diff --git a/lib/spack/spack/schema/concretizer.py b/lib/spack/spack/schema/concretizer.py
index e628519d56f..30f73d7557d 100644
--- a/lib/spack/spack/schema/concretizer.py
+++ b/lib/spack/spack/schema/concretizer.py
@@ -15,6 +15,7 @@
         "additionalProperties": False,
         "properties": {
             "reuse": {"type": "boolean"},
+            "enable_node_namespace": {"type": "boolean"},
             "targets": {
                 "type": "object",
                 "properties": {
diff --git a/lib/spack/spack/solver/asp.py b/lib/spack/spack/solver/asp.py
index 5f387636cc0..cabaa9f2f28 100644
--- a/lib/spack/spack/solver/asp.py
+++ b/lib/spack/spack/solver/asp.py
@@ -595,13 +595,14 @@ def fact(self, head):
         if choice:
             self.assumptions.append(atom)
 
-    def solve(self, setup, specs, reuse=None, output=None, control=None):
+    def solve(self, setup, specs, reuse=None, namespace=False, output=None, control=None):
         """Set up the input and solve for dependencies of ``specs``.
 
         Arguments:
             setup (SpackSolverSetup): An object to set up the ASP problem.
             specs (list): List of ``Spec`` objects to solve for.
             reuse (None or list): list of concrete specs that can be reused
+            namespace (bool): enable node namespacing
             output (None or OutputConfiguration): configuration object to set
                 the output of this solve.
             control (clingo.Control): configuration for the solver. If None,
@@ -624,7 +625,7 @@ def solve(self, setup, specs, reuse=None, output=None, control=None):
         self.assumptions = []
         with self.control.backend() as backend:
             self.backend = backend
-            setup.setup(self, specs, reuse=reuse)
+            setup.setup(self, specs, reuse=reuse, namespace=namespace)
         timer.phase("setup")
 
         # read in the main ASP program and display logic -- these are
@@ -760,6 +761,10 @@ def __init__(self, tests=False):
         # whether to add installed/binary hashes to the solve
         self.tests = tests
 
+        # whether to namespace nodes in the solve
+        # set by setup()
+        self.namespace = None
+
         # If False allows for input specs that are not solved
         self.concretize_everything = True
 
@@ -1348,6 +1353,7 @@ def _spec_clauses(
         # TODO: do this with consistent suffixes.
         class Head(object):
             node = fn.node
+            node_namespace = fn.node_namespace
             virtual_node = fn.virtual_node
             node_platform = fn.node_platform_set
             node_os = fn.node_os_set
@@ -1361,6 +1367,7 @@ class Head(object):
 
         class Body(object):
             node = fn.node
+            node_namespace = fn.node_namespace
             virtual_node = fn.virtual_node
             node_platform = fn.node_platform
             node_os = fn.node_os
@@ -1377,6 +1384,9 @@ class Body(object):
         if spec.name:
             clauses.append(f.node(spec.name) if not spec.virtual else f.virtual_node(spec.name))
 
+        if self.namespace and spec.namespace:
+            clauses.append(f.node_namespace(spec.name, spec.namespace))
+
         clauses.extend(self.spec_versions(spec))
 
         # seed architecture at the root (we'll propagate later)
@@ -1917,7 +1927,7 @@ def define_concrete_input_specs(self, specs, possible):
                 if spec.concrete:
                     self._facts_from_concrete_spec(spec, possible)
 
-    def setup(self, driver, specs, reuse=None):
+    def setup(self, driver, specs, reuse=None, namespace=False):
         """Generate an ASP program with relevant constraints for specs.
 
         This calls methods on the solve driver to set up the problem with
@@ -1928,6 +1938,7 @@ def setup(self, driver, specs, reuse=None):
             driver (PyclingoDriver): driver instance of this solve
             specs (list): list of Specs to solve
             reuse (None or list): list of concrete specs that can be reused
+            namespace (bool): enable namespace matching in the solve
         """
         self._condition_id_counter = itertools.count()
 
@@ -1980,6 +1991,10 @@ def setup(self, driver, specs, reuse=None):
         self.gen.h1("Concrete input spec definitions")
         self.define_concrete_input_specs(specs, possible)
 
+        self.namespace = namespace
+        if namespace:
+            self.gen.fact(fn.enable_node_namespace())
+
         if reuse:
             self.gen.h1("Reusable specs")
             self.gen.fact(fn.optimize_for_reuse())
@@ -2073,6 +2088,9 @@ def node(self, pkg):
         if pkg not in self._specs:
             self._specs[pkg] = spack.spec.Spec(pkg)
 
+    def node_namespace(self, pkg, namespace):
+        self._specs[pkg].namespace = namespace
+
     def _arch(self, pkg):
         arch = self._specs[pkg].architecture
         if not arch:
@@ -2368,6 +2386,7 @@ def __init__(self):
         # These properties are settable via spack configuration, and overridable
         # by setting them directly as properties.
         self.reuse = spack.config.get("concretizer:reuse", False)
+        self.namespace = spack.config.get("concretizer:enable_node_namespace", False)
 
     @staticmethod
     def _check_input_and_extract_concrete_specs(specs):
@@ -2430,7 +2449,9 @@ def solve(
         reusable_specs.extend(self._reusable_specs())
         setup = SpackSolverSetup(tests=tests)
         output = OutputConfiguration(timers=timers, stats=stats, out=out, setup_only=setup_only)
-        result, _, _ = self.driver.solve(setup, specs, reuse=reusable_specs, output=output)
+        result, _, _ = self.driver.solve(
+            setup, specs, reuse=reusable_specs, namespace=self.namespace, output=output
+        )
         return result
 
     def solve_in_rounds(
@@ -2467,7 +2488,7 @@ def solve_in_rounds(
         output = OutputConfiguration(timers=timers, stats=stats, out=out, setup_only=False)
         while True:
             result, _, _ = self.driver.solve(
-                setup, input_specs, reuse=reusable_specs, output=output
+                setup, input_specs, reuse=reusable_specs, namespace=self.namespace, output=output
             )
             yield result
 
diff --git a/lib/spack/spack/solver/concretize.lp b/lib/spack/spack/solver/concretize.lp
index af5dffbc8c8..03d9f50ead9 100644
--- a/lib/spack/spack/solver/concretize.lp
+++ b/lib/spack/spack/solver/concretize.lp
@@ -210,6 +210,14 @@ attr(Name, A1, A2, A3, A4) :- impose(ID), imposed_constraint(ID, Name, A1, A2, A
    not imposed_constraint(Hash, "node_flag", Package, FlagType, Flag),
    internal_error("imposed hash without imposing all flag values").
 
+% cannot have multiple namespaces for a package
+:- node(Package),
+   node_namespace(Package, Namespace1),
+   node_namespace(Package, Namespace2),
+   Namespace1 < Namespace2,
+   enable_node_namespace().
+
+#defined enable_node_namespace/0.
 #defined condition/2.
 #defined condition_requirement/3.
 #defined condition_requirement/4.
@@ -405,6 +413,7 @@ possible_provider_weight(Dependency, Virtual, 100, "fallback") :- provider(Depen
 % These allow us to easily define conditional dependency and conflict rules
 % without enumerating all spec attributes every time.
 node(Package)                          :- attr("node", Package).
+node_namespace(Package, Namespace)     :- attr("node_namespace", Package, Namespace).
 virtual_node(Virtual)                  :- attr("virtual_node", Virtual).
 hash(Package, Hash)                    :- attr("hash", Package, Hash).
 version(Package, Version)              :- attr("version", Package, Version).
@@ -427,6 +436,7 @@ node_flag_propagate(Package, FlagType)
   :- attr("node_flag_propagate", Package, FlagType).
 
 attr("node", Package)                          :- node(Package).
+attr("node_namespace", Package, Namespace)     :- node_namespace(Package, Namespace).
 attr("virtual_node", Virtual)                  :- virtual_node(Virtual).
 attr("hash", Package, Hash)                    :- hash(Package, Hash).
 attr("version", Package, Version)              :- version(Package, Version).
@@ -464,6 +474,7 @@ attr("node_flag_propagate", Package, FlagType)
 #defined node_version_satisfies/2.
 #defined node_compiler_version_satisfies/3.
 #defined root/1.
+#defined node_namespace/2.
 
 %-----------------------------------------------------------------------------
 % External semantics
diff --git a/lib/spack/spack/solver/display.lp b/lib/spack/spack/solver/display.lp
index 4ba8e9e2cb5..54bbe584df7 100644
--- a/lib/spack/spack/solver/display.lp
+++ b/lib/spack/spack/solver/display.lp
@@ -12,6 +12,7 @@
 % Spec-related functions.
 % Used to build the result of the solve.
 #show node/1.
+#show node_namespace/2.
 #show hash/2.
 #show depends_on/3.
 #show version/2.