Chapter 1. Introduction
Past versions of Red Hat OpenStack Platform used services managed with Systemd. However, more recent version of OpenStack Platform now use containers to run services. Some administrators might not have a good understanding of how containerized OpenStack Platform services operate, and so this guide aims to help you understand OpenStack Platform container images and containerized services. This includes:
- How to obtain and modify container images
- How to manage containerized services in the overcloud
- Understanding how containers differ from Systemd services
The main goal is to help you gain enough knowledge of containerized OpenStack Platform services to transition from a Systemd-based environment to a container-based environment.
1.1. Containerized Services and Kolla
Each of the main Red Hat OpenStack Platform services run in containers. This provides a method of keep each service within its own isolated namespace separated from the host. This means:
- The deployment of services is performed by pulling container images from the Red Hat Custom Portal and running them.
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The management functions, like starting and stopping services, operate through the
podmancommand. - Upgrading containers require pulling new container images and replacing the existing containers with newer versions.
Red Hat OpenStack Platform uses a set of containers built and managed with the kolla toolset.
