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diff --git a/doc/sphinx/Pacemaker_Remote/baremetal-tutorial.rst b/doc/sphinx/Pacemaker_Remote/baremetal-tutorial.rst
index a35933d7a5..b1ccb24d77 100644
--- a/doc/sphinx/Pacemaker_Remote/baremetal-tutorial.rst
+++ b/doc/sphinx/Pacemaker_Remote/baremetal-tutorial.rst
@@ -1,331 +1,331 @@
Remote Node Walk-through
------------------------
**What this tutorial is:** An in-depth walk-through of how to get Pacemaker to
integrate a remote node into the cluster as a node capable of running cluster
resources.
**What this tutorial is not:** A realistic deployment scenario. The steps shown
here are meant to get users familiar with the concept of remote nodes as
quickly as possible.
This tutorial requires three machines: two to act as cluster nodes, and
a third to act as the remote node.
Configure Remote Node
#####################
Configure Firewall on Remote Node
_________________________________
Allow cluster-related services through the local firewall:
-::
+.. code-block:: none
# firewall-cmd --permanent --add-service=high-availability
success
# firewall-cmd --reload
success
.. NOTE::
If you are using iptables directly, or some other firewall solution besides
firewalld, simply open the following ports, which can be used by various
clustering components: TCP ports 2224, 3121, and 21064, and UDP port 5405.
If you run into any problems during testing, you might want to disable
the firewall and SELinux entirely until you have everything working.
This may create significant security issues and should not be performed on
machines that will be exposed to the outside world, but may be appropriate
during development and testing on a protected host.
To disable security measures:
- ::
+ .. code-block:: none
# setenforce 0
# sed -i.bak "s/SELINUX=enforcing/SELINUX=permissive/g" /etc/selinux/config
# systemctl mask firewalld.service
# systemctl stop firewalld.service
# iptables --flush
Configure pacemaker_remote on Remote Node
_________________________________________
Install the pacemaker_remote daemon on the remote node.
-::
+.. code-block:: none
# yum install -y pacemaker-remote resource-agents pcs
Create a location for the shared authentication key:
-::
+.. code-block:: none
# mkdir -p --mode=0750 /etc/pacemaker
# chgrp haclient /etc/pacemaker
All nodes (both cluster nodes and remote nodes) must have the same
authentication key installed for the communication to work correctly.
If you already have a key on an existing node, copy it to the new
remote node. Otherwise, create a new key, for example:
-::
+.. code-block:: none
# dd if=/dev/urandom of=/etc/pacemaker/authkey bs=4096 count=1
Now start and enable the pacemaker_remote daemon on the remote node.
-::
+.. code-block:: none
# systemctl enable pacemaker_remote.service
# systemctl start pacemaker_remote.service
Verify the start is successful.
-::
+.. code-block:: none
# systemctl status pacemaker_remote
pacemaker_remote.service - Pacemaker Remote Service
Loaded: loaded (/usr/lib/systemd/system/pacemaker_remote.service; enabled)
Active: active (running) since Fri 2018-01-12 15:21:20 CDT; 20s ago
Main PID: 21273 (pacemaker_remot)
CGroup: /system.slice/pacemaker_remote.service
└─21273 /usr/sbin/pacemaker-remoted
Jan 12 15:21:20 remote1 systemd[1]: Starting Pacemaker Remote Service...
Jan 12 15:21:20 remote1 systemd[1]: Started Pacemaker Remote Service.
Jan 12 15:21:20 remote1 pacemaker-remoted[21273]: notice: crm_add_logfile: Additional logging available in /var/log/pacemaker.log
Jan 12 15:21:20 remote1 pacemaker-remoted[21273]: notice: lrmd_init_remote_tls_server: Starting a tls listener on port 3121.
Jan 12 15:21:20 remote1 pacemaker-remoted[21273]: notice: bind_and_listen: Listening on address ::
Verify Connection to Remote Node
################################
Before moving forward, it's worth verifying that the cluster nodes
can contact the remote node on port 3121. Here's a trick you can use.
Connect using ssh from each of the cluster nodes. The connection will get
destroyed, but how it is destroyed tells you whether it worked or not.
First, add the remote node's hostname (we're using **remote1** in this tutorial)
to the cluster nodes' ``/etc/hosts`` files if you haven't already. This
is required unless you have DNS set up in a way where remote1's address can be
discovered.
Execute the following on each cluster node, replacing the IP address with the
actual IP address of the remote node.
-::
+.. code-block:: none
# cat << END >> /etc/hosts
192.168.122.10 remote1
END
If running the ssh command on one of the cluster nodes results in this
output before disconnecting, the connection works:
-::
+.. code-block:: none
# ssh -p 3121 remote1
ssh_exchange_identification: read: Connection reset by peer
If you see one of these, the connection is not working:
-::
+.. code-block:: none
# ssh -p 3121 remote1
ssh: connect to host remote1 port 3121: No route to host
-::
+.. code-block:: none
# ssh -p 3121 remote1
ssh: connect to host remote1 port 3121: Connection refused
Once you can successfully connect to the remote node from the both
cluster nodes, move on to setting up Pacemaker on the cluster nodes.
Configure Cluster Nodes
#######################
Configure Firewall on Cluster Nodes
___________________________________
On each cluster node, allow cluster-related services through the local
firewall, following the same procedure as in `Configure Firewall on Remote Node`_.
Install Pacemaker on Cluster Nodes
__________________________________
On the two cluster nodes, install the following packages.
-::
+.. code-block:: none
# yum install -y pacemaker corosync pcs resource-agents
Copy Authentication Key to Cluster Nodes
________________________________________
Create a location for the shared authentication key,
and copy it from any existing node:
-::
+.. code-block:: none
# mkdir -p --mode=0750 /etc/pacemaker
# chgrp haclient /etc/pacemaker
# scp remote1:/etc/pacemaker/authkey /etc/pacemaker/authkey
Configure Corosync on Cluster Nodes
___________________________________
Corosync handles Pacemaker's cluster membership and messaging. The corosync
config file is located in ``/etc/corosync/corosync.conf``. That config file must be
initialized with information about the two cluster nodes before pacemaker can
start.
To initialize the corosync config file, execute the following pcs command on
both nodes, filling in the information in <> with your nodes' information.
-::
+.. code-block:: none
# pcs cluster setup --force --local --name mycluster <node1 ip or hostname> <node2 ip or hostname>
Start Pacemaker on Cluster Nodes
________________________________
Start the cluster stack on both cluster nodes using the following command.
-::
+.. code-block:: none
# pcs cluster start
Verify corosync membership
-::
+.. code-block:: none
# pcs status corosync
Membership information
----------------------
Nodeid Votes Name
1 1 node1 (local)
Verify Pacemaker status. At first, the ``pcs cluster status`` output will look
like this.
-::
+.. code-block:: none
# pcs status
Cluster name: mycluster
Stack: corosync
Current DC: NONE
Last updated: Fri Jan 12 16:14:05 2018
Last change: Fri Jan 12 14:02:14 2018
1 node configured
0 resources configured
After about a minute, you should see your two cluster nodes come online.
-::
+.. code-block:: none
# pcs status
Cluster name: mycluster
Stack: corosync
Current DC: node1 (version 1.1.16-12.el7_4.5-94ff4df) - partition with quorum
Last updated: Fri Jan 12 16:16:32 2018
Last change: Fri Jan 12 14:02:14 2018
2 nodes configured
0 resources configured
Online: [ node1 node2 ]
For the sake of this tutorial, we are going to disable stonith to avoid having
to cover fencing device configuration.
-::
+.. code-block:: none
# pcs property set stonith-enabled=false
Integrate Remote Node into Cluster
##################################
Integrating a remote node into the cluster is achieved through the
creation of a remote node connection resource. The remote node connection
resource both establishes the connection to the remote node and defines that
the remote node exists. Note that this resource is actually internal to
Pacemaker's controller. A metadata file for this resource can be found in
the ``/usr/lib/ocf/resource.d/pacemaker/remote`` file that describes what options
are available, but there is no actual **ocf:pacemaker:remote** resource agent
script that performs any work.
Define the remote node connection resource to our remote node,
**remote1**, using the following command on any cluster node.
-::
+.. code-block:: none
# pcs resource create remote1 ocf:pacemaker:remote
That's it. After a moment you should see the remote node come online.
-::
+.. code-block:: none
Cluster name: mycluster
Stack: corosync
Current DC: node1 (version 1.1.16-12.el7_4.5-94ff4df) - partition with quorum
Last updated: Fri Jan 12 17:13:09 2018
Last change: Fri Jan 12 17:02:02 2018
3 nodes configured
1 resources configured
Online: [ node1 node2 ]
RemoteOnline: [ remote1 ]
Full list of resources:
remote1 (ocf::pacemaker:remote): Started node1
Daemon Status:
corosync: active/disabled
pacemaker: active/disabled
pcsd: active/enabled
Starting Resources on Remote Node
#################################
Once the remote node is integrated into the cluster, starting resources on a
remote node is the exact same as on cluster nodes. Refer to the
`Clusters from Scratch <http://clusterlabs.org/doc/>`_ document for examples of
resource creation.
.. WARNING::
Never involve a remote node connection resource in a resource group,
colocation constraint, or order constraint.
Fencing Remote Nodes
####################
Remote nodes are fenced the same way as cluster nodes. No special
considerations are required. Configure fencing resources for use with
remote nodes the same as you would with cluster nodes.
Note, however, that remote nodes can never 'initiate' a fencing action. Only
cluster nodes are capable of actually executing a fencing operation against
another node.
Accessing Cluster Tools from a Remote Node
##########################################
Besides allowing the cluster to manage resources on a remote node,
pacemaker_remote has one other trick. The pacemaker_remote daemon allows
nearly all the pacemaker tools (``crm_resource``, ``crm_mon``,
``crm_attribute``, ``crm_master``, etc.) to work on remote nodes natively.
Try it: Run ``crm_mon`` on the remote node after pacemaker has
integrated it into the cluster. These tools just work. These means resource
agents such as promotable resources (which need access to tools like
``crm_master``) work seamlessly on the remote nodes.
Higher-level command shells such as ``pcs`` may have partial support
on remote nodes, but it is recommended to run them from a cluster node.
diff --git a/doc/sphinx/Pacemaker_Remote/example.rst b/doc/sphinx/Pacemaker_Remote/example.rst
index 0ac65b03d0..196fc01746 100644
--- a/doc/sphinx/Pacemaker_Remote/example.rst
+++ b/doc/sphinx/Pacemaker_Remote/example.rst
@@ -1,130 +1,134 @@
Guest Node Quick Example
------------------------
If you already know how to use Pacemaker, you'll likely be able to grasp this
new concept of guest nodes by reading through this quick example without
having to sort through all the detailed walk-through steps. Here are the key
configuration ingredients that make this possible using libvirt and KVM virtual
guests. These steps strip everything down to the very basics.
+.. index::
+ single: guest node
+ pair: node; guest node
+
Mile-High View of Configuration Steps
#####################################
* Give each virtual machine that will be used as a guest node a static network
address and unique hostname.
* Put the same authentication key with the path ``/etc/pacemaker/authkey`` on
every cluster node and virtual machine. This secures remote communication.
Run this command if you want to make a somewhat random key:
- ::
+ .. code-block:: none
# dd if=/dev/urandom of=/etc/pacemaker/authkey bs=4096 count=1
* Install pacemaker_remote on every virtual machine, enabling it to start at
boot, and if a local firewall is used, allow the node to accept connections
on TCP port 3121.
- ::
+ .. code-block:: none
# yum install pacemaker-remote resource-agents
# systemctl enable pacemaker_remote
# firewall-cmd --add-port 3121/tcp --permanent
.. NOTE::
If you just want to see this work, you may want to simply disable the local
firewall and put SELinux in permissive mode while testing. This creates
security risks and should not be done on a production machine exposed to the
Internet, but can be appropriate for a protected test machine.
* Create a Pacemaker resource to launch each virtual machine, using the
**remote-node** meta-attribute to let Pacemaker know this will be a
guest node capable of running resources.
- ::
+ .. code-block:: none
# pcs resource create vm-guest1 VirtualDomain hypervisor="qemu:///system" config="vm-guest1.xml" meta remote-node="guest1"
The above command will create CIB XML similar to the following:
.. code-block:: xml
<primitive class="ocf" id="vm-guest1" provider="heartbeat" type="VirtualDomain">
<instance_attributes id="vm-guest-instance_attributes">
<nvpair id="vm-guest1-instance_attributes-hypervisor" name="hypervisor" value="qemu:///system"/>
<nvpair id="vm-guest1-instance_attributes-config" name="config" value="guest1.xml"/>
</instance_attributes>
<operations>
<op id="vm-guest1-interval-30s" interval="30s" name="monitor"/>
</operations>
<meta_attributes id="vm-guest1-meta_attributes">
<nvpair id="vm-guest1-meta_attributes-remote-node" name="remote-node" value="guest1"/>
</meta_attributes>
</primitive>
In the example above, the meta-attribute **remote-node="guest1"** tells Pacemaker
that this resource is a guest node with the hostname **guest1**. The cluster will
attempt to contact the virtual machine's pacemaker_remote service at the
hostname **guest1** after it launches.
.. NOTE::
The ID of the resource creating the virtual machine (**vm-guest1** in the above
example) 'must' be different from the virtual machine's uname (**guest1** in the
above example). Pacemaker will create an implicit internal resource for the
pacemaker_remote connection to the guest, named with the value of **remote-node**,
so that value cannot be used as the name of any other resource.
Using a Guest Node
==================
Guest nodes will show up in ``crm_mon`` output as normal. For example, this is the
``crm_mon`` output after **guest1** is integrated into the cluster:
-::
+.. code-block:: none
Stack: corosync
Current DC: node1 (version 1.1.16-12.el7_4.5-94ff4df) - partition with quorum
Last updated: Fri Jan 12 13:52:39 2018
Last change: Fri Jan 12 13:25:17 2018 via pacemaker-controld on node1
2 nodes configured
2 resources configured
Online: [ node1 guest1]
vm-guest1 (ocf::heartbeat:VirtualDomain): Started node1
Now, you could place a resource, such as a webserver, on **guest1**:
-::
+.. code-block:: none
# pcs resource create webserver apache params configfile=/etc/httpd/conf/httpd.conf op monitor interval=30s
# pcs constraint location webserver prefers guest1
Now, the crm_mon output would show:
-::
+.. code-block:: none
Stack: corosync
Current DC: node1 (version 1.1.16-12.el7_4.5-94ff4df) - partition with quorum
Last updated: Fri Jan 12 13:52:39 2018
Last change: Fri Jan 12 13:25:17 2018 via pacemaker-controld on node1
2 nodes configured
2 resources configured
Online: [ node1 guest1]
vm-guest1 (ocf::heartbeat:VirtualDomain): Started node1
webserver (ocf::heartbeat::apache): Started guest1
It is worth noting that after **guest1** is integrated into the cluster, nearly all the
Pacemaker command-line tools immediately become available to the guest node.
This means things like ``crm_mon``, ``crm_resource``, and ``crm_attribute`` will work
natively on the guest node, as long as the connection between the guest node
and a cluster node exists. This is particularly important for any promotable
clone resources executing on the guest node that need access to ``crm_master`` to
set transient attributes.
diff --git a/doc/sphinx/Pacemaker_Remote/intro.rst b/doc/sphinx/Pacemaker_Remote/intro.rst
index bb0ef5088e..903fbeea4d 100644
--- a/doc/sphinx/Pacemaker_Remote/intro.rst
+++ b/doc/sphinx/Pacemaker_Remote/intro.rst
@@ -1,163 +1,186 @@
Scaling a Pacemaker Cluster
---------------------------
Overview
########
In a basic Pacemaker high-availability cluster [#]_ each node runs the full
cluster stack of corosync and all Pacemaker components. This allows great
flexibility but limits scalability to around 16 nodes.
To allow for scalability to dozens or even hundreds of nodes, Pacemaker
allows nodes not running the full cluster stack to integrate into the cluster
and have the cluster manage their resources as if they were a cluster node.
Terms
#####
**cluster node**
A node running the full high-availability stack of corosync and all
Pacemaker components. Cluster nodes may run cluster resources, run
all Pacemaker command-line tools (``crm_mon``, ``crm_resource`` and so on),
execute fencing actions, count toward cluster quorum, and serve as the
cluster's Designated Controller (DC).
+ .. index::
+ single: cluster node
+ pair: node; cluster node
+
**pacemaker_remote**
A small service daemon that allows a host to be used as a Pacemaker node
without running the full cluster stack. Nodes running pacemaker_remote
may run cluster resources and most command-line tools, but cannot perform
other functions of full cluster nodes such as fencing execution, quorum
voting or DC eligibility. The pacemaker_remote daemon is an enhanced
version of Pacemaker's local resource management daemon (LRMD).
+ .. index::
+ single: pacemaker_remote
+
**remote node**
A physical host running pacemaker_remote. Remote nodes have a special
resource that manages communication with the cluster. This is sometimes
referred to as the 'baremetal' case.
+ .. index::
+ single: remote node
+ pair: node; remote node
+
**guest node**
A virtual host running pacemaker_remote. Guest nodes differ from remote
nodes mainly in that the guest node is itself a resource that the cluster
manages.
+ .. index::
+ single: guest node
+ pair: node; guest node
+
.. NOTE::
'Remote' in this document refers to the node not being a part of the underlying
corosync cluster. It has nothing to do with physical proximity. Remote nodes
and guest nodes are subject to the same latency requirements as cluster nodes,
which means they are typically in the same data center.
.. NOTE::
It is important to distinguish the various roles a virtual machine can serve
in Pacemaker clusters:
* A virtual machine can run the full cluster stack, in which case it is a
cluster node and is not itself managed by the cluster.
* A virtual machine can be managed by the cluster as a resource, without the
cluster having any awareness of the services running inside the virtual
machine. The virtual machine is 'opaque' to the cluster.
* A virtual machine can be a cluster resource, and run pacemaker_remote
to make it a guest node, allowing the cluster to manage services
inside it. The virtual machine is 'transparent' to the cluster.
Guest Nodes
###########
+.. index::
+ single: guest node
+ pair: node; guest node
+
**"I want a Pacemaker cluster to manage virtual machine resources, but I also
want Pacemaker to be able to manage the resources that live within those
virtual machines."**
Without pacemaker_remote, the possibilities for implementing the above use case
have significant limitations:
* The cluster stack could be run on the physical hosts only, which loses the
ability to monitor resources within the guests.
* A separate cluster could be on the virtual guests, which quickly hits
scalability issues.
* The cluster stack could be run on the guests using the same cluster as the
physical hosts, which also hits scalability issues and complicates fencing.
With pacemaker_remote:
* The physical hosts are cluster nodes (running the full cluster stack).
* The virtual machines are guest nodes (running the pacemaker_remote service).
Nearly zero configuration is required on the virtual machine.
* The cluster stack on the cluster nodes launches the virtual machines and
immediately connects to the pacemaker_remote service on them, allowing the
virtual machines to integrate into the cluster.
The key difference here between the guest nodes and the cluster nodes is that
the guest nodes do not run the cluster stack. This means they will never become
the DC, initiate fencing actions or participate in quorum voting.
On the other hand, this also means that they are not bound to the scalability
limits associated with the cluster stack (no 16-node corosync member limits to
deal with). That isn't to say that guest nodes can scale indefinitely, but it
is known that guest nodes scale horizontally much further than cluster nodes.
Other than the quorum limitation, these guest nodes behave just like cluster
nodes with respect to resource management. The cluster is fully capable of
managing and monitoring resources on each guest node. You can build constraints
against guest nodes, put them in standby, or do whatever else you'd expect to
be able to do with cluster nodes. They even show up in ``crm_mon`` output as
nodes.
To solidify the concept, below is an example that is very similar to an actual
deployment we test in our developer environment to verify guest node scalability:
* 16 cluster nodes running the full corosync + pacemaker stack
* 64 Pacemaker-managed virtual machine resources running pacemaker_remote configured as guest nodes
* 64 Pacemaker-managed webserver and database resources configured to run on the 64 guest nodes
With this deployment, you would have 64 webservers and databases running on 64
virtual machines on 16 hardware nodes, all of which are managed and monitored by
the same Pacemaker deployment. It is known that pacemaker_remote can scale to
these lengths and possibly much further depending on the specific scenario.
Remote Nodes
############
+.. index::
+ single: remote node
+ pair: node; remote node
+
**"I want my traditional high-availability cluster to scale beyond the limits
imposed by the corosync messaging layer."**
Ultimately, the primary advantage of remote nodes over cluster nodes is
scalability. There are likely some other use cases related to geographically
distributed HA clusters that remote nodes may serve a purpose in, but those use
cases are not well understood at this point.
Like guest nodes, remote nodes will never become the DC, initiate
fencing actions or participate in quorum voting.
That is not to say, however, that fencing of a remote node works any
differently than that of a cluster node. The Pacemaker scheduler
understands how to fence remote nodes. As long as a fencing device exists, the
cluster is capable of ensuring remote nodes are fenced in the exact same way as
cluster nodes.
Expanding the Cluster Stack
###########################
With pacemaker_remote, the traditional view of the high-availability stack can
be expanded to include a new layer:
Traditional HA Stack
____________________
.. image:: images/pcmk-ha-cluster-stack.png
:width: 17cm
:height: 9cm
:alt: Traditional Pacemaker+Corosync Stack
:align: center
HA Stack With Guest Nodes
_________________________
.. image:: images/pcmk-ha-remote-stack.png
:width: 20cm
:height: 10cm
:alt: Pacemaker+Corosync Stack with pacemaker_remote
:align: center
.. [#] See the `<http://www.clusterlabs.org/doc/>`_ Pacemaker documentation,
especially 'Clusters From Scratch' and 'Pacemaker Explained'.
diff --git a/doc/sphinx/Pacemaker_Remote/kvm-tutorial.rst b/doc/sphinx/Pacemaker_Remote/kvm-tutorial.rst
index b429aa5a65..82b7e61982 100644
--- a/doc/sphinx/Pacemaker_Remote/kvm-tutorial.rst
+++ b/doc/sphinx/Pacemaker_Remote/kvm-tutorial.rst
@@ -1,614 +1,614 @@
Guest Node Walk-through
-----------------------
**What this tutorial is:** An in-depth walk-through of how to get Pacemaker to
manage a KVM guest instance and integrate that guest into the cluster as a
guest node.
**What this tutorial is not:** A realistic deployment scenario. The steps shown
here are meant to get users familiar with the concept of guest nodes as quickly
as possible.
Configure the Physical Host
###########################
.. NOTE::
For this example, we will use a single physical host named **example-host**.
A production cluster would likely have multiple physical hosts, in which case
you would run the commands here on each one, unless noted otherwise.
Configure Firewall on Host
__________________________
On the physical host, allow cluster-related services through the local firewall:
-::
+.. code-block:: none
# firewall-cmd --permanent --add-service=high-availability
success
# firewall-cmd --reload
success
.. NOTE::
If you are using iptables directly, or some other firewall solution besides
firewalld, simply open the following ports, which can be used by various
clustering components: TCP ports 2224, 3121, and 21064, and UDP port 5405.
If you run into any problems during testing, you might want to disable
the firewall and SELinux entirely until you have everything working.
This may create significant security issues and should not be performed on
machines that will be exposed to the outside world, but may be appropriate
during development and testing on a protected host.
To disable security measures:
- ::
+ .. code-block:: none
[root@pcmk-1 ~]# setenforce 0
[root@pcmk-1 ~]# sed -i.bak "s/SELINUX=enforcing/SELINUX=permissive/g" /etc/selinux/config
[root@pcmk-1 ~]# systemctl mask firewalld.service
[root@pcmk-1 ~]# systemctl stop firewalld.service
[root@pcmk-1 ~]# iptables --flush
Install Cluster Software
________________________
-::
+.. code-block:: none
# yum install -y pacemaker corosync pcs resource-agents
Configure Corosync
__________________
Corosync handles pacemaker's cluster membership and messaging. The corosync
config file is located in ``/etc/corosync/corosync.conf``. That config file must
be initialized with information about the cluster nodes before pacemaker can
start.
To initialize the corosync config file, execute the following ``pcs`` command,
replacing the cluster name and hostname as desired:
-::
+.. code-block:: none
# pcs cluster setup --force --local --name mycluster example-host
.. NOTE::
If you have multiple physical hosts, you would execute the setup command on
only one host, but list all of them at the end of the command.
Configure Pacemaker for Remote Node Communication
_________________________________________________
Create a place to hold an authentication key for use with pacemaker_remote:
-::
+.. code-block:: none
# mkdir -p --mode=0750 /etc/pacemaker
# chgrp haclient /etc/pacemaker
Generate a key:
-::
+.. code-block:: none
# dd if=/dev/urandom of=/etc/pacemaker/authkey bs=4096 count=1
.. NOTE::
If you have multiple physical hosts, you would generate the key on only one
host, and copy it to the same location on all hosts.
Verify Cluster Software
_______________________
Start the cluster
-::
+.. code-block:: none
# pcs cluster start
Verify corosync membership
-::
+.. code-block:: none
# pcs status corosync
Membership information
----------------------
Nodeid Votes Name
1 1 example-host (local)
Verify pacemaker status. At first, the output will look like this:
-::
+.. code-block:: none
# pcs status
Cluster name: mycluster
WARNING: no stonith devices and stonith-enabled is not false
Stack: corosync
Current DC: NONE
Last updated: Fri Jan 12 15:18:32 2018
Last change: Fri Jan 12 12:42:21 2018 by root via cibadmin on example-host
1 node configured
0 resources configured
Node example-host: UNCLEAN (offline)
No active resources
Daemon Status:
corosync: active/disabled
pacemaker: active/disabled
pcsd: active/enabled
After a short amount of time, you should see your host as a single node in the
cluster:
-::
+.. code-block:: none
# pcs status
Cluster name: mycluster
WARNING: no stonith devices and stonith-enabled is not false
Stack: corosync
Current DC: example-host (version 1.1.16-12.el7_4.5-94ff4df) - partition WITHOUT quorum
Last updated: Fri Jan 12 15:20:05 2018
Last change: Fri Jan 12 12:42:21 2018 by root via cibadmin on example-host
1 node configured
0 resources configured
Online: [ example-host ]
No active resources
Daemon Status:
corosync: active/disabled
pacemaker: active/disabled
pcsd: active/enabled
Disable STONITH and Quorum
__________________________
Now, enable the cluster to work without quorum or stonith. This is required
for the sake of getting this tutorial to work with a single cluster node.
-::
+.. code-block:: none
# pcs property set stonith-enabled=false
# pcs property set no-quorum-policy=ignore
.. WARNING::
The use of ``stonith-enabled=false`` is completely inappropriate for a production
cluster. It tells the cluster to simply pretend that failed nodes are safely
powered off. Some vendors will refuse to support clusters that have STONITH
disabled. We disable STONITH here only to focus the discussion on
pacemaker_remote, and to be able to use a single physical host in the example.
Now, the status output should look similar to this:
-::
+.. code-block:: none
# pcs status
Cluster name: mycluster
Stack: corosync
Current DC: example-host (version 1.1.16-12.el7_4.5-94ff4df) - partition with quorum
Last updated: Fri Jan 12 15:22:49 2018
Last change: Fri Jan 12 15:22:46 2018 by root via cibadmin on example-host
1 node configured
0 resources configured
Online: [ example-host ]
No active resources
Daemon Status:
corosync: active/disabled
pacemaker: active/disabled
pcsd: active/enabled
Go ahead and stop the cluster for now after verifying everything is in order.
-::
+.. code-block:: none
# pcs cluster stop --force
Install Virtualization Software
_______________________________
-::
+.. code-block:: none
# yum install -y kvm libvirt qemu-system qemu-kvm bridge-utils virt-manager
# systemctl enable libvirtd.service
Reboot the host.
.. NOTE::
While KVM is used in this example, any virtualization platform with a Pacemaker
resource agent can be used to create a guest node. The resource agent needs
only to support usual commands (start, stop, etc.); Pacemaker implements the
**remote-node** meta-attribute, independent of the agent.
Configure the KVM guest
#######################
Create Guest
____________
We will not outline here the installation steps required to create a KVM
guest. There are plenty of tutorials available elsewhere that do that.
Just be sure to configure the guest with a hostname and a static IP address
(as an example here, we will use guest1 and 192.168.122.10).
Configure Firewall on Guest
___________________________
On each guest, allow cluster-related services through the local firewall,
following the same procedure as in `Configure Firewall on Host`_.
Verify Connectivity
___________________
At this point, you should be able to ping and ssh into guests from hosts, and
vice versa.
Configure pacemaker_remote
__________________________
Install pacemaker_remote, and enable it to run at start-up. Here, we also
install the pacemaker package; it is not required, but it contains the dummy
resource agent that we will use later for testing.
-::
+.. code-block:: none
# yum install -y pacemaker pacemaker-remote resource-agents
# systemctl enable pacemaker_remote.service
Copy the authentication key from a host:
-::
+.. code-block:: none
# mkdir -p --mode=0750 /etc/pacemaker
# chgrp haclient /etc/pacemaker
# scp root@example-host:/etc/pacemaker/authkey /etc/pacemaker
Start pacemaker_remote, and verify the start was successful:
-::
+.. code-block:: none
# systemctl start pacemaker_remote
# systemctl status pacemaker_remote
pacemaker_remote.service - Pacemaker Remote Service
Loaded: loaded (/usr/lib/systemd/system/pacemaker_remote.service; enabled)
Active: active (running) since Thu 2013-03-14 18:24:04 EDT; 2min 8s ago
Main PID: 1233 (pacemaker_remot)
CGroup: name=systemd:/system/pacemaker_remote.service
└─1233 /usr/sbin/pacemaker-remoted
Mar 14 18:24:04 guest1 systemd[1]: Starting Pacemaker Remote Service...
Mar 14 18:24:04 guest1 systemd[1]: Started Pacemaker Remote Service.
Mar 14 18:24:04 guest1 pacemaker-remoted[1233]: notice: lrmd_init_remote_tls_server: Starting a tls listener on port 3121.
Verify Host Connection to Guest
_______________________________
Before moving forward, it's worth verifying that the host can contact the guest
on port 3121. Here's a trick you can use. Connect using ssh from the host. The
connection will get destroyed, but how it is destroyed tells you whether it
worked or not.
First add guest1 to the host machine's +/etc/hosts+ file if you haven't
already. This is required unless you have DNS setup in a way where guest1's
address can be discovered.
-::
+.. code-block:: none
# cat << END >> /etc/hosts
192.168.122.10 guest1
END
If running the ssh command on one of the cluster nodes results in this
output before disconnecting, the connection works:
-::
+.. code-block:: none
# ssh -p 3121 guest1
ssh_exchange_identification: read: Connection reset by peer
If you see one of these, the connection is not working:
-::
+.. code-block:: none
# ssh -p 3121 guest1
ssh: connect to host guest1 port 3121: No route to host
-::
+.. code-block:: none
# ssh -p 3121 guest1
ssh: connect to host guest1 port 3121: Connection refused
Once you can successfully connect to the guest from the host, shutdown the guest. Pacemaker will be managing the virtual machine from this point forward.
Integrate Guest into Cluster
############################
Now the fun part, integrating the virtual machine you've just created into the cluster. It is incredibly simple.
Start the Cluster
_________________
On the host, start pacemaker.
-::
+.. code-block:: none
# pcs cluster start
Wait for the host to become the DC. The output of ``pcs status`` should look
as it did in `Disable Stonith and Quorum`_.
Integrate as Guest Node
_______________________
If you didn't already do this earlier in the verify host to guest connection
section, add the KVM guest's IP address to the host's ``/etc/hosts`` file so we
can connect by hostname. For this example:
-::
+.. code-block:: none
# cat << END >> /etc/hosts
192.168.122.10 guest1
END
We will use the **VirtualDomain** resource agent for the management of the
virtual machine. This agent requires the virtual machine's XML config to be
dumped to a file on disk. To do this, pick out the name of the virtual machine
you just created from the output of this list.
-::
+.. code-block:: none
# virsh list --all
Id Name State
----------------------------------------------------
- guest1 shut off
In my case I named it guest1. Dump the xml to a file somewhere on the host using the following command.
-::
+.. code-block:: none
# virsh dumpxml guest1 > /etc/pacemaker/guest1.xml
Now just register the resource with pacemaker and you're set!
-::
+.. code-block:: none
# pcs resource create vm-guest1 VirtualDomain hypervisor="qemu:///system" \
config="/etc/pacemaker/guest1.xml" meta remote-node=guest1
.. NOTE::
This example puts the guest XML under /etc/pacemaker because the
permissions and SELinux labeling should not need any changes.
If you run into trouble with this or any step, try disabling SELinux
with ``setenforce 0``. If it works after that, see SELinux documentation
for how to troubleshoot, if you wish to reenable SELinux.
.. NOTE::
Pacemaker will automatically monitor pacemaker_remote connections for failure,
so it is not necessary to create a recurring monitor on the VirtualDomain
resource.
Once the **vm-guest1** resource is started you will see **guest1** appear in the
``pcs status`` output as a node. The final ``pcs status`` output should look
something like this.
-::
+.. code-block:: none
# pcs status
Cluster name: mycluster
Stack: corosync
Current DC: example-host (version 1.1.16-12.el7_4.5-94ff4df) - partition with quorum
Last updated: Fri Jan 12 18:00:45 2018
Last change: Fri Jan 12 17:53:44 2018 by root via crm_resource on example-host
2 nodes configured
2 resources configured
Online: [ example-host ]
GuestOnline: [ guest1@example-host ]
Full list of resources:
vm-guest1 (ocf::heartbeat:VirtualDomain): Started example-host
Daemon Status:
corosync: active/disabled
pacemaker: active/disabled
pcsd: active/enabled
Starting Resources on KVM Guest
_______________________________
The commands below demonstrate how resources can be executed on both the
guest node and the cluster node.
Create a few Dummy resources. Dummy resources are real resource agents used
just for testing purposes. They actually execute on the host they are assigned
to just like an apache server or database would, except their execution just
means a file was created. When the resource is stopped, that the file it
created is removed.
-::
+.. code-block:: none
# pcs resource create FAKE1 ocf:pacemaker:Dummy
# pcs resource create FAKE2 ocf:pacemaker:Dummy
# pcs resource create FAKE3 ocf:pacemaker:Dummy
# pcs resource create FAKE4 ocf:pacemaker:Dummy
# pcs resource create FAKE5 ocf:pacemaker:Dummy
Now check your ``pcs status`` output. In the resource section, you should see
something like the following, where some of the resources started on the
cluster node, and some started on the guest node.
-::
+.. code-block:: none
Full list of resources:
vm-guest1 (ocf::heartbeat:VirtualDomain): Started example-host
FAKE1 (ocf::pacemaker:Dummy): Started guest1
FAKE2 (ocf::pacemaker:Dummy): Started guest1
FAKE3 (ocf::pacemaker:Dummy): Started example-host
FAKE4 (ocf::pacemaker:Dummy): Started guest1
FAKE5 (ocf::pacemaker:Dummy): Started example-host
The guest node, **guest1**, reacts just like any other node in the cluster. For
example, pick out a resource that is running on your cluster node. For my
purposes, I am picking FAKE3 from the output above. We can force FAKE3 to run
on **guest1** in the exact same way we would any other node.
-::
+.. code-block:: none
# pcs constraint location FAKE3 prefers guest1
Now, looking at the bottom of the `pcs status` output you'll see FAKE3 is on
**guest1**.
-::
+.. code-block:: none
Full list of resources:
vm-guest1 (ocf::heartbeat:VirtualDomain): Started example-host
FAKE1 (ocf::pacemaker:Dummy): Started guest1
FAKE2 (ocf::pacemaker:Dummy): Started guest1
FAKE3 (ocf::pacemaker:Dummy): Started guest1
FAKE4 (ocf::pacemaker:Dummy): Started example-host
FAKE5 (ocf::pacemaker:Dummy): Started example-host
Testing Recovery and Fencing
____________________________
Pacemaker's scheduler is smart enough to know fencing guest nodes
associated with a virtual machine means shutting off/rebooting the virtual
machine. No special configuration is necessary to make this happen. If you
are interested in testing this functionality out, trying stopping the guest's
pacemaker_remote daemon. This would be equivalent of abruptly terminating a
cluster node's corosync membership without properly shutting it down.
ssh into the guest and run this command.
-::
+.. code-block:: none
# kill -9 $(pidof pacemaker-remoted)
Within a few seconds, your ``pcs status`` output will show a monitor failure,
and the **guest1** node will not be shown while it is being recovered.
-::
+.. code-block:: none
# pcs status
Cluster name: mycluster
Stack: corosync
Current DC: example-host (version 1.1.16-12.el7_4.5-94ff4df) - partition with quorum
Last updated: Fri Jan 12 18:08:35 2018
Last change: Fri Jan 12 18:07:00 2018 by root via cibadmin on example-host
2 nodes configured
7 resources configured
Online: [ example-host ]
Full list of resources:
vm-guest1 (ocf::heartbeat:VirtualDomain): Started example-host
FAKE1 (ocf::pacemaker:Dummy): Stopped
FAKE2 (ocf::pacemaker:Dummy): Stopped
FAKE3 (ocf::pacemaker:Dummy): Stopped
FAKE4 (ocf::pacemaker:Dummy): Started example-host
FAKE5 (ocf::pacemaker:Dummy): Started example-host
Failed Actions:
* guest1_monitor_30000 on example-host 'unknown error' (1): call=8, status=Error, exitreason='none',
last-rc-change='Fri Jan 12 18:08:29 2018', queued=0ms, exec=0ms
Daemon Status:
corosync: active/disabled
pacemaker: active/disabled
pcsd: active/enabled
.. NOTE::
A guest node involves two resources: the one you explicitly configured creates the guest,
and Pacemaker creates an implicit resource for the pacemaker_remote connection, which
will be named the same as the value of the **remote-node** attribute of the explicit resource.
When we killed pacemaker_remote, it is the implicit resource that failed, which is why
the failed action starts with **guest1** and not **vm-guest1**.
Once recovery of the guest is complete, you'll see it automatically get
re-integrated into the cluster. The final ``pcs status`` output should look
something like this.
-::
+.. code-block:: none
Cluster name: mycluster
Stack: corosync
Current DC: example-host (version 1.1.16-12.el7_4.5-94ff4df) - partition with quorum
Last updated: Fri Jan 12 18:18:30 2018
Last change: Fri Jan 12 18:07:00 2018 by root via cibadmin on example-host
2 nodes configured
7 resources configured
Online: [ example-host ]
GuestOnline: [ guest1@example-host ]
Full list of resources:
vm-guest1 (ocf::heartbeat:VirtualDomain): Started example-host
FAKE1 (ocf::pacemaker:Dummy): Started guest1
FAKE2 (ocf::pacemaker:Dummy): Started guest1
FAKE3 (ocf::pacemaker:Dummy): Started guest1
FAKE4 (ocf::pacemaker:Dummy): Started example-host
FAKE5 (ocf::pacemaker:Dummy): Started example-host
Failed Actions:
* guest1_monitor_30000 on example-host 'unknown error' (1): call=8, status=Error, exitreason='none',
last-rc-change='Fri Jan 12 18:08:29 2018', queued=0ms, exec=0ms
Daemon Status:
corosync: active/disabled
pacemaker: active/disabled
pcsd: active/enabled
Normally, once you've investigated and addressed a failed action, you can clear the
failure. However Pacemaker does not yet support cleanup for the implicitly
created connection resource while the explicit resource is active. If you want
to clear the failed action from the status output, stop the guest resource before
clearing it. For example:
-::
+.. code-block:: none
# pcs resource disable vm-guest1 --wait
# pcs resource cleanup guest1
# pcs resource enable vm-guest1
Accessing Cluster Tools from Guest Node
_______________________________________
Besides allowing the cluster to manage resources on a guest node,
pacemaker_remote has one other trick. The pacemaker_remote daemon allows
nearly all the pacemaker tools (``crm_resource``, ``crm_mon``, ``crm_attribute``,
``crm_master``, etc.) to work on guest nodes natively.
Try it: Run ``crm_mon`` on the guest after pacemaker has
integrated the guest node into the cluster. These tools just work. This
means resource agents such as promotable resources (which need access to tools
like ``crm_master``) work seamlessly on the guest nodes.
Higher-level command shells such as ``pcs`` may have partial support
on guest nodes, but it is recommended to run them from a cluster node.
diff --git a/doc/sphinx/Pacemaker_Remote/options.rst b/doc/sphinx/Pacemaker_Remote/options.rst
index 1487bc4b07..a62fe91883 100644
--- a/doc/sphinx/Pacemaker_Remote/options.rst
+++ b/doc/sphinx/Pacemaker_Remote/options.rst
@@ -1,131 +1,134 @@
Configuration Explained
-----------------------
The walk-through examples use some of these options, but don't explain exactly
what they mean or do. This section is meant to be the go-to resource for all
the options available for configuring pacemaker_remote-based nodes.
+.. index::
+ single: configuration
+
Resource Meta-Attributes for Guest Nodes
########################################
When configuring a virtual machine as a guest node, the virtual machine is
created using one of the usual resource agents for that purpose (for example,
ocf:heartbeat:VirtualDomain or ocf:heartbeat:Xen), with additional metadata
parameters.
No restrictions are enforced on what agents may be used to create a guest node,
but obviously the agent must create a distinct environment capable of running
the pacemaker_remote daemon and cluster resources. An additional requirement is
that fencing the host running the guest node resource must be sufficient for
ensuring the guest node is stopped. This means, for example, that not all
hypervisors supported by VirtualDomain may be used to create guest nodes; if
the guest can survive the hypervisor being fenced, it may not be used as a
guest node.
Below are the metadata options available to enable a resource as a guest node
and define its connection parameters.
.. table:: Meta-attributes for configuring VM resources as guest nodes
+------------------------+-----------------+-----------------------------------------------------------+
| Option | Default | Description |
+========================+=================+===========================================================+
| remote-node | none | The node name of the guest node this resource defines. |
| | | This both enables the resource as a guest node and |
| | | defines the unique name used to identify the guest node. |
| | | If no other parameters are set, this value will also be |
| | | assumed as the hostname to use when connecting to |
| | | pacemaker_remote on the VM. This value **must not** |
| | | overlap with any resource or node IDs. |
+------------------------+-----------------+-----------------------------------------------------------+
| remote-port | 3121 | The port on the virtual machine that the cluster will |
| | | use to connect to pacemaker_remote. |
+------------------------+-----------------+-----------------------------------------------------------+
| remote-addr | 'value of' | The IP address or hostname to use when connecting to |
| | ``remote-node`` | pacemaker_remote on the VM. |
+------------------------+-----------------+-----------------------------------------------------------+
| remote-connect-timeout | 60s | How long before a pending guest connection will time out. |
+------------------------+-----------------+-----------------------------------------------------------+
Connection Resources for Remote Nodes
#####################################
A remote node is defined by a connection resource. That connection resource
has instance attributes that define where the remote node is located on the
network and how to communicate with it.
Descriptions of these instance attributes can be retrieved using the following
``pcs`` command:
-::
+.. code-block:: none
# pcs resource describe remote
ocf:pacemaker:remote - remote resource agent
Resource options:
server: Server location to connect to. This can be an ip address or hostname.
port: tcp port to connect to.
reconnect_interval: Interval in seconds at which Pacemaker will attempt to
reconnect to a remote node after an active connection to
the remote node has been severed. When this value is
nonzero, Pacemaker will retry the connection
indefinitely, at the specified interval.
When defining a remote node's connection resource, it is common and recommended
to name the connection resource the same as the remote node's hostname. By
default, if no **server** option is provided, the cluster will attempt to contact
the remote node using the resource name as the hostname.
Example defining a remote node with the hostname **remote1**:
-::
+.. code-block:: none
# pcs resource create remote1 remote
Example defining a remote node to connect to a specific IP address and port:
-::
+.. code-block:: none
# pcs resource create remote1 remote server=192.168.122.200 port=8938
Environment Variables for Daemon Start-up
#########################################
Authentication and encryption of the connection between cluster nodes
and nodes running pacemaker_remote is achieved using
with `TLS-PSK <https://en.wikipedia.org/wiki/TLS-PSK>`_ encryption/authentication
over TCP (port 3121 by default). This means that both the cluster node and
remote node must share the same private key. By default, this
key is placed at ``/etc/pacemaker/authkey`` on each node.
You can change the default port and/or key location for Pacemaker and
pacemaker_remote via environment variables. How these variables are set varies
by OS, but usually they are set in the ``/etc/sysconfig/pacemaker`` or
``/etc/default/pacemaker`` file.
-::
+.. code-block:: none
#==#==# Pacemaker Remote
# Use a custom directory for finding the authkey.
PCMK_authkey_location=/etc/pacemaker/authkey
#
# Specify a custom port for Pacemaker Remote connections
PCMK_remote_port=3121
Removing Remote Nodes and Guest Nodes
#####################################
If the resource creating a guest node, or the **ocf:pacemaker:remote** resource
creating a connection to a remote node, is removed from the configuration, the
affected node will continue to show up in output as an offline node.
If you want to get rid of that output, run (replacing $NODE_NAME appropriately):
-::
+.. code-block:: none
# crm_node --force --remove $NODE_NAME
.. WARNING::
Be absolutely sure that there are no references to the node's resource in the
configuration before running the above command.

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