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Improve chapter "HA using active/passive - The Pacemaker cluster stack"

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Christian Berendt
2014-09-23 21:36:16 +02:00
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doc/high-availability-guide/ch_pacemaker.xml
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@@ -1,34 +1,31 @@
<?xml version="1.0" encoding="UTF-8"?> <?xml version="1.0" encoding="UTF-8"?>
<chapter xmlns="http://docbook.org/ns/docbook" <chapter xmlns="http://docbook.org/ns/docbook"
xmlns:xi="http://www.w3.org/2001/XInclude" xmlns:xi="http://www.w3.org/2001/XInclude"
xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xlink="http://www.w3.org/1999/xlink"
version="5.0" version="5.0"
xml:id="ch-pacemaker"> xml:id="ch-pacemaker">
<title>The Pacemaker cluster stack</title>
<title>The Pacemaker cluster stack</title> <para>OpenStack infrastructure high availability relies on the
<link xlink:href="http://www.clusterlabs.org">Pacemaker</link> cluster
<para>OpenStack infrastructure high availability relies on the stack, the state-of-the-art high availability and load balancing stack
<link xlink:href="http://www.clusterlabs.org">Pacemaker</link> cluster stack, the for the Linux platform. Pacemaker is storage and application-agnostic,
state-of-the-art high availability and load balancing stack for the and is in no way specific to OpenStack.</para>
Linux platform. Pacemaker is storage and application-agnostic, and is <para>Pacemaker relies on the
in no way specific to OpenStack.</para> <link xlink:href="http://www.corosync.org">Corosync</link> messaging
<para>Pacemaker relies on the <link xlink:href="http://www.corosync.org">Corosync</link> messaging layer for reliable cluster communications. Corosync implements the
layer for reliable cluster communications. Corosync implements the Totem single-ring ordering and membership protocol. It also provides
Totem single-ring ordering and membership protocol. It also provides UDP UDP and InfiniBand based messaging, quorum, and cluster membership to
and InfiniBand based messaging, quorum, and cluster membership to Pacemaker.</para>
Pacemaker.</para> <para>Pacemaker interacts with applications through resource agents
<para>Pacemaker interacts with applications through <emphasis>resource agents</emphasis> (RAs), (RAs), of which it supports over 70 natively. Pacemaker can also
of which it supports over 70 natively. Pacemaker can also easily use easily use third-party RAs. An OpenStack high-availability
third-party RAs. An OpenStack high-availability configuration uses configuration uses existing native Pacemaker RAs (such as those
existing native Pacemaker RAs (such as those managing MySQL managing MySQL databases or virtual IP addresses), existing third-party
databases or virtual IP addresses), existing third-party RAs (such as RAs (such as for RabbitMQ), and native OpenStack RAs (such as those
for RabbitMQ), and native OpenStack RAs (such as those managing the managing the OpenStack Identity and Image Services).</para>
OpenStack Identity and Image Services).</para> <xi:include href="pacemaker/section_install_packages.xml"/>
<xi:include href="pacemaker/section_set_up_corosync.xml"/>
<xi:include href="pacemaker/section_install_packages.xml"/> <xi:include href="pacemaker/section_starting_corosync.xml"/>
<xi:include href="pacemaker/section_set_up_corosync.xml"/> <xi:include href="pacemaker/section_start_pacemaker.xml"/>
<xi:include href="pacemaker/section_starting_corosync.xml"/> <xi:include href="pacemaker/section_set_basic_cluster_properties.xml"/>
<xi:include href="pacemaker/section_start_pacemaker.xml"/> </chapter>
<xi:include href="pacemaker/section_set_basic_cluster_properties.xml"/>
</chapter>

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doc/high-availability-guide/pacemaker/section_install_packages.xml
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@@ -1,43 +1,44 @@
<section xmlns="http://docbook.org/ns/docbook" <?xml version="1.0" encoding="UTF-8"?>
<section xmlns="http://docbook.org/ns/docbook"
xmlns:xi="http://www.w3.org/2001/XInclude" xmlns:xi="http://www.w3.org/2001/XInclude"
xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xlink="http://www.w3.org/1999/xlink"
version="5.0" version="5.0"
xml:id="_install_packages"> xml:id="_install_packages">
<title>Install packages</title> <title>Install packages</title>
<para>On any host that is meant to be part of a Pacemaker cluster, you must <para>On any host that is meant to be part of a Pacemaker cluster, you must
first establish cluster communications through the Corosync messaging first establish cluster communications through the Corosync messaging
layer. This involves installing the following packages (and their layer. This involves installing the following packages (and their
dependencies, which your package manager will normally install dependencies, which your package manager will normally install
automatically):</para> automatically):</para>
<itemizedlist> <itemizedlist>
<listitem> <listitem>
<para><literal>pacemaker</literal> (Note that the crm shell should be downloaded separately.) <para><package>pacemaker</package> (Note that the crm shell should be
</para> downloaded separately.)</para>
</listitem> </listitem>
<listitem> <listitem>
<para> <para>
<literal>crmsh</literal> <package>crmsh</package>
</para> </para>
</listitem> </listitem>
<listitem> <listitem>
<para> <para>
<literal>corosync</literal> <package>corosync</package>
</para> </para>
</listitem> </listitem>
<listitem> <listitem>
<para> <para>
<literal>cluster-glue</literal> <package>cluster-glue</package>
</para> </para>
</listitem> </listitem>
<listitem> <listitem>
<para><literal>fence-agents</literal> (Fedora only; all other distributions use fencing <para><package>fence-agents</package> (Fedora only; all other
agents from <literal>cluster-glue</literal>) distributions use fencing agents from
</para> <package>cluster-glue</package>)</para>
</listitem> </listitem>
<listitem> <listitem>
<para> <para>
<literal>resource-agents</literal> <package>resource-agents</package>
</para> </para>
</listitem> </listitem>
</itemizedlist> </itemizedlist>
</section> </section>

92
doc/high-availability-guide/pacemaker/section_set_basic_cluster_properties.xml
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@@ -1,54 +1,54 @@
<section xmlns="http://docbook.org/ns/docbook" <?xml version="1.0" encoding="UTF-8"?>
<section xmlns="http://docbook.org/ns/docbook"
xmlns:xi="http://www.w3.org/2001/XInclude" xmlns:xi="http://www.w3.org/2001/XInclude"
xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xlink="http://www.w3.org/1999/xlink"
version="5.0" version="5.0"
xml:id="_set_basic_cluster_properties"> xml:id="_set_basic_cluster_properties">
<title>Set basic cluster properties</title>
<title>Set basic cluster properties</title> <para>Once your Pacemaker cluster is set up, it is recommended to set a few
basic cluster properties. To do so, start the <command>crm</command> shell
<para>Once your Pacemaker cluster is set up, it is recommended to set a few and change into the configuration menu by entering
basic cluster properties. To do so, start the <literal>crm</literal> shell and change <literal>configure</literal>. Alternatively, you may jump straight into
into the configuration menu by entering the Pacemaker configuration menu by typing <command>crm configure</command>
<literal>configure</literal>. Alternatively, you may jump straight into the Pacemaker directly from a shell prompt.</para>
configuration menu by typing <literal>crm configure</literal> directly from a shell <para>Then, set the following properties:</para>
prompt.</para> <programlisting>property no-quorum-policy="ignore" \ # <co xml:id="CO2-1"/>
<para>Then, set the following properties:</para>
<programlisting>property no-quorum-policy="ignore" \ # <co xml:id="CO2-1"/>
pe-warn-series-max="1000" \ # <co xml:id="CO2-2"/> pe-warn-series-max="1000" \ # <co xml:id="CO2-2"/>
pe-input-series-max="1000" \ pe-input-series-max="1000" \
pe-error-series-max="1000" \ pe-error-series-max="1000" \
cluster-recheck-interval="5min" # <co xml:id="CO2-3"/></programlisting> cluster-recheck-interval="5min" # <co xml:id="CO2-3"/></programlisting>
<calloutlist> <calloutlist>
<callout arearefs="CO2-1"> <callout arearefs="CO2-1">
<para> <para>Setting <option>no-quorum-policy="ignore"</option> is required
Setting <literal>no-quorum-policy="ignore"</literal> is required in 2-node Pacemaker in 2-node Pacemaker clusters for the following reason: if quorum
clusters for the following reason: if quorum enforcement is enabled, enforcement is enabled, and one of the two nodes fails, then the
and one of the two nodes fails, then the remaining node can not remaining node can not establish a majority of quorum votes necessary
establish a <emphasis>majority</emphasis> of quorum votes necessary to run services, and to run services, and thus it is unable to take over any resources. In
thus it is unable to take over any resources. In this case, the appropriate this case, the appropriate workaround is to ignore loss of quorum in
workaround is to ignore loss of quorum in the cluster. This should only <emphasis>only</emphasis> be done in 2-node clusters: do not set this property in the cluster. This should only only be done in 2-node clusters: do not
Pacemaker clusters with more than two nodes. Note that a two-node cluster with this setting exposes a risk of split-brain because either half of the cluster, or both, are able to become active in the event that both nodes remain online but lose communication with one another. The preferred configuration is 3 or more nodes per cluster. set this property in Pacemaker clusters with more than two nodes. Note
</para> that a two-node cluster with this setting exposes a risk of
</callout> split-brain because either half of the cluster, or both, are able to
<callout arearefs="CO2-2"> become active in the event that both nodes remain online but lose
<para> communication with one another. The preferred configuration is 3 or
Setting <literal>pe-warn-series-max</literal>, <literal>pe-input-series-max</literal> and more nodes per cluster.</para>
<literal>pe-error-series-max</literal> to 1000 instructs Pacemaker to keep a longer </callout>
history of the inputs processed, and errors and warnings generated, by <callout arearefs="CO2-2">
its Policy Engine. This history is typically useful in case cluster <para>Setting <option>pe-warn-series-max</option>,
troubleshooting becomes necessary. <option>pe-input-series-max</option> and
</para> <option>pe-error-series-max</option> to 1000 instructs Pacemaker to
</callout> keep a longer history of the inputs processed, and errors and warnings
<callout arearefs="CO2-3"> generated, by its Policy Engine. This history is typically useful in
<para> case cluster troubleshooting becomes necessary.</para>
Pacemaker uses an event-driven approach to cluster state </callout>
processing. However, certain Pacemaker actions occur at a configurable <callout arearefs="CO2-3">
interval, <literal>cluster-recheck-interval</literal>, which defaults to 15 minutes. It <para>Pacemaker uses an event-driven approach to cluster state
is usually prudent to reduce this to a shorter interval, such as 5 or processing. However, certain Pacemaker actions occur at a configurable
3 minutes. interval, <option>cluster-recheck-interval</option>, which defaults to
</para> 15 minutes. It is usually prudent to reduce this to a shorter interval,
</callout> such as 5 or 3 minutes.</para>
</calloutlist> </callout>
<para>Once you have made these changes, you may <literal>commit</literal> the updated </calloutlist>
configuration.</para> <para>Once you have made these changes, you may <literal>commit</literal>
</section> the updated configuration.</para>
</section>

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doc/high-availability-guide/pacemaker/section_set_up_corosync.xml
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@@ -1,21 +1,20 @@
<section xmlns="http://docbook.org/ns/docbook" <?xml version="1.0" encoding="UTF-8"?>
<section xmlns="http://docbook.org/ns/docbook"
xmlns:xi="http://www.w3.org/2001/XInclude" xmlns:xi="http://www.w3.org/2001/XInclude"
xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xlink="http://www.w3.org/1999/xlink"
version="5.0" version="5.0"
xml:id="_set_up_corosync"> xml:id="_set_up_corosync">
<title>Set up Corosync</title> <title>Set up Corosync</title>
<para>Besides installing the <literal>corosync</literal> package, you must also <para>Besides installing the <package>corosync</package> package, you must
create a configuration file, stored in also create a configuration file, stored in
<filename>/etc/corosync/corosync.conf</filename>. Most distributions ship an example <filename>/etc/corosync/corosync.conf</filename>. Most distributions ship
configuration file (<filename>corosync.conf.example</filename>) as part of the an example configuration file (<filename>corosync.conf.example</filename>)
documentation bundled with the <literal>corosync</literal> package. An example Corosync as part of the documentation bundled with the <package>corosync</package>
configuration file is shown below:</para> package. An example Corosync configuration file is shown below:</para>
<formalpara> <formalpara>
<title>Corosync configuration file (<filename>corosync.conf</filename>)</title>
<title>Corosync configuration file (<filename>corosync.conf</filename>)</title> <para>
<programlisting language="ini">totem {
<para>
<programlisting>totem {
version: 2 version: 2
# Time (in ms) to wait for a token <co xml:id="CO1-1"/> # Time (in ms) to wait for a token <co xml:id="CO1-1"/>
@@ -80,87 +79,77 @@ logging {
subsys: AMF subsys: AMF
debug: off debug: off
tags: enter|leave|trace1|trace2|trace3|trace4|trace6 tags: enter|leave|trace1|trace2|trace3|trace4|trace6
} }}</programlisting>
}</programlisting> </para>
</para> </formalpara>
</formalpara> <calloutlist>
<calloutlist> <callout arearefs="CO1-1">
<callout arearefs="CO1-1"> <para>The <option>token</option> value specifies the time, in
<para> milliseconds, during which the Corosync token is expected to be
The <literal>token</literal> value specifies the time, in milliseconds, during transmitted around the ring. When this timeout expires, the token is
which the Corosync token is expected to be transmitted around the declared lost, and after <option>token_retransmits_before_loss_const</option>
ring. When this timeout expires, the token is declared lost, and after lost tokens the non-responding processor (cluster node) is declared
<literal>token_retransmits_before_loss_const</literal> lost tokens the non-responding dead. In other words,
<emphasis>processor</emphasis> (cluster node) is declared dead. In other words, <option>token</option> × <option>token_retransmits_before_loss_const</option>
<literal>token</literal> × <literal>token_retransmits_before_loss_const</literal> is the maximum is the maximum time a node is allowed to not respond to cluster
time a node is allowed to not respond to cluster messages before being messages before being considered dead. The default for
considered dead. The default for <literal>token</literal> is 1000 (1 second), with 4 <option>token</option> is 1000 (1 second), with 4 allowed
allowed retransmits. These defaults are intended to minimize failover retransmits. These defaults are intended to minimize failover times,
times, but can cause frequent "false alarms" and unintended failovers but can cause frequent "false alarms" and unintended failovers in case
in case of short network interruptions. The values used here are of short network interruptions. The values used here are safer, albeit
safer, albeit with slightly extended failover times. with slightly extended failover times.</para>
</para> </callout>
</callout> <callout arearefs="CO1-2">
<callout arearefs="CO1-2"> <para>With <option>secauth</option> enabled, Corosync nodes mutually
<para> authenticate using a 128-byte shared secret stored in
With <literal>secauth</literal> enabled, Corosync nodes mutually authenticate using <filename>/etc/corosync/authkey</filename>, which may be generated with
a 128-byte shared secret stored in <literal>/etc/corosync/authkey</literal>, which may the <command>corosync-keygen</command> utility. When using
be generated with the <literal>corosync-keygen</literal> utility. When using <literal>secauth</literal>, <option>secauth</option>, cluster communications are also
cluster communications are also encrypted. encrypted.</para>
</para> </callout>
</callout> <callout arearefs="CO1-3">
<callout arearefs="CO1-3"> <para>In Corosync configurations using redundant networking (with more
<para> than one <option>interface</option>), you must select a Redundant
In Corosync configurations using redundant networking (with more Ring Protocol (RRP) mode other than <literal>none</literal>.
than one <literal>interface</literal>), you must select a Redundant Ring Protocol (RRP) <literal>active</literal> is the recommended RRP mode.</para>
mode other than <literal>none</literal>. <literal>active</literal> is the recommended RRP mode. </callout>
</para> <callout arearefs="CO1-4">
</callout> <para>There are several things to note about the recommended interface
<callout arearefs="CO1-4"> configuration:</para>
<para> <itemizedlist>
There are several things to note about the recommended interface <listitem>
configuration: <para>The <option>ringnumber</option> must differ between all
</para> configured interfaces, starting with 0.</para>
<itemizedlist> </listitem>
<listitem> <listitem>
<para> <para>The <option>bindnetaddr</option> is the network address of
The <literal>ringnumber</literal> must differ between all configured interfaces, the interfaces to bind to. The example uses two network addresses
starting with 0. of <literal>/24</literal> IPv4 subnets.</para>
</para> </listitem>
</listitem> <listitem>
<listitem> <para>Multicast groups (<option>mcastaddr</option>) must not be
<para> reused across cluster boundaries. In other words, no two distinct
The <literal>bindnetaddr</literal> is the <emphasis>network</emphasis> address of the interfaces to bind clusters should ever use the same multicast group. Be sure to
to. The example uses two network addresses of <literal>/24</literal> IPv4 subnets. select multicast addresses compliant with
</para> <link xlink:href="http://www.ietf.org/rfc/rfc2365.txt">RFC 2365,
</listitem> "Administratively Scoped IP Multicast"</link>.</para>
<listitem> </listitem>
<para> <listitem>
Multicast groups (<literal>mcastaddr</literal>) <emphasis>must not</emphasis> be reused across cluster <para>For firewall configurations, note that Corosync communicates
boundaries. In other words, no two distinct clusters should ever use over UDP only, and uses <literal>mcastport</literal> (for receives)
the same multicast group. Be sure to select multicast addresses and <literal>mcastport - 1</literal> (for sends).</para>
compliant with <link xlink:href="http://www.ietf.org/rfc/rfc2365.txt">RFC 2365, </listitem>
"Administratively Scoped IP Multicast"</link>. </itemizedlist>
</para> </callout>
</listitem> <callout arearefs="CO1-5">
<listitem> <para>The <literal>service</literal> declaration for the
<para> <literal>pacemaker</literal> service may be placed in the
For firewall configurations, note that Corosync communicates over <filename>corosync.conf</filename> file directly, or in its own
UDP only, and uses <literal>mcastport</literal> (for receives) and <literal>mcastport</literal>-1 (for separate file,
sends). <filename>/etc/corosync/service.d/pacemaker</filename>.</para>
</para> </callout>
</listitem> </calloutlist>
</itemizedlist> <para>Once created, the <filename>corosync.conf</filename> file (and the
</callout> <filename>authkey</filename> file if the <option>secauth</option> option
<callout arearefs="CO1-5"> is enabled) must be synchronized across all cluster nodes.</para>
<para> </section>
The <literal>service</literal> declaration for the <literal>pacemaker</literal> service may be
placed in the <filename>corosync.conf</filename> file directly, or in its own separate
file, <filename>/etc/corosync/service.d/pacemaker</filename>.
</para>
</callout>
</calloutlist>
<para>Once created, the <filename>corosync.conf</filename> file (and the <filename>authkey</filename> file if the
<literal>secauth</literal> option is enabled) must be synchronized across all cluster
nodes.</para>
</section>

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doc/high-availability-guide/pacemaker/section_start_pacemaker.xml
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@@ -1,34 +1,40 @@
<section xmlns="http://docbook.org/ns/docbook" <?xml version="1.0" encoding="UTF-8"?>
<section xmlns="http://docbook.org/ns/docbook"
xmlns:xi="http://www.w3.org/2001/XInclude" xmlns:xi="http://www.w3.org/2001/XInclude"
xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xlink="http://www.w3.org/1999/xlink"
version="5.0" version="5.0"
xml:id="_start_pacemaker"> xml:id="_start_pacemaker">
<title>Start Pacemaker</title> <title>Start Pacemaker</title>
<para>Once the Corosync services have been started and you have established <para>Once the Corosync services have been started and you have established
that the cluster is communicating properly, it is safe to start that the cluster is communicating properly, it is safe to start
<literal>pacemakerd</literal>, the Pacemaker master control process:</para> <systemitem class="service">pacemakerd</systemitem>, the Pacemaker
<itemizedlist> master control process:</para>
<listitem> <itemizedlist>
<para><literal>/etc/init.d/pacemaker start</literal> (LSB) <listitem>
</para> <para>
</listitem> <command>/etc/init.d/pacemaker start</command> (LSB)
<listitem> </para>
<para><literal>service pacemaker start</literal> (LSB, alternate) </listitem>
</para> <listitem>
</listitem> <para>
<listitem> <command>service pacemaker start</command> (LSB, alternate)
<para><literal>start pacemaker</literal> (upstart) </para>
</para> </listitem>
</listitem> <listitem>
<listitem> <para>
<para><literal>systemctl start pacemaker</literal> (systemd) <command>start pacemaker</command> (upstart)
</para> </para>
</listitem> </listitem>
</itemizedlist> <listitem>
<para>Once Pacemaker services have started, Pacemaker will create a default <para>
empty cluster configuration with no resources. You may observe <command>systemctl start pacemaker</command> (systemd)
Pacemaker’s status with the <literal>crm_mon</literal> utility:</para> </para>
<screen><computeroutput>============ </listitem>
</itemizedlist>
<para>Once Pacemaker services have started, Pacemaker will create a default
empty cluster configuration with no resources. You may observe
Pacemaker's status with the <command>crm_mon</command> utility:</para>
<screen><computeroutput>============
Last updated: Sun Oct 7 21:07:52 2012 Last updated: Sun Oct 7 21:07:52 2012
Last change: Sun Oct 7 20:46:00 2012 via cibadmin on node2 Last change: Sun Oct 7 20:46:00 2012 via cibadmin on node2
Stack: openais Stack: openais
@@ -39,4 +45,4 @@ Version: 1.1.6-9971ebba4494012a93c03b40a2c58ec0eb60f50c
============ ============
Online: [ node2 node1 ]</computeroutput></screen> Online: [ node2 node1 ]</computeroutput></screen>
</section> </section>

80
doc/high-availability-guide/pacemaker/section_starting_corosync.xml
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@@ -1,38 +1,42 @@
<section xmlns="http://docbook.org/ns/docbook" <?xml version="1.0" encoding="UTF-8"?>
<section xmlns="http://docbook.org/ns/docbook"
xmlns:xi="http://www.w3.org/2001/XInclude" xmlns:xi="http://www.w3.org/2001/XInclude"
xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xlink="http://www.w3.org/1999/xlink"
version="5.0" version="5.0"
xml:id="_starting_corosync"> xml:id="_starting_corosync">
<title>Starting Corosync</title>
<title>Starting Corosync</title> <para>Corosync is started as a regular system service. Depending on your
distribution, it may ship with an LSB init script, an
<para>Corosync is started as a regular system service. Depending on your upstart job, or a systemd unit file. Either way, the service is
distribution, it may ship with an LSB init script, an usually named <systemitem class="service">corosync</systemitem>:</para>
upstart job, or a systemd unit file. Either way, the service is <itemizedlist>
usually named <literal>corosync</literal>:</para> <listitem>
<itemizedlist> <para>
<listitem> <command>/etc/init.d/corosync start</command> (LSB)
<para><literal>/etc/init.d/corosync start</literal> (LSB) </para>
</para> </listitem>
</listitem> <listitem>
<listitem> <para>
<para><literal>service corosync start</literal> (LSB, alternate) <command>service corosync start</command> (LSB, alternate)
</para> </para>
</listitem> </listitem>
<listitem> <listitem>
<para><literal>start corosync</literal> (upstart) <para>
</para> <command>start corosync</command> (upstart)
</listitem> </para>
<listitem> </listitem>
<para><literal>systemctl start corosync</literal> (systemd) <listitem>
</para> <para>
</listitem> <command>systemctl start corosync</command> (systemd)
</itemizedlist> </para>
<para>You can now check the Corosync connectivity with two tools.</para> </listitem>
<para>The <literal>corosync-cfgtool</literal> utility, when invoked with the <literal>-s</literal> option, </itemizedlist>
gives a summary of the health of the communication rings:</para> <para>You can now check the Corosync connectivity with two tools.</para>
<screen><prompt>#</prompt> <userinput>corosync-cfgtool -s</userinput> <para>The <command>corosync-cfgtool</command> utility, when invoked with
<computeroutput>Printing ring status. the <option>-s</option> option, gives a summary of the health of the
communication rings:</para>
<screen><prompt>#</prompt> <userinput>corosync-cfgtool -s</userinput>
<computeroutput>Printing ring status.
Local node ID 435324542 Local node ID 435324542
RING ID 0 RING ID 0
id = 192.168.42.82 id = 192.168.42.82
@@ -40,15 +44,15 @@ RING ID 0
RING ID 1 RING ID 1
id = 10.0.42.100 id = 10.0.42.100
status = ring 1 active with no faults</computeroutput></screen> status = ring 1 active with no faults</computeroutput></screen>
<para>The <literal>corosync-objctl</literal> utility can be used to dump the Corosync cluster <para>The <command>corosync-objctl</command> utility can be used to dump the
member list:</para> Corosync cluster member list:</para>
<screen><prompt>#</prompt> <userinput>corosync-objctl runtime.totem.pg.mrp.srp.members</userinput> <screen><prompt>#</prompt> <userinput>corosync-objctl runtime.totem.pg.mrp.srp.members</userinput>
<computeroutput>runtime.totem.pg.mrp.srp.435324542.ip=r(0) ip(192.168.42.82) r(1) ip(10.0.42.100) <computeroutput>runtime.totem.pg.mrp.srp.435324542.ip=r(0) ip(192.168.42.82) r(1) ip(10.0.42.100)
runtime.totem.pg.mrp.srp.435324542.join_count=1 runtime.totem.pg.mrp.srp.435324542.join_count=1
runtime.totem.pg.mrp.srp.435324542.status=joined runtime.totem.pg.mrp.srp.435324542.status=joined
runtime.totem.pg.mrp.srp.983895584.ip=r(0) ip(192.168.42.87) r(1) ip(10.0.42.254) runtime.totem.pg.mrp.srp.983895584.ip=r(0) ip(192.168.42.87) r(1) ip(10.0.42.254)
runtime.totem.pg.mrp.srp.983895584.join_count=1 runtime.totem.pg.mrp.srp.983895584.join_count=1
runtime.totem.pg.mrp.srp.983895584.status=joined</computeroutput></screen> runtime.totem.pg.mrp.srp.983895584.status=joined</computeroutput></screen>
<para>You should see a <literal>status=joined</literal> entry for each of your constituent <para>You should see a <literal>status=joined</literal> entry for each of
cluster nodes.</para> your constituent cluster nodes.</para>
</section> </section>