diff --git a/lib/constants.py b/lib/constants.py
index 4b6d4188363fe45c02b49eae454610fcf9e15ead..eb38fb3f23e444928bb73adc9d3a3300edb2728d 100644
--- a/lib/constants.py
+++ b/lib/constants.py
@@ -545,6 +545,7 @@ HV_SECURITY_DOMAIN = "security_domain"
 HV_KVM_FLAG = "kvm_flag"
 HV_VHOST_NET = "vhost_net"
 HV_KVM_USE_CHROOT = "use_chroot"
+HV_CPU_MASK = "cpu_mask"
 
 HVS_PARAMETER_TYPES = {
   HV_BOOT_ORDER: VTYPE_STRING,
@@ -580,6 +581,7 @@ HVS_PARAMETER_TYPES = {
   HV_KVM_FLAG: VTYPE_STRING,
   HV_VHOST_NET: VTYPE_BOOL,
   HV_KVM_USE_CHROOT: VTYPE_BOOL,
+  HV_CPU_MASK: VTYPE_STRING,
   }
 
 HVS_PARAMETERS = frozenset(HVS_PARAMETER_TYPES.keys())
@@ -918,6 +920,7 @@ HVC_DEFAULTS = {
     HV_INIT_SCRIPT: "/ganeti-chroot",
     },
   HT_LXC: {
+    HV_CPU_MASK: "",
     },
   }
 
diff --git a/lib/hypervisor/hv_base.py b/lib/hypervisor/hv_base.py
index 6bcf6d7bf5243ed9acb01e9fc77e42d295cbd2eb..ce8754d77dcb930afe8ee5a1ca2297da6002c679 100644
--- a/lib/hypervisor/hv_base.py
+++ b/lib/hypervisor/hv_base.py
@@ -47,6 +47,14 @@ from ganeti import utils
 from ganeti import constants
 
 
+def _IsCpuMaskWellFormed(cpu_mask):
+  try:
+    cpu_list = utils.ParseCpuMask(cpu_mask)
+  except errors.ParseError, _:
+    return False
+  return isinstance(cpu_list, list) and len(cpu_list) > 0
+
+
 # Read the BaseHypervisor.PARAMETERS docstring for the syntax of the
 # _CHECK values
 
@@ -58,6 +66,12 @@ _FILE_CHECK = (utils.IsNormAbsPath, "must be an absolute normalized path",
 _DIR_CHECK = (utils.IsNormAbsPath, "must be an absolute normalized path",
              os.path.isdir, "not found or not a directory")
 
+# CPU mask must be well-formed
+# TODO: implement node level check for the CPU mask
+_CPU_MASK_CHECK = (_IsCpuMaskWellFormed,
+                   "CPU mask definition is not well-formed",
+                   None, None)
+
 # nice wrappers for users
 REQ_FILE_CHECK = (True, ) + _FILE_CHECK
 OPT_FILE_CHECK = (False, ) + _FILE_CHECK
@@ -65,6 +79,8 @@ REQ_DIR_CHECK = (True, ) + _DIR_CHECK
 OPT_DIR_CHECK = (False, ) + _DIR_CHECK
 NET_PORT_CHECK = (True, lambda x: x > 0 and x < 65535, "invalid port number",
                   None, None)
+OPT_CPU_MASK_CHECK = (False, ) + _CPU_MASK_CHECK
+REQ_CPU_MASK_CHECK = (True, ) + _CPU_MASK_CHECK
 
 # no checks at all
 NO_CHECK = (False, None, None, None, None)
diff --git a/lib/hypervisor/hv_lxc.py b/lib/hypervisor/hv_lxc.py
index 23a79746e1d53828d16daf9250524e3fa335fda1..3779a68cd6a077293c3d629c3f59142386e7d599 100644
--- a/lib/hypervisor/hv_lxc.py
+++ b/lib/hypervisor/hv_lxc.py
@@ -88,6 +88,7 @@ class LXCHypervisor(hv_base.BaseHypervisor):
   _DIR_MODE = 0755
 
   PARAMETERS = {
+    constants.HV_CPU_MASK: hv_base.OPT_CPU_MASK_CHECK,
     }
 
   def __init__(self):
@@ -149,17 +150,8 @@ class LXCHypervisor(hv_base.BaseHypervisor):
     except EnvironmentError, err:
       raise errors.HypervisorError("Getting CPU list for instance"
                                    " %s failed: %s" % (instance_name, err))
-    # cpuset.cpus format: comma-separated list of CPU ids
-    # or dash-separated id ranges
-    # Example: "0-1,3"
-    cpu_list = []
-    for range_def in cpus.split(","):
-      boundaries = range_def.split("-")
-      n_elements = len(boundaries)
-      lower = int(boundaries[0])
-      higher = int(boundaries[n_elements - 1])
-      cpu_list.extend(range(lower, higher + 1))
-    return cpu_list
+
+    return utils.ParseCpuMask(cpus)
 
   def ListInstances(self):
     """Get the list of running instances.
@@ -207,7 +199,9 @@ class LXCHypervisor(hv_base.BaseHypervisor):
     return data
 
   def _CreateConfigFile(self, instance, root_dir):
-    """Create an lxc.conf file for an instance"""
+    """Create an lxc.conf file for an instance.
+
+    """
     out = []
     # hostname
     out.append("lxc.utsname = %s" % instance.name)
@@ -231,6 +225,19 @@ class LXCHypervisor(hv_base.BaseHypervisor):
 
     # TODO: additional mounts, if we disable CAP_SYS_ADMIN
 
+    # CPUs
+    if instance.hvparams[constants.HV_CPU_MASK]:
+      cpu_list = utils.ParseCpuMask(instance.hvparams[constants.HV_CPU_MASK])
+      cpus_in_mask = len(cpu_list)
+      if cpus_in_mask != instance.beparams["vcpus"]:
+        raise errors.HypervisorError("Number of VCPUs (%d) doesn't match"
+                                     " the number of CPUs in the"
+                                     " cpu_mask (%d)" %
+                                     (instance.beparams["vcpus"],
+                                      cpus_in_mask))
+      out.append("lxc.cgroup.cpuset.cpus = %s" %
+                 instance.hvparams[constants.HV_CPU_MASK])
+
     # Device control
     # deny direct device access
     out.append("lxc.cgroup.devices.deny = a")
@@ -261,8 +268,8 @@ class LXCHypervisor(hv_base.BaseHypervisor):
   def StartInstance(self, instance, block_devices):
     """Start an instance.
 
-    For LCX, we try to mount the block device and execute 'lxc-start
-    start' (we use volatile containers).
+    For LCX, we try to mount the block device and execute 'lxc-start'.
+    We use volatile containers.
 
     """
     root_dir = self._InstanceDir(instance.name)
diff --git a/man/gnt-instance.sgml b/man/gnt-instance.sgml
index b12337506835835051d9912fcd8ac13cbc6439b4..c19eb95f036e6f27d6195c4dcf3d4cf7b58dd659 100644
--- a/man/gnt-instance.sgml
+++ b/man/gnt-instance.sgml
@@ -711,6 +711,24 @@
               </listitem>
             </varlistentry>
 
+            <varlistentry>
+              <term>cpu_mask</term>
+              <listitem>
+                <simpara>Valid for the LXC hypervisor.</simpara>
+
+                <simpara>The processes belonging to the given instance are
+                only scheduled on the specified CPUs.
+                </simpara>
+
+                <simpara>
+                The parameter format is a comma-separated list of CPU IDs or
+                CPU ID ranges. The ranges are defined by a lower and higher
+                boundary, separated by a dash. The boundaries are inclusive.
+                </simpara>
+
+              </listitem>
+            </varlistentry>
+
           </variablelist>
 
         </para>