Chapter 10. Performing basic overcloud administration tasks

OpenStack Platform runs services in containers on the undercloud and overcloud nodes. In certain situations, you might need to control the individual services on a host. This section contains information about some common commands you can run on a node to manage containerized services.

$ sudo podman ps

To include stopped or failed containers in the command output, add the --all option to the command:

$ sudo podman ps --all

To list container images, run the following command:

$ sudo podman images

$ sudo podman inspect keystone

To check a container status, run the systemctl status command:

$ sudo systemctl status tripleo_keystone
● tripleo_keystone.service - keystone container
   Loaded: loaded (/etc/systemd/system/tripleo_keystone.service; enabled; vendor preset: disabled)
   Active: active (running) since Fri 2019-02-15 23:53:18 UTC; 2 days ago
 Main PID: 29012 (podman)
   CGroup: /system.slice/tripleo_keystone.service
           └─29012 /usr/bin/podman start -a keystone

To stop a container, run the systemctl stop command:

$ sudo systemctl stop tripleo_keystone

To start a container, run the systemctl start command:

$ sudo systemctl start tripleo_keystone

To restart a container, run the systemctl restart command:

$ sudo systemctl restart tripleo_keystone

As no daemon monitors the containers status, Systemd automatically restarts most containers in these situations:

For more information about Systemd services, see the systemd.service documentation.

To list all OpenStack Platform containers timers, run the systemctl list-timers command and limit the output to lines containing tripleo:

$ sudo systemctl list-timers | grep tripleo
Mon 2019-02-18 20:18:30 UTC  1s left       Mon 2019-02-18 20:17:26 UTC  1min 2s ago  tripleo_nova_metadata_healthcheck.timer            tripleo_nova_metadata_healthcheck.service
Mon 2019-02-18 20:18:33 UTC  4s left       Mon 2019-02-18 20:17:03 UTC  1min 25s ago tripleo_mistral_engine_healthcheck.timer           tripleo_mistral_engine_healthcheck.service
Mon 2019-02-18 20:18:34 UTC  5s left       Mon 2019-02-18 20:17:23 UTC  1min 5s ago  tripleo_keystone_healthcheck.timer                 tripleo_keystone_healthcheck.service
Mon 2019-02-18 20:18:35 UTC  6s left       Mon 2019-02-18 20:17:13 UTC  1min 15s ago tripleo_memcached_healthcheck.timer                tripleo_memcached_healthcheck.service
(...)

To check the status of a specific container timer, run the systemctl status command for the healthcheck service:

$ sudo systemctl status tripleo_keystone_healthcheck.service
● tripleo_keystone_healthcheck.service - keystone healthcheck
   Loaded: loaded (/etc/systemd/system/tripleo_keystone_healthcheck.service; disabled; vendor preset: disabled)
   Active: inactive (dead) since Mon 2019-02-18 20:22:46 UTC; 22s ago
  Process: 115581 ExecStart=/usr/bin/podman exec keystone /openstack/healthcheck (code=exited, status=0/SUCCESS)
 Main PID: 115581 (code=exited, status=0/SUCCESS)

Feb 18 20:22:46 undercloud.localdomain systemd[1]: Starting keystone healthcheck...
Feb 18 20:22:46 undercloud.localdomain podman[115581]: {"versions": {"values": [{"status": "stable", "updated": "2019-01-22T00:00:00Z", "..."}]}]}}
Feb 18 20:22:46 undercloud.localdomain podman[115581]: 300 192.168.24.1:35357 0.012 seconds
Feb 18 20:22:46 undercloud.localdomain systemd[1]: Started keystone healthcheck.

To stop, start, restart, and show the status of a container timer, run the relevant systemctl command against the .timer Systemd resource. For example, to check the status of the tripleo_keystone_healthcheck.timer resource, run the following command:

$ sudo systemctl status tripleo_keystone_healthcheck.timer
● tripleo_keystone_healthcheck.timer - keystone container healthcheck
   Loaded: loaded (/etc/systemd/system/tripleo_keystone_healthcheck.timer; enabled; vendor preset: disabled)
   Active: active (waiting) since Fri 2019-02-15 23:53:18 UTC; 2 days ago

If the healthcheck service is disabled but the timer for that service is present and enabled, it means that the check is currently timed out, but will be run according to timer. There is always a possibility to start the check manually.

Paunch and the container-puppet.py script configure podman containers to push their outputs to the /var/log/containers/stdout directory, which creates a collection of all logs, even for the deleted containers, such as container-puppet-* containers.

The host also applies log rotation to this directory, which prevents huge files and disk space issues.

In case a container is replaced, the new one outputs to the same log file, since podman is instructed to use the container name instead of container ID.

You can also check the logs for a containerized service using the podman logs command. For example, to view the logs for the keystone container, run the following command:

$ sudo podman logs keystone

$ sudo podman exec -it keystone /bin/bash

To enter the shell for the keystone container as the root user, run the following command:

$ sudo podman exec --user 0 -it <NAME OR ID> /bin/bash

To exit from the container, run the following command:

# exit

Sometimes you might want to modify the overcloud to add additional features, or change the way it operates. To modify the overcloud, make modifications to your custom environment files and Heat templates, then rerun the openstack overcloud deploy command from your initial overcloud creation. For example, if you created an overcloud using Section 6.11, “Deployment command”, rerun the following command:

$ source ~/stackrc
(undercloud) $ openstack overcloud deploy --templates \
  -e ~/templates/node-info.yaml \
  -e /usr/share/openstack-tripleo-heat-templates/environments/network-isolation.yaml \
  -e ~/templates/network-environment.yaml \
  -e ~/templates/storage-environment.yaml \
  --ntp-server pool.ntp.org

The director checks the overcloud stack in heat, and then updates each item in the stack with the environment files and heat templates. The director does not recreate the overcloud, but rather changes the existing overcloud.

If you aim to include a new environment file, add it to the openstack overcloud deploy command with the`-e` option. For example:

$ source ~/stackrc
(undercloud) $ openstack overcloud deploy --templates \
  -e ~/templates/new-environment.yaml \
  -e /usr/share/openstack-tripleo-heat-templates/environments/network-isolation.yaml \
  -e ~/templates/network-environment.yaml \
  -e ~/templates/storage-environment.yaml \
  -e ~/templates/node-info.yaml \
  --ntp-server pool.ntp.org

This command includes the new parameters and resources from the environment file into the stack.

This procedure contains steps migrate virtual machines from an existing OpenStack environment to your Red Hat OpenStack Platform environment.

This process migrates all instances from a Compute node. You can now perform maintenance on the node without any instance downtime. To return the Compute node to an enabled state, run the following command:

$ source ~/overcloudrc
(overcloud) $ openstack compute service set [hostname] nova-compute --enable

The director can run Ansible-based automation on your OpenStack Platform environment. The director uses the tripleo-ansible-inventory command to generate a dynamic inventory of nodes in your environment.

Delete any existing overcloud:

$ source ~/stackrc
(undercloud) $ openstack overcloud delete overcloud

Confirm the deletion of the overcloud:

(undercloud) $ openstack stack list

Deletion takes a few minutes.

Once the removal completes, follow the standard steps in the deployment scenarios to recreate your overcloud.