openstack-manuals/doc/admin-guide-network/app_demo_multi_dhcp_agents.xml
Diane Fleming 64b6c9261e Folder rename, file rename, flattening of directories
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bug: #1220407

Change-Id: Id5ffc774b966ba7b9a591743a877aa10ab3094c7
author: diane fleming
2013-09-08 15:15:50 -07:00

542 lines
33 KiB
XML

<?xml version="1.0" encoding="UTF-8"?>
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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>
<informalfigure>
<mediaobject>
<imageobject>
<imagedata fileref="figures/demo_multiple_dhcp_agents.png" contentwidth="6in"/>
</imageobject>
</mediaobject>
</informalfigure>
<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>Runs the Neutron service, Keystone and all of the Nova services that are
required to deploy VMs. The node must have at least one network interface,
this should be connected to the "Management Network".
<emphasis role="bold">Note</emphasis>
<systemitem class="service">nova-network</systemitem>
should not be running since it is replaced by
Neutron.</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>
<para>
<itemizedlist>
<listitem>
<para><emphasis role="bold">controlnode - Neutron Server</emphasis></para><orderedlist>
<listitem>
<para>Neutron configuration file
<filename>/etc/neutron/neutron.conf</filename>:
</para>
<screen><computeroutput>[DEFAULT]
core_plugin = neutron.plugins.linuxbridge.lb_neutron_plugin.LinuxBridgePluginV2
rabbit_host = controlnode
allow_overlapping_ips = True
host = controlnode
agent_down_time = 5
</computeroutput></screen>
</listitem>
<listitem>
<para>Update the plugin configuration file <filename
>/etc/neutron/plugins/linuxbridge/linuxbridge_conf.ini</filename>:
</para>
<screen><computeroutput>[vlans]
tenant_network_type = vlan
network_vlan_ranges = physnet1:1000:2999
[database]
sql_connection = mysql://root:root@127.0.0.1:3306/neutron_linux_bridge
reconnect_interval = 2
[linux_bridge]
physical_interface_mappings = physnet1:eth0
</computeroutput></screen>
</listitem>
</orderedlist>
</listitem>
<listitem>
<para><emphasis role="bold">HostA and HostB - L2 Agent</emphasis></para>
<orderedlist>
<listitem>
<para>Neutron configuration file <filename
>/etc/neutron/neutron.conf</filename>:
</para>
<screen><computeroutput>[DEFAULT]
rabbit_host = controlnode
rabbit_password = openstack
# host = HostB on hostb
host = HostA
</computeroutput></screen>
</listitem>
<listitem>
<para>Update the plugin configuration file <filename
>/etc/neutron/plugins/linuxbridge/linuxbridge_conf.ini</filename>:
</para>
<screen><computeroutput>[vlans]
tenant_network_type = vlan
network_vlan_ranges = physnet1:1000:2999
[database]
sql_connection = mysql://root:root@127.0.0.1:3306/neutron_linux_bridge
reconnect_interval = 2
[linux_bridge]
physical_interface_mappings = physnet1:eth0</computeroutput></screen>
</listitem>
<listitem>
<para>Update the nova configuration
file <filename
>/etc/nova/nova.conf</filename>:
</para>
<screen><computeroutput>[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
</computeroutput></screen>
</listitem>
</orderedlist>
</listitem>
<listitem>
<para><emphasis role="bold">HostA and HostB - DHCP Agent</emphasis></para><orderedlist>
<listitem>
<para>Update the DHCP configuration file <filename
>/etc/neutron/dhcp_agent.ini</filename>:
</para>
<screen><computeroutput>[DEFAULT]
interface_driver = neutron.agent.linux.interface.BridgeInterfaceDriver
</computeroutput></screen>
</listitem>
</orderedlist>
</listitem></itemizedlist>
</para>
</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>Please ensure that the following environment variables are set.
These are used by the various clients to access
Keystone.</para>
<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>
</para></note>
<para>
<itemizedlist>
<listitem>
<para><emphasis role="bold">Settings</emphasis></para>
<para>We need some VMs and a neutron network to experiment. Here they
are:</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>$</prompt> <userinput>neutron net-list</userinput>
<computeroutput>+--------------------------------------+------+--------------------------------------+
| id | name | subnets |
+--------------------------------------+------+--------------------------------------+
| 89dca1c6-c7d4-4f7a-b730-549af0fb6e34 | net1 | f6c832e3-9968-46fd-8e45-d5cf646db9d1 |
+--------------------------------------+------+--------------------------------------+</computeroutput></screen>
</listitem>
<listitem>
<para><emphasis role="bold">Manage agents in neutron
deployment</emphasis></para>
<para>Every agent which supports these extensions will register itself with the
neutron server when it starts up.</para>
<orderedlist>
<listitem>
<para>List all agents:</para>
<screen><prompt>$</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>Just as shown, we have four agents now, and they have reported
their state. The <literal>'alive'</literal> will be
<literal>':-)'</literal> if the agent reported its state within
the period defined by the option
<literal>'agent_down_time'</literal> in neutron server's
neutron.conf. Otherwise the <literal>'alive'</literal> is
<literal>'xxx'</literal>.</para>
</listitem>
<listitem>
<para>List the DHCP agents hosting a given network</para>
<para>In some deployments, one DHCP
agent is not enough to hold all the
network data. In addition, we should
have backup for it even when the
deployment is small one. The same
network can be assigned to more than one
DHCP agent and one DHCP agent can host
more than one network. Let's first go
with command that lists DHCP agents
hosting a given network.</para>
<screen><prompt>$</prompt> <userinput>neutron dhcp-agent-list-hosting-net net1</userinput>
<computeroutput>+--------------------------------------+-------+----------------+-------+
| id | host | admin_state_up | alive |
+--------------------------------------+-------+----------------+-------+
| a0c1c21c-d4f4-4577-9ec7-908f2d48622d | HostA | True | :-) |
+--------------------------------------+-------+----------------+-------+
</computeroutput></screen>
</listitem>
<listitem>
<para>List the networks hosted by a
given DHCP agent.</para>
<para>This command is to show which networks a given dhcp agent is managing.</para>
<screen><prompt>$</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>
</listitem>
<listitem>
<para>Show the agent detail
information.</para>
<para>The <command>agent-list</command> command
gives very general information about
agents. To obtain the detailed
information of an agent, we can use
<command>agent-show</command>.</para>
<screen><prompt>$</prompt> <userinput>neutron agent-show a0c1c21c-d4f4-4577-9ec7-908f2d48622d</userinput>
<computeroutput>+---------------------+----------------------------------------------------------+
| Field | Value |
+---------------------+----------------------------------------------------------+
| admin_state_up | True |
| agent_type | DHCP agent |
| alive | False |
| binary | neutron-dhcp-agent |
| configurations | { |
| | "subnets": 1, |
| | "use_namespaces": true, |
| | "dhcp_driver": "neutron.agent.linux.dhcp.Dnsmasq", |
| | "networks": 1, |
| | "dhcp_lease_time": 120, |
| | "ports": 3 |
| | } |
| created_at | 2013-03-16T01:16:18.000000 |
| description | |
| heartbeat_timestamp | 2013-03-17T01:37:22.000000 |
| host | HostA |
| id | 58f4ce07-6789-4bb3-aa42-ed3779db2b03 |
| started_at | 2013-03-16T06:48:39.000000 |
| topic | dhcp_agent |
+---------------------+----------------------------------------------------------+
</computeroutput></screen>
<para>In the above output, <literal>'heartbeat_timestamp'</literal>
is the time on neutron server. So we don't need all agents synced to
neutron server's time for this extension to run well.
<literal>'configurations'</literal> is about the agent's static
configuration or run time data. We can see that this agent is a DHCP
agent, and it is hosting one network, one subnet and 3 ports.</para>
<para>Different type of agents has different detail. Below is information for
a <literal>'Linux bridge agent'</literal></para>
<screen><prompt>$</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>Just as shown, we can see bridge-mapping and the number of VM's virtual network devices on this L2 agent.</para>
</listitem>
</orderedlist>
</listitem>
<listitem>
<para><emphasis role="bold">Manage assignment of networks to DHCP agent</emphasis>
</para>
<para>We have shown
<command>net-list-on-dhcp-agent</command> and
<command>dhcp-agent-list-hosting-net</command>
commands. Now let's look at how to add a network
to a DHCP agent and remove one from it.
</para>
<orderedlist>
<listitem>
<para>Default scheduling.</para>
<para>When a network is created and one port is created on it, we
will try to schedule it to an active
DHCP agent. If there are many active
DHCP agents, we select one randomly.
(We can design more sophisticated
scheduling algorithm just like we do
in nova-schedule later.)</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>We can see it is allocated to DHCP agent on HostA.
If we want to validate the behavior via <command>dnsmasq</command>,
don't forget to create a subnet for the network
since DHCP agent starts the dnsmasq service only if
there is a DHCP enabled subnet on it.</para>
</listitem>
<listitem>
<para>Assign a network to a given DHCP
agent.</para>
<para>We have two DHCP agents, and we want another DHCP agent to host the network too.</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>We can see both DHCP agents are hosting <literal>'net2'</literal> network.
</para>
</listitem>
<listitem>
<para>Remove a network from a given
DHCP agent.</para>
<para>This command is the sibling
command for the previous one.
Let's remove <literal>'net2'</literal> from HostA's DHCP
agent.</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>We can see now only HostB's DHCP agent is hosting <literal>'net2'</literal> network.</para>
</listitem>
</orderedlist>
</listitem>
<listitem>
<para><emphasis role="bold">HA of DHCP agents</emphasis></para>
<para>First we will boot a VM on net2, then we let both DHCP agents host <literal>'net2'</literal>.
After that, we fail the agents in turn and to see if
the VM can still get the wanted IP during that time.</para>
<orderedlist>
<listitem>
<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>$</prompt> <userinput>nova list</userinput>
<computeroutput>+--------------------------------------+-----------+--------+---------------+
| ID | Name | Status | Networks |
+--------------------------------------+-----------+--------+---------------+
| c394fcd0-0baa-43ae-a793-201815c3e8ce | myserver1 | ACTIVE | net1=10.0.1.3 |
| 2d604e05-9a6c-4ddb-9082-8a1fbdcc797d | myserver2 | ACTIVE | net1=10.0.1.4 |
| c7c0481c-3db8-4d7a-a948-60ce8211d585 | myserver3 | ACTIVE | net1=10.0.1.5 |
| f62f4731-5591-46b1-9d74-f0c901de567f | myserver4 | ACTIVE | net2=9.0.1.2 |
+--------------------------------------+-----------+--------+---------------+
</computeroutput></screen>
</listitem>
<listitem>
<para>Make sure both DHCP agents
hosting 'net2'.</para>
<para>We can use commands shown before to assign the network to agents.
</para>
<screen><prompt>$</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>
</listitem>
<listitem>
<procedure>
<title>To 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 (Beside stopping the
<code>neutron-dhcp-agent</code> binary, we must make sure dnsmasq processes are
gone too.)
</para>
</step>
<step>
<para>Run a DHCP client in VM. We can see it can get the wanted IP.
</para>
</step>
<step>
<para>Stop the DHCP agent on HostB too.</para>
</step>
<step>
<para>Run
<literal>'udhcpc'</literal> in
VM. We can see it cannot get the
wanted IP.
</para>
</step>
<step>
<para>Start DHCP agent on HostB. We can see VM can get the wanted IP again.
</para>
</step>
</procedure>
</listitem>
</orderedlist>
</listitem>
<listitem>
<para>Disable and remove an agent</para>
<para>An admin user wants to disable an
agent if there is a system upgrade
planned, whatever hardware or software. Some
agents which support scheduling support
disable or enable too, such as L3 agent and
DHCP agent. Once the agent is disabled,
the scheduler will not schedule new resources
to the agent. After the agent is
disabled, we can remove the agent safely.
We should remove the resources on
the agent before we delete the agent
itself.</para>
<para>To run the commands below, we need first 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 we restart
the DHCP agent, it will be on agent list
again.</para>
</listitem>
</itemizedlist>
</para>
</section>
</section>