Check if network namespaces are supported

Make sure that network namespaces are supported when
installing neutron componented and use_namespaces
option is enabled. Otherwise, raise install exception.

Change-Id: I19e7e3276f99db685f3406c1924722255bf174f8

anvil/components/neutron.py

@@ -15,6 +15,7 @@
 #    under the License.
 
 from anvil import colorizer
+from anvil import exceptions
 from anvil import log as logging
 from anvil import shell as sh
 
@@ -45,6 +46,23 @@ class NeutronInstaller(binstall.PythonInstallComponent, NeutronPluginMixin):
         super(NeutronInstaller, self).__init__(*args, **kargs)
         self.configurator = qconf.NeutronConfigurator(self)
 
+    def pre_install(self):
+        # Check if network namespaces are supported.
+        if self.get_option("use_namespaces", default_value=True):
+            try:
+                # "ip netns" command is used for network namespace management.
+                # We are trying to execute this command and if it was executed
+                # successfully then network namespaces support is enabled.
+                sh.execute(["ip", "netns"])
+            except exceptions.ProcessExecutionError:
+                raise exceptions.InstallException(
+                    "Network namespaces are not supported in your system. "
+                    "Please, install kernel and iproute with network "
+                    "namespaces support. To install them from RDO you can "
+                    "use the following script: "
+                    "./tools/install-neutron-ns-packages.sh")
+        super(NeutronInstaller, self).pre_install()
+
     def post_install(self):
         super(NeutronInstaller, self).post_install()
         if self.get_bool_option("db-sync"):

tools/install-neutron-ns-packages.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+
+# This script is used to install 'kernel' and 'iproute'
+# with network namespaces support for openstack-neutron
+# from RDO havana repository.
+
+set -e
+
+echo "Adding RDO havana repo..."
+sudo rpm -i --force http://rdo.fedorapeople.org/openstack-havana/rdo-release-havana.rpm
+sudo yum clean all
+
+echo "Installing 'kernel' and 'iproute' from RDO..."
+sudo yum install -y kernel iproute
+
+echo "Kernel updated. Please, reboot into it!"