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

Zun requires kuryr and etcd services, for more information about how to configure kuryr refer to ../containers/kuryr-guide.

To allow Zun Compute connect to the Docker Daemon, add the following in the docker.service file on each zun-compute node.

ExecStart= -H tcp://<DOCKER_SERVICE_IP>:2375 -H unix:///var/run/docker.sock --cluster-store=etcd://<DOCKER_SERVICE_IP>:2379 --cluster-advertise=<DOCKER_SERVICE_IP>:2375

Note

DOCKER_SERVICE_IP is zun-compute host IP address. 2375 is port that allows Docker daemon to be accessed remotely.

By default zun is disabled in the group_vars/all.yml. In order to enable it, you need to edit the file globals.yml and set the following variables:

enable_zun: "yes"
enable_kuryr: "yes"
enable_etcd: "yes"

Deploy the OpenStack cloud and zun.

$ 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.