kolla-ansible/doc/source/reference/compute/zun-guide.rst

Zun - Container service

"Zun is an OpenStack Container service. It aims to provide an OpenStack API for provisioning and managing containerized workload on OpenStack." For more details about Zun, see OpenStack Zun Documentation.

Preparation and Deployment

By default Zun and its dependencies are disabled. In order to enable Zun, you need to edit globals.yml and set the following variables:

enable_zun: "yes"
enable_kuryr: "yes"
enable_etcd: "yes"
docker_configure_for_zun: "yes"
containerd_configure_for_zun: "yes"

Currently Kuryr does not support Docker 23 and later due to dropped --cluster-store option (bug bug).You need to cap docker by setting the following variables in globals.yml.

docker_apt_package_pin: "5:20.*"
docker_yum_package_pin: "20.*"

Debian Bookworm is not recommended as a host OS for Zun. It does not support a version of Docker with the deprecated option. Compatibility with Zun is not tested in CI.

Docker reconfiguration requires rebootstrapping before deploy. Make sure you understand the consequences of restarting Docker. Please see rebootstrapping for details. If it's initial deploy, then there is nothing to worry about because it's initial bootstrapping as well and there are no running services to affect.

$ kolla-ansible bootstrap-servers

Finally deploy:

$ kolla-ansible deploy

Verification

1. Generate the credentials file:

   $ kolla-ansible post-deploy

2. Source credentials file:

   $ . /etc/kolla/admin-openrc.sh

3. Download and create a glance container image:

   $ docker pull cirros
   $ docker save cirros | openstack image create cirros --public \
     --container-format docker --disk-format raw

4. Create zun container:

   $ zun create --name test --net network=demo-net cirros ping -c4 8.8.8.8

   Note

   Kuryr does not support networks with DHCP enabled, disable DHCP in the subnet used for zun containers.

   $ openstack subnet set --no-dhcp <subnet>

5. Verify container is created:

   $ zun list
   
   +--------------------------------------+------+---------------+---------+------------+------------+-------+
   | uuid                                 | name | image         | status  | task_state | addresses  | ports |
   +--------------------------------------+------+---------------+---------+------------+------------+-------+
   | 3719a73e-5f86-47e1-bc5f-f4074fc749f2 | test | cirros        | Created | None       | 172.17.0.3 | []    |
   +--------------------------------------+------+---------------+---------+------------+------------+-------+

6. Start container:

   $ zun start test
   Request to start container test has been accepted.

7. Verify container:

   $ zun logs test
   PING 8.8.8.8 (8.8.8.8): 56 data bytes
   64 bytes from 8.8.8.8: seq=0 ttl=45 time=96.396 ms
   64 bytes from 8.8.8.8: seq=1 ttl=45 time=96.504 ms
   64 bytes from 8.8.8.8: seq=2 ttl=45 time=96.721 ms
   64 bytes from 8.8.8.8: seq=3 ttl=45 time=95.884 ms
   
   --- 8.8.8.8 ping statistics ---
   4 packets transmitted, 4 packets received, 0% packet loss
   round-trip min/avg/max = 95.884/96.376/96.721 ms

For more information about how zun works, see zun, OpenStack Container service.