diff --git a/.gitignore b/.gitignore
--- a/.gitignore
+++ b/.gitignore
@@ -5,8 +5,6 @@
 *.log
 *.profile
 BUILD*
-dist
-dist-newstyle
 OUT
 *.orig
 /.cabal-sandbox/
@@ -25,3 +23,4 @@
 *.qcow2
 *.tar
 *.vmdk
+dist*
diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,13 @@
 # Changelog for B9
 
+
+## 1.1.1
+
+* When `unique_build_dirs` __is enabled:__ 
+    use a truely random build-id, such that no matter how much
+    or how little time passes between two consequitive builds, the `BUILD_ID`s 
+    will always differ with the same probability.
+
 ## 1.1.0
 
 * Fix unintended deletion of images that are wrongly classified as obsolete.
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -376,20 +376,20 @@
 This example is the current default configuration:
 
     [global]
-    build_dir_root: Nothing
+    build_dir_root: /foo/binary
     keep_temp_dirs: False
-    log_file: Nothing
-    max_cached_shared_images: Just 2
-    repository: Nothing
-    repository_cache: Just (InB9UserDir "repo-cache")
+    log_file: /tmp/b9.log
+    max_cached_shared_images: 2
+    repository: tilia
+    repository_cache: InB9UserDir "repo-cache"
     unique_build_dirs: True
-    verbosity: Just LogInfo
-    default_timeout_seconds: Just 3600
-    timeout_factor: Just 4
+    verbosity: LogInfo
+    default_timeout_seconds: 3600
+    timeout_factor: 4
 
     [libvirt-lxc]
     connection: lxc:///
-    emulator_path: Just "/usr/lib/libvirt/libvirt_lxc"
+    emulator_path: /usr/lib/libvirt/libvirt_lxc
     guest_capabilities: [CAP_MKNOD,CAP_SYS_ADMIN,CAP_SYS_CHROOT,CAP_SETGID,CAP_SETUID,CAP_NET_BIND_SERVICE,CAP_SETPCAP,CAP_SYS_PTRACE,CAP_SYS_MODULE]
     guest_ram_size: RamSize 1 GB
     network: Nothing
@@ -397,19 +397,19 @@
 
     [podman]
     guest_capabilities: [CAP_MKNOD,CAP_SYS_ADMIN,CAP_SYS_CHROOT,CAP_SETGID,CAP_SETUID,CAP_NET_BIND_SERVICE,CAP_SETPCAP,CAP_SYS_PTRACE,CAP_SYS_MODULE]
-    network: Nothing
+    network: default
 
     [systemdNspawn]
     console: read-only
-    executable: Nothing
-    extra_args: Nothing
+    executable: /nix/store/bl92gd78ygdwmc94lrqy20ych0lrfis5-systemd-243.7/bin/systemd-nspawn
+    extra_args: "--user foo"
     guest_capabilities: [CAP_MKNOD,CAP_SYS_ADMIN,CAP_SYS_CHROOT,CAP_SETGID,CAP_SETUID,CAP_NET_BIND_SERVICE,CAP_SETPCAP,CAP_SYS_PTRACE,CAP_SYS_MODULE]
-    max_lifetime_seconds: Just 14400
+    max_lifetime_seconds: 14400
     use_sudo: True
 
     [docker]
     guest_capabilities: [CAP_MKNOD,CAP_SYS_ADMIN,CAP_SYS_CHROOT,CAP_SETGID,CAP_SETUID,CAP_NET_BIND_SERVICE,CAP_SETPCAP,CAP_SYS_PTRACE,CAP_SYS_MODULE]
-    network: Nothing
+    network: default 
 
 
 ### The `[global]` Section
diff --git a/b9.cabal b/b9.cabal
--- a/b9.cabal
+++ b/b9.cabal
@@ -1,6 +1,6 @@
 cabal-version:       2.4
 name:                b9
-version:             1.1.0
+version:             1.1.1
 
 synopsis:            A tool and library for building virtual machine images.
 
diff --git a/src/lib/B9/BuildInfo.hs b/src/lib/B9/BuildInfo.hs
--- a/src/lib/B9/BuildInfo.hs
+++ b/src/lib/B9/BuildInfo.hs
@@ -34,6 +34,7 @@
 import GHC.Stack
 import System.Directory
 import System.FilePath
+import System.IO.B9Extras
 import Text.Printf
 
 -- | Build meta information.
@@ -76,9 +77,9 @@
   Eff (BuildInfoReader ': e) a ->
   Eff e a
 withBuildInfo action = withRootDir $ do
-  now <- lift getCurrentTime -- TODO reproducability: make configurable how the build-date is generated, e.g. by using always 1970/01/01-00:01
+  now <- lift getCurrentTime
   let buildDate = formatTime undefined "%F-%T" now -- TODO make configurable how the build date is formatted
-  buildId <- generateBuildId buildDate
+  buildId <- generateBuildId 
   withBuildDir buildId (runImpl buildId buildDate now)
   where
     withRootDir f = do
@@ -91,12 +92,13 @@
       localB9Config
         (projectRoot ?~ root)
         (addLocalStringBinding ("projectRoot", root) f)
-    generateBuildId buildDate = do
+    generateBuildId = do
       -- TODO generate a proper, reproducable build id!
       unqiueBuildDir <- _uniqueBuildDirs <$> getB9Config
       cfgHash <- hash . show <$> getB9Config
+      actionHash <- hash . show <$> randomUUID -- TODO use the actual hash of the input
       if unqiueBuildDir
-        then return (printf "%08X-%08X" cfgHash (hash buildDate))
+        then return (printf "%08X-%08X" cfgHash (hash actionHash))
         else return (printf "%08X" cfgHash)
     withBuildDir buildId f = do
       root <- _projectRoot <$> getB9Config