diff --git a/buildchain/buildchain/config.py b/buildchain/buildchain/config.py
index 4647cd8456..05f3bb2ce7 100644
--- a/buildchain/buildchain/config.py
+++ b/buildchain/buildchain/config.py
@@ -17,7 +17,7 @@
 from buildchain import ROOT
 
 
-# /!\ All the global defined here must be documented in BUILDING.md /!\
+# /!\ All the global defined here must be documented in docs/developer/building/configuration.rst /!\
 
 
 # Project name.
@@ -58,14 +58,11 @@ class ExtCommand(enum.Enum):
     GIT = os.getenv("GIT_BIN", "git")
     GOFMT = os.getenv("GOFMT_BIN", "gofmt")
     HARDLINK = os.getenv("HARDLINK_BIN", "hardlink")
-    HELM = os.getenv("HELM_BIN", "helm")
     IMPLANTISOMD5 = os.getenv("IMPLANTISOMD5_BIN", "implantisomd5")
     MAKE = os.getenv("MAKE_BIN", "make")
     MKISOFS = os.getenv("MKISOFS_BIN", "mkisofs")
     SKOPEO = os.getenv("SKOPEO_BIN", "skopeo")
-    TOX = os.getenv("TOX_BIN", "tox")
     VAGRANT = os.getenv("VAGRANT_BIN", "vagrant")
-    KUSTOMIZE = os.getenv("KUSTOMIZE_BIN", "kustomize")
 
     @property
     def command_name(self) -> str:
diff --git a/buildchain/buildchain/iso.py b/buildchain/buildchain/iso.py
index dc7fd6a0b4..d2b2197d2d 100644
--- a/buildchain/buildchain/iso.py
+++ b/buildchain/buildchain/iso.py
@@ -52,11 +52,12 @@
 FILE_TREES: Tuple[helper.FileTree, ...] = (
     helper.FileTree(
         basename="_iso_add_tree",
+        source_prefix=Path("examples"),
         files=(
-            Path("examples/new-node.yaml"),
-            Path("examples/new-node_vagrant.yaml"),
-            Path("examples/prometheus-sparse.yaml"),
-            Path("examples/loki-sparse.yaml"),
+            Path("new-node.yaml"),
+            Path("new-node_vagrant.yaml"),
+            Path("prometheus-sparse.yaml"),
+            Path("loki-sparse.yaml"),
         ),
         destination_directory=constants.ISO_ROOT,
         task_dep=["_iso_mkdir_root"],
@@ -131,7 +132,7 @@
                     "DEVELOPMENT_RELEASE": "1"
                     if versions.VERSION_SUFFIX == "-dev"
                     else "0",
-                    "BUILD_TIMESTAMP": dt.datetime.utcnow().strftime(
+                    "BUILD_TIMESTAMP": dt.datetime.now(dt.timezone.utc).strftime(
                         "%Y-%m-%dT%H:%M:%SZ"
                     ),
                     "BUILD_HOST": socket.gethostname(),
diff --git a/docs/developer/building/configuration.rst b/docs/developer/building/configuration.rst
index 0b94108900..4acd848ab0 100644
--- a/docs/developer/building/configuration.rst
+++ b/docs/developer/building/configuration.rst
@@ -12,14 +12,14 @@ Available options are:
 - ``VAGRANT_PROVIDER``: type of machine to spawn with Vagrant
 - ``VAGRANT_UP_ARGS``: command line arguments to pass to ``vagrant up``
 - ``VAGRANT_SNAPSHOT_NAME``: name of auto generated Vagrant snapshot
-- ``DOCKER_BIN``: Docker binary (name or path to the binary)
 - ``GIT_BIN``: Git binary (name or path to the binary)
+- ``GOFMT_BIN``: gofmt binary (name or path to the binary)
 - ``HARDLINK_BIN``: hardlink binary (name or path to the binary)
+- ``IMPLANTISOMD5_BIN``: implantisomd5 binary (name or path to the binary)
+- ``MAKE_BIN``: Make binary (name or path to the binary)
 - ``MKISOFS_BIN``: mkisofs binary (name or path to the binary)
 - ``SKOPEO_BIN``: skopeo binary (name or path to the binary)
 - ``VAGRANT_BIN``: Vagrant binary (name or path to the binary)
-- ``GOFMT_BIN``: gofmt binary (name or path to the binary)
-- ``OPERATOR_SDK_BIN``: the Operator SDK binary (name or path to the binary)
 
 Default settings are equivalent to the following ``.env``:
 
@@ -29,11 +29,12 @@ Default settings are equivalent to the following ``.env``:
    export BUILD_ROOT=_build
    export VAGRANT_PROVIDER=virtualbox
    export VAGRANT_UP_ARGS="--provision  --no-destroy-on-error --parallel --provider $VAGRANT_PROVIDER"
-   export DOCKER_BIN=docker
-   export HARDLINK_BIN=hardlink
+   export VAGRANT_SNAPSHOT_NAME=bootstrap.autosnapshot
    export GIT_BIN=git
+   export GOFMT_BIN=gofmt
+   export HARDLINK_BIN=hardlink   
+   export IMPLANTISOMD5_BIN=implantisomd5
+   export MAKE_BIN=make
    export MKISOFS_BIN=mkisofs
    export SKOPEO_BIN=skopeo
    export VAGRANT_BIN=vagrant
-   export GOFMT_BIN=gofmt
-   export OPERATOR_SDK_BIN=operator-sdk
diff --git a/doit.sh b/doit.sh
index 8234d159d3..8e7ee4c7b3 100755
--- a/doit.sh
+++ b/doit.sh
@@ -10,8 +10,8 @@ BUILDCHAIN=buildchain
 BUILDENV="${BUILDCHAIN}/.venv"
 # requirements.txt for the buildchain.
 REQUIREMENTS="${BUILDCHAIN}/requirements.txt"
-# Dummy file to keep track of when the virtual environment was installed.
-WITNESS_FILE="${BUILDENV}/installed.tstamp"
+# Marker file defined by PEP 405 to keep track of when the venv was created.
+MARKER_FILE="${BUILDENV}/pyvenv.cfg"
 # File containing environment variables.
 DOTENV=./.env
 
@@ -30,6 +30,7 @@ then
     exit 1
 fi
 
+# Get unix timestamp (seconds since epoch)
 if [ "$OSTYPE" = "Darwin" ]
 then
     GET_FILE_STAMP='stat -f %m'
@@ -39,15 +40,14 @@ fi
 
 # Can't use `[ file1 -nt file2 ]` directly because it's not POSIX :'(
 REQ_TSTAMP=$($GET_FILE_STAMP "${REQUIREMENTS}")
-WIT_TSTAMP=$($GET_FILE_STAMP "${WITNESS_FILE}" 2> /dev/null || echo '0')
+MKR_TSTAMP=$($GET_FILE_STAMP "${MARKER_FILE}" 2> /dev/null || echo '0')
 
 # Install/reinstall the virtual environment only if it either doesn't exist or
 # the requirements have changed since its creation.
-if [ "${REQ_TSTAMP}" -gt "${WIT_TSTAMP}" ]
+if [ "${REQ_TSTAMP}" -gt "${MKR_TSTAMP}" ]
 then
     "${PYTHON_SYS}" -m venv --clear "${BUILDENV}"
     "${BUILDENV}/bin/pip" install -r "${REQUIREMENTS}"
-    touch "${WITNESS_FILE}"
 fi
 
 # Load customized environment variables from dotenv file, if exists.
@@ -57,4 +57,5 @@ then
     . "${DOTENV}"
 fi
 
+# Run doit and pass all arguments to it.
 exec "${BUILDENV}/bin/python" -m doit "$@"