Add a compute node¶

This section describes how to add a new compute node to an existing OpenStack environment.

To add a compute node:

1. Add a physical node using MAAS as described in the MCP Deployment Guide: Provision physical nodes using MAAS.

2. Verify that the compute node is defined in /classes/cluster/<cluster_name>/infra/config.yml.

   Note

   Create as many hosts as you have compute nodes in your environment within this file.

   Note

   Verify that the count parameter is increased by the number of compute nodes being added.

   Configuration example if the dynamic compute host generation is used:

   reclass:
     storage:
       node:
         openstack_compute_rack01:
           name: ${_param:openstack_compute_rack01_hostname}<<count>>
           domain: ${_param:cluster_domain}
           classes:
           - cluster.${_param:cluster_name}.openstack.compute
           repeat:
             count: 20
             start: 1
             digits: 3
             params:
               single_address:
                 value: 172.16.47.<<count>>
                 start: 101
               tenant_address:
                 value: 172.16.47.<<count>>
                 start: 101
           params:
             salt_master_host: ${_param:reclass_config_master}
             linux_system_codename: xenial
   

   Configuration example if the static compute host generation is used:

   reclass:
     storage:
       node:
         openstack_compute_node01:
           name: cmp01
           domain: ${_param:cluster_domain}
           classes:
           - cluster.${_param:cluster_name}.openstack.compute
           params:
             salt_master_host: ${_param:reclass_config_master}:
             linux_system_codename: xenial
             single_address: 10.0.0.101
             deploy_address: 10.0.1.101
             tenant_address: 10.0.2.101
   

3. Define the cmp<NUM> control address and hostname in the <cluster>/openstack/init.yml file:

   _param:
     openstack_compute_node<NUM>_address: <control_network_IP>
     openstack_compute_node<NUM>_hostname: cmp<NUM>
   
   linux:
     network:
       host:
         cmp<NUM>:
           address: ${_param:openstack_compute_node<NUM>_address}
           names:
           - ${_param:openstack_compute_node<NUM>_hostname}
           - ${_param:openstack_compute_node<NUM>_hostname}.${_param:cluster_domain}
   

4. Apply the reclass.storage state on the Salt Master node to generate node definitions:

   salt '*cfg*' state.sls reclass.storage
   

5. Verify that the target nodes have connectivity with the Salt Master node:

   salt '*cmp<NUM>*' test.ping
   

6. Apply the following states:

   salt 'cfg*' state.sls salt.minion.ca
   salt '*cmp<NUM>*' state.sls salt.minion.cert
   

7. Deploy a new compute node as described in MCP Deployment Guide: Deploy physical servers.

   Caution

   Do not use compounds for this step, since it will affect already running physical servers and reboot them. Use the Salt minion IDs instead of compounds before running the pipelines or deploying physical servers manually.

   Incorrect:

   salt -C 'I@salt:control or I@nova:compute or I@neutron:gateway' \
    cmd.run "touch /run/is_rebooted"
   salt --async -C 'I@nova:compute' cmd.run 'salt-call state.sls \
    linux.system.user,openssh,linux.network;reboot'
   

   Correct:

   salt cmp<NUM> cmd.run "touch /run/is_rebooted"
   salt --async cmp<NUM> cmd.run 'salt-call state.sls \
    linux.system.user,openssh,linux.network;reboot'
   

   Note

   We recommend that you rerun the Jenkins Deploy - OpenStack pipeline that runs on the Salt Master node with the same parameters as you have set initially during your environment deployment. This guarantees that your compute node will be properly set up and added.