diff --git a/Makefile.install b/Makefile.install
index 6f5b31924..680b26c62 100644
--- a/Makefile.install
+++ b/Makefile.install
@@ -29,6 +29,29 @@ LIBDIR ?= $(PREFIX)/lib
 export PREFIX BINDIR SBINDIR MANDIR RUNDIR
 export LIBDIR INCLUDEDIR LIBEXECDIR PLUGINDIR
 
+# Detect externally managed Python environment (PEP 668).
+PYTHON_EXTERNALLY_MANAGED := $(shell $(PYTHON) -c 'import os, sysconfig; print(int(os.path.isfile(os.path.join(sysconfig.get_path("stdlib"), "EXTERNALLY-MANAGED"))))')
+PIP_BREAK_SYSTEM_PACKAGES ?= 0
+
+# If Python environment is externally managed and PIP_BREAK_SYSTEM_PACKAGES is not set, skip pip install.
+SKIP_PIP_INSTALL := 0
+ifeq ($(PYTHON_EXTERNALLY_MANAGED),1)
+ifeq ($(PIP_BREAK_SYSTEM_PACKAGES),0)
+
+SKIP_PIP_INSTALL := 1
+$(info Warn: Externally managed python environment)
+$(info Consider using PIP_BREAK_SYSTEM_PACKAGES=1)
+
+endif
+endif
+
+# Default flags for pip install:
+# --upgrade: Upgrade crit/pycriu packages
+# --ignore-installed: Ignore existing packages and reinstall them
+PIPFLAGS ?= --upgrade --ignore-installed
+
+export SKIP_PIP_INSTALL PIPFLAGS
+
 install-man:
 	$(Q) $(MAKE) -C Documentation install
 .PHONY: install-man
diff --git a/crit/Makefile b/crit/Makefile
index 9a856db6d..33bd68eed 100644
--- a/crit/Makefile
+++ b/crit/Makefile
@@ -1,6 +1,3 @@
-PYTHON_EXTERNALLY_MANAGED := $(shell $(PYTHON) -c 'import os, sysconfig; print(int(os.path.isfile(os.path.join(sysconfig.get_path("stdlib"), "EXTERNALLY-MANAGED"))))')
-PIP_BREAK_SYSTEM_PACKAGES := 0
-
 VERSION_FILE := $(if $(obj),$(addprefix $(obj)/,crit/version.py),crit/version.py)
 
 all-y	+= ${VERSION_FILE}
@@ -10,31 +7,19 @@ ${VERSION_FILE}:
 	$(Q) echo "__version__ = '${CRIU_VERSION}'" > $@
 
 install: ${VERSION_FILE}
-ifeq ($(PYTHON_EXTERNALLY_MANAGED),1)
-ifeq ($(PIP_BREAK_SYSTEM_PACKAGES),0)
-	$(E) "  SKIP INSTALL crit: Externally managed python environment (See PEP 668 for more information)"
-	$(E) "  Consider using PIP_BREAK_SYSTEM_PACKAGES=1 make install"
-else
+ifeq ($(SKIP_PIP_INSTALL),0)
 	$(E) "  INSTALL " crit
-	$(Q) $(PYTHON) -m pip install --upgrade --ignore-installed --prefix=$(DESTDIR)$(PREFIX) ./crit
-endif
+	$(Q) $(PYTHON) -m pip install $(PIPFLAGS) --prefix=$(DESTDIR)$(PREFIX) ./crit
 else
-	$(E) "  INSTALL " crit
-	$(Q) $(PYTHON) -m pip install --upgrade --ignore-installed --prefix=$(DESTDIR)$(PREFIX) ./crit
+	$(E) " SKIP INSTALL crit"
 endif
 .PHONY: install
 
 uninstall:
-ifeq ($(PYTHON_EXTERNALLY_MANAGED),1)
-ifeq ($(PIP_BREAK_SYSTEM_PACKAGES),0)
-	$(E) " SKIP UNINSTALL crit: Externally managed python environment (See PEP 668 for more information)"
-	$(E) " Consider using PIP_BREAK_SYSTEM_PACKAGES=1 make uninstall"
-else
+ifeq ($(SKIP_PIP_INSTALL),0)
 	$(E) " UNINSTALL" crit
 	$(Q) $(PYTHON) ./scripts/uninstall_module.py --prefix=$(DESTDIR)$(PREFIX) crit
-endif
 else
-	$(E) " UNINSTALL" crit
-	$(Q) $(PYTHON) ./scripts/uninstall_module.py --prefix=$(DESTDIR)$(PREFIX) crit
+	$(E) " SKIP UNINSTALL crit"
 endif
 .PHONY: uninstall
diff --git a/lib/Makefile b/lib/Makefile
index ae371e78e..4b8a6cbb8 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -4,9 +4,6 @@ UAPI_HEADERS		:= lib/c/criu.h images/rpc.proto images/rpc.pb-c.h criu/include/ve
 
 all-y	+= lib-c lib-a lib-py
 
-PYTHON_EXTERNALLY_MANAGED := $(shell $(PYTHON) -c 'import os, sysconfig; print(int(os.path.isfile(os.path.join(sysconfig.get_path("stdlib"), "EXTERNALLY-MANAGED"))))')
-PIP_BREAK_SYSTEM_PACKAGES := 0
-
 #
 # C language bindings.
 lib/c/Makefile: ;
@@ -57,17 +54,11 @@ install: lib-c lib-a lib-py lib/c/criu.pc.in
 	$(Q) mkdir -p $(DESTDIR)$(LIBDIR)/pkgconfig
 	$(Q) sed -e 's,@version@,$(CRIU_VERSION),' -e 's,@libdir@,$(LIBDIR),' -e 's,@includedir@,$(dir $(INCLUDEDIR)/criu/),' lib/c/criu.pc.in > lib/c/criu.pc
 	$(Q) install -m 644 lib/c/criu.pc $(DESTDIR)$(LIBDIR)/pkgconfig
-ifeq ($(PYTHON_EXTERNALLY_MANAGED),1)
-ifeq ($(PIP_BREAK_SYSTEM_PACKAGES),0)
-	$(E) "  SKIP INSTALL pycriu: Externally managed python environment (See PEP 668 for more information)"
-	$(E) "  Consider using PIP_BREAK_SYSTEM_PACKAGES=1 make install"
-else
+ifeq ($(SKIP_PIP_INSTALL),0)
 	$(E) "  INSTALL " pycriu
-	$(Q) $(PYTHON) -m pip install --upgrade --ignore-installed --prefix=$(DESTDIR)$(PREFIX) ./lib
-endif
+	$(Q) $(PYTHON) -m pip install $(PIPFLAGS) --prefix=$(DESTDIR)$(PREFIX) ./lib
 else
-	$(E) "  INSTALL " pycriu
-	$(Q) $(PYTHON) -m pip install --upgrade --ignore-installed --prefix=$(DESTDIR)$(PREFIX) ./lib
+	$(E) " SKIP INSTALL pycriu"
 endif
 .PHONY: install
 
@@ -80,16 +71,10 @@ uninstall:
 	$(Q) $(RM) $(addprefix $(DESTDIR)$(INCLUDEDIR)/criu/,$(notdir $(UAPI_HEADERS)))
 	$(E) " UNINSTALL" pkgconfig/criu.pc
 	$(Q) $(RM) $(addprefix $(DESTDIR)$(LIBDIR)/pkgconfig/,criu.pc)
-ifeq ($(PYTHON_EXTERNALLY_MANAGED),1)
-ifeq ($(PIP_BREAK_SYSTEM_PACKAGES),0)
-	$(E) " SKIP UNINSTALL pycriu: Externally managed python environment (See PEP 668 for more information)"
-	$(E) " Consider using PIP_BREAK_SYSTEM_PACKAGES=1 make uninstall"
-else
+ifeq ($(SKIP_PIP_INSTALL),0)
 	$(E) " UNINSTALL" pycriu
 	$(Q) $(PYTHON) ./scripts/uninstall_module.py --prefix=$(DESTDIR)$(PREFIX) pycriu
-endif
 else
-	$(E) " UNINSTALL" pycriu
-	$(Q) $(PYTHON) ./scripts/uninstall_module.py --prefix=$(DESTDIR)$(PREFIX) pycriu
+	$(E) " SKIP UNINSTALL pycriu"
 endif
 .PHONY: uninstall