openstack-manuals/doc/install-guide/section_neutron-initial-networks.xml
Yair Fried b9db6828ff Fix misleading guidance for Neutron external network
External networks shouldn't be "shared"

Change-Id: I7511e2f956c219ab2155ca44023bdc6754400828
Closes-bug: #1405403
2014-12-24 16:26:11 +02:00

267 lines
15 KiB
XML

<?xml version="1.0" encoding="UTF-8"?>
<section xmlns="http://docbook.org/ns/docbook"
xmlns:xi="http://www.w3.org/2001/XInclude"
xmlns:xlink="http://www.w3.org/1999/xlink"
version="5.0"
xml:id="neutron-initial-networks">
<title>Create initial networks</title>
<para>Before launching your first instance, you must create the
necessary virtual network infrastructure to which the instance will
connect, including the
<link linkend="neutron_initial-external-network">external network</link>
and
<link linkend="neutron_initial-tenant-network">tenant network</link>.
See <xref linkend="neutron_figure-neutron-initial-networks"/>. After
creating this infrastructure, we recommend that you
<link linkend="neutron_initial-networks-verify">verify
connectivity</link> and resolve any issues before proceeding further.
<xref linkend="neutron_figure-neutron-initial-networks"/> provides a
basic architectural overview of the components that Networking implements
for the initial networks and shows how network traffic flows from the
instance to the external network or Internet.</para>
<figure xml:id="neutron_figure-neutron-initial-networks">
<title>Initial networks</title>
<mediaobject>
<imageobject>
<imagedata contentwidth="6in"
fileref="../common/figures/installguide-neutron-initialnetworks.png"/>
</imageobject>
</mediaobject>
</figure>
<section xml:id="neutron_initial-external-network">
<title>External network</title>
<para>The external network typically provides Internet access for
your instances. By default, this network only allows Internet
access <emphasis>from</emphasis> instances using
<glossterm>Network Address Translation (NAT)</glossterm>. You can
enable Internet access <emphasis>to</emphasis> individual instances
using a <glossterm>floating IP address</glossterm> and suitable
<glossterm>security group</glossterm> rules. The <literal>admin</literal>
tenant owns this network because it provides external network
access for multiple tenants.</para>
<note>
<para>Perform these commands on the controller node.</para>
</note>
<procedure>
<title>To create the external network</title>
<step>
<para>Source the <literal>admin</literal> credentials to gain access to
admin-only CLI commands:</para>
<screen><prompt>$</prompt> <userinput>source admin-openrc.sh</userinput></screen>
</step>
<step>
<para>Create the network:</para>
<screen><prompt>$</prompt> <userinput>neutron net-create ext-net --router:external True \
--provider:physical_network external --provider:network_type flat</userinput>
<computeroutput>Created a new network:
+---------------------------+--------------------------------------+
| Field | Value |
+---------------------------+--------------------------------------+
| admin_state_up | True |
| id | 893aebb9-1c1e-48be-8908-6b947f3237b3 |
| name | ext-net |
| provider:network_type | flat |
| provider:physical_network | external |
| provider:segmentation_id | |
| router:external | True |
| shared | False |
| status | ACTIVE |
| subnets | |
| tenant_id | 54cd044c64d5408b83f843d63624e0d8 |
+---------------------------+--------------------------------------+</computeroutput></screen>
</step>
</procedure>
<para>Like a physical network, a virtual network requires a
<glossterm>subnet</glossterm> assigned to it. The external network
shares the same subnet and <glossterm>gateway</glossterm> associated
with the physical network connected to the external interface on the
network node. You should specify an exclusive slice of this subnet
for <glossterm>router</glossterm> and floating IP addresses to prevent
interference with other devices on the external network.</para>
<procedure>
<title>To create a subnet on the external network</title>
<step>
<para>Create the subnet:</para>
<screen><prompt>$</prompt> <userinput>neutron subnet-create ext-net --name ext-subnet \
--allocation-pool start=<replaceable>FLOATING_IP_START</replaceable>,end=<replaceable>FLOATING_IP_END</replaceable> \
--disable-dhcp --gateway <replaceable>EXTERNAL_NETWORK_GATEWAY</replaceable> <replaceable>EXTERNAL_NETWORK_CIDR</replaceable></userinput></screen>
<para>Replace <replaceable>FLOATING_IP_START</replaceable> and
<replaceable>FLOATING_IP_END</replaceable> with the first and last
IP addresses of the range that you want to allocate for floating IP
addresses. Replace <replaceable>EXTERNAL_NETWORK_CIDR</replaceable>
with the subnet associated with the physical network. Replace
<replaceable>EXTERNAL_NETWORK_GATEWAY</replaceable> with the gateway
associated with the physical network, typically the ".1" IP address.
You should disable <glossterm>DHCP</glossterm> on this subnet because
instances do not connect directly to the external network and
floating IP addresses require manual assignment.</para>
<para>For example, using <literal>203.0.113.0/24</literal> with
floating IP address range <literal>203.0.113.101</literal> to
<literal>203.0.113.200</literal>:</para>
<screen><prompt>$</prompt> <userinput>neutron subnet-create ext-net --name ext-subnet \
--allocation-pool start=203.0.113.101,end=203.0.113.200 \
--disable-dhcp --gateway 203.0.113.1 203.0.113.0/24</userinput>
<computeroutput>Created a new subnet:
+-------------------+------------------------------------------------------+
| Field | Value |
+-------------------+------------------------------------------------------+
| allocation_pools | {"start": "203.0.113.101", "end": "203.0.113.200"} |
| cidr | 203.0.113.0/24 |
| dns_nameservers | |
| enable_dhcp | False |
| gateway_ip | 203.0.113.1 |
| host_routes | |
| id | 9159f0dc-2b63-41cf-bd7a-289309da1391 |
| ip_version | 4 |
| ipv6_address_mode | |
| ipv6_ra_mode | |
| name | ext-subnet |
| network_id | 893aebb9-1c1e-48be-8908-6b947f3237b3 |
| tenant_id | 54cd044c64d5408b83f843d63624e0d8 |
+-------------------+------------------------------------------------------+</computeroutput></screen>
</step>
</procedure>
</section>
<section xml:id="neutron_initial-tenant-network">
<title>Tenant network</title>
<para>The tenant network provides internal network access for instances.
The architecture isolates this type of network from other tenants. The
<literal>demo</literal> tenant owns this network because it only
provides network access for instances within it.</para>
<note>
<para>Perform these commands on the controller node.</para>
</note>
<procedure>
<title>To create the tenant network</title>
<step>
<para>Source the <literal>demo</literal> credentials to gain access to
user-only CLI commands:</para>
<screen><prompt>$</prompt> <userinput>source demo-openrc.sh</userinput></screen>
</step>
<step>
<para>Create the network:</para>
<screen><prompt>$</prompt> <userinput>neutron net-create demo-net</userinput>
<computeroutput>Created a new network:
+-----------------+--------------------------------------+
| Field | Value |
+-----------------+--------------------------------------+
| admin_state_up | True |
| id | ac108952-6096-4243-adf4-bb6615b3de28 |
| name | demo-net |
| router:external | False |
| shared | False |
| status | ACTIVE |
| subnets | |
| tenant_id | cdef0071a0194d19ac6bb63802dc9bae |
+-----------------+--------------------------------------+</computeroutput></screen>
</step>
</procedure>
<para>Like the external network, your tenant network also requires
a subnet attached to it. You can specify any valid subnet because the
architecture isolates tenant networks. By default, this subnet will
use DHCP so your instances can obtain IP addresses.</para>
<procedure>
<title>To create a subnet on the tenant network</title>
<step>
<para>Create the subnet:</para>
<screen><prompt>$</prompt> <userinput>neutron subnet-create demo-net --name demo-subnet \
--gateway <replaceable>TENANT_NETWORK_GATEWAY</replaceable> <replaceable>TENANT_NETWORK_CIDR</replaceable></userinput></screen>
<para>Replace <replaceable>TENANT_NETWORK_CIDR</replaceable> with the
subnet you want to associate with the tenant network and
<replaceable>TENANT_NETWORK_GATEWAY</replaceable> with the gateway
you want to associate with it, typically the ".1" IP address.</para>
<para>Example using <literal>192.168.1.0/24</literal>:</para>
<screen><prompt>$</prompt> <userinput>neutron subnet-create demo-net --name demo-subnet \
--gateway 192.168.1.1 192.168.1.0/24</userinput>
<computeroutput>Created a new subnet:
+-------------------+------------------------------------------------------+
| Field | Value |
+-------------------+------------------------------------------------------+
| allocation_pools | {"start": "192.168.1.2", "end": "192.168.1.254"} |
| cidr | 192.168.1.0/24 |
| dns_nameservers | |
| enable_dhcp | True |
| gateway_ip | 192.168.1.1 |
| host_routes | |
| id | 69d38773-794a-4e49-b887-6de6734e792d |
| ip_version | 4 |
| ipv6_address_mode | |
| ipv6_ra_mode | |
| name | demo-subnet |
| network_id | ac108952-6096-4243-adf4-bb6615b3de28 |
| tenant_id | cdef0071a0194d19ac6bb63802dc9bae |
+-------------------+------------------------------------------------------+</computeroutput></screen>
</step>
</procedure>
<para>A virtual router passes network traffic between two or more virtual
networks. Each router requires one or more
<glossterm baseform="interface">interfaces</glossterm> and/or gateways
that provide access to specific networks. In this case, you will create
a router and attach your tenant and external networks to it.</para>
<procedure>
<title>To create a router on the tenant network and attach the external
and tenant networks to it</title>
<step>
<para>Create the router:</para>
<screen><prompt>$</prompt> <userinput>neutron router-create demo-router</userinput>
<computeroutput>Created a new router:
+-----------------------+--------------------------------------+
| Field | Value |
+-----------------------+--------------------------------------+
| admin_state_up | True |
| external_gateway_info | |
| id | 635660ae-a254-4feb-8993-295aa9ec6418 |
| name | demo-router |
| routes | |
| status | ACTIVE |
| tenant_id | cdef0071a0194d19ac6bb63802dc9bae |
+-----------------------+--------------------------------------+</computeroutput></screen>
</step>
<step>
<para>Attach the router to the <literal>demo</literal> tenant
subnet:</para>
<screen><prompt>$</prompt> <userinput>neutron router-interface-add demo-router demo-subnet</userinput>
<computeroutput>Added interface b1a894fd-aee8-475c-9262-4342afdc1b58 to router demo-router.</computeroutput></screen>
</step>
<step>
<para>Attach the router to the external network by setting it as
the gateway:</para>
<screen><prompt>$</prompt> <userinput>neutron router-gateway-set demo-router ext-net</userinput>
<computeroutput>Set gateway for router demo-router</computeroutput></screen>
</step>
</procedure>
</section>
<section xml:id="neutron_initial-networks-verify">
<title>Verify connectivity</title>
<para>We recommend that you verify network connectivity and resolve any
issues before proceeding further. Following the external network
subnet example using <literal>203.0.113.0/24</literal>, the tenant
router gateway should occupy the lowest IP address in the floating
IP address range, <literal>203.0.113.101</literal>. If you configured
your external physical network and virtual networks correctly, you
should be able to <command>ping</command> this IP address from any
host on your external physical network.</para>
<note>
<para>If you are building your OpenStack nodes as virtual machines,
you must configure the hypervisor to permit promiscuous mode on the
external network.</para>
</note>
<procedure>
<title>To verify network connectivity</title>
<step>
<para>Ping the tenant router gateway:</para>
<screen><prompt>$</prompt> <userinput>ping -c 4 203.0.113.101</userinput>
<computeroutput>PING 203.0.113.101 (203.0.113.101) 56(84) bytes of data.
64 bytes from 203.0.113.101: icmp_req=1 ttl=64 time=0.619 ms
64 bytes from 203.0.113.101: icmp_req=2 ttl=64 time=0.189 ms
64 bytes from 203.0.113.101: icmp_req=3 ttl=64 time=0.165 ms
64 bytes from 203.0.113.101: icmp_req=4 ttl=64 time=0.216 ms
--- 203.0.113.101 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 2999ms
rtt min/avg/max/mdev = 0.165/0.297/0.619/0.187 ms</computeroutput></screen>
</step>
</procedure>
</section>
</section>