openstack-manuals/doc/admin-guide-cloud/section_networking-multi-dhcp-agents.xml
nerminamiller eefd494d0b Move Networking scenarios section from Configuration Reference to Cloud Admin Guide
Moved networking-config-identity, networking-scenarios,
networking-adv-config, networking-multi-dhcp-agents from Config Ref to
Networking ch of Cloud Admin Guide

Change-Id: I1c14e9b7017fee976c2c80b6f0c8c7bcb15eb046
backport: none
Closes-Bug: #1255295
author: nermina miller
2014-01-03 15:49:46 -05:00

503 lines
30 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="app_demo_multi_dhcp_agents">
<title>Scalable and highly available DHCP agents</title>
<para>This section describes how to use the agent management
(alias agent) and scheduler (alias agent_scheduler) extensions
for DHCP agents scalability and HA.</para>
<note>
<para>Use the <command>neutron ext-list</command> client
command to check if these extensions are enabled:
<screen><prompt>$</prompt> <userinput>neutron ext-list -c name -c alias</userinput>
<computeroutput>+-----------------+--------------------------+
| alias | name |
+-----------------+--------------------------+
| agent_scheduler | Agent Schedulers |
| binding | Port Binding |
| quotas | Quota management support |
| agent | agent |
| provider | Provider Network |
| router | Neutron L3 Router |
| lbaas | LoadBalancing service |
| extraroute | Neutron Extra Route |
+-----------------+--------------------------+
</computeroutput></screen></para>
</note>
<mediaobject>
<imageobject>
<imagedata
fileref="../common/figures/demo_multiple_dhcp_agents.png"
contentwidth="6in"/>
</imageobject>
</mediaobject>
<para>There will be three hosts in the setup.
<table rules="all">
<caption>Hosts for demo</caption>
<thead>
<tr>
<th>Host</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr>
<td>OpenStack Controller host - controlnode</td>
<td><para>Runs the Neutron, Keystone, and Nova
services that are required to deploy VMs.
The node must have at least one network
interface that is connected to the
Management Network.</para>
<para>Note that <systemitem class="service"
>nova-network</systemitem> should
not be running because it is replaced
by Neutron.</para>
</td>
</tr>
<tr>
<td>HostA</td>
<td>Runs Nova compute, the Neutron L2 agent and
DCHP agent</td>
</tr>
<tr>
<td>HostB</td>
<td>Same as HostA</td>
</tr>
</tbody>
</table>
</para>
<section xml:id="multi_agent_demo_configuration">
<title>Configuration</title>
<procedure>
<title>controlnode&#151;Neutron Server</title>
<step>
<para>Neutron configuration file
<filename>/etc/neutron/neutron.conf</filename>:</para>
<programlisting language="ini">[DEFAULT]
core_plugin = neutron.plugins.linuxbridge.lb_neutron_plugin.LinuxBridgePluginV2
rabbit_host = controlnode
allow_overlapping_ips = True
host = controlnode
agent_down_time = 5</programlisting>
</step>
<step>
<para>Update the plug-in configuration file
<filename>/etc/neutron/plugins/linuxbridge/linuxbridge_conf.ini</filename>:</para>
<programlisting language="ini">[vlans]
tenant_network_type = vlan
network_vlan_ranges = physnet1:1000:2999
[database]
connection = mysql://root:root@127.0.0.1:3306/neutron_linux_bridge
retry_interval = 2
[linux_bridge]
physical_interface_mappings = physnet1:eth0</programlisting>
</step>
</procedure>
<procedure>
<title>HostA and HostB&#151;L2 Agent</title>
<step>
<para>Neutron configuration file
<filename>/etc/neutron/neutron.conf</filename>:</para>
<programlisting language="ini">[DEFAULT]
rabbit_host = controlnode
rabbit_password = openstack
# host = HostB on hostb
host = HostA</programlisting>
</step>
<step>
<para>Update the plug-in configuration file
<filename>/etc/neutron/plugins/linuxbridge/linuxbridge_conf.ini</filename>:</para>
<programlisting language="ini">[vlans]
tenant_network_type = vlan
network_vlan_ranges = physnet1:1000:2999
[database]
connection = mysql://root:root@127.0.0.1:3306/neutron_linux_bridge
retry_interval = 2
[linux_bridge]
physical_interface_mappings = physnet1:eth0</programlisting>
</step>
<step>
<para>Update the nova configuration file
<filename>/etc/nova/nova.conf</filename>:</para>
<programlisting language="ini">[DEFAULT]
network_api_class=nova.network.neutronv2.api.API
neutron_admin_username=neutron
neutron_admin_password=servicepassword
neutron_admin_auth_url=http://controlnode:35357/v2.0/
neutron_auth_strategy=keystone
neutron_admin_tenant_name=servicetenant
neutron_url=http://100.1.1.10:9696/
firewall_driver=nova.virt.firewall.NoopFirewallDriver</programlisting>
</step>
</procedure>
<procedure>
<title>HostA and HostB&#151;DHCP Agent</title>
<step>
<para>Update the DHCP configuration file
<filename>/etc/neutron/dhcp_agent.ini</filename>:</para>
<programlisting language="ini">[DEFAULT]
interface_driver = neutron.agent.linux.interface.BridgeInterfaceDriver</programlisting>
</step>
</procedure>
</section>
<section xml:id="demo_multiple_operation">
<title>Commands in agent management and scheduler
extensions</title>
<para>The following commands require the tenant running the
command to have an admin role.</para>
<note>
<para>Ensure that the following environment variables are
set. These are used by the various clients to access
Keystone.</para>
<programlisting language="bash">export OS_USERNAME=admin
export OS_PASSWORD=adminpassword
export OS_TENANT_NAME=admin
export OS_AUTH_URL=http://controlnode:5000/v2.0/</programlisting>
</note>
<procedure>
<title>Settings</title>
<step><para>To experiment, you need VMs and a neutron
network:</para>
<screen><prompt>$</prompt> <userinput>nova list</userinput>
<computeroutput>+--------------------------------------+-----------+--------+---------------+
| ID | Name | Status | Networks |
+--------------------------------------+-----------+--------+---------------+
| c394fcd0-0baa-43ae-a793-201815c3e8ce | myserver1 | ACTIVE | net1=10.0.1.3 |
| 2d604e05-9a6c-4ddb-9082-8a1fbdcc797d | myserver2 | ACTIVE | net1=10.0.1.4 |
| c7c0481c-3db8-4d7a-a948-60ce8211d585 | myserver3 | ACTIVE | net1=10.0.1.5 |
+--------------------------------------+-----------+--------+---------------+
</computeroutput>
<prompt>$</prompt> <userinput>neutron net-list</userinput>
<computeroutput>+--------------------------------------+------+--------------------------------------+
| id | name | subnets |
+--------------------------------------+------+--------------------------------------+
| 89dca1c6-c7d4-4f7a-b730-549af0fb6e34 | net1 | f6c832e3-9968-46fd-8e45-d5cf646db9d1 |
+--------------------------------------+------+--------------------------------------+</computeroutput></screen>
</step>
</procedure>
<procedure>
<title>Manage agents in neutron deployment</title>
<para>Every agent which supports these extensions will
register itself with the neutron server when it
starts up.</para>
<step>
<para>List all agents:</para>
<screen><prompt>$</prompt> <userinput>neutron agent-list</userinput>
<computeroutput>+--------------------------------------+--------------------+-------+-------+----------------+
| id | agent_type | host | alive | admin_state_up |
+--------------------------------------+--------------------+-------+-------+----------------+
| 1b69828d-6a9b-4826-87cd-1757f0e27f31 | Linux bridge agent | HostA | :-) | True |
| a0c1c21c-d4f4-4577-9ec7-908f2d48622d | DHCP agent | HostA | :-) | True |
| ed96b856-ae0f-4d75-bb28-40a47ffd7695 | Linux bridge agent | HostB | :-) | True |
| f28aa126-6edb-4ea5-a81e-8850876bc0a8 | DHCP agent | HostB | :-) | True |
+--------------------------------------+--------------------+-------+-------+----------------+
</computeroutput></screen>
<para>The output shows information for four
agents. The <literal>alive</literal> field
shows <literal>:-)</literal> if the agent
reported its state within the period
defined by the
<option>agent_down_time</option>
option in the
<filename>neutron.conf</filename>
file. Otherwise the <option>alive</option>
is <literal>xxx</literal>.</para>
</step>
<step>
<para>List the DHCP agents that host a
specified network</para>
<para>In some deployments, one DHCP agent is
not enough to hold all network data. In
addition, you must have a backup for it
even when the deployment is small. The
same network can be assigned to more than
one DHCP agent and one DHCP agent can host
more than one network.</para>
<para>List DHCP agents that a a specified
network:</para>
<screen><prompt>$</prompt> <userinput>neutron dhcp-agent-list-hosting-net net1</userinput>
<computeroutput>+--------------------------------------+-------+----------------+-------+
| id | host | admin_state_up | alive |
+--------------------------------------+-------+----------------+-------+
| a0c1c21c-d4f4-4577-9ec7-908f2d48622d | HostA | True | :-) |
+--------------------------------------+-------+----------------+-------+
</computeroutput></screen>
</step>
<step>
<para>List the networks hosted by a given DHCP
agent.</para>
<para>This command is to show which networks a
given dhcp agent is managing.</para>
<screen><prompt>$</prompt> <userinput>neutron net-list-on-dhcp-agent a0c1c21c-d4f4-4577-9ec7-908f2d48622d</userinput>
<computeroutput>+--------------------------------------+------+---------------------------------------------------+
| id | name | subnets |
+--------------------------------------+------+---------------------------------------------------+
| 89dca1c6-c7d4-4f7a-b730-549af0fb6e34 | net1 | f6c832e3-9968-46fd-8e45-d5cf646db9d1 10.0.1.0/24 |
+--------------------------------------+------+---------------------------------------------------+
</computeroutput></screen>
</step>
<step>
<para>Show agent details.</para>
<para>The <command>agent-list</command>
command shows details for a specified
agent:</para>
<screen><prompt>$</prompt> <userinput>neutron agent-show a0c1c21c-d4f4-4577-9ec7-908f2d48622d</userinput>
<computeroutput>+---------------------+----------------------------------------------------------+
| Field | Value |
+---------------------+----------------------------------------------------------+
| admin_state_up | True |
| agent_type | DHCP agent |
| alive | False |
| binary | neutron-dhcp-agent |
| configurations | { |
| | "subnets": 1, |
| | "use_namespaces": true, |
| | "dhcp_driver": "neutron.agent.linux.dhcp.Dnsmasq", |
| | "networks": 1, |
| | "dhcp_lease_time": 120, |
| | "ports": 3 |
| | } |
| created_at | 2013-03-16T01:16:18.000000 |
| description | |
| heartbeat_timestamp | 2013-03-17T01:37:22.000000 |
| host | HostA |
| id | 58f4ce07-6789-4bb3-aa42-ed3779db2b03 |
| started_at | 2013-03-16T06:48:39.000000 |
| topic | dhcp_agent |
+---------------------+----------------------------------------------------------+
</computeroutput></screen>
<para>In this output,
<literal>heartbeat_timestamp</literal>
is the time on the neutron server. You do
not need to synchronize all agents to this
time for this extension to run correctly.
<literal>configurations</literal>
describes the static configuration for the
agent or run time data. This agent is a
DHCP agent and it hosts one network, one
subnet, and three ports.</para>
<para>Different types of agents show different
details. The following output shows
information for a Linux bridge
agent:</para>
<screen><prompt>$</prompt> <userinput>neutron agent-show ed96b856-ae0f-4d75-bb28-40a47ffd7695</userinput>
<computeroutput>+---------------------+--------------------------------------+
| Field | Value |
+---------------------+--------------------------------------+
| admin_state_up | True |
| binary | neutron-linuxbridge-agent |
| configurations | { |
| | "physnet1": "eth0", |
| | "devices": "4" |
| | } |
| created_at | 2013-03-16T01:49:52.000000 |
| description | |
| disabled | False |
| group | agent |
| heartbeat_timestamp | 2013-03-16T01:59:45.000000 |
| host | HostB |
| id | ed96b856-ae0f-4d75-bb28-40a47ffd7695 |
| topic | N/A |
| started_at | 2013-03-16T06:48:39.000000 |
| type | Linux bridge agent |
+---------------------+--------------------------------------+</computeroutput></screen>
<para>The output shows
<literal>bridge-mapping</literal> and
the number of virtual network devices on
this L2 agent.</para>
</step>
</procedure>
<procedure>
<title>Manage assignment of networks to DHCP agent</title>
<para>Now that you have run the
<command>net-list-on-dhcp-agent</command> and
<command>dhcp-agent-list-hosting-net</command>
commands, you can add a network to a DHCP agent
and remove one from it.</para>
<step>
<para>Default scheduling.</para>
<para>When you create a network with one port,
you can schedule it to an active DHCP
agent. If many active DHCP agents are
running, select one randomly. You can
design more sophisticated scheduling
algorithms in the same way as <systemitem
class="service"
>nova-schedule</systemitem> later
on.</para>
<screen><prompt>$</prompt> <userinput>neutron net-create net2</userinput>
<prompt>$</prompt> <userinput>neutron subnet-create net2 9.0.1.0/24 --name subnet2</userinput>
<prompt>$</prompt> <userinput>neutron port-create net2</userinput>
<prompt>$</prompt> <userinput>neutron dhcp-agent-list-hosting-net net2</userinput>
<computeroutput>+--------------------------------------+-------+----------------+-------+
| id | host | admin_state_up | alive |
+--------------------------------------+-------+----------------+-------+
| a0c1c21c-d4f4-4577-9ec7-908f2d48622d | HostA | True | :-) |
+--------------------------------------+-------+----------------+-------+</computeroutput></screen>
<para>It is allocated to DHCP agent on HostA.
If you want to validate the behavior
through the <command>dnsmasq</command>
command, you must create a subnet for the
network because the DHCP agent starts the
<systemitem class="service"
>dnsmasq</systemitem> service only if
there is a DHCP.</para>
</step>
<step>
<para>Assign a network to a given DHCP
agent.</para>
<para>To add another DHCP agent to host the
network, run this command:</para>
<screen><prompt>$</prompt> <userinput>neutron dhcp-agent-network-add f28aa126-6edb-4ea5-a81e-8850876bc0a8 net2</userinput>
<computeroutput>Added network net2 to dhcp agent</computeroutput>
<prompt>$</prompt> <userinput>neutron dhcp-agent-list-hosting-net net2</userinput>
<computeroutput>+--------------------------------------+-------+----------------+-------+
| id | host | admin_state_up | alive |
+--------------------------------------+-------+----------------+-------+
| a0c1c21c-d4f4-4577-9ec7-908f2d48622d | HostA | True | :-) |
| f28aa126-6edb-4ea5-a81e-8850876bc0a8 | HostB | True | :-) |
+--------------------------------------+-------+----------------+-------+</computeroutput></screen>
<para>Both DHCP agents host the
<literal>net2</literal>
network.</para>
</step>
<step>
<para>Remove a network from a specified DHCP
agent.</para>
<para>This command is the sibling command for
the previous one. Remove
<literal>net2</literal> from the DHCP
agent for HostA:</para>
<screen><prompt>$</prompt> <userinput>neutron dhcp-agent-network-remove a0c1c21c-d4f4-4577-9ec7-908f2d48622d net2</userinput>
<computeroutput>Removed network net2 to dhcp agent</computeroutput>
<prompt>$</prompt> <userinput>neutron dhcp-agent-list-hosting-net net2</userinput>
<computeroutput>+--------------------------------------+-------+----------------+-------+
| id | host | admin_state_up | alive |
+--------------------------------------+-------+----------------+-------+
| f28aa126-6edb-4ea5-a81e-8850876bc0a8 | HostB | True | :-) |
+--------------------------------------+-------+----------------+-------+</computeroutput></screen>
<para>You can see that only the DHCP agent for
HostB is hosting the
<literal>net2</literal>
network.</para>
</step>
</procedure>
<procedure>
<title>HA of DHCP agents</title>
<para>Boot a VM on net2. Let both DHCP agents host
<literal>net2</literal>. Fail the agents in
turn to see if the VM can still get the desired
IP.</para>
<step>
<para>Boot a VM on net2.</para>
<screen><prompt>$</prompt> <userinput>neutron net-list</userinput>
<computeroutput>+--------------------------------------+------+--------------------------------------------------+
| id | name | subnets |
+--------------------------------------+------+--------------------------------------------------+
| 89dca1c6-c7d4-4f7a-b730-549af0fb6e34 | net1 | f6c832e3-9968-46fd-8e45-d5cf646db9d1 10.0.1.0/24|
| 9b96b14f-71b8-4918-90aa-c5d705606b1a | net2 | 6979b71a-0ae8-448c-aa87-65f68eedcaaa 9.0.1.0/24 |
+--------------------------------------+------+--------------------------------------------------+</computeroutput>
<prompt>$</prompt> <userinput>nova boot --image tty --flavor 1 myserver4 \
--nic net-id=9b96b14f-71b8-4918-90aa-c5d705606b1a</userinput>
<prompt>$</prompt> <userinput>nova list</userinput>
<computeroutput>+--------------------------------------+-----------+--------+---------------+
| ID | Name | Status | Networks |
+--------------------------------------+-----------+--------+---------------+
| c394fcd0-0baa-43ae-a793-201815c3e8ce | myserver1 | ACTIVE | net1=10.0.1.3 |
| 2d604e05-9a6c-4ddb-9082-8a1fbdcc797d | myserver2 | ACTIVE | net1=10.0.1.4 |
| c7c0481c-3db8-4d7a-a948-60ce8211d585 | myserver3 | ACTIVE | net1=10.0.1.5 |
| f62f4731-5591-46b1-9d74-f0c901de567f | myserver4 | ACTIVE | net2=9.0.1.2 |
+--------------------------------------+-----------+--------+---------------+</computeroutput></screen>
</step>
<step>
<para>Make sure both DHCP agents hosting
'net2'.</para>
<para>Use the previous commands to assign the
network to agents.</para>
<screen><prompt>$</prompt> <userinput>neutron dhcp-agent-list-hosting-net net2</userinput>
<computeroutput>+--------------------------------------+-------+----------------+-------+
| id | host | admin_state_up | alive |
+--------------------------------------+-------+----------------+-------+
| a0c1c21c-d4f4-4577-9ec7-908f2d48622d | HostA | True | :-) |
| f28aa126-6edb-4ea5-a81e-8850876bc0a8 | HostB | True | :-) |
+--------------------------------------+-------+----------------+-------+</computeroutput></screen>
</step>
</procedure>
<procedure>
<title>Test the HA</title>
<step>
<para>Log in to the
<literal>myserver4</literal> VM,
and run <literal>udhcpc</literal>,
<literal>dhclient</literal> or
other DHCP client.</para>
</step>
<step>
<para>Stop the DHCP agent on HostA.
Besides stopping the
<code>neutron-dhcp-agent</code>
binary, you must stop the
<command>dnsmasq</command>
processes.</para>
</step>
<step>
<para>Run a DHCP client in VM to see
if it can get the wanted IP.
</para>
</step>
<step>
<para>Stop the DHCP agent on HostB
too.</para>
</step>
<step>
<para>Run <command>udhcpc</command> in
the VM; it cannot get the wanted
IP.</para>
</step>
<step>
<para>Start DHCP agent on HostB. The
VM gets the wanted IP again.</para>
</step>
</procedure>
<procedure>
<title>Disable and remove an agent</title>
<para>An administrator might want to disable an agent
if a system hardware or software upgrade is
planned. Some agents that support scheduling also
support disabling and enabling agents, such as L3
and DHCP agents. After the agent is disabled, the
scheduler does not schedule new resources to the
agent. After the agent is disabled, you can safely
remove the agent. Remove the resources on the
agent before you delete the agent.</para>
<step><para>To run the following commands, you must stop the
DHCP agent on HostA.</para>
<screen><prompt>$</prompt> <userinput>neutron agent-update --admin-state-up False a0c1c21c-d4f4-4577-9ec7-908f2d48622d</userinput>
<prompt>$</prompt> <userinput>neutron agent-list</userinput>
<computeroutput>+--------------------------------------+--------------------+-------+-------+----------------+
| id | agent_type | host | alive | admin_state_up |
+--------------------------------------+--------------------+-------+-------+----------------+
| 1b69828d-6a9b-4826-87cd-1757f0e27f31 | Linux bridge agent | HostA | :-) | True |
| a0c1c21c-d4f4-4577-9ec7-908f2d48622d | DHCP agent | HostA | :-) | False |
| ed96b856-ae0f-4d75-bb28-40a47ffd7695 | Linux bridge agent | HostB | :-) | True |
| f28aa126-6edb-4ea5-a81e-8850876bc0a8 | DHCP agent | HostB | :-) | True |
+--------------------------------------+--------------------+-------+-------+----------------+</computeroutput>
<prompt>$</prompt> <userinput>neutron agent-delete a0c1c21c-d4f4-4577-9ec7-908f2d48622d</userinput>
<computeroutput>Deleted agent: a0c1c21c-d4f4-4577-9ec7-908f2d48622d</computeroutput>
<prompt>$</prompt> <userinput>neutron agent-list</userinput>
<computeroutput>+--------------------------------------+--------------------+-------+-------+----------------+
| id | agent_type | host | alive | admin_state_up |
+--------------------------------------+--------------------+-------+-------+----------------+
| 1b69828d-6a9b-4826-87cd-1757f0e27f31 | Linux bridge agent | HostA | :-) | True |
| ed96b856-ae0f-4d75-bb28-40a47ffd7695 | Linux bridge agent | HostB | :-) | True |
| f28aa126-6edb-4ea5-a81e-8850876bc0a8 | DHCP agent | HostB | :-) | True |
+--------------------------------------+--------------------+-------+-------+----------------+</computeroutput></screen>
<para>After deletion, if you restart the DHCP agent,
it appears on the agent list again.</para>
</step>
</procedure>
</section>
</section>