Pacemaker Remote Quick Start #

Install and set up a basic two-node cluster as described in Kurzanleitung zur Installation und Einrichtung. This leads to a two-node cluster with two physical hosts, alice and bob.

On a physical host (charlie) that you want to use as remote node, install SUSE Linux Enterprise Server 15 SP6 and add SUSE Linux Enterprise High Availability 15 SP6 as extension. However, do not install the High Availability installation pattern, because the remote node needs only individual packages (see Section 3.3).

On all cluster nodes, check /etc/hosts and add an entry for charlie.

Create a specific authentication key for the pacemaker_remote service:

# dd if=/dev/urandom of=/etc/pacemaker/authkey bs=4k count=1

The key for the pacemaker_remote service is different from the cluster authentication key that you create in the YaST cluster module.

Synchronize the authentication key among all cluster nodes and your future remote node with scp:

# scp -r -p /etc/pacemaker/ bob:/etc
# scp -r -p /etc/pacemaker/ charlie:/etc

The key needs to be kept synchronized all the time.

On charlie, proceed as follows:

1. In the firewall settings, open the TCP port 3121 for pacemaker_remote.

2. Install the pacemaker-remote and crmsh packages:

   # zypper in pacemaker-remote crmsh

3. Enable and start the pacemaker_remote service on charlie:

   # systemctl enable pacemaker_remote
   # systemctl start pacemaker_remote

On alice or bob, verify the host connection to the remote node by using ssh:

# ssh -p 3121 charlie

This SSH connection fails, but how it fails shows if the setup is working:

If needed, add more remote nodes and configure them as described above.

Make sure the cluster services are already started on all the cluster nodes. If not, run the following command to start the cluster services on all nodes:

# crm cluster start --all

On node alice, create a ocf:pacemaker:remote primitive:

# crm configure
crm(live)configure# primitive charlie ocf:pacemaker:remote \
     params server=charlie reconnect_interval=15m \
     op monitor interval=30s
crm(live)configure# commit
crm(live)configure# quit

Check the status of the cluster with the command crm status. It should contain a running cluster with nodes that are all accessible:

# crm status
[...]
Online: [ alice bob ]
RemoteOnline: [ charlie ]

Full list of resources:
charlie (ocf:pacemaker:remote): Started alice
 [...]

Install and set up a basic two-node cluster as described in the Kurzanleitung zur Installation und Einrichtung. This leads to a two-node cluster with two physical hosts, alice and bob.

Create a KVM guest on alice. For details, see the Virtualization Guide for SUSE Linux Enterprise Server 15 SP6.

On the KVM guest (doro) that you want to use as guest node, install SUSE Linux Enterprise Server 15 SP6 and add SUSE Linux Enterprise High Availability 15 SP6 as extension. However, do not install the High Availability installation pattern, because the remote node needs only individual packages (see Section 4.3).

On all cluster nodes, check /etc/hosts and add an entry for doro.

Create a specific authentication key for the pacemaker_remote service:

# mkdir -p --mode=0755 /etc/pacemaker
# dd if=/dev/urandom of=/etc/pacemaker/authkey bs=4k count=1

The key for the pacemaker_remote service is different from the cluster authentication key that you create in the YaST cluster module.

Synchronize the authentication key among all cluster nodes and your guest node with scp:

# scp -r -p /etc/pacemaker/ bob:/etc
# scp -p /etc/pacemaker/ doro:/etc

The key needs to be kept synchronized all the time.

On doro, proceed as follows:

1. In the firewall settings, open the TCP port 3121 for pacemaker_remote.

2. Install the pacemaker-remote and crmsh packages:

   # zypper in pacemaker-remote crmsh

3. Enable and start the pacemaker_remote service on alice:

   # systemctl enable pacemaker_remote
   # systemctl start pacemaker_remote

On alice or bob, verify the host connection to the guest by running ssh:

# ssh -p 3121 doro

This SSH connection fails, but how it fails shows if the setup is working:

If needed, add more guest nodes and configure them as described above.

Shut down the guest node and proceed with Section 4.4, “Integrating a guest node into the cluster”.

Make sure the cluster services are already started on all the cluster nodes. If not, run the following command to start the cluster services on all nodes:

# crm cluster start --all

Dump the XML configuration of the KVM guest that you need in the next step:

# virsh list --all
 Id    Name         State
-----------------------------------
 -     doro       shut off
# virsh dumpxml doro > /etc/pacemaker/doro.xml

On node alice, create a VirtualDomain resource to launch the virtual machine. Use the dumped configuration from Step 2:

# crm configure
crm(live)configure# primitive vm-doro ocf:heartbeat:VirtualDomain \
  params hypervisor="qemu:///system" \
         config="/etc/pacemaker/doro.xml" \
         meta remote-node=doro

Pacemaker automatically monitors pacemaker_remote connections for failure, so it is not necessary to create a recurring monitor on the VirtualDomain resource.

Tip: Enabling live migration

To enable live migration of the resource, set the meta attribute allow-migrate to true. The default is false.

Check the status of the cluster with the command crm status. It should contain a running cluster with nodes that are all accessible.

Create a dummy resource:

# crm configure primitive fake1 ocf:pacemaker:Dummy

Check the cluster status with the crm status command. You should see something like the following:

# crm status
[...]
Online: [ alice bob ]
GuestOnline: [ doro@alice ]

Full list of resources:
vm-doro (ocf:heartbeat:VirtualDomain): Started alice
fake1           (ocf:pacemaker:Dummy): Started bob

To move the Dummy primitive to the guest node (doro), use the following command:

# crm resource move fake1 doro

The status changes to this:

# crm status
[...]
Online: [ alice bob ]
GuestOnline: [ doro@alice ]

Full list of resources:
vm-doro (ocf:heartbeat:VirtualDomain): Started alice
fake1           (ocf:pacemaker:Dummy): Started doro

To test whether fencing works, kill the pacemaker-remoted daemon on doro:

# kill -9 $(pidof pacemaker-remoted)

After a few seconds, check the status of the cluster again. It should look like this:

# crm status
[...]
Online: [ alice bob ]

Full list of resources:
vm-doro (ocf::heartbeat:VirtualDomain): Started alice
fake1           (ocf:pacemaker:Dummy): Stopped

Failed Actions:
* doro_monitor_30000 on alice 'unknown error' (1): call=8, status=Error, exitreason='none',
    last-rc-change='Tue Jul 18 13:11:51 2017', queued=0ms, exec=0ms