ha-cluster-pacemaker

Role for configuring and expanding basic pacemaker cluster on CentOS/RHEL 6/7/8/9, AlmaLinux 8/9, Rocky Linux 8/9, Fedora 31/32/33/34/35/36/37/38 and CentOS 8 Stream systems.

This role can configure following aspects of pacemaker cluster:

• enable needed system repositories
• install needed packages
• create and configure users and groups for running pacemaker cluster
• configure firewall
• generate items in /etc/hosts
• authorize cluster nodes
• create cluster or expand cluster (check allow_cluster_expansion)
  • "2 or more" node cluster
  • single heartbeat, rrp or knet with up to 8 links
  • remote nodes
  • use autodetected or custom selected interfaces/IPs for heartbeat
• start and enable cluster on boot
• configure stonith devices
  • by default install and configure fence_xvm stonith devices
  • optionally configure fence_kdump
  • optionally configure fence_vmware (SOAP/REST) or any other fence_* stonith devices
  • optionally configure fence_aws

Role fully supports --check mode for default configuration and partially supports it for most of other options.

When reporting issue please provide following information (if possible):

• used ansible version
• OS from which ansible was run
• playbook and invetory file that produced error (remove sensitive information where appropriate)
• error message or description of missbehaviour that you have encountered

Requirements

This role depend on role ondrejhome.pcs-modules-2.

Ansible 2.8 or later. (NOTE: it might be possible to use earlier versions, in case of issues please try updating Ansible to 2.8+)

RHEL 6/7/8: It is expected that machines will already be registered. Role will by default enable access to 'High Availability' or 'Resilient storage' channel. If this is not desired check the enable_repos variable.

RHEL/CentOS 7: This role requires at least version 2.9 of python-jinja2 library. If not present you may encounter error described in Issue #6. To get the updated version of python-jinja2 and its dependencies you can use following RPM repository - https://copr.fedorainfracloud.org/coprs/ondrejhome/ansible-deps-el7/ for both CentOS 7 and RHEL 7.

CentOS 8 Stream Tested with version 20201211 minimal usable ansible version is 2.9.16/2.10.4. Version 2.8.18 was not working at time of testing. This is related to Service is in unknown state #71528.

Debian Buster Tested with version 20210310 with ansible version 2.10 and Debian Bullseye Tested with version 20220326 with ansible version 2.12. Debian part of this role does not include the stonith configuration and the firewall configuration. Note: This role went only through limited testing on Debian - not all features of this role were tested.

Debian Bookworm Tested with ansible version 2.14 and Debian Bookwork. Debian part of this role does not include the stonith configuration and the firewall configuration. Note: This role went only through limited testing on Debian - not all features of this role were tested.

Ansible version 2.9.10 and 2.9.11 will fail with error "'hostvars' is undefined" when trying to configure remote nodes. This applies only when there is at least one node with cluster_node_is_remote=True. Avoid these Ansible versions if you plan to configure remote nodes with this role.

On CentOS Linux 8 you have to ensure that BaseOS and Appstream repositories are working properly. As the CentOS Linux 8 is in the End-Of-Life phase, this role will configure HA repository to point to vault.centos.org if repository configuration (enable_repos: true) is requested (it is by default).

pcs-0.11 version distributions (AlmaLinux 9, Rocky Linux 9, RHEL 9, Fedora 36/37/38) are supported only with ondrejhome.pcs-modules-2 version 27.0.0 or higher.

Role Variables

• user used for authorizing cluster nodes

  cluster_user: 'hacluster'
  

• password for user used for authorizing cluster nodes

  cluster_user_pass: 'testtest'
  

• group to which cluster user belongs (should be 'haclient')

  cluster_group: 'haclient'
  

• name of the cluster

  cluster_name: 'pacemaker'
  

• configuration of firewall for clustering, NOTE in RHEL/Centos 6 this replaces iptables configuration file!

  cluster_firewall: true
  

• enable cluster on boot on normal (not pacemaker_remote) nodes

  cluster_enable_service: true
  

• configure cluster with fence_xvm fencing device ? This will copy /etc/cluster/fence_xvm.key to nodes and add fencing devices to cluster NOTE: you need to define 'vm_name' in the inventory for each cluster node

  cluster_configure_fence_xvm: true
  

• configure cluster with fence_vmware_soap/fence_vmware_rest fencing device ? This will install fence_vmware_soap/fence_vmware_rest fencing agent and configure it. When this is enabled you have to specify 3 additional variables with information on accessing the vCenter. NOTE: You also need to define 'vm_name' in the inventory for each cluster node specifying the name or UUID of VM as seen on the hypervisor or in the output of fence_vmware_soap -o list/fence_vmware_rest command.

  cluster_configure_fence_vmware_soap: false
  cluster_configure_fence_vmware_rest: false
  fence_vmware_ipaddr: ''
  fence_vmware_login: ''
  fence_vmware_passwd: ''
  

  You can optionally change the additional attributes passed to fence_vmware_soap/fence_vmware_rest using the variable fence_vmware_options. By default this variable enables encryption but disables validation of certificates.

  fence_vmware_options: 'ssl="1" ssl_insecure="1"'
  

  NOTE: Only one of fence_vmware_soap/fence_vmware_rest can be configured as stonith devices share same name.

• configure cluster with fence_kdump fencing device ? This starts kdump service and defines the fence_kdump stonith devices. NOTE: if the kdump service is not started this won't work properly or at all

  cluster_configure_fence_kdump: false
  

• configure cluster with fence_aws fencing device? You must provide instance id/region of AWS and Instance Profile that is able to start/stop instances for this cluster. When this is enabled you have to specify fence_aws_region variable with information on AWS region. NOTE: If you don't set up instance profile, it won't work properly or at all

  cluster_configure_fence_aws: false
  fence_aws_region: ''
  

  NOTE: You also need to define instance_id in the inventory for each cluster node by specifying the instance id as seen in the AWS web console or in the output of fence_aws -o list command. (man fence_aws)

  You can optionally change the additional attributes passed to fence_aws using the fence_aws_options variable.

  fence_aws_options: ''
  

  NOTE: Examples of proper options for some specific use cases can be found in documents below.
  https://access.redhat.com/articles/4175371#create-stonith
  https://docs.aws.amazon.com/sap/latest/sap-hana/sap-hana-on-aws-cluster-resources-1.html

• How to map fence devices to cluster nodes? By default for every cluster node a separate stonith devices is created ('one-device-per-node'). Some fence agents can fence multiple nodes using same stonith device ('one-device-per-cluster') and can have trouble when using multiple devices due to same user login count limits. Available options:

  • one-device-per-node - (default) - one stonith device per cluster node is created
  • one-device-per-cluster - (on supported fence agents) - only one cluster-wide stonith device is created for all nodes, supported fence agents: fence_vmware_rest, fence_vmware_soap, fence_xvm, fence_kdump

  cluster_configure_stonith_style: 'one-device-per-node'
  

• (RHEL/CentOS/AlmaLinux/Rocky) enable the repositories containing needed packages

  enable_repos: true
  

• (RHEL only) enable the extended update (EUS) repositories containint packages needed

  enable_eus_repos: false
  

• (RHEL only) enable the SAP Solutions update service (E4S) repositories containint packages needed

  enable_e4s_repos: false
  

• (RHEL only) enable Beta repositories containint packages needed

  enable_beta_repos: false
  

• (RHEL only) type of enable repositories, note that E4S repos have only 'ha' type available

  • ha - High-Availability
  • rs - Resilient Storage

  repos_type: 'ha'
  

• (RHEL only) custom_repository allows enabling an arbitrarily named repository to be enabled. RHEL8 repo names can be found at http://downloads.redhat.com/redhat/rhel/rhel-8-beta/rhel-8-beta.repo

  custom_repository: ''
  
  

• (CentOS only) install the needed packages from the CD-ROM media available at /dev/cdrom

  use_local_media: false
  

• Enable or disable PCSD web GUI. By default the role keeps the default of installation means that PCSD web GUI is disabled on CentOS/RHEL 6.X and enabled on CentOS/RHEL 7.X. true or false can be passed to this variable to make sure that PCSD web GUI is enabled or disabled.

  enable_pcsd_gui: 'nochange'
  

• Cluster transport protocol. By default this role will use what is default for give OS. For CentOS/RHEL 6.X this means 'udp' (UDP multicast) and for CentOS/RHEL 7.X this means 'udpu' (UDP unicast). This variable accepts following options: default, udp and udpu.

  cluster_transport: 'default'
  

• Allow adding nodes to existing cluster when used with ondrejhome.pcs-modules-2 v16 or newer.

  allow_cluster_expansion: false
  

• Cluster network interface. If specified the role will map hosts to primary IPv4 address from this interface. By default the IPv4 address from ansible_default_ipv4 or first IPv4 from ansible_all_ipv4_addressesis used. For exmaple to use primary IPv4 address from interface ens8 use cluster_net_iface: 'ens8'. Interface must exists on all cluster nodes.

  cluster_net_iface: ''
  

• Redundant network interface. If specified the role will setup a corosync redundant ring using the default IPv4 from this interface. Interface must exist on all cluster nodes.

    rrp_interface: ''
  

  NOTE: you can define this variable either in defaults/main.yml, in this case the same rrp_interface name is used for all hosts in the hosts file. Either you specify an interface for each host present in the hosts file: this allows to use a specific interface name for each host (in the case they dont have the same interface name). Also note that instead of defining rrp_interface for a host, you can define rrp_ip: in this case this alternate ip is used to configure corosync RRP (this IP must be different than the host' default IPv4 address). This allows to use an alternate ip belonging to the same primary interface.

• Whether to add hosts to /etc/hosts. By default an entry for the hostname given by cluster_hostname_fact is added for each host to /etc/hosts. This can be disabled by setting cluster_etc_hosts to false.

  cluster_etc_hosts: true
  

• Which Ansible fact to use as the hostname of cluster nodes. By default this role uses the ansible_hostname fact as the hostname for each host. In some environments it may be useful to use the Fully Qualified Domain Name (FQDN) ansible_fqdn or node name ansible_nodename.

  cluster_hostname_fact: "ansible_hostname"
  

• Whether the node should be setup as a remote pacemaker node. By default this is false, and the node will be a full member of the Pacemaker cluster. Pacemaker remote nodes are not full members of the cluster, and allow exceeding the maximum cluster size of 32 full members. Note that remote nodes are supported by this role only on EL7 and EL8.

  cluster_node_is_remote: false
  

• Ordered list of variables for detecting primary cluster IP (ring0). First matched IPv4 is used and rest of detected IPv4s are skipped. In majority cases this should not require change, in some special cases such as when there is no default GW or non-primary IPv4 from given interface should be used this can be adjusted.

  ring0_ip_ordered_detection_list:
    - "{{ hostvars[inventory_hostname]['ansible_'+cluster_net_iface].ipv4.address|default('') }}"
    - "{{ ansible_default_ipv4.address|default('') }}"
    - "{{ ansible_all_ipv4_addresses[0]|default('') }}"
  
  

• Configure cluster properties (Not mandatory)

  cluster_property:
    - name: required
      node: optional
      value: optional
  

• Configure cluster resource defaults (Not mandatory)

  cluster_resource_defaults:
    - name: required
      defaults_type: optional
      value: optional
  

• Configure cluster resources (Not mandatory)

  cluster_resource:
    - name: required
      resource_class: optional
      resource_type: optional
      options: optional
      force_resource_update: optional
      ignored_meta_attributes: optional
      child_name: optional
  

• Configure cluster order constraints (Not mandatory)

  cluster_constraint_order:
    - resource1: required
      resource1_action: optional
      resource2: required
      resource2_action: optional
      kind: optional
      symmetrical: optional
  

• Configure cluster colocation constraints (Not mandatory)

  cluster_constraint_colocation:
    - resource1: required
      resource1_role: optional
      resource2: required
      resource2_role: optional
      score: optional
      influence: optional
  

• Configure cluster location constraints (Not mandatory)

  cluster_constraint_location:
    - resource: required
      node_name: required
      score: optional
  

Security considerations

Please consider updating the default value for cluster_user_pass.

To protect the sensitive values in variables passed to this role you can use ansible-vault to encrypt them. The recommended approach is to create a separate file with desired variables and their values, encrypt the whole file with ansible-vault encrypt and then include this file in pre_tasks: section so it is loaded before the role is executed. Example below illustrates this whole process.

Creating encrypted_vars.yaml file

• 1. Create plain text encrypted_vars.yaml file with your desired secret values

  # cat encrypted_vars.yaml
  ---
  cluster_user_pass: 'cluster-user-pass'
  fence_vmware_login: 'vcenter-user'
  fence_vmware_passwd: 'vcenter-pass'
  

• 2. Encrypt file suing ansible-vault

  # ansible-vault encrypt encrypted_vars.yaml
  

• 3. Verify the new content of encrypted_vars.yaml

  # cat encrypted_vars.yaml
  $ANSIBLE_VAULT;1.1;AES256
  31306461386430...
  

Example playbook that is using values from encrypted_vars.yaml

- hosts: cluster
   pre_tasks:
     - include_vars: encrypted_vars.yaml
   roles:
     - { role: 'ondrejhome.ha-cluster-pacemaker', cluster_name: 'test-cluster' }

NOTE: Encrypting only the variable's value and putting it into vars: is discouraged as it could results in errors like argument 1 must be str, not AnsibleVaultEncryptedUnicode. Approach that encrypts whole file seems to be not affected by this issue.

Ansible module_defaults

While this role does not expose all configuration options through variables, one can use the module_defaults to change the default values of parameters that this role does not use. Below is non-exhaustive list of examples where this may become useful.

Example module_default A for setting the totem token to 15 seconds

- hosts: cluster
  modules_defaults:
    pcs_cluster:
      token: 15000               # default is 'null' - depends on OS default value

Example module_default B for disabling installation of weak dependencies on EL8+/Fedora systems

- hosts: cluster
  modules_defaults:
    yum:
      install_weak_deps: false   # default is 'true'

Example module_default C for disabling installation of package recommends on Debian systems

- hosts: cluster
  modules_defaults:
    apt:
      install_recommends: false  # default is 'null' - depends on OS configuration

NOTE: The module_defaults only applies to options that are not specified in task - you cannot override value that is set by task in this role, only the value of options that are not used can be changed.

Example Playbook

Example playbook A for creating cluster named 'test-cluster' enabled on boot, with fence_xvm and firewall settings. NOTE: cluster_name is optional and defaults to pacemaker.

- hosts: cluster
  roles:
     - { role: 'ondrejhome.ha-cluster-pacemaker', cluster_name: 'test-cluster' }

Example playbook B for creating cluster named 'test-cluster' without configuring firewall and without fence_xvm. For cluster to get properly authorized it is expected that firewall is already configured or disabled.

- hosts: cluster
  roles:
     - { role: 'ondrejhome.ha-cluster-pacemaker', cluster_name: 'test-cluster', cluster_firewall: false, cluster_configure_fence_xvm: false }

Example playbook C for creating cluster named vmware-cluster with fence_vmware_soap fencing device.

- hosts: cluster
  vars:
    fence_vmware_ipaddr: 'vcenter-hostname-or-ip'
    fence_vmware_login: 'vcenter-username'
    fence_vmware_passwd: 'vcenter-password-for-username'
  roles:
     - { role: 'ondrejhome.ha-cluster-pacemaker', cluster_name: 'vmware-cluster', cluster_configure_fence_xvm: false, cluster_configure_fence_vmware_soap: true }

Example playbook D for creating cluster named test-cluster where /etc/hosts is not modified:

- hosts: cluster
  roles:
     - { role: 'ondrejhome.ha-cluster-pacemaker', cluster_name: 'test-cluster', cluster_etc_hosts: false }

Example playbook E for creating cluster named vmware-cluster with single fence_vmware_rest fencing device for all cluster nodes.

- hosts: cluster
  vars:
    fence_vmware_ipaddr: 'vcenter-hostname-or-ip'
    fence_vmware_login: 'vcenter-username'
    fence_vmware_passwd: 'vcenter-password-for-username'
  roles:
     - { role: 'ondrejhome.ha-cluster-pacemaker', cluster_name: 'vmware-cluster', cluster_configure_fence_xvm: false, cluster_configure_fence_vmware_rest: true, cluster_configure_stonith_style: 'one-device-per-cluster' }

Example playbook F for creating cluster named aws-cluster with single fence_aws fencing device for all cluster nodes.

- hosts: cluster
  roles:
    - { role: 'ondrejhome.ha-cluster-pacemaker', cluster_name: 'aws-cluster', cluster_configure_fence_xvm: false, cluster_configure_fence_aws: true, cluster_configure_stonith_style: 'one-device-per-cluster', enable_repos: false, fence_aws_region: 'aws-region' }

Example playbook Resources configuration .

- hosts: cluster
  vars:
    cluster_property:
      - name: 'maintenance-mode'
        value: 'true'
    cluster_resource:
      - name: 'apache2'
        resource_type: 'systemd:apache2'
        options: 'meta migration-threshold=2 op monitor interval=20s timeout=10s'
      - name: 'cluster_vip'
        resource_type: 'ocf:heartbeat:IPaddr2'
        options: 'ip=192.168.1.150 cidr_netmask=24 meta migration-threshold=2 op monitor interval=20'
    cluster_constraint_colocation:
      - resource1: 'cluster_vip'
        resource2: 'apache2'
        score: 'INFINITY'
    cluster_resource_defaults:
      - name: 'failure-timeout'
        value: '30'
  roles:
     - { role: 'ondrejhome.ha-cluster-pacemaker', cluster_name: 'apache-cluster'}

Inventory file example for CentOS/RHEL/Fedora systems createing basic clusters.

[cluster-centos7]
192.168.22.21 vm_name=fastvm-centos-7.8-21
192.168.22.22 vm_name=fastvm-centos-7.8-22
[cluster-fedora32]
192.168.22.23 vm_name=fastvm-fedora32-23
192.168.22.24 vm_name=fastvm-fedora32-24
[cluster-rhel8]
192.168.22.25 vm_name=fastvm-rhel-8.0-25
192.168.22.26 vm_name=fastvm-rhel-8.0-26

Inventory file example for cluster using RRP interconnnect on custom interface and/or using custom IP for RRP

[cluster-centos7-rrp]
192.168.22.27 vm_name=fastvm-centos-7.6-21 rrp_interface=ens6
192.168.22.28 vm_name=fastvm-centos-7.6-22 rrp_ip=192.168.22.29

Inventory file example with two full members and two remote nodes:

[cluster]
192.168.22.21 vm_name=fastvm-centos-7.6-21
192.168.22.22 vm_name=fastvm-centos-7.6-22
192.168.22.23 vm_name=fastvm-centos-7.6-23 cluster_node_is_remote=True
192.168.22.24 vm_name=fastvm-centos-7.6-24 cluster_node_is_remote=True

Inventory file example with fence_aws:

[cluster]
172.31.0.1	instance_id="i-acbdefg1234567890"
172.31.0.2	instance_id="i-acbdefg0987654321"

Old video examples of running role with defaults for:

• CentOS 7.6 installing CentOS 7.6 two node cluster: https://asciinema.org/a/226466
• Fedora 29 installing Fedora 29 two node cluster: https://asciinema.org/a/226467

License

GPLv3

Author Information

To get in touch with author you can use email [email protected] or create a issue on github when requesting some feature.