Chapter 10. Performing basic overcloud administration tasks

This chapter contains information about basic tasks you might need to perform during the lifecycle of your overcloud.

10.1. Managing containerized services

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.

Listing containers and images

To list running containers, run the following command:

$ 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

Inspecting container properties

To view the properties of a container or container images, use the podman inspect command. For example, to inspect the keystone container, run the following command:

$ sudo podman inspect keystone

Managing containers with Systemd services

Previous versions of OpenStack Platform managed containers with Docker and its daemon. In OpenStack Platform 15, the Systemd services interface manages the lifecycle of the containers. Each container is a service and you run these commands to run specific operations for each container.

Note

It is not recommended to use the Podman CLI to stop, start, and restart containers because Systemd applies a restart policy. Use Systemd service commands instead.

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:

  • Clean exit code or signal, such as running podman stop command.
  • Unclean exit code, such as the podman container crashing after a start.
  • Unclean signals.
  • Timeout if the container takes more than 1m 30s to start.

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

Note

Any changes to the service configuration files within the container revert after restarting the container. This is because the container regenerates the service configuration based on files on the node’s local file system in /var/lib/config-data/puppet-generated/. For example, if you edit /etc/keystone/keystone.conf within the keystone container and restart the container, the container regenerates the configuration using /var/lib/config-data/puppet-generated/keystone/etc/keystone/keystone.conf on the node’s local file system, which overwrites any the changes made within the container before the restart.

Monitoring podman containers with Systemd timers

The Systemd timers interface manages container health checks. Each container has a timer that runs a service unit that executes health check scripts.

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.

Note

The podman ps command does not show the container health status.

Checking container logs

OpenStack Platform 15 introduces a new logging directory: /var/log/containers/stdout. It contains all the containers standard output (stdout) and standard errors (stderr) consolidated in one single file per container.

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

Accessing containers

To enter the shell for a containerized service, use the podman exec command to launch /bin/bash. For example, to enter the shell for the keystone container, run the following command:

$ 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

10.2. Modifying the overcloud environment

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.

Important

Removing parameters from custom environment files does not revert the parameter value to the default configuration. You must identify the default value from the core heat template collection in /usr/share/openstack-tripleo-heat-templates and set the value in your custom environment file manually.

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.

Important

It is not advisable to make manual modifications to the overcloud configuration as the director might overwrite these modifications later.

10.3. Importing virtual machines into the overcloud

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

Procedure

  1. On the existing OpenStack environment, create a new image by taking a snapshot of a running server and download the image:

    $ openstack server image create instance_name --name image_name
    $ openstack image save image_name --file exported_vm.qcow2
  2. Copy the exported image to the undercloud node:

    $ scp exported_vm.qcow2 stack@192.168.0.2:~/.
  3. Log into the undercloud as the stack user.
  4. Source the overcloudrc file:

    $ source ~/overcloudrc
  5. Upload the exported image into the overcloud:

    (overcloud) $ openstack image create imported_image --file exported_vm.qcow2 --disk-format qcow2 --container-format bare
  6. Launch a new instance:

    (overcloud) $ openstack server create  imported_instance --key-name default --flavor m1.demo --image imported_image --nic net-id=net_id
Important

These commands copy each VM disk from the existing OpenStack environment and into the new Red Hat OpenStack Platform. Snapshots using QCOW will lose their original layering system.

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

10.4. Running the dynamic inventory script

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.

Procedure

  1. To view a dynamic inventory of nodes, run the tripleo-ansible-inventory command after sourcing stackrc:

    $ source ~/stackrc
    (undercloud) $ tripleo-ansible-inventory --list

    The --list option returns details about all hosts. This command outputs the dynamic inventory in a JSON format:

    {"overcloud": {"children": ["controller", "compute"], "vars": {"ansible_ssh_user": "heat-admin"}}, "controller": ["192.168.24.2"], "undercloud": {"hosts": ["localhost"], "vars": {"overcloud_horizon_url": "http://192.168.24.4:80/dashboard", "overcloud_admin_password": "abcdefghijklm12345678", "ansible_connection": "local"}}, "compute": ["192.168.24.3"]}
  2. To execute Ansible playbooks on your environment, run the ansible command and include the full path of the dynamic inventory tool using the -i option. For example:

    (undercloud) $ ansible [HOSTS] -i /bin/tripleo-ansible-inventory [OTHER OPTIONS]
    • Replace [HOSTS] with the type of hosts to use. For example:

      • controller for all Controller nodes
      • compute for all Compute nodes
      • overcloud for all overcloud child nodes i.e. controller and compute
      • undercloud for the undercloud
      • "*" for all nodes
    • Replace [OTHER OPTIONS] with additional Ansible options. Some useful options include:

      • --ssh-extra-args='-o StrictHostKeyChecking=no' to bypasses confirmation on host key checking.
      • -u [USER] to change the SSH user that executes the Ansible automation. The default SSH user for the overcloud is automatically defined using the ansible_ssh_user parameter in the dynamic inventory. The -u option overrides this parameter.
      • -m [MODULE] to use a specific Ansible module. The default is command, which executes Linux commands.
      • -a [MODULE_ARGS] to define arguments for the chosen module.
Important

Custom Ansible automation on the overcloud is not part of the standard overcloud stack. Subsequent execution of the openstack overcloud deploy command might override Ansible-based configuration for OpenStack Platform services on overcloud nodes.

10.5. Removing the overcloud

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.