diff --git a/doc/sphinx/Pacemaker_Remote/kvm-tutorial.rst b/doc/sphinx/Pacemaker_Remote/kvm-tutorial.rst index 210af8021a..8b9202ed92 100644 --- a/doc/sphinx/Pacemaker_Remote/kvm-tutorial.rst +++ b/doc/sphinx/Pacemaker_Remote/kvm-tutorial.rst @@ -1,623 +1,684 @@ .. index:: single: guest node; walk-through 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 + # pcs cluster setup 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 + + WARNINGS: + No stonith devices and stonith-enabled is not false + + Cluster Summary: + * Stack: corosync + * Current DC: pcmk-2 (version 2.0.5-8.el8-ba59be7122) - partition with quorum + * Last updated: Tue Mar 2 14:32:02 2021 + * Last change: Tue Mar 2 14:32:01 2021 by hacluster via crmd on pcmk-2 + * 1 node configured + * 0 resource instances configured + + Node List: + * Node example-host: UNCLEAN (offline) + + Full List of Resources: + * No 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 + + WARNINGS: + No stonith devices and stonith-enabled is not false + + Cluster Summary: + * Stack: corosync + * Current DC: pcmk-2 (version 2.0.5-8.el8-ba59be7122) - partition with quorum + * Last updated: Tue Mar 2 14:35:12 2021 + * Last change: Tue Mar 2 14:35:11 2021 by hacluster via crmd on pcmk-2 + * 1 node configured + * 0 resource instances configured + + Node List: + * Online: [ example-host ] + + Full List of Resources: + * No 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 + Cluster Summary: + * Stack: corosync + * Current DC: pcmk-2 (version 2.0.5-8.el8-ba59be7122) - partition with quorum + * Last updated: Tue Mar 2 14:35:54 2021 + * Last change: Tue Mar 2 14:35:49 2021 by hacluster via crmd on pcmk-2 + * 1 node configured + * 0 resource instances configured - 1 node configured - 0 resources configured - - Online: [ example-host ] + Node List: + * Online: [ example-host ] - No active resources + Full List of Resources: + * No 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 + # yum install -y libvirt qemu-kvm 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). .. index:: single: guest node; firewall 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_remoted ___________________________ Install ``pacemaker_remoted``, 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_remoted``, and verify the start was successful: .. code-block:: none # systemctl start pacemaker_remote # systemctl status pacemaker_remote + + ● pacemaker_remote.service - Pacemaker Remote executor daemon + Loaded: loaded (/usr/lib/systemd/system/pacemaker_remote.service; enabled; vendor preset: disabled) + Active: active (running) since Wed 2021-03-17 08:31:01 EDT; 1min 5s ago + Docs: man:pacemaker-remoted + https://clusterlabs.org/pacemaker/doc/en-US/Pacemaker/2.0/html-single/ Pacemaker_Remote/index.html + Main PID: 90160 (pacemaker-remot) + Tasks: 1 + Memory: 1.4M + CGroup: /system.slice/pacemaker_remote.service + └─90160 /usr/sbin/pacemaker-remoted + + Mar 17 08:31:01 guest1 systemd[1]: Started Pacemaker Remote executor daemon. + Mar 17 08:31:01 guest1 pacemaker-remoted[90160]: notice: Additional logging available in /var/log/pacemaker/pacemaker.log + Mar 17 08:31:01 guest1 pacemaker-remoted[90160]: notice: Starting Pacemaker remote executor + Mar 17 08:31:01 guest1 pacemaker-remoted[90160]: notice: Pacemaker remote executor successfully started and accepting connections - 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: +output before disconnecting, the connection works, because port 3121 is +attached to the pacemaker remote service: .. 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 +If you see this, then the connection is working, but port 3121 is attached +to SSH, which it should not be. + +.. code-block:: none + + # ssh -p 3121 guest1 + kex_exchange_identification: banner line contains invalid characters + 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 + # pcs resource create vm-guest1 VirtualDomain hypervisor="qemu:///system" config="vm-guest1.xml" meta .. 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 + + Cluster Summary: + * Stack: corosync + * Current DC: pcmk-1 (version 2.0.5-8.el8-ba59be7122) - partition with quorum + * Last updated: Wed Mar 17 08:37:37 2021 + * Last change: Wed Mar 17 08:31:01 2021 by root via cibadmin on pcmk-1 + * 2 nodes configured + * 2 resource instances configured + + Node List: + * Online: [ example-host ] + * GuestOnline: [ guest1@example-host ] + + Full List of Resources: + * vm-guest1 (ocf::heartbeat:VirtualDomain): 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 + 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 + 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 + + Cluster Summary: + * Stack: corosync + * Current DC: pcmk-1 (version 2.0.5-8.el8-ba59be7122) - partition with quorum + * Last updated: Wed Mar 17 08:37:37 2021 + * Last change: Wed Mar 17 08:31:01 2021 by root via cibadmin on pcmk-1 + * 2 nodes configured + * 7 resource instances configured + + Node List: + * Online: [ example-host ] + * GuestOnline: [ guest1@example-host ] + + Full List of Resources: + * vm-guest1 (ocf::heartbeat:VirtualDomain): 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 + last-rc-change='Wed Mar 17 08:32:01 2021', 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 + # pcs status + Cluster name: mycluster + + Cluster Summary: + * Stack: corosync + * Current DC: pcmk-1 (version 2.0.5-8.el8-ba59be7122) - partition with quorum + * Last updated: Wed Mar 17 08:37:37 2021 + * Last change: Wed Mar 17 08:31:01 2021 by root via cibadmin on pcmk-1 + * 2 nodes configured + * 7 resource instances configured + + Node List: + * Online: [ example-host ] + * GuestOnline: [ guest1@example-host ] + + Full List of Resources: + * vm-guest1 (ocf::heartbeat:VirtualDomain): 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 + 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 + Last updated: Fri Jan 12 18:15: 2021 + Last change: Fri Jan 12 08:33:0- 2021 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 + last-rc-change='Wed Mar 17 08:32:01 2021', 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.