Zun in Kolla

Zun in Kolla

“Zun is an OpenStack Container service. It aims to provide an OpenStack API for provisioning and managing containerized workload on OpenStack.” [1].

Preparation and Deployment

Zun requires kuryr and etcd services, for more information about how to configure kuryr refer to Kuryr in Kolla.

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

Verify

Generate the credentials file.

$ kolla-ansible post-deploy

Source credentials file.

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

Download and create a glance container image.

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

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>

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 | []    |
+--------------------------------------+------+---------------+---------+------------+------------+-------+

Start container.

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

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

[1] https://github.com/openstack/zun

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