Chapter 10. Rebooting Nodes

Some situations require a reboot of nodes in the undercloud and overcloud. The following procedures show how to reboot different node types. Be aware of the following notes:

  • If rebooting all nodes in one role, it is advisable to reboot each node individually. This helps retain services for that role during the reboot.
  • If rebooting all nodes in your OpenStack Platform environment, use the following list to guide the reboot order:

Recommended Node Reboot Order

  1. Reboot the director
  2. Reboot Controller nodes
  3. Reboot Ceph Storage nodes
  4. Reboot Compute nodes
  5. Reboot object Storage nodes

10.1. Rebooting the Director

To reboot the director node, follow this process:

  1. Reboot the node:

    $ sudo reboot
  2. Wait until the node boots.

When the node boots, check the status of all services:

$ sudo systemctl list-units "openstack*" "neutron*" "openvswitch*"
Note

It might take approximately 10 minutes for the openstack-nova-compute to become active after a reboot.

Verify the existence of your Overcloud and its nodes:

$ source ~/stackrc
$ openstack server list
$ openstack baremetal node list
$ openstack stack list

10.2. Rebooting Controller Nodes

To reboot the Controller nodes, follow this process:

  1. Select a node to reboot. Log into it and reboot it:

    $ sudo reboot

    The remaining Controller Nodes in the cluster retain the high availability services during the reboot.

  2. Wait until the node boots.
  3. Log into the node and check the cluster status:

    $ sudo pcs status

    The node rejoins the cluster.

    Note

    If any services fail after the reboot, run sudo pcs resource cleanup, which cleans the errors and sets the state of each resource to Started. If any errors persist, contact Red Hat and request guidance and assistance.

  4. Check all systemd services on the Controller Node are active:

    $ sudo systemctl list-units "openstack*" "neutron*" "openvswitch*"
  5. Log out of the node, select the next Controller Node to reboot, and repeat this procedure until you have rebooted all Controller Nodes.

10.3. Rebooting Ceph Storage Nodes

To reboot the Ceph Storage nodes, follow this process:

  1. Log into a Ceph MON or Controller node and disable Ceph Storage cluster rebalancing temporarily:

    $ sudo ceph osd set noout
    $ sudo ceph osd set norebalance
  2. Select the first Ceph Storage node to reboot and log into it.
  3. Reboot the node:

    $ sudo reboot
  4. Wait until the node boots.
  5. Log into the node and check the cluster status:

    $ sudo ceph -s

    Check that the pgmap reports all pgs as normal (active+clean).

  6. Log out of the node, reboot the next node, and check its status. Repeat this process until you have rebooted all Ceph storage nodes.
  7. When complete, log into a Ceph MON or Controller node and enable cluster rebalancing again:

    $ sudo ceph osd unset noout
    $ sudo ceph osd unset norebalance
  8. Perform a final status check to verify the cluster reports HEALTH_OK:

    $ sudo ceph status

10.4. Rebooting Compute Nodes

Reboot each Compute node individually and ensure zero downtime of instances in your OpenStack Platform environment. This involves the following workflow:

  1. Select a Compute node to reboot
  2. Migrate its instances to another Compute node
  3. Reboot the empty Compute node

List all Compute nodes and their UUIDs:

$ nova list | grep "compute"

Select a Compute node to reboot and first migrate its instances using the following process:

  1. From the undercloud, select a Compute Node to reboot and disable it:

    $ source ~/overcloudrc
    $ openstack compute service list
    $ openstack compute service set [hostname] nova-compute --disable
  2. List all instances on the Compute node:

    $ openstack server list --host [hostname] --all-projects
  3. Migrate each instance from the disabled host. Use one of the following commands:

    1. Migrate the instance to a specific host of your choice:

      $ openstack server migrate [instance-id] --live [target-host]--wait
    2. Let nova-scheduler automatically select the target host:

      $ nova live-migration [instance-id]
      Note

      The nova command might cause some deprecation warnings, which are safe to ignore.

  4. Wait until migration completes.
  5. Confirm the instance has migrated from the Compute node:

    $ openstack server list --host [hostname] --all-projects
  6. Repeat this step until you have migrated all instances from the Compute Node.
Important

For full instructions on configuring and migrating instances, see Section 8.8, “Migrating VMs from an Overcloud Compute Node”.

Reboot the Compute node using the following process

  1. Log into the Compute Node and reboot it:

    $ sudo reboot
  2. Wait until the node boots.
  3. Enable the Compute Node again:

    $ source ~/overcloudrc
    $ openstack compute service set [hostname] nova-compute --enable
  4. Check whether the Compute node is enabled:

    $ openstack compute service list

10.5. Rebooting Object Storage Nodes

To reboot the Object Storage nodes, follow this process:

  1. Select a Object Storage node to reboot. Log into it and reboot it:

    $ sudo reboot
  2. Wait until the node boots.
  3. Log into the node and check the status:

    $ sudo systemctl list-units "openstack-swift*"
  4. Log out of the node and repeat this process on the next Object Storage node.