] , boolSystem "/bin/sh" [] ) putStrLn "Container is still running. Press ^P^Q to detach." where job = forever . void . tryIO reapzombies = void $ getAnyProcessStatus True False -- | Once a container is running, propellor can be run inside -- it to provision it. -- -- Note that there is a race here, between the simplesh -- server starting up in the container, and this property -- being run. So, retry connections to the client for up to -- 1 minute. provisionContainer :: ContainerId -> Property provisionContainer cid = containerDesc cid $ property "provision" $ liftIO $ do let shim = Shim.file (localdir "propellor") (localdir shimdir cid) r <- simpleShClientRetry 60 (namedPipe cid) shim params (go Nothing) when (r /= FailedChange) $ setProvisionedFlag cid return r where params = ["--continue", show $ Chain $ containerHostName cid] go lastline (v:rest) = case v of StdoutLine s -> do maybe noop putStrLn lastline hFlush stdout go (Just s) rest StderrLine s -> do maybe noop putStrLn lastline hFlush stdout hPutStrLn stderr s hFlush stderr go Nothing rest Done -> ret lastline go lastline [] = ret lastline ret lastline = pure $ fromMaybe FailedChange $ readish =<< lastline stopContainer :: ContainerId -> IO Bool stopContainer cid = boolSystem dockercmd [Param "stop", Param $ fromContainerId cid ] stoppedContainer :: ContainerId -> Property stoppedContainer cid = containerDesc cid $ property desc $ ifM (liftIO $ elem cid <$> listContainers RunningContainers) ( liftIO cleanup `after` ensureProperty (boolProperty desc $ stopContainer cid) , return NoChange ) where desc = "stopped" cleanup = do nukeFile $ namedPipe cid nukeFile $ identFile cid removeDirectoryRecursive $ shimdir cid clearProvisionedFlag cid removeContainer :: ContainerId -> IO Bool removeContainer cid = catchBoolIO $ snd <$> processTranscript dockercmd ["rm", fromContainerId cid ] Nothing removeImage :: Image -> IO Bool removeImage image = catchBoolIO $ snd <$> processTranscript dockercmd ["rmi", image ] Nothing runContainer :: Image -> [RunParam] -> [String] -> IO Bool runContainer image ps cmd = boolSystem dockercmd $ map Param $ "run" : (ps ++ image : cmd) commitContainer :: ContainerId -> IO (Maybe Image) commitContainer cid = catchMaybeIO $ takeWhile (/= '\n') <$> readProcess dockercmd ["commit", fromContainerId cid] data ContainerFilter = RunningContainers | AllContainers deriving (Eq) -- | Only lists propellor managed containers. listContainers :: ContainerFilter -> IO [ContainerId] listContainers status = catMaybes . map toContainerId . concat . map (split ",") . catMaybes . map (lastMaybe . words) . lines <$> readProcess dockercmd ps where ps | status == AllContainers = baseps ++ ["--all"] | otherwise = baseps baseps = ["ps", "--no-trunc"] listImages :: IO [Image] listImages = lines <$> readProcess dockercmd ["images", "--all", "--quiet"] runProp :: String -> RunParam -> Property runProp field val = pureInfoProperty (param) $ dockerInfo $ mempty { _dockerRunParams = [\_ -> "--"++param] } where param = field++"="++val genProp :: String -> (HostName -> RunParam) -> Property genProp field mkval = pureInfoProperty field $ dockerInfo $ mempty { _dockerRunParams = [\hn -> "--"++field++"=" ++ mkval hn] } dockerInfo :: DockerInfo -> Info dockerInfo i = mempty { _dockerinfo = i } -- | The ContainerIdent of a container is written to -- /.propellor-ident inside it. This can be checked to see if -- the container has the same ident later. propellorIdent :: FilePath propellorIdent = "/.propellor-ident" -- | Named pipe used for communication with the container. namedPipe :: ContainerId -> FilePath namedPipe cid = "docker" fromContainerId cid provisionedFlag :: ContainerId -> FilePath provisionedFlag cid = "docker" fromContainerId cid ++ ".provisioned" clearProvisionedFlag :: ContainerId -> IO () clearProvisionedFlag = nukeFile . provisionedFlag setProvisionedFlag :: ContainerId -> IO () setProvisionedFlag cid = do createDirectoryIfMissing True (takeDirectory (provisionedFlag cid)) writeFile (provisionedFlag cid) "1" checkProvisionedFlag :: ContainerId -> IO Bool checkProvisionedFlag = doesFileExist . provisionedFlag shimdir :: ContainerId -> FilePath shimdir cid = "docker" fromContainerId cid ++ ".shim" identFile :: ContainerId -> FilePath identFile cid = "docker" fromContainerId cid ++ ".ident" readIdentFile :: ContainerId -> IO ContainerIdent readIdentFile cid = fromMaybe (error "bad ident in identFile") . readish <$> readFile (identFile cid) dockercmd :: String dockercmd = "docker.io" report :: [Bool] -> Result report rmed | or rmed = MadeChange | otherwise = NoChange